I’m running a little (okay, a lot – over a month) behind on processing the images I captured from the front patio during a string of clear nights in early October 2023 before we departed for our trip to Los Alamos, New Mexico for the annular solar eclipse. I used Big Bertha, since she wasn’t going along on the eclipse trip and because I had finally correctly calculated the back focus needed for the field flattener to actually correct coma in the images, rather than exacerbate it! I wanted to give the correctly assembled ASI2400-BB-FF-LeX imaging train a test run…three nights in a row of clear skies gave me that chance!
IC1848 Soul Nebula – 4-tile mosaic
This was the first image captured after I finally figured out the proper back focus for the TS-RCFLAT2 field flattener! In almost two weeks of back and forth email with Marc Fischer from Teleskop Service, he kept telling me I needed 109mm of back focus for the FF to properly correct the coma. Further, he kept telling me the M54M-M48F 21L connector was 21mm of that distance. I was completely bewildered, because for over a week I was measuring the M54M-M48F 21L connector as 220mm (180mm if I deleted the length of the female threads). I couldn’t for the life of me figure out how I was going to get the proper back focus when the connector that came with the camera was already double what I needed. Saturday morning, after a good night’s sleep on Friday night, I found and read a great article by Agena Astro on back focus that talked about both the back focus of the telescope (the debacle with the extension tubes I’d just been through) and the back focus for optical accessories, like a field flattener. (That article is: A Primer on Back Focus in Astronomy at: https://agenaastro.com/articles/miscellaneous/a-primer-on-back-focus-in-astronomy). The light began to dawn! For over a week, I was doing the conversation from cm to mm wrong! Thinking the 109mm was 1.09cm or about half an inch, instead of the proper 10.9cm or about 3.5 inches! All I can say is that I’m simultaneously embarrassed (how many math classes have I taken throughout the course of my high school and college years?) and relieved. With this “new math” I had to add length to the equation, rather than subtracting! AND I had the 2” tubes in house (because Paul had mistakenly ordered me a 2” long, 2” diameter tube when we were searching for the BB extension tubes – I needed that, the M54M-M48F 21L and the M48F 16.5L connector that also came with the camera (the distance inside the camera to the sensor is 17.5mm) – so all that put together was 89.7mm. Darn near close enough to the needed 91.5mm to give it a try. What I saw in the first subframe (even in the focusing frames) was a beautifully coma-free star field from corner to corner of the image!
See the gallery entry for the fun facts, equipment and other capture details: https://beersastrophotography.com/gallery/ic1848-soul-nebula/
NGC6820 Vulpecula Nebula
This object is not officially named the Vulpecula Nebula – in all sources, it is simply NGC6820. But since it’s in Vulpecula, I decided it needed a name and in getting extremely creative, I chose Vulpecula Nebula ;-}. After processing it, I’m seeing all sorts of “things” in the image – reminiscent of the days when we were kids, laying on our backs, looking up at the clouds and naming what we saw. Can you see a pig’s face (snout and mouth), a puppy with big dark eyes, and a donkey? Perhaps it should be the Barnyard Nebula instead?? (I have NOT been drinking! Sleep deprived? Well, okay yes.)
See the gallery entry for the fun facts, equipment and other capture details: https://beersastrophotography.com/gallery/ngc6820-vulpecula-nebula/
NGC7822 Flaming Skull Nebula
You may be thinking “I’ve seen this before, recently, and it didn’t look at all like this.” If so, you are correct. I imaged this same object during our August trip to the public lands of the Comanche National Grasslands in Springfield, Colorado. That image was captured with the Southern Cross (600mm focal length), while this one was captured with Big Bertha (1600mm focal length). So, essentially this is the “close up” view, while August’s was the “wide field” view (at least with respect to my equipment – no comparison to Hubble or James Webb, please!). Also, August’s image was captured during my 2×2 binning experimentation phase – what turned out to be something that sounded good (capturing twice the data in half the time), but wasn’t!
Both images and the “rest of the story” with the target fun facts, equipment, capture, and processing notes is in the gallery at: https://beersastrophotography.com/gallery/ngc7822-flaming-skull-nebula/