We have quite a few things to talk about here. First, this is a repeat of the last object I posted: the Fireworks Galaxy. The reason I'm creating a separate post for it is because THIS image is with totally new data from a totally new location: I moved my entire imaging rig to Deep Sky West out in New Mexico about a week ago, and this image was created using all my same equipment from VA, just installed at DSW. It's intended as a crude compare-contrast test between what I was able to get under my red zone suburban skies outside Richmond, VA to what I can now get under the seriously-couldn't-see-my-hand-in-front-of-my-face-it's-so-dark skies in Middle of Nowhere, More Mountain Lions Than People, New Mexico. It's a completely different experience. Here's what I learned/some observations:
- Did I mention it's dark out there? This means re-thinking exposure times and integration times. To give you an example, a 1 minute Luminance exposure at gain 100 in VA registers about 2,000 ADU according to SGP. At DSW under a similar moon? Maybe 580 - 590. I still need to play around with exposure times to see what the new optimal is. I also need to see if I can get away with less integration time, which I imagine I can: this image has about half the integration time as the last Fireworks from my former location, and is far more detailed and less noisy.
- The data is clean clean clean. Way less light pollution means way less noise which means less background extraction (if at all) and way more signal. I know this is the no-duh point of imaging from a dark location but I really wasn't quite prepared for just how big of a difference it would be. Aside from MureDenoise on the LRGB masters, which I do just as a matter of course, I did zero noise reduction on this image in Pixinsight, Lightroom, Photoshop, or otherwise. I still need to learn the implications of this level of cleanliness: it likely means I can stretch it further to bring out more detail, etc... it's going to take some practice. I have a lot to learn in terms of processing data like this.
- Seeing matters more. When I had lots of light pollution to contend with, I had to fight to just be able to reveal any detail. With that eliminated, the major rate limiting factor is seeing: I imagine if I am going after something small and detailed, like a galaxy, I'll need to be ruthless with only choosing subs where the seeing was good. In the subs for this image, I can tell a major difference between those with better seeing. I averaged them all together anyway for this image, because the point of this image wasn't detail, just proof of concept.
- As a side note, I have learned that my mount (a Paramount MX+) doesn't need good polar alignment or even anything close to it to be able to image well. I got installed out there when it was cloudy, and had to leave back to VA before I could get properly polar aligned: we just kinda eyeballed it based on where all the other mounts were pointing in the building. I had a couple of clear nights before the DSW folks could make it out there to get me actually polar aligned, so I figured what the hell let's see what we can do. So I built a 115 point model and learned I was 88 minutes off in azimuth and 9 in altitude. I figured I was toast, but just out of morbid curiosity I turned on Protrack and started guiding and was nothing less than SHOCKED to see my guiding just bumping along at 0.45" total RMS, like it was no big deal: I got a whole night of imaging done like that! All the luminance for this image, in fact. And to think, all that time I used to obsess over *perfect* polar alignment....not saying I won't be as meticulous in the future, just that I had NO idea this was even possible. Learn something new every day, I suppose.
Anyway! I have a ton more to learn how to image under these skies, and then process this data: it's so different than what I'm used to. But wanted to at least share my experience: as always, I welcome all commentary.
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