parallaxerr

Here's my first attempt - M31 William Optics Zenithstar 66SD on a Celestron Nexstar SE Alt/Az mount. Nikon D3200 w/Baader MPCC. Approx. 1hr of 30sec subs stacked in DSS with darks, flats & flat darks, processed in Star Tools (hardest part!). Poor conditions with hazy cloud hence the noise in the image.

Go to top of the class Ian, what a great video! Having the program writer explain what each of the filters/modules are actually doing really helps to understand what's going on. I watched the tutorial with Ivo whilst re-working my M31. It's obvious I have shed loads of noise which is hard to get rid of, more subs and clearer skies required. It's easy to forget what it is you're processing and I have to remind myself I captured it in my back garden, so, for my first fully processed attempt, I'm very pleased with this. Final post of M31 with these (poor) subs! Thanks to everyone for the guidance

Hi Ian, neither of those images have been wiped, just auto developed. This lead me to think there was less info in the one with no calibration. HOWEVER, light bulb moment! I had previously NOT been re-stratching after wiping, because with colour calibrated images from DSS ended up with mega amounts of noise which washed out the detail. BUT, having just re-stretched a non-colour calibrated image, the detail came back Thanks!!! Still very noisy but the colours look much better without having been adjusted, so I think I'm making progress. Just need to work out where to go from here...

I've been doing some trial & error testing with DSS and ST. Every "correct DSS settings for ST" thread I read suggests turning off RGB Background Calibration and Per Channel Background Calibration. BUT, if I turn both of these calibration methods off, I seem to lose data in the developed image in ST. Pictures attached show the difference. Any ideas? I assume the orange glow to the non-corrected image is light pollution but as you can see there is less detail in M31, which further processing does not seem to be able to bring out.

Definitely. My first attempts have exceeded my expectations by far Until I saw the images in this thread I assumed AP was out of reach until funds became available for better equipment, but, all it required was a small investment in a few adaptors and a flattener. There is so much to learn with post processing that I think any further investment in gear right now would be wasted and add complexity and confusion!

Thanks everyone for the encouragement. I'm pleased with the progress and "starting" to understand ST a little, the colour tool is definitely the one I need to work most at. Also, I don't think my subs were that great in hindsight, lots of thin cloud cover so really looking forward to some clear, crisp air and dark skies

Progress OK so I selected standard stacking instead of mosaic which knocked 100MB off the FITs file, which then opened instantly in ST. Also set RGB background calibration and got colour! However, I then read an ST instruction which says to set for no colour calibration so trying without that setting now. Anyhoo, a bit rough and noisy but there's colour

Nope, no drizzle. Overnight was just convenience, I'm re-stacking 1hrs worth at the moment with various settings. Takes about 15mins. That's what I've been using, trying standard now. Hmm, 24MP so quite large. Yup, 64bit and 12GB of triple channel RAM. Looks like there's a few tweaks to be made, watch this space! Thanks everyone for your input Jon

Yeah but you told me not to use TIFFs!? The TIFF I was using was about 180MB and that loaded fine within a minute or so.

Thanks for all the pointers everyone, getting somewhere at least. However, just hit the next problem, harrumph..... The FITS file output from DSS is 379MB in size and star tools just will not load it up. Program hangs and if I click anything it goes into not responding mode. I think this is just a size issue, what size FITS files are you guys working with?

My bad Ian, was looking at the column titled depth which reads gray 16bit. The coloured icon is there

OK made a bit of progress. Changed DSS output file to FITS, which ST now reads OK. Also noted DSS is classifying my RAWs as gray 16bit, thought that was the colour issue but apparently not. Turns out RGB background calibration was turned off, tried a stack of 3 frames and had colour so now restacking 190 good frames. Also changed light frames from average to Kappa-sigma clipping as per recommended. Will see what comes out the other side!

ST won't open it for some reason, says it's incompatible?

Yes there is Fil, I've just found it and I am re-stacking with frames under a score of 1000 ignored. Definitely think I'm missing something. After developing and wiping in ST I've got a B&W image. Not sure if it's DSS or ST settings that I need to adjust, will have to play around a bit. ST does offer 3 options on loading a new image that mentions debayering so will look there. Also, ST wont open the autosaved TIFFs from DSS, but WILL open a TIFF if I save it manually. However, in the latter case the file size is about half?

Agreed. As it happens I came across this post just after posting my image... Although it was taken on an EQ mount with a little more aperture and longer subs, it's only about 60% of the exposure time of my attempt. Definitely think there's more processing required. One issue I find with my images is a complete lack of colour, they're almost B&W after stacking. Also, some peoples images show far more detail than mine post stacking, before being processed? EDIT: Just re-visited my RAW light frames and I've noticed a good proportion have cloud cover. I didn't notice last night when adding them to DSS. I assume DSS rejects these, is there a way to find out how many were actually stacked?

Had a reasonably clear last night so had a second stab at M31. I've got to grips with the Auto Two Star alignment via camera live view much better now. I found a grid overlay option which allows me to put the alignment starts absolutely central and I then carried out a precise goto align on Mirach as suggested by the mount. After slewing to M31 I took a few subs to confirm alignment and it was very good. I stepped up to 30secs exposure this time as per Ians suggestion, accepting that I would lose some subs to trailing. In total I captured 225x30s lights + 50x30s darks. Flats and dark flats were carried out prior to lights, 50 of each. Total light frame capture was limited due to physical camera/mount interference at 60° Alt. My setup is still tail heavy so come payday I'm planning on getting an ADM dovetail to shove the whole lot forward so it balances better and will increase available alt. I did note however how the mount accelerated in alt later in the session and field rotation got faster. Threw the whole lot into DSS about 11pm and went to bed. Had my stack waiting this morning so put it through ST and got the image below. Much better than last time, calibration frames certainly reduced gradients & vignetting. Still finding ST a little clunky, so just got a trial licence for PixInsight and will have a play with that over the next month or so.

Yeah the lights went off and the blinds were closed for exposures, this was just for show

Forecast clear, clouds slowly disappearing, flats in progress, fingers crossed...

I've just had to buy a 12GB triple channel kit for my i7-940 quad-core. Star tools is the first program that's maxed out my current 6GB!

Ah that's a shame Kat, I got it @ £7, maybe it will come down again. I've noticed kindle book prices jumping around before.

Good to know. Admittedly I saw some trailing in the first 30s exposure on the camera screen so reduced to 20s. It could be that the tracking was lagging as the mount is set to approach up and right whereas I may need to set right and down to keep the alt gear loaded after slewing, due to being tail heavy. Worth a try. Interesting Nige, I tried it and got a different result, will retry with the original file.

Perfect timing Ian, I just spent the last hour trialing Star Tools and came up with the image below. I followed a simple tutorial (which left plenty unexplained), however I'm amazed at what the program has brought out in the image. Considering the major lack of subs here, I'm impressed and will buy a licence for ST, it will be interesting to see what it can do with more photons! P.S. Low res screen grab!

Thanks Nigel - I must admit I'm very happy with the way the setup looks. I like my equipment to look good as well as perform well, although I don't think I'm alone on that one. Fil - Wow!!! OK so there's definitely more information in there than I thought and you make a very strong case for post processing, another steep learning curve coming up I feel.

Thanks for the comments guys... I am pleased with the stars Ian, the Bahtinov mask & live view made focusing very straight forward and the focus point is about 9mm from the end of draw tube travel. I don't know GIMP either but I lost my copy of Photoshop CS3 when I changed to an SSD hard drive recently, although I never really got on with it. Good point on the camera strap, I'll fit it, or perhaps add a little paracord tether to the mount, just in case. Steve - the Giga-T is very easy to use. You can set delay, exposure duration, interval etc. all very easily then just press play and off it goes (camera has to be in bulb mode). I kept an eye on the exposure count from the warmth of the kitchen watching it count down

Well, as can be expected the cloud has rolled in. I managed to get about 13 minutes of M31, mostly through a light haze of cloud. However, I'm happy to say that, I just took my first bunch of Astro images AND, I just tried my hand at DSS & GIMP for the first time. It's been a valuable first night of trial and error. I saw some star trailing on 30s exposures so reduced to 20s which got rid. The Baader multi-purpose coma corrector does indeed work well with this scope, the stars in the corners of the images are elongated only a touch, hopefully I can adjust this out by tweaking the sensor spacing. So here it is, output from DSS (light frames only) and another with curves adjusted (a lot) just to see if there's any hint of spiral arms, and there is Absolutely school boy in comparison to the other images in the thread but I've made a start!