M109 Barred Spiral Galaxy / 67.2 ± 23 million light years in Ursa Major

Description: M109 (or NGC 3992) is a beautiful barred spiral galaxy in Ursa Major one interesting feature of which is its ring structure. By integrating 298x300s subs for a total exposure of 24.8 hours I was able to obtain a reasonably well-defined ring structure.

 

Date / Location: 24, 26-28 February 2023; 1, 4-6 March 2023 / Washington D.C.

 

Equipment:

 

Scope: WO Zenith Star 81mm f/6.9 with WO 6AIII Flattener/Focal Reducer x0.8

 

OSC Camera: ZWO ASI 2600 MC Pro at 100 Gain and 50 Offset

 

Mount: iOptron GEM28-EC

 

Guider: ZWO Off-Axis Guider

 

Guide Camera: ZWO ASI 174mm mini

 

Focuser: ZWO EAF

 

Light Pollution Filter: Chroma LoGlow Broadband

 

Processing Software: Pixinsight

 

Processing Steps:

 

Preprocessing: I preprocessed 298x300s subs (= 24.8 hours) in Pixinsight to get an integrated image using the following processes: Image Calibration > Cosmetic Correction > Subframe Selector > Debayer > Select Reference Star and Star Align > Image Integration.

 

Linear Postprocessing: Dynamic Background Extractor (both subtraction to remove light pollution gradients and division for flat field corrections) > Background Neutralization > Color Calibration > Noise Xterminator.

 

Nonlinear Postprocessing: Histogram Transformation > Local Histogram Equalization > Curves Transformation.

 

I also inserted, as needed, additional Noise Xterminator steps as well as an SCNR Noise Reduction step in postprocessing.

Done