AKB

Just this: background subtraction (DBE) colour correction noise reduction (TGV) arcsin / histogram / curve stretching

This is very good. The red/green spots are from hot pixels stacked in slightly different places after the stars have been aligned. Bias/darks may help and/or a more sophisticated stacking process (sigma clip, etc.) A quick look at your raw TIFF shows more there than you have shown – you have the 'Running Man' nicely too: Great stuff! My early ones (or even recent) are often not so good! Tony

Yes, indeed, the Baader UFC system should be able to do this. It has variable length components and different thread adaptors. Expensive, though! https://www.firstlightoptics.com/baader-filters/baader-ufc-universal-filter-changer-system.html

Nice images. How strange, I shot the same targets on Jan 5, but for a little longer (75 min on Flaming Star and 30 min on M33) although with a smaller and slower scope (120 APO, F8.) Both of them I traditionally find to be quite challenging in their own way, tending to look (at least my attempts) a bit messy. More time, and calibration with flats, will definitely improve your results even further. Tony

Nice data! I wonder if your latest isn't a bit too smooth? Using it as colour and a lightly processed version of your previously posted mono image for luminance, gives this result (albeit with the hot pixels inevitably returning.) Hope you don't mind me giving this a go (my own data gathering last night was a bit of a disaster!) Tony

Mesu e200? …Ah, unguided. Well, perhaps not.

Bit of old yoga mat stuck on with Velcro works well for me... Tony

The colour really adds a special quality to this image. Great shot!

Several threads on this recently… bigger cameras highlight the issue! Try this for a start – I’d always (usually!) believe the way @ollypenrice approaches things… In terms of actually correcting it, aside from an separate tilt adjuster, a very thin shim on the offending side, under the thread, should do it. You can buy such things, but the tag on this one, suggested by @gorann might be too large for a Hyperstar: HTH Tony

I have to say that this looks a bit like both tilt and wrong offset. What camera are you using (ie. what size frame) ? The filter, of course, does have an impact on the spacing, typically quoted as requiring 1/3 of the filter thickness added to the back focus. Have you checked things without the filter? For comparison, here is a 10 minute stretched stack of the corners from my Hyperstar 9.25" with a small, uncooled, camera (Ultrastar) with 11.2mm diagonal. This is, undoubtedly, smaller than yours (I/m guessing an ASI 1600, 22mm diam, judging from the pixel count?) but shows the quality that you should be able to get if everything is (nearly) right. I think I do still have a small amount of tilt in the camera chip itself. Tony

Oh, well I had cropped the L early on, but not the RGB, so this was simply to apply the same crop to RGB before LRGB combination.

One final go – I tried a little harder by combining the L channel with a synthetic L from the RGB combination. So really you've got something good going there – just need more data and careful processing. Tony

Yes, fair question! I didn't put any details earlier in case you weren't really interested in following up. I processed this with an L-RGB approach, keeping the L stack separate initially, and combining the RGB ones. L processing: large crop around edges to remove stacking artefacts DBE to remove background TGV noise reduction – you have only very little data. Histogram/Curvers – stretch, but not too much StarXTerminator – to separate nebula and stars Starless image – stretch and Local Histogram Equalisation to enhance contrast PixelMath – to recombine with stars RGB processing: Noise reduction stretch SCNR to remove green cast L-RGB combination: register RGB with L use LRGB to combine That's about it really. Since you have so few frames, there is nothing clever you can do in the stacking to remove noise even better (Sigma clip, and the like.) More frames would definitely help here. One things very noticeable is that your separate frames are of very different quality, and some would have been rejected if more were available. Here's a couple of L frames cropped: Was this, perhaps, high level cloud? How good is the guiding? HTH Tony

That’s really impressive! Well done indeed. Tony

Thanks for that. Here's my quick attempt. I clipped off the edges since the registered frames are fairly scattered about. Not so different from yours, perhaps, but I've tried to address some of the things on my list. Not so much data there, so more would help, and focus could, perhaps, be a bit sharper?

I am not an expert by any means, but I was interested to look at your data. A commented above, it's a bit hard to say too much without some processing details. If you wanted some detailed input from experts, then I think that posting a raw stack FITS file would be the way to go. I see the following things: background – indeed, there is a noticeable gradient which should be removed early on to help with the rest of the processing green cast – easily removed with SCNR noise – some from the limited data, no doubt, but some also introduced, or exacerbated, by something in your processing... sharpening or filtering? colour saturation – your choice, but it's quite a muted palette stars – seem quite large. This may be focus, or stretching. Just my thoughts. Tony

Just halfway through an evaluation, so I only know what it’s like at the moment. Certainly fewer artefacts than Starnet++, but perhaps a slightly softer result? Is your example using linear or stretched data? Tony

That's a good start. It's exciting to get to grips with new gear. So far as processing goes, it helps to avoid clipping the black point, and be careful not to overstretch. Colo(u)r balance help too, and a little noise reduction. I've tried to adjust all of the above a bit on your image and get this result. There may well be more detail in the linear data. Looks like your new scope will deliver some great stuff! Tony

A little longer than the 2–5 minutes exposures that I usually use for EEVA, here's 3.5 hours worth of five minute subs, on the Cave nebula last night (10-Dec-2021) with 50% moon. Esprit 120 ED ASI 294MC OSC IDAS P2 filter The seeing, as reported by many here, was not that good, and clouds came in around 11pm. The guiding, however, seemed exceptional, achieving 0.3–0.4" total RMS. I'm not happy with the brighter stars, but otherwise it seems OK – although other views welcomed! Tony

I get extra diffraction spikes if the elevation is low enough for the observatory wall to obstruct some of the FOV. I guess that a garden fence, or building, can do the same? Tony

My dream was always this one… https://www.dezeen.com/2017/07/31/anmahian-winton-zinc-clad-observatory-enables-stargazing-new-hampshire-mountain/

Discovered to my surprise that the sky had cleared a bit last night (6-Dec-2021), although the seeing was not great and it was later in the evening than I usually start, so I just chose a part of the accessible sky, which happened to be Gemini. By accident, I stumbled across an interesting group of galaxies, including NGC 2289, which, having plate solved in Jocular, I learn to be WBL 126. Searching around the web, I found this post in the other place... https://www.cloudynights.com/topic/465171-compact-galaxy-group-wbl-126uzc-cg-050/ which also links to a full resolution annotated version here: http://www.spacebanter.com/attachment.php?attachmentid=5150&d=1402289253 over seven years old and, very sadly, no comments on it. I simply direct you there rather than regurgitate any part of it. Interesting to compare the superior colo(u)r image there (from a 14" SCT and ~2 hours exposures) with my usual 5 minutes here. Also very surprised to read that these are classified as lenticular or elliptical, because in their image, several certainly look spiral. Any further information on this group is most welcome. Is there somewhere else I should go for more information? Thanks Tony