Chasing Comet Lemmon

Last October, excitement was building in the astronomy community about Comet Lemmon (C/2025 A3), which was predicted to reach around 3rd magnitude – bright enough to be seen with the naked eye from a dark site. As the comet’s closest approach to Earth drew near, I began planning a photography mission to capture this icy visitor. With the closest approach set for October 21, I kept a close eye on the weather for Monday the 20th. The forecast was uncertain, with a storm system expected to clear just in time for the evening. I decided to focus on photography, using my trusty 7x50 Celestron binoculars for visual observation. After dusting off the Star Adventurer Tracker – dormant since my trip to the 2023 Annular Eclipse in New Mexico – I began scouting locations within a few hours’ drive.

A light pollution map led me to the Zumbrun Overlook in Green Ridge State Forest, between Hagerstown and Cumberland. Online photos showed a promising platform with a clear western horizon. I opted for an overnight trip, staying in Cumberland to avoid a late-night drive home. I reached out to my astro-photography friend Steve, but he was busy with another shoot. Fortunately, Deb was interested in joining, and we looked forward to enjoying the fall foliage on our drive. After morning appointments, we headed west on I-70, stopping for lunch in Hagerstown before arriving at our hotel in Cumberland.

Zumbrun Overlook

After checking in, I drove out to the Zumbrun Overlook near Flintstone to get familiar with the site. The spot looked ideal, though a tree at the front of the platform meant I’d need to choose my position carefully depending on the comet’s location. My goal was to set up by 6:15 p.m., but dinner at Puccini’s ran late, and I arrived at the overlook around 6:30 p.m. At the overlook, two amateur astronomers from NOVAC had already claimed the front row, so I set up behind them. The sky was very clear, with moderate winds and a limiting magnitude of about 5.5. As twilight deepened, Comet Lemmon became visible in Boötes, just above and to the right of Arcturus. The clouds cleared just in time, and although I had to shoot over the NOVAC observers, the Star Adventurer tracker performed well. Deb joined me at the overlook to enjoy the overhead Milky Way, which was on full display.

Around 7:45 p.m. I spent some time observing Comet Lemmon through 7x50 binoculars. The comet showed a bright coma with a tail extending roughly 1.5° northeast. No greenish color was detected; the coma appeared white. I estimated its brightness at about 4th magnitude – just visible with averted vision. The scene was enhanced by the presence of orange r Boo and blue s Boo in the field. One of the NOVAC astronomers also graciously shared a view of the comet through her 8” SCT (but it seemed to lack a sharp focus).

Comet Lemmon Amid Boötes

Arriving back home the next day I was disappointed to discover my images were slightly out of focus. I salvaged them somewhat using BlurXTerminator in PixInsight on each individual shot before stacking them in Sequator. Despite some streaky clouds photobombing Lemmon, the final image captured was reasonable and serves as a wonderful memento from that night. While not spectacular, Comet Lemmon 2025/A3 was a wonderful visitor from the deep freeze of our outer solar system.

A Shadow Missed But A Surge Gained

On the evening of September 19th, I was gearing up to record one of the final Titan shadow transits of the season. An ALPO colleague had tipped me off to the upcoming event, a rare alignment that won’t grace our skies again until August 2038. If I’m still around at 83, I’ll be chasing it again. Luckily, for this particular event the forecast from Astropheric promised above-average seeing, and I was eager to make the most of it.

Knowing the transit window would be brief (just 2.5 hours, with only a portion ideal for imaging) I prepped the scope early, aligning the finder and checking collimation before trying (unsuccessfully) to grab a few hours of sleep. By 1 a.m., I was back outside, scope thermally settled, laptop in hand, and Saturn hanging clear in the sky.

I began imaging with the ASI178MC, focusing on the northern polar region where Titan’s shadow should have been visible. But something seemed off. The shadow normally is like taking a paper punch to the globe, creating a very high-contrast object that is readily detected. Even the disk of Titan, with a much lower albedo level compared to the clouds, should have been evident. I dutifully continued on capturing AVI runs, thinking perhaps I just needed to be closer to mid-transit for it to be visible on the laptop monitor. 

As we approached 2 a.m. I decided to do a quick processing run to investigate the situation.  The mystery was promptly solved by the outcome: I had miscalculated the Universal Time conversion. The transit wasn’t happening for another 24 hours. A rookie mistake - one I’d like to blame on the emotional fog of having been laid off from my SSA contract earlier that day. That’s my story, and I’m sticking to it!

Still, the seeing was solid, so I pressed on. I captured both white light and Baader 685nm “Deep Red” filtered images, the latter always better at teasing out Saturn’s atmospheric banding. Of course, the grayscale results of the Baader image lack the visual charm of color, but I’d recently watched a tutorial by Damian Peach on blending R-IR data as a luminance layer with color images. The video skipped a few key steps, so I played around in Photoshop and sought the advice of my friend Steve Stewart (a PS master), experimenting until I found a technique that worked. The final composite was well worth the effort - sharp, detailed, and visually satisfying.

One surprise emerged during processing: the rings were noticeably brighter than in my earlier summer captures. Comparing the September 19th image to one from July, the difference was striking. Then it hit me. Saturn was mere hours from opposition on the 21st. Could this be the Seeliger effect, the so-called “opposition surge”? It certainly looked that way. The rings, previously muted, had taken on a luminous sheen, likely due to the Sun-Saturn-Earth alignment minimizing shadows and maximizing reflectivity.

I’ll be curious to see if the rings dim again in my next imaging session. For now, I’ll chalk this night up as a win despite the missed transit. The imaging run delivered a beautiful Saturn and a reminder that even a seasoned observer with half a century behind the eyepiece can still slip up. 

A Regal Conjunction

On September 19, 2025, a rare celestial event unfolded in the pre-dawn skies over Maryland: the conjunction of the Moon, Venus, and Regulus. I had high anticipation for this conjunction for several reasons. First, the tight grouping of the three celestial bodies was remarkable. Venus, the waning crescent Moon, and Regulus (Leo the Lion’s lucida) were packed within a 1-degree field of view. This meant that they were close enough to fit under a fingertip held at arm’s length, or easily with my telephoto lens racked out to 300mm.

So often the word “rare” is thrown about with abandon in regard to astronomical events. But this one does merit the appellation. A similarly tight grouping won’t occur again until September 22, 2041, when the trio will fit within a 7.2° circle. My research could not find any evidence of another triple conjunction from Maryland that will fit within a 1.0° field of view for at least the next 50 years.

Preparation

A few days out, the weather forecast looked very favorable for the morning of September 19^th, so I set about planning for it. I jumped on the Heavens-Above website and used their interactive sky chart and twilight times to get a preview. Those tools let me know that the event would be low on my eastern horizon, which was a problem due to the trees and houses that blocked my eastern view from home.

I needed a better venue and thought that somewhere along the nearby Loch Raven Reservoir might offer a clearer eastern horizon. I ruled out any trails as it could be risky navigating an unfamiliar path in the dark while carrying my camera equipment. Exploring virtually with Google maps, I noticed several small “observation decks” along the eastern side of the Dulaney Valley road bridge that crosses the reservoir. By midweek I had a game plan: park my car off on the shoulder near the bridge and walk a quarter mile to the platform.

The day before the conjunction, I weighed doing a reconnaissance of the bridge, anticipating that I would swing by right after work around 3:30 p.m. However, fate had other plans. Around 10 a.m., I received news that I was being laid off as part of budget cuts and had to hand in my laptop by 2 p.m. Given that 2026 was going to be my last year of part-time work as an OCR software developer, the layoff was not a significant impact, although there was the emotional aspect of no longer being employed after over half a century of work. The immediate upside was that it gave me an early departure time to head out to the reservoir. My drive out to the bridge validated my plans to park the car just before the bridge and walk out to the first fishing platform.

The Conjunction

I set my alarm for 4:30 a.m. Thursday evening, but I was up before the alarm went off. I dressed quickly and hustled out the door with my camera. I was at the pull-off area south of the bridge within a few minutes, parking the car and gathering my equipment. As I used my cell phone’s torch to light the path out to the platform, I pushed away the slight anxiety that creeps in, that sense of caution mixed with danger when doing something like this.

As I rounded the corner and stepped onto the bridge I saw my prize: an ocher-colored Moon rising, with Venus hanging just below it, both attenuated by the atmosphere. Regulus was not visible at that point, either hiding behind the trees or extinguished by the horizon haze. I was a bit surprised to see the Moon was in front of me rather than to my right over the water. As I advanced towards the bridge, the tree line slowly loomed taller and taller. By the time I was at the platform, the Moon and Venus were just skirting the treetops on the opposite shore. While not the imagined view of Moon rising over the waters of the reservoir, the setting was certainly beautiful.

The Crescent Moon & Venus

I set up the camera and bracketed a few shots of the slender orange crescent juxtaposed with a cream-colored Venus dangling below it. Time passed quickly, and as the duo climbed out of the haze, I could soon see Regulus hanging below Venus, forming a remarkable straight line. The earthshine was now evident, adding to the sublime nature of the appulse. For the next 45 minutes, I captured images at various focal lengths and exposures. Even at the full 300mm of the telephoto lens, all three members of the conjunction were in the frame due to the tightness of the conjunction. I knew the more challenging aspect in replicating with the camera what my eyes were witnessing would be the brightness contrast of these three. Venus outshone Regulus by about 100 times, while the Moon was just 5–6% illuminated, creating a dramatic visual contrast that our logarithmic eyes can handle well but pixels struggle to faithfully reproduce. Some things are just seemingly made for naked eye observation.

Moon, Venus, Regulus (and earthshine)

I had to contend with the southbound traffic coming from Jarrettsville Pike, timing my shots to miss their oncoming headlights intruding into my frame, even with the lens hood attached. I also noted that at times when some vehicles passed by on the bridge, there was some vibration, which likely ruined some shots. After about an hour and with dawn beginning to lighten the horizon, I packed up the camera and began the trip back home.

Conjunction reflected in the water below

As I pulled up in front of my house around 6:20 a.m., I assessed where the Moon was. It was still hidden behind trees, so I walked around to the backyard, camera and tripod in hand. It was not until I moved to the farthest southwest corner of the yard that the trio of conjunction companions cleared the rooftops. I fired off a couple of shots as the eastern sky gradually grew brighter, concluding my engagement with this magnificent conjunction by about 6:30 a.m.

The conjunction from my backyard

Witnessing this triple conjunction of the Moon, Venus, and Regulus was absolutely an unforgettable experience. The planning, the anticipation, and the sheer beauty of the event made it a night to remember, and the images will serve as a wonderful reminder of that September morning out at Loch Raven as the heavens aligned.

Mercury!

As an avid planetary imager, I've had my fair share of accomplishments, but Mercury has always eluded me. One of my goals for 2025 was to end that frustration and finally capture an image of the smallest planet in our solar system. This current mid-to-late August apparition offered the best opportunity of the year. Fall morning apparitions provide the most favorable geometry, with the planet's solar separation translating to vertical height above the horizon due to the inclination of the ecliptic in the autumnal pre-dawn sky.

Due to the trees (which need trimming this winter), Mercury must reach about 40° altitude to clear them, necessitating a daytime observation. That’s not too difficult for Venus, but it posed a bigger challenge for Mercury, which isn’t visible in the finder scope. Fortunately, the ALPO webinar last spring on daytime planetary imaging provided valuable tips and encouragement, confirming that I had the equipment and skills needed for success.

The weather from spring through much of summer this year was dismal. Clouds were the norm, and even when the skies cleared, seeing conditions were often below average or marred by smoke from the Canadian wildfires. So when a forecast for below-average transparency but average seeing presented itself on August 17th during the favorable morning apparition, I decided to commit to an imaging run.

I stepped out at 4 a.m. to align my telescope, only to be greeted by a strong haze that limited visibility to 2nd magnitude stars. By 9 a.m., the clouds had worsened, making it difficult to even spot the fat crescent Moon. However, I managed to bring Mercury into the camera’s field of view and run some captures. The resulting image showed a chubby crescent phase with little to no discernible albedo features - a technical success, but not truly satisfying.

With a forecast for better transparency and above-average seeing on the morning of Saturday, August 23rd, I decided to give it another shot, with Mercury just past dichotomy. I set up my scope to cool and went to bed Friday evening, again waking at 4 a.m. to align the CGX-L mount. The alignment was good enough to bring targets into the low-power view. After aligning, I did a couple of lucky imaging runs on Saturn in color under pretty good seeing conditions. I then moved on to Jupiter for more practice and captured an IR image as dawn approached.

Then, despite being plugged in, my laptop died unexpectedly. Clearly, the recently purchased AC adapter will need to be returned. Frustrated, I took it back upstairs to charge while waiting for Mercury to clear the tree line at 8 a.m.

Returning to the driveway, I was pleased to see clear blue skies with only minor clouds. The morning breeze was gentle, and transparency and seeing conditions seemed promising. I started by slewing to Venus to practice my hand controller motions, ensuring that one short press to the right and 2–3 presses up would bring the slewed object into range.

Finally, I slewed to Mercury for the moment of truth—and the planet popped into view! Initially, it looked turbulent, but after adjusting the focus manually and using SharpCap’s Fourier Detail Detection routine, I was able to achieve a good focus. The strong surface brightness of the innermost planet allowed for high frame rates, and I adjusted the exposure, gain, and region of interest to achieve over 100 frames per second.

The planet danced wildly due to the rising Sun and atmospheric currents, with only fleeting moments where the half-moon phase was discernible. I captured a series of three 3-minute videos at 3ms exposure and a gain of 180, followed by experimentation with higher gain and lower exposure to increase the frame rate. In total, I captured about 20 minutes of video.

Processing the data later that day revealed good-quality images, with sufficient seeing to produce a reasonable stack. I whittled down nearly 64,000 frames from the 3ms videos to create a nice image. I also experimented with AstroSurface for the first time to sharpen the result and was pleased with the tool.

While this face of Mercury lacked high-contrast albedo features, my image showed a mottled surface, reflecting large-scale features. After all, at only 6.6 arcseconds in size, I’m targeting something roughly the size of a tomato seed viewed from across a football field! With this success under my belt, I’m looking forward to making Mercury imaging an annual event—weather permitting!

Achieving a Bucket List Item

There are certain astronomical events that intersect our lives only episodically, and Titan shadow transits has been one of those elusive moments for me. Years ago, as a young amateur seeing Jupiter’s moons cast their shadows on the giant planet, I wondered why I did not see that with Saturn. Of course, I soon realized that Saturnian moons do not do this routinely due to the planet’s axial tilt of 27°, lifting (or dropping) their orbits so that they don’t cut in front of the planet when it is facing the Sun. Only when Saturn is around the time of its equinox (when its rings appear very thin) do the moons begin to intersect the Sun’s plane as they move in front of their host planet. We are roughly halfway through such a season with the ringed planet having reached autumnal equinox for its Northern hemisphere last May. I know that only a few months remain of this opportunity, my last realistic chance for years to come. The next similar alignment won’t take place until 2038, at which point I’ll be a much older observer, perhaps with a little more wisdom but a little less stamina for predawn adventures.

Given that Titan orbits the planet every 16 days these transits will take place only once or twice a month. And given that the orbit is almost exactly 16 days you have to be on the right side of Earth with Saturn in a reasonably dark sky. Thankfully the Western hemisphere is well position for the current series. The window opened as Saturn emerged from Solar conjunction this spring. My concerns of missing it have been slowly nagging me as I watched the May and June windows be clouded out and the July 2^nd opportunity unavailable as I was away.

July 18th was on my calendar as the next transit, but as it approached it came with iffy forecasts: some sources predicted hopelessly thick clouds, while others suggested there might just be enough breaks to make an attempt worthwhile. I set my alarm anyway and, with a quiet stubbornness familiar to many amateur astronomers, rose at 3:15 a.m. to scan the skies. It was quite overcast but there still were occasional breaks through which Saturn would pop out for a few minutes. I rolled out the Cyrus 10” f/6 Newtonian and performed a quick mirror collimation.

I decided to prioritize visual observation rather than seeing it on a laptop screen, wanting to witness this event with my own eyes. When a sizable break appeared a little after 4 a.m., I popped in my 8mm TMB eyepiece and Meade 2x Barlow and brought the planet into focus. Perched on the first rung of my step ladder, I saw the planet as a light tan orb with the rings as a spike through it. I continued studying the planet, waiting for those fleeting moments of steady seeing. My first micro-glimpse was uncertain – did I see something or was it a trick from my aging eyes? But after a couple of minutes the dark dot continued to pop in & out of view, clinching it as the shadow of Saturn’s largest moon.

All too soon the clouds reclaimed the view. I swapped out the eyepiece for camera in hopes they would relent for a few minutes so that I could grab an image of the event. But it was an hour of frustration as the planet never emerged for an encore. But while the imaging effort failed, it was a pure delight and sense of accomplishment to witness that shadow cast across another world.

Last week the forecast for early Thursday morning caught my attention with partly cloudy skies and predicted above average seeing – rare conditions for this spring and early summer of 2025. Unable to pass on the prospect, I set out the Cyrus scope around 10 p.m. and settled in for a short rest with the alarm set for 3 a.m. As usual I ended up naturally waking up ahead of the alarm – odd how your body will do that! 

As I stepped outside I was greeted by warm, muggy air; just the sort of atmospheric hush that can often presage very good seeing. The malingering clouds were punctuated by generous breaks, one of which framed Saturn. I started the usual pre-observing sequence: mirror collimation, finder alignment before commanding the scope slew to Saturn. I centered it on the laptop screen and honed the focus, using the high-contrast edge of the rings' black shadow on Saturn’s bright equator as my guide.

Imaging began in the deep red/infrared wavelength using a Baader 685 filter, firing off five 2-minute video runs. Next I changed camera filters to begin a run of color captures. I did a quick stack and sharpen of one of the early video captures and was happy that it revealed delicate banding and even a hint of the Cassini Division. Encouraged by seeing conditions nudging up to 8/10, I pressed on to take a total of nine videos. Then with the laptop battery flagging I invested in capturing a nearby star’s Airy disk as a sharpening reference, managing two short videos before the battery gave up a little after 5 a.m. Time to pack it in and get ready for work!

The next day’s processing brought a pleasant surprise with the best Saturn images I’ve had in months. The R/IR set showcased layered bands, with the NEB and SEB standing out sharply. I was especially intrigued by the dark SPR, perhaps a lingering effect from Saturn’s long winter. The rings, though dim, opened enough to reveal the Cassini Division at their tips, while the planet’s shadow starkly cut off the rings where they ducked behind the globe.

The true showpiece, though, was the color session. Saturn’s pastel hues—blue to tan—came through beautifully. Again, the NEB and SEB dominated, while the SPR, though less sharply defined, was the darkest and bluest region on the disk. What caught my eye most was a subtle bluish belt in the NTR region, around latitude +50°, visible in each of the nine runs, so surely not an artifact. I’ll be curious to see if it turns up again in my next imaging session.

Observing opportunities given the lousy weather seem to come at a premium these days, especially when a quick shower and heading out to work follows your pre-dawn session. But these two sessions this month made every lost minute of sleep worth it. And among the many milestones, I can now add the thrill of witnessing a Titan Transit shadow—a sight I’ll not soon forget. 

Ghost Rings

It’s been a frustrating few months here—cloudy skies, a rainy spring, and the usual march of obligations that come with being back in the office. But I managed to sneak in a planetary session one Thursday morning before work. Not easy when you’ve got to be clocked in shortly after 6 a.m., but sometimes the sky gives you a narrow window, and you take it.

This was my first planetary observation in quite a while. I had the 10-inch f/6 Newtonian out, laser-collimated and ready. Saturn was hanging low and I didn’t have the time to work the ADC into the train, so I kept things simple. Seeing hovered around 6/10, transparency worse—perhaps a 4/10 thanks to persistent Canadian wildfire smoke over the mid-Atlantic.

Still, I managed a “deep red” imaging run, capturing Saturn shortly after its recent Autumnal Equinox last month. What struck me most when I finally got the planet centered and focused on the laptop screen was how dim the rings appeared.

At such a shallow B ring angle, the rings appeared ghostly, dimmer than I recall seeing them in years. On the laptop, they seemed to fade into the background, lacking the sharp border that can help in achieving focus. Visually, through the 10" at 187x, they were brighter—a shining needle skewering a ball of yarn—but still far from their previous brilliance.

So why the dimming? Some research was in order, and I must admit having AI as an assistant for such things is fantastic.

With us just past equinox the Sun is illuminating the rings edge-on. At this angle, the sunlight strikes the rings so obliquely that their icy particles scatter much less light toward us—especially in red and IR wavelengths. Unlike the globe, which reflects more consistently reflects the light back at the observer, the rings become dramatically muted under these conditions. And with the B angle so close to zero, we’re seeing not only less illumination but also less material: the thin plane of the rings reveals little vertical structure from this 

Interestingly, the rings looked darker than my last deep red image back in January of this year when we were still viewing the northern plane, despite having a similar B angle. The geometry and light-scattering behavior are that sensitive.

As for Saturn itself—the image shows subtle bands representing the NEB and SEB bands, and, interestingly, perhaps a darker SPR region. Overall it’s a small win in less-than-ideal conditions. This isn’t the showiest Saturn I’ve captured, but it’s a subtle reminder of just how dynamic the outer planets can be—not just from year to year, but from month to month in our own observing windows.

Mounting Problems

A few weeks ago, I was inspired by an ALPO webinar on daytime observing of planets, so I decided to try locating Mercury during it spring western elongation. Equipped with my Celestron CGX-L mount, I had high hopes of using its GoTo functionality for enabling me to find the planet amid the bright blue sky. However, what should have been a straightforward task quickly turned into a puzzling challenge. When I keyed in the time—just a little after noon—the mount's computer inexplicably believed it was just after midnight. As a result, daytime targets like Venus and Mercury refused to appear in the GoTo menu. After triple-checking every input and even rebooting the system multiple times, I felt equal parts baffled and frustrated.

Needing to get to the bottom of this, I opened a support ticket with Celestron. Their team responded promptly and suggested I double-check whether I was selecting AM/PM properly. While that might seem like a simple oversight, I assured them this wasn’t the issue—I had been meticulous in my entries. Notably, if I set the time to 11 a.m. instead of 12 p.m. the menu would display the expected roster of daytime planets in the sky.

The recommendation came back to update the firmware. Sounds easy enough, and there was even a link to a user’s video showing how to do it – but his mount and mine were different. Without the gory details it proved to be a process that I had to retry a couple of times before I got it right. And then, following the firmware upgrade, another issue arose where the scope would not properly return to the Home position. Another round of correspondence ending in a helpful call where the technician talked me through that issue and finally brought full resolution.

Though the experience was undeniably frustrating at times, I felt appreciation for the support Celestron provided. Their willingness to actually get on the phone and guide me in resolving the issue renewed my confidence in the brand and their equipment. Now with a little luck the next time Mercury has a decent elongation in the morning sky everything will work as expected!

The evening of the recent Lunar eclipse brought to light yet another technical snafu, this time with my iOptron HEM27 mount that I use with my Vixen scope. I planned to align the mount as soon as Polaris was out, but the iPolar software had other ideas. I’ve used it many times in the past with good results but that evening it would not display the crosshair that one must align to. Worse, the software was also crashing at times. I went with a manual alignment which worked well enough over the course of the frustrating evening which ended up in clouds engulfing the Moon moments before totality arrived.

About a week later I tried troubleshooting it. I first confirmed that the problem could be reproduced. Then I tried uninstalling and re-installing the software. Nothing worked and the software crashed upon each attempt. The next day I opened a ticket with iOptron.

Following guidance from the company, I downloaded and successfully applied a firmware update and took a new dark frame as suggested. However, to my disappointment, the core issue remained—iPolar continued to crash upon clicking the "Confirm Position One" button, as shown in a video I shared with them. I also ensured to clear the "Center of Camera" settings before testing further.

In response, iOptron Support requested details about the specific iPolar version and firmware I was using, directing me to check through their provided link. So, the back and forth continues without resolution. I am hoping that it can be resolved soon and certainly without having to send the unit back to the factory. The troubleshooting process with iOptron serves as a reminder of the challenges and patience required in astrophotography, where technical hiccups can cause you to miss opportunities to gather those photons.

 

 

Carbon Capture

A few weeks ago I found that my iPolar software in my HEM27 iOptron mount was routinely crashing when trying to perform polar alignment. The latest missive from tech support suggested that I should update the firmware. So with a clear sky and open schedule I took the opportunity to finally apply the update and re-test the software. Sadly, and a bit frustratingly, it still crashed when trying to do an alignment.

Despite the technical hiccup, I decided to pop on the Vixen and start an observation session with the objectives of evaluating the new (to me) 13mm TeleVue Delite eyepiece purchased at the HAL Christmas Party auction and visiting some items on the AL Carbon Star observing list. The sky was devoid of moonlight, offering seemingly clear visibility with a thin haze. Orion was dropping below the western tree line while Boötes was yet to climb over the roof from my backyard vantage point.

To keep it simple I elected to visit three carbon stars for the evening’s itinerary. Carbon stars are a fascinating subset of stellar objects that capture the interest of many amateur astronomers. These stars, characterized by their deep red hues, have atmospheres containing more carbon than oxygen, leading to the formation of carbon compounds that give them their distinctive color. The attraction of carbon stars lies not only in their sometimes striking appearance but also in their varying luminosity. They lend themselves well to the skies often encountered by the suburban amateur astronomer.

My first target was Y CVn, a carbon star in Canes Venatici, also known as “La Superba.” Despite the challenges with the iPolar alignment, the accuracy of the pointing allowed me to use the Slew & Center function efficiently on Cor Caroli. Upon keying in the coordinates for Y Canis Venaticorum, I inspected the field at low power and immediately identified the star by its red tint compared to other field stars. Switching to the 13mm eyepiece enhanced the color slightly, but the sparse field and light pollution subdued the redness. In comparison, I recalled Mu Cephei and Hind’s Crimson Star as being more striking.

Next, I attempted to observe T Cnc in Cancer. Using the Sync to Target function after slewing to Mars, I fine-tuned the positioning and centered the object. Initially, the field appeared pleasant but lacked any sun with the characteristic cerise coloration. Increasing magnification to 46x revealed a star with a slight hint of red, which I am guessing was T Cancri. Its faintness (probably at around 9th magnitude according to current AAVSO observations) likely made it challenging to detect its red coloration distinctly. It’d be worth targeting again with either a larger aperture or maybe from a darker sky.

After my challenging observation at T Cnc, I bid the scope to move a couple degrees to neighboring carbon star X Cancri. This time the low power view, a field busy with stars of a wide range in brightness, quickly revealed one breaking the monochrome black and white palette with a distinctive ruddy glow. Again, the 13mm eyepiece offered a better view at 46x by darkening the background a bit to increase the contrast a tad. To my eye this one is similar in brightness and redness (maybe even a slight bit ruddier?) than La Superba visited at the start of the session. That along with a more interesting field makes this a nice addition to the Astronomical League’s Carbon Star observing program.

Observing carbon stars for the suburban astronomer requires a little patience and modest equipment to work with their faint luminosity and distinctive color which can be obscured by light pollution or a sky lacking good transparency. Nevertheless, the pursuit of these celestial furnaces nearing their end of life certainly can be a rewarding endeavor and a pleasant evening’s celestial pursuit.

Eclipse Cloudout

A couple of weeks ago, the Moon’s orbit carried it into the Earth’s shadow during the early morning hours of March 14th. This eclipse was ideally positioned for those of us in the United States, so I was excited and hopeful to have a chance to witness it and capture some beautiful shots during totality.

I started monitoring the weather forecast in earnest on Thursday morning. The sources didn’t agree much. Underground Weather and WeatherBug predicted a significant cloud deck, whereas Astropheric and Clear Outside were far more optimistic. It seemed like an offshore system might creep westward and potentially cloud us out. The pattern suggested it might be advantageous to try and outrun the clouds by heading to western Maryland or West Virginia. However, since that wasn’t a sure thing, I opted for the comfort and convenience of watching from my backyard.

I downloaded and set up the Lunar Eclipse Timer and Camera Controller (LETnC) application the day before. I had used the solar eclipse counterpart to this software during last year’s Total Solar Eclipse, so I was hoping to leverage it for this lunar eclipse. I ensured that both my Canon Mark II and Canon t6i had charged batteries. The former would provide nice views of the full Moon through the 80mm Vixen telescope, while the latter could be used for a variety of shots with the 300mm telephoto lens.

Around 9 PM, I brought the equipment out from the garage, aligned the mount, and balanced the Vixen on it. The iPolar was acting a bit quirky, so it took longer than expected—I even rebooted and reinstalled the software to no avail. Fortunately, there was plenty of time before the eclipse would start, and the rough alignment provided by the glitchy iPolar would suffice.

As we approached the point where the Earth’s penumbra began to creep onto the disk, I took a shot of Luna in her pre-eclipsed state. I noticed some very high, thin clouds creating a slight glow around the Moon, but through the telescope, their impact was negligible. Although chilly, the seeing seemed fairly good—around 5/10, with transparency at about 6/10.

Uneclipsed Moon

Slightly before midnight, the Earth’s outer shadow touched the Moon. However, as usual, the effect was too subtle to see. Only when we got within about 15 minutes of the first contact with the darker umbra could one begin to appreciate a darkening on the Moon’s limb. By C1 at 1:09 AM, the clouds were slowly thickening, but not enough to seriously impact the spectacle or my photography.

A few minutes after C1

Over the next hour, I continued to document the encroaching shadow, re-centering the Moon in the Vixen and hopping over to the telephoto setup to reel off a few bracketed shots. Unfortunately, the cloud cover seemed to be matching the depth of the eclipse, gradually but inexorably thickening as the minutes ticked down towards totality. I had to edit the LETnC script to make the exposures a little longer, and it became clear it would be a race to see if the clouds would win out and block totality. A look at the satellite infrared image was not at all promising, with offshore clouds pushing into our area.

About 30 minutes before totality

By a little after 2 AM, it was clear that the weather had won this round. As the Moon was further engulfed in shadow, it was first lost from eyesight, and then even the telescope's light-gathering advantage was overwhelmed in my effort to continue photographing the eclipse. When C2 arrived a little before 2:30 AM, there was nothing to see, and the hope of witnessing the beautiful coppery orb floating in the spring sky slipped away along with the Moon.

I retreated inside to rest a bit and set an alarm for 3 AM, just in case the clouds relented. But when I checked the window, there was still no hint of the Moon in the sky, so I turned in for the night. Interestingly, some other members of HAL went out to Alpha Ridge to view the eclipse, and their skies held clear enough up until totality to capture some nice images. And so it goes in this often-frustrating hobby that depends so heavily on having a clear sky above!

Leveraging Starlight for Sharpening Planets

The field of digital planetary imaging is where art meets science, particularly in post-processing. After using our preferred tools to distill a video of several thousand frames into a stacked and aligned image, there is still much work to do. We need to refine it into a sharpened view of the target before applying some tweaks in a program like Photoshop. To achieve that sharpened image, we have two techniques at our disposal: wavelet sharpening and deconvolution.

Wavelet sharpening is a key feature of the freeware application Registax6, a staple of planetary imagers for many years. The author of the software, Cor Berrevoets, has not issued an update to the venerable program since 2011. He has, however, created a successor in the form of another freeware application called waveSharp. Both of these tools decompose the selected image into layers - from large-scale components of the image to fine scale. By adjusting the sliders, you can selectively enhance these aspects of your image. The finer scale adjustments must be done with a light touch to avoid introducing significant noise to the final result. Fortunately, one can combat the noise by suppressing the finer scale adjustment.

The ability to apply deconvolution is appearing in more tools for the planetary imager. One excellent new addition is the Lucky Stack Worker (LSW) freeware application (a video by the author, Wilco Kasteleijn, is on the ALPO channel). Another is AstroSurface, an application with extensive filters and functions for not only the planetary imager but the deep sky enthusiast as well.

So, what is deconvolution? In brief, it is using a contemporary representation of an Airy disk to help recover detail lost through atmospheric turbulence, soft focus, or optical issues. Under perfect conditions, when examining a moderately bright star, you would expect to see a small disk with diffraction rings emanating from it, known as its Point Spread Function (PSF). The interface on the LSW has two checkboxes - one for "Deconvolve" and one for "Sharpen" (i.e., wavelet sharpening). If we select the Deconvolve and select the "bullseye" adjacent to it, we see that LSW is offering us a synthetic PSF with sliders to allow us to adjust it.

Impacts when adjusting the Seeing Index slider

You could take a few minutes before or after your imaging run to inspect a nearby star and make a note of its Airy disk appearance to emulate it in the synthetic version. But why not record an image to capture the PSF for that particular imaging session? This is exactly the sort of thing that Wilco Kasteleijn advocates in the LSW manual and references a nice article by Marco Lorenzi on how to do this.

A couple of nights ago, Astropheric was displaying that the seeing would be "average" with temperatures in the 40s, so it was an opportunity to try this technique and maybe gain some experience acquiring a PSF image to leverage in my processing. Like a deep sky flat frame, the PSF image should be taken with the same imaging setup and without pointing the telescope too far from the target.

My first attempt using a star near Jupiter did not yield results, as it ended up being too faint and requiring a longer exposure. That, in turn, blurred the Airy disk by its scintillation. For Mars, I targeted a brighter star and had more success with a frames-per-second rate nearing 100. Even so, it is challenging to get it right; in retrospect, I should have lowered the gain further to avoid "blowing out" the Airy disk.

The PSF image taken during the imaging run

So, here are the results! Even with only a fair PSF image processed by Autostakkert, the LSW did a nice job of recovering the details from what turned out to be sub-par seeing. Applying sharpening and denoising to the image resulted in a reasonable, if not admirable, image showing albedo features, the polar cap, and likely cloud features.

To me, this technique of capturing a PSF image as part of the Lucky Imaging session holds great promise. As a final note, here is a Copilot-assisted comparison of how these two techniques help us achieve fantastic planetary images.

Chasing Planets: January's Observations and Challenges

The media has been hawking the auspicious "planetary parade" that allows an observer to see 6 planets during frosty January evenings. Of course two of those (Uranus and Neptune) are not naked eye objects. I do not mind articles that generate interest in our hobby, but my fear is always the "over promising and under deliver" risk.

However, January was indeed a fun month for us planet observers. Mars was occulted by the nearly Full Moon on the evening of the 13^th, and then two days later came to opposition for this apparition. Jupiter was positioned well and decided to throw a major eruption amid its North Tropical Zone southern jet stream on January 10^th, garnering a lot of attention. Venus also ascended the Zodiac after lying close to the southwestern horizon most of its current evening apparition, reaching greatest elongation on the 10^th heading for its highest altitude in the western sky on February 2^nd. The only downside has been the weather with classic winter turbulent seeing amid very cold temps.

Mars Occultation

The skies were clear but quite cold for the occultation of Mars. I set up the 10" Cyrus telescope and verified its collimation. The Moon served as a convenient focus target as I set up about 20 minutes before the scheduled disappearance. I knew that the difference in brightness would be a challenge and thought I'd have time to fiddle with the gain setting right before the occultation, but it happened so fast that I really did not get a great capture with the Moon very overexposed. Still, it was a very cool event to watch the Moon relentlessly approach the red orb and cover it up with about 30 seconds.

The Moon ready to cover Mars

January 17th Session

The evening of the 17th was predicted to have average seeing and temperature right around the freezing mark, which is fairly good for this region in winter. I again set the Cyrus scope out early to cool and verified its collimation. As Venus emerged from encroaching twilight I set to work on capturing our sister planet. 

Starting with the Deep Red filter (642+nm) and no Barlow, Venus provided a bright target upon which to focus. Doing a 5 minute capture resulted in a nice image, showing the planet past dichotomy and a common cue-ball appearance. I have yet to truly discern any cloud details in IR light.

Swapping out the Deep Red filter for an IR-block and UV set, I retargeted the planet and adjusted the settings to bring up the brightness in the fainter UV light. I could make out even on the on-screen image that there was uneven brightness in the sunlight reflecting off the Venusian cloud tops.

Processing produced a nice greyscale image with a some cloud structure. Interestingly, a well defined cusp cap was not really seen, although you might argue one was around the south pole region. This is somewhat in agreement with the UV Venus images I have been seeing submitted to the ALPO for the current evening apparition; cusp caps are not as prominent as I believe they were during the last apparition.

By now Saturn was visible in the deepening twilight, close and to the left of Venus. I figured why not give it one last capture since the upcoming mid-March solar conjunction and my obstructed western horizon meant it would soon be inaccessible. I added the Barlow back into the imaging path and returned to the Deep Red filter. Seeing was not very good, and the rings had closed up again compared to a few months ago. I had enough juice in the laptop for two 2-minute captures, resulting in a sub-par image where it is hard to even detect the globe's shadow being cast against the rings. Au revoir Saturn - until we meet again in the late spring!

Getting the AC adapter hooked up to the laptop I next swung over to Jupiter. My hopes were to get multiple captures into the evening if the weather held, recording not only the very recent North Tropical Zone southern jet stream eruption but also that continually expanding disturbance in the South Equatorial Belt that started back in November.

The seeing ended up being fairly good over the course of about 5 hours, allowing me to capture a lot of interesting features, including that NTrZ outbreak. As we began to close in on midnight the gods conspired to end my run as the cirrus clouds began to thicken and the tracking on the Celestron mount suddenly had a stall (it is always amazing how quickly the planet exits the frame when this happens). Rather than fight to recenter and continue amid the deteriorating seeing and transparency I decided to wrap things up on Jupiter.

In the middle of my Jupiter captures I had to take a break due to the location of the planet. When an object is high and near the meridian, the Cyrus telescope tube runs up against one of the tripod legs. The resolution would be to raise the tube up off the saddle, somewhat like extending with a pier. But that would be a lot of effort and so is not likely to happen in the near future (if at all). 

But rather than waste the time I opted to do a run on Mars which had just passed opposition a few days earlier. While at only about 13" in size the disk was large enough to take in some nice albedo features such as Syrtis Major setting and Sinus Sabaeus and Sinus Meridiani on the central meridian. The NPC was also a brilliant white and was a good feature to leverage in trying to get the best possible focus. Hopefully I will get in a few more sessions with Mars for this apparition, but it's going to shrink in size quickly now that it is past opposition.

While I did not achieve all my goals for the evening (I missed seeing the SEB disturbance on Jupiter), it was quite a good night for the middle of January. It reflects why planetary observing provides such a rich experience for the amateur astronomer.