Although probably not the most mature decision, I couldn’t let the serendipitous alignment of crystal clear skies, cool weather, a new moon, and a weekend pass without maximizing the exploitation of said gooderies. I drove back to Huntsville last night and imaged the Cygnus region again. Specifically, it was NGC 7000, the North American Nebula and it was all wide-field. I had this grand plan to reconfigure the CCD with a directly attached plate to mount it with my fastest lens, the EF 85mm f/1.2L, and bin the narrowband exposures for some crazy signal to noise ratios. However, I had conveniently forgotten that the 85L focuser required power and could not be manually focused. Fortunately, I brought a back-up lens and albeit less sharp, the EF 70-200mm f/2.8L IS on the wide end was close to my desired field of view. I started out with a 2×2 binned Hydrogen Alpha, Sulfur II, and Oxygen III run and switched to a non-binned Luminance run after the meridian transit without consideration for the added difficulty of integration or the lack of need for Lum data when integrating NB. This is how we learn. Anyhoo, I didn’t get home until 6am and only got a couple of hours of sleep before I needed to be up and functional. It took some doing, but I managed to pull together a “first pass” at this data. I need to digest a little tribal knowledge before making another attempt. This is a lot more complex than I anticipated.
Monthly Archives: September 2015
Layering new with old…
I’m on the fence about heading back out tonight for some wide-field imaging. I have this idea about going deep RGB on NGC7000, but not shooting full spectrum red at all. Shoot Ha for the red channel and standard green/blue all binned 2×2 and then shoot a luminance set binned 1×1 and see how that turns out. I think I could pull it off in one night because of the lens speed, but it’s a big effort to pack up and drive an hour+ each way a second night in a row.
Disappointed that I didn’t capture what I set out to last night, I was cold and done with time to wait while another imager was finishing his run of 15 minute subs, so I set up a short series of 5 minute luminance subs while we waited for our window to tear down. I registered those this morning and manually integrated them, then took an already integrated OSC data set from October of 2014 that I shot with a stock DSLR and converted both from linear to non-linear and did a simple LRGB combination folding the new lum data into the old color data. I didn’t do a color calibration or anything, so I’m certain there are far better ways to do this… I was just messing around and didn’t want to waste the data. It didn’t turn out half bad! Once I develop my post-processing Fu some more, I would like to have a catalog of “good” data that I can keep adding to over time.
Proficiency comes with regular practice…
It was a beautiful night last night. The sky was clear and dark (moon at 2%). Due to some power problems at Tranquility Base, Dave and I had to divert to the observatory in Huntsville. By the time we arrived, it was dark, so it was good to practice assembling my entire imaging rig almost entirely by touch. I had a little issue with balance due to using my older side-by-side saddle because I wanted the faster f/4 focal ratio of my camera lens versus my f/7 refracting telescope. The configuration is a little wonky and whether it works well or not depends greatly on where the target is in the sky relative to the meridian. This also impacts my star alignment routine because in order to get the parallel imaging element and guide element pointed the right way using the saddle, I have to rotate the equatorial mount head 90 degrees on the declination axis. I can’t prove this should cause an issue, but it seems to always give me trouble – so maybe it’s just me. The result is longer/multiple alignment passes and often missing targets on the slew stop. This happened last night. I was trying to locate NGC 6888 for my first bi-color narrow-band attempt. Cygnus was high in the sky and I felt really excited about having a solid imaging run ahead. The only problem was – I never found the target. After several hours of tinkering, I decided to just image where I was at and try another night for the Crescent. It wasn’t until I plate solved the result that I found I was somewhere very near IC 1318, the diffuse emission nebula surrounding Sadr (or Gamma Cygni). I was close, but the temperature was quite surprisingly dropping and I wanted at least something to practice with in post. I love being barefoot. Somehow I must have subliminally “forgotten” my shoes when I left the house and I also just-so-happened to be in my usual uniform of shorts and tee-shirt. When the temp bottomed out at 59 Fahrenheit, it was time to pack up and head home.