M101 LRGB

[discardedastro]

Not that much light (recurring theme - I do need to pick a good target and focus on it for maybe 10, 20 hours) but this turned out alright. Light from two nights in August and September. M101 (Pinwheel Galaxy).

48x300s subs total, of which about 15 Lum. Baader filters, 200PDS, EQ6-R Pro, PHD2 guiding on a Primalucelab 60mm guidescope. ASI183MM-PRO imager, ASI120MC guider.

Processing my usual DSO routine in PixInsight; stacked with local normalization, cropped, DBE'd, deconvolved with dynamicPSF+mask, combined RGB, ABE, background neutralization, SCNR, photometric colour cal, MLT denoise, histogram transform, LRGB combination, final curves+a bit of saturation before TGVdenoise.

[ollypenrice]

That's very good if a bit short on colour. I know what I'd do in Photoshop though not in Pixinsight - but I bet you have more colour in there.

Olly

[discardedastro]

3 hours ago, ollypenrice said:

That's very good if a bit short on colour. I know what I'd do in Photoshop though not in Pixinsight - but I bet you have more colour in there.

Olly

I do, but I always feel a bit wary of oversaturating the image - it's a bit hard to judge the balance through LRGBCombination, though. I used a slightly nonlinear saturation curve to avoid over-exaggerating the reds too much. I'll maybe have another play with the combination of L and RGB tomorrow. I also don't have a colour-calibrated monitor, so a bit wary of what I see sometimes; when I replace this desktop I'm also planning to upgrade the monitor and get a calibration device.

Very happy with the sharpness of the image, though, which has been an ongoing challenge for me. Guiding is working well and producing sub-arcsecond results - I think the only thing I can do to improve on that is going to be an improved guide camera and OAG (though my very-very-rigid guidescope mount doesn't seem to be suffering from any differential flexure - they're solid milled blocks of alu which are friction-fit onto the guidescope and bolted onto an ADM dovetail setup). Then a better mount, of course!

The deconvolution for this was 50 rounds w/ 3 wavelet layers, and I might be able to improve on the result - I didn't use local support as I did all of the processing of this image from raw frames to finished photo on two fairly short coach journeys, and I didn't have time for it. I did do a 200-star DynamicPSF round to get as good a PSF as I could, and did mask the processing for all lights to avoid artefacts in dark areas.

Edit: I just tweaked the JPEG, in lieu of having the real data to hand (it's on my laptop and I've had too much gin to muck about getting that going):

Edited September 3, 2019 by discardedastro

[ollypenrice]

The colour's there all right. Maybe just a bit on the green-cyan side now. A small swing towards the magenta ought to do it.

Olly

[Dragon_Astro]

Very nice with the colour boosted a bit 👍🏻

Gin huh? Which one are you drinking? 😁

[peter shah]

super image scale with lovely detail

[discardedastro]

1 hour ago, Dragon_Astro said:

Very nice with the colour boosted a bit 👍🏻

Gin huh? Which one are you drinking? 😁

Tanqueray tonight. It's the only way to cope with the politics.

Definitely going to have another crack at this target and get some more data, I think. When clouds permit...