NGC4731

NGC4731 is a very distorted galaxy in the Virgo constellation, about 65 million light years from us.

It was a struggle to get this image. I expected to acquire 32 subframes over a six-hour period each night, but clouds and an error consipired against that. Here's a summary of the four nights:

April 13: 3 subs (clouds)
April 14: 13 subs (too few subs specified, so lost 4 hours when plan ended early – oops!)
April 15: 12 subs (clouds)
April 16: 26 subs (got 32, but lost 6 due to sky glow from returning Moon)

Exposure	• 9 hours (54 X 10 minutes @ -20°C • Dusk flats • Camera position angle: 0°
Processing	• With PixInsight: ☞ Calibrate, star-align, and integrate subframes ☞ Crop to eliminate extraneous surrounding area ☞ Background neutralization ☞ Histogram transformation ☞ Curve transformation • Noise reduction with Topaz DeNoise AI • Final tweaking and sizing in Photoshop CS6
Date and Location	• 2021: April 13, 14, 15 & 16 • Louisa County, Virginia, USA
Equipment	• TMB-130SS APO refractor @ f/7 on an A-P 1200 mount • ZWO ASI-1600MC Pro color camera • Guided with an ST-402 camera on a 60mm f/5 scope • Imaging and autoguiding with MaxIm DL 6.20 • Automated image acquisition with ACP Observatory Control

Updated May 23, 2023