Circumventing an Obstacle

Roughly 18 months ago I pulled the trigger on a PoleMaster for my Atlas mount. If you're unfamiliar with the instrument, it's a digital camera that attaches to the front of your mount so that it is aligned with the RA axis. Then with accompanying software you can perfect your alignment to achieve the best possible tracking from your system. While there are other gadgets and techniques that are useful to get a good polar alignment I found this system to be a solid, workable approach for me.

My Orion Atlas mount has been a good work horse for well over two decades in my observing. It was my first "real" mount that could adequately track the sky, opening up not only a more pleasant observing experience but also planetary "lucky imaging" with my 6" reflector and then deep space targets when I acquired my Vixen 80mm scope. It was portable enough to fit in the back of my Rogue, traveling with me to nearby Alpha Ridge or out to Wyoming as part of my Great American Eclipse road trip. The power source was never a worry - a simple battery pack of 4 D cell batteries that seemed to last forever (and easily acquired at the corner drug store if they were to give out.)

The "Leo Triplet" taken with Vixen 80mm & Atlas mount

But even with the PoleMaster, the tracking was not accurate enough to allow for exposures beyond 20 seconds, causing me to resort to a very large number of short subs in order to arrive at a respectable image. Another shortcoming is the weight bearing capacity of the Atlas - there is no way it would be able to support my 10" reflector that I am hoping to complete refurbishing this year. After taking several months to research various mounts on the market that would work within my budget I finally took the plunge and invested in a Celestron CGX-L mount which arrived in September.

In the almost six months since acquiring the CGX-L I have had it out perhaps a dozen times. The first couple were to simply get acquainted with the unit (I am glad no one witnessed my first night when it took me over 40 minutes to realize that there was an "on" switch that had to be toggled - I had just assumed that when I plugged in the battery that it was ready to go like my Atlas!) With it powered up I followed the instructions on how to perform a two-star alignment with an optional 4 additional stars. Once that was done the computer assisted tracking worked surprisingly well. And, truth be told, that "goto" functionality really makes me feel like I'm cheating after a lifetime of star hoping. 

Polar alignment, however, is back to roughly eyeballing the RA axis in the direction of Polaris. According to the manual one also can precisely align to NCP following the star alignment process by entering the "align mount" routine. In theory, you center a star in your eyepiece and then the computer moves the scope to where the star should be if you were properly centered on the pole. Your task is then to use the mount's azimuth and altitude controls to center the star and thereby refine your polar alignment.

I will confess that I have yet to try this routine. I could not help but want to use the PoleMaster which worked so well. But, alas, the design of the CGX-L has a handle bar directly in front of the RA axis of the mount. It seemed that I would not be able to have my cake and eat it too - those handles are indispensable for positioning the heavy mount head onto its tripod. 

Thinking I was likely not the first CGX-L owner to feel frustrated by this obstacle I spent time searching online for solutions that others may have come up with to use their PoleMaster. And, as so often happens, the Internet did not disappoint. On Cloudy Nights there was a reference to a guy who designed a literal workaround; a 3-D printed component that attaches to the face plate with a detachable U shaped bracket to hold the PoleMaster camera. Genius! Brilliant! And the best part was that he was selling them on eBay with about a week's turn around time. The credit card came out within sixty seconds of watching the video demo of it. 

Last month I finally got the chance to install the adapter and try it out. The Celestron mounting plate was readily removed and replaced by the custom printed plate. The U bracket's holes aligned beautifully with the PoleMaster camera so that I could transfer it from the Atlas adapter to the 3-D one. And to make attaching the U bracket to the face plate foolproof the creator provided two guide pins that snap into place thanks to a couple of strong molybdenum magnets. (It brought back memories of my dentistry days, fabricating dentures that seated and held fast with the use of such magnets - but that's a story for a different blog 😉). The video below shows the component and how easy it is to use. Problem solved!

I have a feeling that this recent experience reflects yet another paradigm shift for amateur astronomy. While 3-D technology has been around for a while it is clearly becoming more mainstream and allowing imaginative engineers to bring their designs to rapid prototype and market. We recently had a discussion on HAL's email group regarding this very topic, and several folks chimed in about how they were using parts/accessories created in this fashion. In the "good old days" this was the realm of the machinist who had access to a shop where equipment could turn out custom parts. What we may lose in the durability of a machined part is going to be offset by the accessibility to many more people with innovative approaches to solving problems and creating new tools for our astronomical community. I can hardly wait to see what comes next!