Evolution

I'm waiting for the next new moon. There isn't much to do aside from looking at the smoke plumes and wondering when they will go away. (September? October? November??)  A diversion is needed, so here it is....

Remember Ed Ting? Of course you do. Here's a video of his from this month; I've cued it up at the salient point for my post today but I think you'll enjoy by watching the entire video. (In the video Mr. Ting is giving his thoughts on what current astronomy opinion is or is not an overreaction.)

His mention of reprocessing some of his old data and seeing how much better it looks now inspired me to reprocess some of my own.

I'll start with an image from 2016 of the M81 / M82 field. The data for this was collected using a TV-102  telescope (focal length about 700 mm and f/6.9) and modified Canon 550d with a peak quantum efficiency of about 40%.   I collected 44 light frames of 3 minutes each,  15 dark frames, and no flats. Evidently ten years ago I didn't appreciate the importance of flat frames. Ten years ago I thought it was a nice image, so I posted it at AstroBin.

The 2016 processing used (the now gone) ImagesPlus and Photoshop with a couple of add-ons that existed back then; in 2026 the reprocess is all in PixInsight + a few addons including most notably the Xterminator triplets. 

I've placed the images in this post consecutively so that you can open one and then use your left/right cursor buttons to toggle back and forth between old and new. The images have been cropped to and scaled to match each other fairly well. You can click any image to expand it to its unscaled resolution.

2016 Processing

2026 Processing

The first thing that hits me is how much better my modern color calibration is. In 2016 the image is plagued with an overall green hue and the background leans dark blue.

The 2016 image is full of walking noise, which is probably why I clipped the background. The 2026 version handles it better. Ideally I'd be dithering, but that was something I was still learning how to do back then.

For structure, let's look at the galaxies.

M81 - 2016 Processing

M81 - 2026 processing

M82 - 2016 Processing

M82 - 2026 Processing

M81 is substantially improved, both in terms of color and dynamic range. 

If you look closely, you can see the small dwarf galaxy Holmberg IX, at top center of the M81 frames. In the new processing you can see its two dark lanes and evidence of granularity. The dark lanes are barely there in the old image.

The improvement is more dramatic for M82, where some structure is visible for the hydrogen streamers now. 

I'm actually impressed with the data -- it wasn't half bad. In 2016 I was imaging on an original version CGEM and doing all the focusing manually.  With a DSLR I was weaving blocks of dark frames between bigger blocks of lights in order to better match temperatures; set point temperatures were for my CCD camera. And guiding used an old Orion guide camera. Today I can't even give that camera away! 

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So, the smoke is still going strong and new moon is only 11 days away. Oh well....