Laurin Dave

Very interesting post Goran and it identifies the feature I'd seen at the edge of my Heart Nebula image. I've also had a look at some wide field Telescope Live data that I got which shows it. It seems particularly strong in Sii. Please excuse the slight green tinge Dave

Yes that's correct

You need the 11mm extender ring which should have come with the camera, just screw it on the camera and then onto the EOS adapter minus the 5 mm extender, plus maybe some of the thin shims to get correct backfocus.

I had the same issue a year ago.. The Blue glass filter was free and took about 10 days to arrive from Germany. As Peter says easy to remove - I used a lens spanner to unscrew it. And the deposit cleans off the old one with lime scale remover Cillit Band or Mr Muscle as myself and @tooth_dr have found. Dave

FLO do ADM Universal Adapter Blocks which may fit your set up .. I use them with my Esprit150 for the same reason

Also some discussion of the flats issue on the ZWO forum ASI294 MM-Pro flat field question - ZWO User Forum (astronomy-imaging-camera.com) Dave

Indeed.... cable management needs work though

Very Nice Olly.... and Adam, its a typo I believe... should be ASI2600mc Dave

Nice one Steve.... I downloaded Starnet v2 yesterday and its a big improvement over an already excellent tool. Dave

The Horsehead (IC434) and Flame (NGC2024) plus reflection nebulae IC431, IC432, IC435 and NGC2023 in L_HaRGB Four panel mosaic through Esprit150SX46 and Esprit100ASI1600mm, 3hrs lum, 2hrs each RGB and Ha per panel. Processed in Pixinsight and Photoshop. Mosaiced in Pixinsight using Mosaic by Co-ordinates and Photometric Mosaic scripts. Captured between 1 Nov 2021 and 9 January 2022. Dave

You need to subtract the Bias plus appropriate Dark current signal from both Lights and Flats in order for calibration to work properly .. Darks may not be needed with the ASI553 (because its Dark current is so low) but Bias certainly is ...

Suggest you post up a raw light, dark flat, dark and flat for folks to look at

From what you've said it sounds like you're not using Darks and Flat Darks to calibrate your lights and flats, which would account for the bright corners dark middle, and which you need to use to calibrate correctly

Yes PM is quite daunting at first but the documentation is very good so don't be put off... and I'd certainly try NSG as that will help APP get a good result (the author of both is a member of my Astro Society so in return for a bit of testing we've had personal tuition ) .. By the way what equipment do you use? Dave

Very nice, as @geeklee said mbb helps as does (in my experience) APPs Local Normalisation option, also as you have Pixinsight it's worth looking at the Photometric Mosaic scripts as that also does an excellent job and if you've not done so then before integration run Normalise Scale Gradient on subs for each panels... this makes any residual gradient much easier to deal with either by APP or Pixinsight's PM script.

Adam Block worked with the author to develop some videos although not sure they're free.. the script documentation is however very good (for a change!)

Plus one for staying with a guide scope and OAG would just make life more difficult... what was it that made you consider one? the blips looks like they correspond with the worm cycle of the mount which is about 8 minutes - although I'm not sure what you can do about it

Thank you Carole, clearly I agree with leaving a touch of green in as I do think it adds to the image and after all it is between blue and yellow. When I first started doing SHO I blasted them with scnr or HLVG to get rid of the green and the result was as you say rather flat. Dave

Hi Goran, Interesting.. maybe call it the Hole Palette Dave

Thanks Steve.. per panel its 1hr each RGB 8hrs Ha, 6hrs each Oiii and Sii so 46 hrs total through two scopes Dave

And here it is... I did! although much earlier in the year than I had expected thanks to the three clear nights at New Moon in early January.. the full Soul Nebula in SHO and HaR_OiiiG_OiiiB.. Thanks for looking Dave

Hi... Astronomy Tools astronomy.tools has a Dust donut Calculator which will confirm where the dust is, looks like you've posted a crop as it gave a distance of 13.5mm which is impossible given the 17.5mm backfocus of your camera. I'd agree it looks like the Moon was the issue, hopefully a moon free night will confirm this. Another thought about your system, is there any way the filter can be inserted facing the wrong way, if indeed it has a right way. Having the anti-reflective side facing the wrong way can cause issues.

One more thought would be to look at the first and last calibrated registered subs and see if the arcs move.. this may show whether the filter is moving as the scope tracks

Strange then... was there a meridian flip involved? if so maybe integrate pre and post flip subs and see if there's a difference, its possible something shifted on the flip. Also your single sub doesn't look too bad but that I believe is because its only one and integrating however many you have would show the dust bunnies more clearly..

Looks to me like your filter has moved slightly between lights and flats or the camera has rotated slightly with respect to the filter. Also in my experience the moon makes flat fielding trickier. I'd make sure everything is screwed up tight before your next session. Nice image by the way, to fix I'd remove the stars and sort the arcs in photoshop, then put the stars back Dave