GalaxyGael

This one owes me nothing at this stage, and the vignetting form the visual-type small secondary was just too much even for micro 4/3 sensors. The 2600MC pro was black all around the frame. Luckily, the three glue-type dots on the secondary holder remained so I made a pretty good estimate where it should be and fixed the focuser position to check the offset, and I got a bit lucky. the main mirror cell is so well constructed. My current issue is the helical focuser. Manual focusing only, but it holds very well all night. No screw adaption for the camera so if I see tilt issue I tap the camera to the side and go from there! The compression ring is not what they are nowadays, so I'll either upgrade the focuser or get a new imaging scope at slightly bigger aperture at around 1"/pixel scale.

Yes, the 127 mm aperture MN56.

Thanks Russ. To be honest, the ASI2600MC is just amazing, after years of slit spectroscopy measurements using huge CCDs. These backlit CMOS chips are quite the thing, with 16bit native depth. I have a version with processing pushed more, but it affected galaxy detail but did bring out the dust in this region and there a lot of it. I'm glad to see someone appreciate holding back on the processing and letting the stack do the talking. I used only some noise reduction (colormancer plugin) and color saturation using match color (matching image to itself). I decided to avoid almost every other image processing (sharpening, screen mask inverts, selective color etc.) and I like the minimalist approach when I'm lucky to get a decent set of data. I'm still surprised what the Intes can do, even after I butchered it by sticking a 46mm short axis secondary (originally has a 30 mm one) on it without any measurements (position, offset etc.), just stuck it on there and it collimated OK! CS, Colm

I thought I'd share my first image content post on SGL with the most recent one. Fireworks Galaxy (NGC 6946) and the Ghost Bush cluster (NGC 6939), medium field image. Captured using my beloved and 'ancient' Intes MN56 Maksutov-Newtonian, at 760 mm focal length f/6. This is 10 hrs of exposure using 240s subs (-10C) with the ASI2600MC Pro . ~1"/pixel scale, no darks, masterflat used. Guided with 240 mm f/4 scope (asi290mm mini) on iOptron GEM45G on tri-pier. EDIT: I used Gain 100 on the 2600MC, no filters except the UV-IR cut on the camera. At f/6, I'll keep gain 100 but reduce exposure to 180 s from now on to reduce a bit of star clipping just a little. CS, Colm

Lovely image, and nice detail delicately balanced. I'm just about to post a wider field (760 mm f/6) version of this region. Nice to see what the detail look like up close.

And the gradient removal tool in APP will work better than most, and not require comex geometries in pixinsight DBE of that leaves strangely brighter patches. I have found app to be really excellent to get a stretched image ready for the latter processing stages, and there are tools hidden in check boxes. One option is align channels in the calibration tab. Once debayered, calibrate the frames and then save calibrated frames. Then reload them fresh, but without debayering option selected (align channels does the debayering step) and proceed from there. This removes red and blue sides from atmospheric dispersion in all images before stacking, very very good. Light pollution tool for me with three led jheadlight down into my imaging area is beyond comare from any software and it will do wonders for your stack. Great data though from a vc200l unguided. I have always wanted this scope, wish I could turn the spuder vanes to 45 degrees😜. Do you shoot at native 1800mm? It always calls to me as a scope design. Look forward to see what you do with it in time. Cs, Colm

Reviving this thread just in case you see it and maybe check this longish video (use auto translate if you don't have German like me). It seems like a similar issue for the 15028 HNT version, and I am looking at one of the other of these myself. About 22 minutes in:

Hi Steve, I guess my reply to you is my first post! I had the 86SDQ version of these scopes. Great in principle but here is my advice. In my case, it suited the asi1600 with 1.4"/pixel as far as I recall. The 533 has the 3.76 um pixels so you're at slightly better resolution at the longer focal length (mine was 464 mm). Its a nice combination for a square smallish sensor size. You might be able to get away with flats and darks for a while. Ask for a bench test before shipping, although FLO will likely do one?. Mine had pinched optics in the main cell, and these are made a little better than before so the lens cell is not a twist off, but a series of push-pull screws that I did not want to play with. Focuser is excellent, although a little backlash in the fine focus I found. Check too that none of the oil or adhesive moved onto the lenses. It did in my case so I assume that lens installation is common to these models. Now, I may have had several unusual one-offs all happening at the same time to be fair. Color correction is fine, but mine was FCD100, not quite as good as FPL53 and its was a pair of doublets instead of a triplet with single lens inbuilt corrector. I found blue/red fringing on many stars, especially if low in the horizon, and is common with these petzvals. One good alternative is the 94 EDPH with flattener. Considerably cheaper and runs at f/4.4. with 414 focal length, maybe that is too wide for you? Good reviews of this model too out there. Petzvals handy though, and I have a TS version of the 71 f/4.9 that is really good and flat. It too had pinched optics, so definitely get the bench test at FLO for peace of mind whichever you go for.