Wednesday, April 10, 2024

Reflections on the 2024 Eclipse

It's not been quite 48 hours since "the event", and I'm taking a couple days to relax with my wife in Texas before re-entering the world I normally inhabit on Monday. But - what an experience it was! Exhilarating, tiring, triumphant, tense, communal, frenetic, and blessed are all terms I'd use in describing it.

The Long Term Prep

Like many who saw the 2017 Great American Eclipse my planning to be in the path of totality in 2024 started not long after that marvelous eclipse experience, with things becoming serious (i.e., investing money and whitling down locations) about 18 months ago. The weather history for early April indicated that Texas was likely the place to be to avoid being clouded out. I found a lakeside Airbnb spot in Flint, TX from which I could head out early the morning of the eclipse to dodge clouds if needed, so I paid the deposit and crossed my fingers.

Other investments happened over the next year and a half. One significant one was acquiring a full frame camera since my existing Canon t6i which I used in 2017 is a cropped sensor model. I got a treasure trove of shots out of that setup, but I could see that I was limiting capture of the full glory of the corona. And with this one happening close to Solar Maximum, I felt a wider view was worth picking up a second-hand Mark II camera. The addition of some solar filters (a Baader mylar for the Vixen to hopefully improve crispness of the view and a set for my 15x70 Oberwek binoculars) was also undertaken.

A preliminary dry run in February showed me that while the camera battery would hold up for the length of the eclipse, my laptop would not have enough juice. To solve that issue I ordered a simple Jackery backup battery unit for a couple hundred dollars. The nice thing about that is it'll come in handy after the eclipse around the home when we get a power outage.

Dress Rehearsal

An inexpensive and easy item to add to the mix was a temperature recorder. I got that as a gift when celebrating my March birthday and added it to my staging area of eclipse equipment.

Time and training were also expended in the lead up to this eclipse. The 2017 images came at an expense, and I'm not speaking financially. I did not have a software program to control the camera so I opted for manually firing off shots using my pad connected to the camera. That meant I spent way too much time looking at the eclipse on my screen rather than gazing upward and soaking in the surreal scene before me. This time around I was determined to minimize my engagement with equipment and researched the available software to automate taking exposures of the eclipse, settling on SETnC. A couple more runs using the software gave me a feeling of confidence that I could give it the reins on eclipse day.

While that probably should have been enough, I was fascinated in a couple of other phenomenon that only emerge during an eclipse like this. One was the affect of the thin crescent Sun on casting shadows; another was witnessing a Purkinje effect on red/green colors. My young grandson Noah and I spent some quality time on a Saturday creating a contraption that had 3 rods separated by 45° that would test the theory. Picking up a high school science fair tagboard completed the work, serving as a backdrop for our shadow caster and our red & green Purkinje photo. 

By the middle of March my armamentarium was established for hopefully maximizing my enjoyment and recording memories of the experience:

  • The 80mm f/7.5 Vixen refractor teamed up with the Canon Mark II and SETnC would be photographing the event using the Baader filter. My lightweight HEM27 mount would carry the payload.

  • The Canon t6i with its crop sensor would sit atop a tripod to capture wide field images using SETnC running on a spare laptop that we have. I also planned at mid-eclipse to flip the mode to video to capture the last minute or so of totality.

  • A tripod and smart camera adapter so I could use the phone to record the totality experience I underwent along with the reactions of whomever (or whatever) was around me.

  • My 15x70 Oberwek binoculars fitted with Seymour mylar filters to monitor the partial phases and drink in a close up view of the eclipsed Sun.

  • My science fair tagboard with its payload of the Tomney Shadow Casting Experiment / Purkinje Experiment / Temperature Monitoring Experiment.

The Week Prior

About a week out I began to assess (and obsess over) the weather predictions for Texas on April 8th. One of the better sites I found was Pivotal Weather which had a dedicated eclipse page that showed predicted cloud cover for the eclipse path. It allowed the user to pick a state as well as one of several models to guesstimate their chances of seeing the eclipse. Texas started off looking pretty grim; actually a large swath of the path as it emerged from Mexico and ran up middle America looked to be questionable. The northeast, however, looked to have significantly better prospects. 

The Thursday before the eclipse required a decision on the general area of the country that I'd travel to in hopes of seeing this eclipse. Texas cloud cover had improved slightly but they were also now talking about the area at risk for severe weather. Clouded out is one thing, but trying to break down equipment in the face of a fast approaching thunderstorm is another. I pulled the trigger and canceled my reservation so that I could get at least a partial refund.

With Texas off the board the decision became - where to? The northeast continued to hold promise, with the farther north and east you went with the better prospects. Having made the trip to Stellafane several times as well as vacations in Maine I knew that the I-95 corridor was often congested in normal situations, and I had visions of sitting in an interstate traffic jam somewhere outside the path of totality when the moment came. The better strategy seemed to be to target upstate New York. If the approaching clouds from the west were tardy I could set up in the Rochester area. If they were advancing I could try to outrun them by going to Plattsburg near the Vermont border. 

At this point I needed to locate a place that would allow me to wake up early on eclipse day and head out to wherever seemed best. The law of supply and demand was in full force, with simple 2-star hotels commanding several hundred dollars to spend Sunday night. Airbnb was also picked over, but I did find a room in the Finger Lakes region for under a hundred dollars. Didn't need fancy, just clean and comfortable enough to grab some sleep before setting off. I also found a more conventional booking in New Paltz along the NY State Thruway for the evening after the eclipse to avoid having to drive all the way back home in what was predicted to be heavy traffic.

Finalizing Destination

Saturday I laid out all the equipment so as to not forget anything. Sunday morning I packed the car and drove the 5 hours to the Airbnb accommodation. The host was probably as excited to see me as I was about the eclipse since I was actually her first customer. After grabbing a nice dinner at a local place she recommended I came back and reviewed the forecasts. The weather on the drive up was spectacular with clear, cerulean skies that would be ideal for viewing any celestial event. By evening there were telltale signs of an approaching front as some high cirrus began to arrive in the west. At that point the die was cast on Plattsburg in hopes that the cloud deck would hold off until after the eclipse. I finalized my SETnC exposure grid for Plattsburg and turned in to get some sleep.

Sleep was fitful and maybe totaled 4 hours, getting up at 6am to place my bags in the car and head off towards my destination. Dawn's early light revealed poor conditions with a Sun covered by fairly dense cirrus clouds, but as I made my way east they did thin until eventually they were backlit by a blue sky. Some large sections of the sky actually looked pretty decent as my route swung north for the final hour's march towards Plattsburg. The traffic on I-87 up to the city was probably above average but thankfully not onerous. 

The internet is truly an amazing resource. My advance scouting of Plattsburg using satellite views allowed me to identify the Champlain Center Mall as a good location to set up shop along the parking lot's outer perimeter. I arrived about 11:30 am and found the mall easily, doing a drive around to scout it out on the ground. People were already setting up blankets and lawn chairs on the grassy area at the entrance to the place, which was a good sign indicating the mall was allowing people to view the eclipse from their property. I thought about joining them briefly but then realized that I'd likely attract a crowd that could inadvertently compromise my eclipse objectives. Outreach needed to take a back seat today. After circling the mall I headed off to find a local fast food spot for a bite to eat and final pre-eclipse restroom break. 


Even in the parking lot on the back side of the Champlain Center Mall there were a few people gathering. I picked a spot that looked like I would not be obstructed by any light poles and began unpacking the equipment. I used compass and noon-time shadows to guesstimate the true north location and aligned the mount. Mounting the Vixen and attaching the camera to it came next, with the usual battle trying to get the setup reasonably balanced (I have to resort to jury-rigging some ankle weights to the front of the scope to achieve it). Slewing the scope to the Sun was off the target but not horribly, so I felt it was workable. By this time it is after 1 p.m. and we are on eclipse time now where everything seems to be moving faster than you'd like! I set up the three tripods (one for binoculars, one for Canon 6ti, and one for smart phone) and attach the Oberwerks to their mount with solar filters in place. The view is clean and shows one prominent sunspot (AR3628) and a couple of smaller ones.

I turn my attention to connecting the laptop to the Canon Mark II on the telescope and press the power button. Nothing. Nothing lights up. OK, do not panic, maybe it's out of juice and just needs the external battery I've brought. I fish the AC adapter out and plug it in to the Jackery. Oh my God - still nothing. I spend about 5 minutes trying to see if I can get it up but no luck. Time to pivot on the fly. I decide that the spare laptop that was to run the wide-field photo sequence of shots on the Canon t6i would instead be used for orchestrating the images snapped through the telescope. I'll just do the t6i partial shots manually and at totality take the filter off and switch it to video mode. 

By now I have a couple of visitors, and we chat while I am setting up and checking the equipment, exchanging pleasantries and backgrounds as I wrestle to secure the tagboard in place at the front of my car. Despite my efforts to stabilize it the wind keeps knocking it over, and the duct tape I brought is really not doing the job of helping to stabilize the shadow experiment on it. One of my new found friends, Navaneet, offers to work on it so that I can focus on a last minute check of laptop connectivity to the camera as we hit 2 p.m. with only minutes to go before C1. The sky has been gradually accumulating cirrus clouds over the last hour, making me wonder how well - or even if - we'll be able to see the total phase of the eclipse with its delicate corona. I try to be stoic about the prospects of missing it after all this effort and offer a last minute prayer that it doesn't worsen.

At 2:13 p.m. I hear the SETnC click off a series of pre-eclipse exposures, and a minute later we see the Moon take its first nibble out of the Sun's edge. The software appears to be doing fine, taking exposures every five minutes. The tracking of the mount is another matter - it is adequate but not as good as I would have liked, forcing me to check and recenter the Sun about every 5 minutes. The alignment was clearly not as good as I had hoped, but it is not something to mess with now. Every time I hear the Vixen fire off shots I step over to the Canon taking wide field shots and take a set manually. The cirrus cloud deck is persistent and possibly thickening, making me worry that totality will be very compromised. There are no nearby trees to see mini-crescents filtered through natural pin-hole cameras, and the little leather medallion that I brought does not seem to be serving as a pin-hole projection tool as I had hoped.


By 3:20 p.m. we're a little more than five minutes away from C2 and the start of totality. The sunlight is now that dim, twilight sort of intensity that seems so odd in the afternoon and a hallmark of an eclipse. The time crunch is on as I hurry to try to ensure everything is ready, especially re-centering in the scope and verifying focus there and at the wide field camera. I start my FB live session and position the smart phone to frame the Sun near the top of the frame so that the parking lot and small crowd is visible. 

Suddenly the SETnC calls out "Remove Filters!" and it's on. I start by pulling the filter from the Vixen and then move to the t6i to remove its filter and flip it to video. I look up just in time to see a stunningly beautiful Diamond Ring fading out at about the 11 o'clock position. The corona emerges and all my concerns about it being hidden vanish. I look over and see a couple of my new eclipse friends still wearing the glasses. "Get your glasses off!" I shout, and as they remove them they gasp and shout in amazement.

Diamond Ring at C2

The corona looks relatively round visually - no long streamers noticed despite us being at Solar Maximum (or perhaps the fainter portions are being obscured by the thin clouds - a likely scenario). I look around and easily notice Venus and Jupiter farther above it, pointing them out to the folks nearby. Other stars and planets may be visible but I don't spend a lot of time searching for them since we don't have good sky transparency. 

Full Eclipsed Sun with Corona

Suddenly someone in the crowd calls out "the seagulls - listen to them!" Like many malls near water, there's a collection of opportunistic gulls here, and they are obviously startled by the sudden darkness that has descended as they call out in mass and fly about. Of my three TSE experiences this is the first one where I've witnessed the impact on animals in the area. I then shift my attention to take in the beautiful 360° sunset that appears to be occurring on the horizon.

At this point I realize that I have yet to look through the binoculars! I quickly move over to them and remove the filters and recenter the eclipsed Sun. I let out an audible gasp as I see the glowing corona surrounding the black orb in the sky. Along the edge of the Moon there are hot pink areas and a couple of prominences. At the bottom of the disk is a riveting, large prominence that commands attention. I invite those around me to take a look at this stunning and ephemeral view of the Sun. As I glance back to the Sun I can hardly believe my eyes: that prominence is actually visible naked-eye! Just how massive is this thing!!

Solar Prominences on Display

The Denouement

Baily's Beads at C3
All too soon the SETnC barks out "Apply Filters!", signaling the end of the totality and emergence of the C3 Diamond Ring as the Sun reclaims its dominance in the sky. I quickly move the binoculars off the Sun and throw pillow cases over the scope and t6i camera. I sign off on the FB live stream and stand there pondering what I've just experienced. I'm filled with emotions - grateful that all the planning and driving paid off, thrilled at the soul-touching spectacle I just witnessed, a tinge of sadness that this is quite likely the last TSE I'll be able to see, and hopeful that I'll have some wonderful images for my scrapbook. But regardless of what's on the SD card I am convinced that my decision to focus more on experiencing the totality as opposed to capturing it was a great decision.

With a thin crescent in the sky it's prime time to check out the shadow and Purkinje experiments. Glancing at the red-green-blue block photo I cannot really discern any desaturation among the green and red. The shadow experiment, however, pays off. There is a clear difference in the shadows created by the rods, with the one roughly horizontal (i.e., more tangential to the crescent Sun) is much sharper than the vertical one. 

The Shadow Experiment: A is sharper than B, C 

I reattach the filters in time for the first round of post-totality partial shots. As in my previous eclipse experiences the crowd heads for the exits, a vain effort to escape the traffic jams that are coming. My eclipse friends leave their email addresses and we'll exchange images. One of them, Harry, had brought a drone that he launched just prior to C2 in an effort to record the shadow approaching. That will be interesting to see.

Like sitting through the movie's credits I dutifully continue to document the Moon's egress from the Solar disk. I begin to selectively pack up the car and glance to my left where one can see the nearby I-87 traffic. It's already a rolling backup, and I just hope that by some miracle by the time I leave it's better. By 4:37 p.m. the Moon exits and the Great North American Eclipse of 2024 is in the history books. I methodically break down the remaining equipment and pack it into the Rogue for my trip down the NY Thruway to New Paltz. 

The Epic Traffic Jam

I consider trying to grab some dinner but the few nearby places I check out have significant lines. I head for the interstate and make a pit stop to get some water at a quickie mart. I hoped to use the restroom but again, long line there. I enter the hotel's address and start the navigation. 

Traffic is a rolling backlog with a few rare exceptions that tease me. The navigation app is chronically telling me "there's a backup ahead but you are still on the fastest route." It also is unwittingly funny with the occasional warning "there's a speed trap ahead" when we are hitting top speeds of 30 mph. 

On a normal day one could expect to go from Plattsburg to New Paltz in about 3½ hours. But today the journey takes 7½, finally arriving at the hotel at 1:30 a.m. Normally I'd be quite alone checking in at that hour, but instead I see another eclipse family doing the same thing. It's 2 a.m. by the time my head hits the pillow and I'm quickly asleep. 


With the eclipse in my rearview I've taken inventory of how everything panned out following the hours of planning and investment. A quick look at the Mark II SD card reveals a good news - bad news situation. I did indeed get some very nice photos using the automated routine, but somehow the setting was at JPG instead of RAW, which will impact the post-processing capabilities. I also realized that in starting the video of the eclipse I failed to remember to rack the zoom lens fully out to get the largest diameter of the eclipsed Sun. However, the video is a wonderful record and even captures the startled seagulls flying across the frame. I also realize that I totally forgot to have my distance glasses on during the eclipse, so I am left wondering what clarity of the corona I inadvertently compromised. 

Lots of work ahead to process the images and see if the temperature recorder did its job. But it'll all be a labor of love as I create a scrapbook for this successful journey to see one of the most beautiful events in our heavens. 

Monday, March 25, 2024

Eclipse Prep Notes

Wow - I turn around and suddenly we are down to two weeks to go for the Total Solar Eclipse (TSE)! While I have been trying to read, prepare, and bullet-proof (except for weather - that's the wildcard) for the event there's still things to do on my checklist. Among the things I have checked off my list are the following:

Solar Filter: Glass or Film?

Partial Phase - Aug 21 2017
For the 2017 TSE I purchased a Seymour glass solar filter for my 80mm Vixen. That worked out pretty well, allowing me to capture photos with my Canon t6i with good clarity (click the image at left to enlarge). However, this time around in an effort to capture even more of what promises to be a stunning corona near sunspot maximum, I have purchased a used full-frame Canon body. The solar disk is smaller so I'll need sharp focus to enable enlargement without degradation.

One question in my mind was whether a good quality mylar solar film type  might yield sharper images. I invested in a Baader filter from Aegna Astro and did a side-by side comparison a couple weeks ago. The glass filter gives a slightly better color (yellow-orange) but of course our star is actually closer to white in appearance - which is how it looks with the Baader. While not a ton of difference between them, the Baader may be yielding a slightly crisper rendering of the sunspots. But on the other hand the Seymour is easier to slip on & off the scope. 

Comparing Baader film (white) to Seymour (red)

Filtered Smart Phone

At the HAL meeting the other week I mentioned that a simple, low-tech hack for getting images of the partial phases might be trimming one of the eclipse viewing glasses into a makeshift filter taped to your smart phone. The phone I used for this was an older Motorola (Android) that I recently replaced. I cut around the filter of one of the eyeglasses and taped it to cover the camera lens, very simple and quick. Unfortunately, all my attempts to capture the Sun were wildly overexposed. The phone's camera interface supposedly did allow me to adjust the ISO and camera shutter in "Pro" mode, but I was hard pressed to see any difference. While it didn't work for me, it is still an inexpensive and easy modification to your phone, and some better phones (I am quite frugal in what I'll spend for a phone), like an Apple iPhone or Google Pixel, might allow shutter speeds that will render a proper looking Sun. I will say that it is hard to see the Sun on the camera's screen when pointing it at the Sun, so rigging up some sort of shield might pay dividends if you find your camera can snap solar images.

SETnC Trial

If you've been doing some reading about photographing an eclipse you have probably come across the advice of "don't do it, just enjoy those precious moments!" And there is truth in that statement. At the 2017 event I spent a lot of time looking at the eclipse via my pad through which I was controlling the camera. I still took time during totality to soak in the corona and twilight horizon, but not as much as I might have liked. Part of the issue was that a week before the eclipse I decided that the software I was hoping to automate taking the photos to free me up was a little to unpredictable, so I opted to go the manual route. And to be sure, I treasure those shots I took that day.

This TSE will hopefully be different. I came across the Solar Eclipse Timer and Camera controller application (SETnC) and, although the interface is a little "busy", it seemed quite straightforward and nicely programable for firing off shots during the eclipse. You specify your location and the software identifies the C1 - C4 times and provides an Excel-style grid where you define what exposures to take at specific times during the eclipse.

True to forecasts, Sunday was a cloudless day that was perfect for a full dry run - all the equipment set up as if it were the real thing. The only difference is not taking the filter off during "totality"! 😉I began the session about 12:25 pm, roughly when it will start in Texas the day of the eclipse. The software worked flawlessly, so I feel very comfortable turning over the picture taking to it during totality. I did find that while the camera battery and Celestron Power Tank for the mount lasted throughout the simulated eclipse, my laptop would come close to running out of juice near C2. That was solved by my small Jackery 300 portable battery generator.

I also discovered that the HEM27 mount gradually began to struggle tracking the Sun once it had crossed the meridian. I found to my surprise that doing the meridian flip was not as horrific as I had imagined. The main thing was picking up the laptop and walking it to its new position once the slew was finished, plus re-centering the Sun. If you haven't practiced the meridian flip and are planning to take photos, I'd strongly suggest you practice this at least once in case you find you need to do it.

Tip: Sun Centering & Solar Projection

One of the challenges in Solar observing with a telescope (or binoculars mounted on a tripod) is centering the Sun in the field. One great technique that I learned as a teenager is that by watching the shadow of your telescope/binoculars on the ground and adjusting your instrument to create the smallest possible shadow, the Sun will pop into view. Here is a video I created demonstrating the technique. 

At the March HAL meeting I also mentioned that using Solar Projection was a time-honored technique for sharing a view of the Sun with a group of people. In short, you pop in an eyepiece and direct the sunlight emerging from the eyepiece onto a white surface. You focus until you have a nice, crisp view of the Sun for all to see. This technique also works for binoculars as well, especially suitable if they can be mounted on a tripod. The main caveat is to occasionally give the telescope's optics a break and move it off the Sun for a few minutes. You can see a video of the technique here.

Activities for Maryland

Even if you are not able to get into the totality line, there are some interesting observations you can make with a deep partial eclipse such as what Maryland will experience. First, as you hit maximum eclipse (about 3:21 pm in central Maryland), can you detect any Purkinje Effect? In brief, due to the diminished sunlight, the cones in your eye are used less and the rods begin to come into play. Because the rods are more blue-light sensitive, you may notice that red and green colors lose some of their saturation. See the video below for a fuller explanation:

The second phenomenon to observe is how a thin crescent Sun will impact shadows on the ground. Shadows are normally a bit fuzzy on their edges because the Sun appears as a significant disk in our sky, not a point source. That’s in part why the shadow of one of Jupiter’s moons on its clouds is much sharper than our Moon during an eclipse since the Sun is much smaller as seen from Jupiter. If you have a rod/stick oriented tangential to the crescent, and another perpendicular to it, then the tangential one should have a sharper shadow. Check out this video for more information on this effect.

Whether you are heading out to catch totality or staying put to enjoy the deep partial eclipse, my hope is for clear skies and my #1 tip is to be sure you do your observing safely. With any luck we'll all have some wonderful stories and photos to share at HAL in upcoming meetings!

Wednesday, February 28, 2024

Full Frame Focus

We're getting close now to the big event - the April 8th Total Solar Eclipse! And as the days fly by I'm trying to finalize my strategy for getting some memorable shots while balancing my desire to also "be in the moment" during the 4+ minutes that are going to whip by in time-warp fashion.

For the 2017 eclipse I used our "family" camera - a Canon t6i - attached to my Vixen 600mm refractor. That particular model has an APC (or cropped) sensor, which has the effect of increasing the focal length. Per Fred Espenak ("Mr. Eclipse"), a cropped sensor will increase the size of the Sun in your photo by about 50%. And while I was blessed to get some very nice shots using it at the 2017 eclipse, I felt that I wanted to have a bit more space around the Sun to better capture the full extent of the corona. While the 300mm telephoto lens on the t6i would certainly do that (and worked well for the Albuquerque Annular eclipse), I like the sharp optics and higher focal length of the Vixen.

And so began my research into getting a "full frame" camera body. There are basically two options now - a standard DSLR that has a flip-mirror in the optical path, or a "mirrorless" design where the sensor feeds directly to the screen on the camera rather than looking through a view finder. The latter is still fairly expensive (IMO anyway) at over $1,300 for a decent quality unit. 

But with users switching over to the mirrorless format, I reasoned that their old cameras might be popping up on eBay. After an afternoon of evaluating the offerings I found a Canon 5D Mark II camera body for $350. Sold!

A few days later the camera arrived. The body cosmetically looked acceptable, so the next step was to charge the battery to verify it turns on and works. That test passed, but then the challenges of getting it eclipse-ready started. The first disconnect was the SD card I ordered did not fit - these older units take a much larger UDMA card. Fortunately I could find one with adequate capacity and good transfer rate.

With the camera charged and outfitted with a card I turned my attention to hooking it up to the Vixen to see if I could get some Sun pictures. While my existing T-ring that I use to hook up my Canon t6i fit the Mark II, I immediately realized that since it was a 1¼ inch design I was shooting myself in the foot by not having a 2" T-ring. A little internet searching turned up a great company, Telescope Adapters, that had just what I needed. A couple days later I had my adapter and was ready to target first Solar light for the full frame camera. On the 9th of this month that took place, and I was pretty impressed with the wider field.

The final hurdle was to integrate the camera with laptop software to automatically take a sequence of shots during the eclipse. In 2017 I had tried Eclipse Orchestrator but did not feel confident enough to let it run the session, and ended up manually taking shots via the Canon app on my tablet. That definitely impacted my ability to "be in the moment" for the eclipse (but it was still a riveting, surreal experience!) Additional research turned up the Solar Eclipse Timer and Camera Controller (SETnC) application. This seems a little simpler and hopefully will prove to instill greater confidence in turning the camera control over to it.

Last weekend I set the Vixen up again and played with the SETnC taking exposures. While setting up an exposure sequence and executing it went well, I did find that the best rate for snapping off shots is roughly 1 per second, even with the premium UDMA card. That is a bit of a disappointment as I was hoping to be able to click off at least 2 shots per second to provide some bracketing during the C2 and C3 events  (e.g., trying to capture Bailey's Beads or Diamond Ring). Given the age of the camera it is really not a surprise, but at this point I think I am going to let fate dictate the outcome and hope for some great souvenirs of my last Total Solar Eclipse. After all, luck is always a factor in any such endeavor (just ask someone who's been clouded out for their celestial event!)

Image of naked-eye sunspot AR3590
with Mark II and Vixen 80mm

Sunday, January 21, 2024

Jupiter's June

With the exception of Mercury at only 0.03°, all the planets have some tilt to their axis. As any fifth grader should be able to explain to you, Earth has an inclination of 23½° and that is what gives us our seasons as we orbit the Sun. As amateur astronomers we can sometimes notice the tilt when observing some of our planetary neighbors. Mars' axial tilt is about a degree larger than Earth's and can present one hemisphere more favorably than another. For example, our best views of Mars are when it comes to opposition right around the time of its perihelion. As it turns out Mars is always close to its Winter Solstice at that point in its orbit, so we see  southern hemisphere features like Hellas and Syrtis Major better because they are tilted towards us while northern albedo markings such as Mare Acidalium are tough to discern (map). 

Hubble captures Titan's Transit - Feb 24, 2009
Saturn, with an inclination of 26¾° is the easiest example of noticing the affect of axial tilt. At its spring and fall equinoxes the rings all but disappear as we view the planet's equator straight on. At its solstices we are treated to the full grandeur of the ring system during maximal display. Another aspect is that only when Saturn approaches its equinoxes will the orbital planes of its moons begin to intersect the globe of the planet from our vantage point. It is only at those points in its ~29-year orbit that we get to see Titan transit and cast its large shadow upon the clouds below. While not as rare as a Venus transit, seeing our Solar System's largest moon cut in front of its home planet is an infrequent event (and one that is on my bucket list for the upcoming equinox!)

And where does Jupiter lie on the axial tilt spectrum? It comes in at a mere 3°, barely tipping towards or away from our view. We never get a nice look at its polar regions as with Saturn, it is consistently featuring its full-on view. Despite Jove's stingy axial tilt, the observant amateur astronomer can still discern evidence of the inclination, even with a modest telescope, by studying the Galilean moons. 

Yesterday (January 20, 2024) on Jupiter the Druids assembled at their Stonehenge to celebrate their Northern Summer Solstice, the maximal tilt of the planet's north pole towards the Sun. About a week earlier I was out imaging Jupiter (under very poor seeing) with a serendipitous alignment three out of the four Galilean moons. Io was about to slip behind the planet, while Europa had just start its trek across the planet's face. Ganymede stood nearby just off the limb awaiting its turn to begin transiting the planet.

Jupiter on Jan 13, 2024 7:39 p.m. EST
Like most planetary moons, the Galilean quartet have their orbital planes roughly aligned to Jupiter's equatorial plane (i.e., if we could see those planes it'd be similar to seeing Saturn's rings). But in my capture we note that despite having orbits lying in that equatorial plane, none of them appear near the planet's equator as they approach Jupiter. We see that the two that are about to cut in front of the globe will do so across Southern hemisphere cloud tops, while the one that is about to duck behind the planet appears at a northern Jovian latitude. This let's us know that Jupiter's northern hemisphere, and by extension the orbital planes of these moons, is currently tilted towards us.

There's another piece of information to be gleaned from the image taken on the 13th. If we use WinJUPOS to apply a grid overlay on Jupiter, we can more easily see that the distance the moons lie from the equator varies. Io is closest to the equator at roughly 20°, Europa is about double at ~38°, while Ganymede is doing a more polar crossing at about 55°. If we consider the schematic below that approximates how a set of orbits lying in the planet's equatorial plane might appear with a north-leaning planet tilt, we can see the significance of this. Io must be orbiting closest to the planet since it is nearest the equator. Europa must lie (very roughly) twice as distant. and Ganymede is orbiting at a distance perhaps some 2½ times that of Io. When we check our hypothesis we see that our analysis was an acceptable swag: 
  • Io: 422 km
  • Europa: 671 km
  • Ganymede: 1,070 km

But what about Callisto, the farthest out of the 4 Galilean moons at 1,883 km? If Callisto had been in the frame we would have seen it floating above or below Jupiter given the combination of the moon's more distant orbit and the planet's current maximum northerly tilt (much like the green orbit in our schematic above). 

Of course now that Jupiter has passed the Northern Summer Solstice in its orbit it will be moving towards an Autumnal Equinox roughly 3 years from now. As we head there you'll see the moons gradually fall back towards transiting the planet along its equator, and Callisto will once again join her siblings in crossing the Jovian cloud tops from as seen from our home planet. 

So often we set up the telescope and take a just a quick peek at our target, not tarrying to inspect the view in the eyepiece nor record what was seen. So here's a challenge for you to do something more. Observe Jupiter when a Galilean moon event is set to occur (S&T has a great online tool to predict when these occur, with three opportunities this coming week on the 22nd, 24th, and 29th). In a notebook sketch what you see (and you do not need a large scope to see these events). Continue to do this over the next three years and you'll have a cool record that shows the shifting tilt of the planet as evidenced by the changing appearance of the 4 brightest moons when near or in front of the planet. While you won't get an award for your effort, I bet you'll feel a reward for being able to demonstrate some of the mechanics of our Solar System through a patient recording of what you've seen first-hand.

Sunday, January 14, 2024

Tovala Telescopes?

Did you feel the amateur astronomy ground shift under your feet last year? While in the making for decades, AI exploded and took center stage in 2023 with the promise (or threat) of doing things for us. And while we have had "smart telescopes" such as the Unistellar eVscope since about 2020, the entry of products such as ZWO's SeeStar and Dwarf2 with a much more affordable price point of about $500 promises to be game a changer to our hobby. 

For those unfamiliar with these instruments, they abstract away most of the challenges in acquiring images of deep sky objects. Their refractor design means no worries collimating anything, and their stacking using short ~10-second captures means minimal tracking snafus. Plate-solving ensures your target is centered in the field. Polar alignment isn't required. It seems the most challenging part is just getting the unit level. The end result is that what used to be a significant threshold in terms of time and money to produce beautiful images of deep space objects has been dramatically lowered. And for those who want to refine the tiny scope's output there's the potential to download the individual subs to play with in your favorite photo processing software. The outcome - as seen here in this example from a photo Ken Sall forwarded from a FB group - is pretty astounding. 

I always grow a bit philosophical when confronted by these sort of advancements to our hobby and their impact. Progress is inevitable (especially if a profit is to be had) and often a boon to us. GoTo technology allows one to be far more efficient in an observing session and obviates the need to employ star-hoping skills. And who would want to go back to capturing photons on film save for the nostalgia of it? (I can smell the pungent aroma of the darkroom's stop-bath  as I typed that...)

And yet - does this sort of quantum leap remove some of the essence of why we take those photos? What is it that pulls us out under the stars in the first place? One approach to answering that question might be to consider Maslow's Hierarchy of Needs in which the 20th century psychologist postulated what makes us tick. The hierarchy is often shown as a pyramid in which a person works their way up from the bottom towards the top. The base of the pyramid deals with one's physical needs - food, shelter, safety. Once those are met we are free to move higher up to psychological needs of friendships and esteem. At the pyramid's pinnacle we have creative activities. Certainly it is in those areas that we find the impetus for people joining our hobby. 

Like any hobby astronomy certainly offers the opportunity for community and friendships that often accompany it. That is the raison d'etre for HAL. And, at the moment at least, there is a bond among SeeStar owners as they share their experiences using the scope that isn't seen for most other types of scopes. 

But how do the EAA telescopes fare in terms of fulfilling the esteem and creativity motivators within us? Their popularity would argue they indeed can provide their owners with a sense of pride and spirit of creativity as they image the wonders of the universe. That image of M42 demonstrates that. But over the long haul will that hold up? Those who delve into the processing of the little scope's stack of images to enhance and amplify the resulting photograph will likely continue to have those esteem and creative itches scratched. But for the person whose input is mostly just telling the machine what to target, I suspect that their initial psychological rewards will fade once the sky has done a full turn. Will we see a plethora of eBay listings of these scopes in a couple years?

There is another aspect that is, to me, a little unsettling. How ironic that a telescope calling itself SeeStar actually doesn't allow you to peer through it! There is a wonderful sense of awe peering through the eyepiece at the universe. Some targets, such as Saturn, need no introduction and can become an experience you'll always remember. Others, like seeing the stellar point of light at the center of galaxy M77 and knowing it represents an active galactic nucleus powered by a black hole, are more subtle but just as profound. Many of us also delight in the success of catching a glimpse of a challenging object such as discerning the active star forming region NGC 604 within the Triangulum galaxy or sleuthing out which faint star is actually distant Pluto. I suspect that we can thank another form of progress - light pollution - for the making such things more difficult and fueling our desire to swap out our eyes for the CMOS photon sponges.

All this being said, I need to disclose I've never used one of these scopes - perhaps I'd become their evangelist upon using one! I do sincerely hope that they bring hours of enjoyment to their owners and help grow the ranks of our amateur astronomy community. In our recent HAL board meetings discussing whether we should acquire a unit for club use, I was a solid "aye" vote in the matter (and my thanks to Grace Coventry for her efforts on making that a reality for us). If EAA entices people away from mindless scrolling on social media and brings them out under the night sky for a semi-virtual exploration of the heavens, then it is a huge win - not only for the hobby but for that individual as well.

Monday, December 18, 2023

When Smaller Is Better

Venus is a notorious tease. Her brilliance in the deepening twilight sky is a lure to any beginning astronomer, yet nearly all come away disappointed after centering the planet in the eyepiece. No details are to be had (at least none to an untrained eye without the aid of a filter) other than the changing phase of a featureless cue ball. 

The exception is when we view Venus in UV light. Thanks to an as yet unknown compound in the Venusian atmosphere that absorbs ultraviolet light the planet shows structure in its omnipresent cloud deck. As we know, UV is not something our eyes can discern. The best we can do visually is to apply a violet filter such as a Wratten #47 that reduces the glare a teases out a tiny bit of that structure as low contrast shadings. Most common of these (and with a scientific rationale for their existence) are the "cusp caps" seen at either or both poles.

All is not lost, however. The amateur who has outfitted his rig for planetary imaging can take advantage of the fact that the camera's sensor can record in UV. Some cameras are better than others in terms of their sensitivity in the UV portion of the spectrum, but even if you do not happen to have one of the more UV friendly models the odds are good that with the addition of an ultraviolet filter you can capture some details. A little over a year ago I purchased an Astrodon UVenus filter to pair with my ZWO ASI178MC (color) camera to see if I could capture the cloud patterns, and was delighted to have success earlier this year.

In researching the best approach to obtaining a good image of Venus in UV one of the tips that I ran across was to avoid lenses in the optical path. The anti-reflection coatings on them can apparently cut down on the UV transmission, making the image dimmer (and consequently requiring a lower frames-per-second rate that introduces atmospheric smearing). It has also been noted that the corrector plate on an SCT is not designed to provide correction in the UV range, so that design may be a bit handicapped when attempting UV capture.1

Another factor I have noticed is that while you can detect cloud markings when Venus has become a large but slender crescent on either side of an inferior conjunction, the results seem far more interesting when the phase is somewhere greater than 35%. Enough of the disk is presented to allow one to often capture cups caps/collars as well as streaks in the middle of the planet that a crescent won't show.

My recent session a couple weeks ago was under average seeing with only fair transparency. Our sister planet was sporting a 70% phase and a diameter of only 16" as the planet continues to pull away from us following last August's inferior conjunction. Having to forego the 2.5x Barlow means it is a small image that one gets to work with, but it was clear even on the laptop screen during capture that the cusp caps were visible. Post processing can afford some help in enlarging the image (such as adding drizzle in AutoStakkert3!, leveraging the resizing functionality in Registax, or even using a custom resizing application like Topaz's GigaPixel product).

Since I had the time I decided to do a second capture, but this time with the Tele Vue 2.5x Powermate Barlow in the imaging train. I could immediately see the impact in terms of a dimer image, dropping my fps from 32 down to 9. This of course allows more time for atmospheric blurring to occur, reducing the number of frames of steady seeing that can be harvested. 

So while the image was certainly larger, the attenuation of UV light by the Barlow gave an image with far less clarity. Yes, the cusp caps are there, but the details in the smaller image, even after undergoing enlargement, were far superior. The verdict was clear - leave the Barlow in the box and work with whatever size we have to get the best UV image of the elusive Venusian cloud details.


Wednesday, November 1, 2023

Heavenly Symmetry

A first impression the prospect of traveling halfway across the country to catch an annular eclipse seemed extravagant to me. After all, we do not get to see the ghostly corona and fiery prominences during that period where Moon occults Sun. The stars do not come out and nature reacts far less confused when the Sun, even a small amount of it, remains exposed. You might be tempted to equate it with seeing a 99% partial eclipse of the Sun. 

However, the facts were that witnessing an Annular Solar Eclipse was an unchecked item on my astronomy bucket list, and the one this October was (given my age and location) very likely my last opportunity to catch such an event. What the heck - YOLO, right?

The first step in the journey was selecting a location. Studying the path and the weather prospects I decided to target New Mexico for a long weekend. The path crossed two interesting cities - Albuquerque and Roswell. Given the almost legendary dark skies of the southwest I felt that spending a couple evenings at an Airbnb outside Roswell might offer the additional perks of checking out the UFO/Alien scene in Roswell by day and then enjoying a star-studded sky in the evenings. By the end of March I had my flight, rental car, and accommodations all set. 

Practice Run Capturing Clouds & Sun
Discussing my plans over Labor Day weekend with my son Dave I was delighted that he took me up on my offer to come along. We edited the itinerary a bit so that we'd be at the Albuquerque Balloon Festival to witness the eclipse rather than Roswell. With the venue change I pondered whether I might get a unique photo opportunity since there were plans to launch balloons during the eclipse. I spent the next several weeks researching how to filter the Sun sufficiently while still getting some of the background in the picture, something I've seen before that make annular/partial solar eclipse photos interesting. In the end a set of neutral density filters (one of them variable) and an IR/UV blocking filter seemed to offer the promise that if a balloon floated by the eclipsed Sun I could hopefully capture that bit of serendipity.

Travel day - Friday the 13th - started off with a curveball. Southwest texted me at 6 a.m. that they had cancelled the first leg our flight and rebooked us to a direct flight that was departing a half hour earlier. We hustled along to get to the airport to allow enough time to check bags and clear security (I was happy that my long rectangular box holding my tripod was not any issue getting checked in). Several hours later we were in Albuquerque and scouting out online reviews for a good Tex-Mex lunch.

The next morning as we stepped out from the room we could see a host of colorful hot-air balloons hanging off in the distance. The weather, despite forecasts for 80% clouds at the start of the week, looked promising with some scattered, high cirrus hanging around. We Ubered to the Balloon Festival field with camera, tripod, folding chair, and filtered binoculars in tow by 8:15. It was packed, but fortunately the field was quite large and accommodated the tons of people who had assembled for a good time. We found our plot of land and set up our little camp.

The first 45 minutes we enjoyed seeing some of the colorful and fanciful balloons taking off. A pretty steady breeze out of the north was making it a chilly fall morning, and unfortunately it soon caused the event planners to put a hold on launching any more balloons. The field MC was providing a running commentary of what was going on interspersed with some music.

8:38 a.m. MDT
I strap on the mylar solar filters to my 7x50 binoculars and check out the Sun. No major sunspots are present but a couple can be made out when I steady my hand. I fire off a couple of shots to refine the exposure settings and await for the action to begin. 

9:15 a.m. MDT
The announcer tells the crowd that the eclipse has begun, and a bit of a cheer goes up as everyone sees the tiny, initial bite taken out of the top of the Sun using our solar safety glasses that were being passed out upon entering the field. Which makes me wonder - how disappointed were the vendors that were trying to sell them? 😏

Moon marching across the Solar disk, ready to cover AR3465

The field MC provides updates on the eclipse's progress between the songs being played, and in a moment of bad science around quarter after 10 he mentions that people with good eyesight might see that the edge of the Moon has crept up upon the sunspot and will be covering it soon. While AR3465 is clearly the largest sunspot on the face of ol' Sol today and easily seen in my binoculars, it would be impossible for us to see it naked eye.

With about 20 minutes before 2nd contact we're also told that there won't be any balloon launches as we approach maximum. It's a disappointment but understandable as the winds have been constant since our arrival and would likely make it too dangerous. They still hope to do a "balloon glow" on the field during the time of greatest eclipse where the balloon is inflated but tethered to the ground.

10:20 a.m. MDT
I stop for a moment to look for Venus, and it takes very little time for me to pick it out high above us in the deep blue desert sky (even without my "distance" glasses). Once I point to it Dave can also quickly see it, although at first is not sure whether it's a plane at high altitude catching the glint of sunlight. The binoculars quickly resolve the question as I can see a disk exhibiting a phase to it. I try to grab a picture of it but the camera cannot do it, yielding only an overexposed sky, yet again demonstrating the amazing ability of our eyes to take in a logarithmic range of brightness that a CMOS sensor cannot.

By 10:25 the field has taken on that odd late-in-the-afternoon light that seems surreal for the hour of the day. There is not any wildlife in the area to observe, but given how my human instinct tells me the Sun should be close to setting I strongly suspect that our fellow animals are likely reacting to the change in light, albeit not as profoundly as in a total eclipse. 

This is the first eclipse I have experienced without any of the "pinhole projector" effects. Normally there are some deciduous trees around and they provide the multiple crescent images at this point, but in a wide, empty field suited for hot-air balloons there are none. The field announcer mentions that if you have a Saltine cracker, the dozen or so holes that perforate it will serve nicely as a makeshift projector. Perhaps that should have been part of the handout along with the solar eclipse glasses? 😄

With less than 10 minutes to go we are told that even the balloon glow cannot take place due to the winds, and instead the best that can be done is a "candlestick", where the propane burner is fired to create a tower of flame sans balloon. 

And finally we are at the moment we've waited for!

10:34:41 MDT
Second contact is announced and the crowd cheers as people begin to make out the off-center unbroken ring of light encircling the Moon.

10:37:12 MDT
We've reached the climax of maximum eclipse. To the unfiltered eye the Sun is still glaring and without hint of being 90% covered, but with eclipse glasses, and especially in the binoculars, there is this amazing alignment to behold. A perfect glowing circle of bright light that seems like it is a Hollywood special effect made for Lord of the Rings stands before us. Lots of cheers and the roar of the hot-air balloon burners lighting up the field makes the entire experience unique and unforgettable. This is what I came for - that incredible, visceral connection that an eclipse can provide during those brief seconds of totality/annularity. While I wondered if the annular version would come close in that impact, the stunning symmetry in the sky does not disappoint!  

Facebook Livestream:

10:39:35 MDT
All too soon Luna has crept to the eastern solar rim and prepares to exit. Dave is using the binoculars as we head to 3rd contact and - without any foreknowledge of the Baily's Beads effect - mentions to me that he sees the brief sparkling of the sunlight along the Moon's limb as it exits. My constant firing off shots allows me to also capture the phenomenon digitally.  

As the Moon begins to retreat from the face of the Sun, many of the folks assembled on the field begin to head out as well. It really has become noticeably cooler, and judging from the comments I overhear I am not the only one wishing I had brought a heavier jacket. While it is a bit anti-climatic it seems that it would be almost rude for me to break down the modest equipment and hail our Uber. Dave takes the time to explore the long line of vendors' tents in search of some souvenirs for us to remember the day while I continue to document the egress towards 4th contact. 

By noon we collapse the tripod and camp chair and place the request for our ride. With only a few more minutes left I take my final shots of the Moon departing the Sun in hand-held fashion as we make our way out. While not the epic traffic jam that I encountered following the 2017 total eclipse, the wait and fees for the Uber tell us that a lot of people have participated in this annular eclipse. While a bit tired I am joyful at what God granted me in witnessing this eclipse with my son and checking off another of my astronomical bucket-list items!