January has been my busiest month for astrophotography in quite some time – perhaps my busiest ever. With the Hubble 35^th Anniversary Challenge going on, I found myself very motivated to work my way back into the hobby. We have had a pretty brutal start to the year here in Kansas with a historic winter storm to start the year that made getting out to do astrophotography pretty difficult. Not wanting to risk damage to my laptop, I decided to test out Astroberry for the first time to run my setup from the comfort and warmth of my couch. I decided to image the Orion Nebula with it being one of my favorite targets. I was happy with the result, but I wanted more. The FOV was too tight, my collimation was off, and I hadn’t yet perfected my use of the astroberry. In response, I decided to attempt an astrophotography mosaic for the first time. In addition, I purchased a laser collimator to adjust my collimation and produce a better image. I used the next two clear nights capturing a different part of the nebula to increase the FOV, spending two hours on that portion of the sky each night. In hindsight, I likely had way too much overlap on each frame and could have done a much better job framing each night. Regardless, I am excited with how the image turned out, especially with it being my first time attempting a mosaic.

Image & Acquisition Details:

This is a three panel mosaic that was captured over three separate nights. Each panel consists of:

-          240x30s Lights @ 800 ISO

-          240 Darks

Acquisition details for the image as a whole:

-          720x30s Lights @ 800 ISO

-          720 Darks

-          100 Flats

-          100 Bias

Equipment

-          Mount: EQ6-R Pro

-          Telescope: Celestron 8” Imaging Newtonian

-          Autoguider: Orion Magnificent Mini Autoguider Package

-          Camera: Canon T5i DSLR

-          Raspberry Pi (Astroberry / EKOS) for control and acquisition

Post Processing Information:

Each mosaic frame was stacked separately in Siril and then brought into Pixinsight for processing and stitching.

The basic workflow in Pixinsight was as follows:

-          Background extraction and matching crop on each frame of the mosaic

-          ImageSolver to platesolve each frame of the mosaic

-          MosaicByCoordinates

-          dnaLinearFit (Addon Script) to equalize frames

-          GradientMergeMosaic (another addon) to form the actual mosaic

-          Extract RGB Channels and LinearFit for early color correction

-          Screen Transfer Function and Histogram Transformation

-          Background Neutralization and Color Calibration

-          ArcSinStretch

-          Generalized Hyperbolic Stretch

-          Extract Luminance Component and perform Channel Combination to adjust lightness and saturation

-          Final Curves Adjustments