'Single' Frame Challenge - M31 HaRGB

[signal storm]

This is an update of a recent 'single frame challenge' image. After taking a single 5-min exposure of the Andromeda Galaxy, I thought it really needed some extra pop. So, I broke my own rules and took another single frame with a dual-band filter to add some of those hydrogen regions. So I suppose this is now a 'two' frame challenge.

Processing this one was tricky and I used some new methods in continuum subtraction and noise reduction to extract the very faint Ha signal from just one frame of exposure. I also did a quick process of the Oiii channel but there was really not enough signal to contribute to the image.

Anyway, I hope you enjoy this updated 'two frame' challenge image.

• IMX571 OSC
• HAE29
• 6" f4 Newtonian
• Antlia ALP-T

Total Integration - 1x5 min OSC + 1x10 min Ha
24 Dec 2024 (~B4)
20 Jan 2025 (~B3)

[heady quarry]

looks amazing

[vocal iris]

This is diabolical wtfff

[proper remnant]

Brother what

[jade ice]

Ah yes my anti beginner crushing technique

[proven mirage]

how do you possibly get this much detail with only five minutes of integration, on a six inch scope nonetheless?? What the hell man

Absolutely nuts

[signal storm]

When I just started astrophotography, I found that the small details matter. I'm trying to use this series to find out what I can achieve and how to improve. Here were some things I did specifically:

• Dark skies: I live in an apartment near Seattle and quickly realized that light pollution is challenging. This image was taken about 2.5hr drive away to darker skies (5hr round trip). It is a huge time commitment since I usually need to go to work the next day though, and sleeping in a car is cold and difficult.
• Choice of target: I choose the target specifically in its location in the sky. As high as possible, facing the least light polluted domes. The result is to optimize for sky darkness, and ensure any gradients are as wide-scale as possible. This means different targets for different seasons.
• Proper calibration frames: A lot of time was invested into proper bias and flat frames. I built a little jig to hold my modified flat panel (to make it as even as possible), taking a lot of frames and rotating it.
• Take advantage of your equipment: The IMX571 sensor is very good, I cool it as much as possible (at least -20C) where the dark current becomes extremely low.
• Avoid the moon: I try to only image when there is no moon in the sky just to optimize the data I get and make the most out of each session (since I do not have a backyard or permanent set up).

• Collimation: Since I drive out each time with a Newtonian, I end up spending a bunch of time collimating it before each session. Admittedly a lot of work to get it just right, but when the stars turn out good, it's worth it. I also ensure the equipment is cooled down properly (usually ~45min).
• Weather: I try to only image during nights which are excellent (since it is a big time commitment). I choose locations specifically to reduce fog, wind, car lights. This can be pretty challenging sometimes! I set up the equipment in a way to block the wind with my car whenever possible.
• Take advantage of modern processing tools: More of a learning experience for myself, I try to incorporate a new method of processing each time I work on an image. There are some really amazing tools today - Pixinsight, Russell's tools, GraXpert, and so forth.
• Learn: This is a learning process and I have learned much from the community here. There's always room for improvement so I appreciate any comments, critiques, feedback. Thank you.

Of course, all this is applicable to the normal longer-integration images as well!