DaveS

For anyone else mad enough to go after the HCGs these should give some idea of their size on the sensor. ASI 533 on ODK 12 at 2040 mm focal length and theoretical 0.38"/px, which is totally bonkers.

And a test of my new ASI 533. All images are 2 hours Luminance in 10 min subs at -10C using the Medium Gain setting in the ZWO driver, Gain 100, Offset 60. Stacked in AstroArt 8 with straight Flat and Dark frames. Bias was not used as it stuffed up the calibration. Crop, Gradient Reduction, DDP and Histogram Stretch in the cases on HCG 2 and 99 due to moonlight contamination. North is up (Plate solve reported 179.5 degrees, so rotated where necessary). So, in order of RA (99 was done before 2 due to the meridian) HCG 2 HCG 99 HCG 35 Could do with reframing, Stellarium was unclear HCG 41 The complete frame as captured was 19' on a side, reduced slightly due to alignment cropping.

I'm also taking the opportunity to try out the ASI 533 that I recently bought from FLO. Getting saturated stars, but that's OK, I'm not that interested in the stars. 600 secs Bin 1 and gain 100.

Having said it's no good for galaxy imaging, I'm running framing check sequences on some of the HCGs that I want to image properly when the moon gets out of the way. Only 2 hours each in Luminance.

Yeah, a clear night but DSO imaging is pretty much no-go especially for galaxies.

Not interested in Harmonic Drive... HOWEVER If Synta / Skywatcher brought out a Direct Drive - Encoder mount to fill in the space left by ASA, that could be VERY interesting. Especially at Skywatcher rather than ASA prices.

My Moravian G3 16200 with filter wheel weighs in excess of 2.5 kg, so puts a fair old load on the focuser.

The 185 would ride happily on my little DDM 60. I could be tempted if I hadn't sworn off buying new gear.

Brilliant image, especially given our rubbish weather this year (All year). I sort of had this on my hit list but headed down the HCG rabbit hole instead.

Only anecdotally, but as late as 1988 I could, on a good night from west London see all the main stars off UMi, and a faint trail of the milky way.

M33 is a tougher target than many people imagine, very low surface brightness. From where I live it's easy binocular and just about naked eye under very good conditions.

Well, the faint blue excess was too close to other detail for Attenuate Singe Colour, but I had another play with it, giving the RGB layer a stronger Noise X in PI plus a bit of Histogram Stretch on the finished LRGB amd a masked Saturation Boost on NGC 7549. I may leave it here as I think it will be "good enough" for my project.

Thanks Göran. There's a very useful tool in AstroArt 8 for attenuating a single colour using level and range. I think I will give it a go on Blue.

And to add that the blue cast has been bugging me too, most likely in the RGB layer. More data, more better 😀.

Thanks all. Yes, I will revisit this after taking a short break to allow my eyes to recover. One slight possibility is to capture more data while waiting for the next target to get high enough.

Thanks Neil, yes I think it needs more (Careful) work on the background. More data always helps but there's already 12 hours in there and with our rubbish weather a decision has to be made as to whether to capture more data or move on to the next target. This is part of my project to image as many of the Hickson Compact Groups as I can. This is the fourth that I've got into a nearly finished state, out of a catalogue of 100, so a way to go yet.

...Or not? I dunno. This is 6 hours Bin 1 Luminance and 6 hours Bin 2 RGB, all at -26C and 600 sec subs captured, with the ODK 12 and SX 694 through Baader filters. The RGB was captured on the 7th October and the Luminance on the 14th. I waited until I had my main PC with PI and the RC tools back from repair, and been fighting with it for 4 days now but decided to post anyway My main concern is in NGC 7549 (Top centre) and whether the structures shown are genuine or a deconvolution artifact. I'm still not sure. I'm also concerned that I've blown out the galaxy cores. Don't care about the stars, they will blow out anyway. In any case, here it is, please take the time for any constructive criticism.

I've been running just the ODK 12 rig for a long time now, but finally decided to make a concerted effort to get the little 130 mm Photoline rig up and running. So far only rebooted the remote PC, hopefully tonight will be clear enough for me to get the mount synched and modelled. The alternative is a bit terrifying, sell everything apart from the ODK 12 and DDM 85, then roll the money and savings into a Moravian G5 461 and a set of 50 mm square filters. I don't want to think how much it would cost, but well into 5 figures.

I went online with Scan Computers and built a high-end but not extreme PC. Speaking personally I wouldn't touch Macs with the proverbial, as I don't want to be locked into an ecosystem I won't touch ASIAir for the same reason. No need to go Thread Ripper unless you do this professionally with huge data sets.

And this is the dismal result, hardly worth bothering except to check the framing. It's HCG 10 in Andromeda. It was very low and I think 3 of the subs picked up stray light from an upstairs window that I had forgotten about.

I tried imaging tonight, got 90 mins before the cloud rolled in. Of the 9 subs only 6 were useable.

Could he make the wretched thing disappear, like, forever please.

Just to think outside the box, how about a Richey-Chretien?

The OP is in the USA so has to use their miserable excuse for mains voltage ⚡.

I long ago stopped wasting money on astro kit, there's no point in this rubbish country.