As noted elsewhere, I’m in the early stages of trying to make the transition from what has mostly been “electronically assisted astronomy” to producing some nice images. So I present last night’s effort here for input, with particular regard to acquisition technique.
Shot from by backyard, Bortle 7 or 8.
Roughly 14 hours total acquisition time over two nights. I threw out the first and last 1.5 hour from each night because of high background illumination close to the horizon
Individual exposures were 40 or 60 seconds, which kept the histogram peak distribution curve well separated from baseline but less than ÂĽ from the far left of the histogram. The little bump at 64,000 for saturated stars was minimal
Carbon fiber C8 with the Starizona 0.63c reducer/coma corrector - I am usually resistant to removing the reducer because of coma and because it is a big hassle to find focus again when the reducer has been removed/reinstalled
ASI1600 camera binned 2Ă—2. Per the usual online tools this gives me 1.22 arcsec per pixel
I set the gain up pretty high (249 out of a possible 300) to suppress the dynamic range, which I figured I’d just end up doing during processing anyway due to the bright galactic core issue
Guiding was fine. I use a Celestron OAG modified to accept an ASI432 guide camera. The guide camera was not binned due to its large pixels. As seeing was quite good guiding averaged 0.4 arcsec
Minimal processing in Astro Pixel Processor.
My take:
Signal to noise is not great given the amount of acquisition time
Stars are a little ragged, probably due in part to my use of the Celestron dew heater ring which heats the objective directly. But its really hard to control dew in Florida using a heated dew shield only, so maybe I am stuck with this
There was aslo a small amount of dew on the objective for part of one night and I’m not sure I’ve eliminated all those subs
In spite of the calculated 1.22 arcsec pixel scale, the FITS (not shown) looks a little pixelated
Had a pretty tough time working out the background gradients while processing, in spite of having used a full set of calibration frames
Raw stacked image and lightly processed version below.
đź“· image.png
đź“· M_63-session_1_session_2-crop-lpc-cbg-csc-vc-St.jpg
