NGC 4565 – Needle Galaxy

Acquisition Date: February 10, 2019

I wanted to do more color with my monochrome camera but the number of steps involved with capturing calibration frames and light frames using four different filters was overwhelming to accomplish manually in a single evening. For a while I thought I would simply spread imaging over four nights: one night for luminance, the second for red, etc. But then I realized that clear nights are hard to come by. Sometimes it takes well over a month to accumulate four nights. So that’s when I decided that I needed to come up with an automated solution to get an entire LRGB sequence in one night.

I took a three month rest from imaging while I developed a “Flip-Flat” work-alike since I couldn’t get myself to part with the $500 cost for the original. I ended up spending more on development but the experience was worth it. I call mine The Flatinator. I will write more about it later.

Ordinarily I use SharpCap software for image acquisition but in this instance I chose INDI/Ekos due to its advanced automation. The next version of SharpCap promises better features.

Technical Details:

William Optics 71mm f/5.9
Altair 290M camera (uncooled)
Optolong LRGB Filters
Unitron Model 142 GEM
The Flatinator
Passive tracking with PEC
No active guiding

Gain 200 (1.74 e-/ADU, FWD: 7100e-, Read Noise: 1.55e-)
Offset: 25 ADU
Exposure: Multiple
Camera rotation: 5 deg E of N

Luminance: 72x 25s
Red: 30x 30s
Green: 30x 30s
Blue: 25x 36s

Flats: 100x per channel
Darks: 20x per channel
Bias: 100x all channels

Total integration time: 74 minutes
Total time at telescope: 122 minutes

SharpCap 3.1.5219 for Polar Alignment and Periodic Error Correction
INDI/Ekos for Image Acquisition
APP 1.071 for Stacking and Image Processing