The Admiral

I think you've done very well with that Jon. I'd be happy with it if it was mine. Ian

Have a look at this Google Hangout where Ivo takes you through StarTools. It's a long presentation, with glitches, and if you can stay awake there's some useful stuff which'll help you. Ian

Yes, the orange glow is light pollution, that's what I get. The purpose of WIPE is to remove that and to get rid of any gradients etc, but in order for wipe to work properly you need to crop the picture to get rid of the stacking artefacts which you can see around the edges (i.e. where field rotation is evident after stacking). Then, after WIPE, you need to redo the global stretch, either by clicking Auto-Development, or Development and adjusting parameters yourself. I shouldn't think you'll be losing data through those DSS settings. By not cropping the image before WIPE you are getting a background and a gradient, which may be masking the target details. See what happens if you crop. Ian

Your workflow is the one I normally adopt, and I normally up the dark anomaly slider for wipe and develop. Just thought I'd give the Auto-Dev a go as Ivo seemed to extol its benefits. Not sure why this isn't pertinent to No Eq, as I used an Alt-Az mount. Or were your asterisks left over from a previous post? Ian

Well I've been watching Ivo's long video on using ST, and made a few notes along the way. I thought I'd re-process my M33 image, the primary difference being the use of Auto-Develop rather than just Develop, and hopefully using the parameter controls a bit more intelligently . What do you guys think, better or worse? Certainly looks noisier. I'm not sure I'm getting it as I want it, if that's ever possible! New version:

Where would we be without W10! Ian

Are you using Kappa-Sigma clipping Nige? I was under the impression that should remove things like satellite trails, not that I can confirm or otherwise. What do you mean by "both options"? Ian

Hi Nige, that is odd, I haven't had any trouble downloading, opening, and applying the licence file. Considering it's a zipped file I find that even more strange. I'm running win 7. It might be worth dropping Ivo an email. Ian

I came across this guide from Ivo (StarTools) about creating a multi exposure length HDR composite, but if you read through to the end it looks as though it needs the latest alpha release 1.4.324, which on the download page is shown as unstable. I've just downloaded it and we'll see how it runs. What are you guys on and have you found any instability? Ian

Super Jon, that's a lot more like it! Is that using the colour module? Looks like you are on your way Ian

Seems quite large to me, mine are around 190MB with a 16MB APS camera. I have the 64-bit ST and I've not had any loading issues. You are not using drizzle are you? I gather that can give huge files. That might explain why you left it processing over night, or was that just convenience? Otherwise, check out the ST forum and see if anything like this has been reported. Ian

Are you saying that the little icon next to the raw file didn't show the four-colour array? That doesn't sound right. My camera doesn't do conventional Bayer raws, but I still get a colour icon, although not in an array. Background calibration is off, what I thought ST required. Perhaps someone who uses a conventional Bayer camera could chip in here? Could it be something in the RAW settings? Ian

+1 to what Ken said, except I think you were using StarTools rather than gimp weren't you? First things first. I assume that you are using your RAWs directly in DSS? If not, you really ought to be. If you are using ST, make sure that you follow the guidance given in the ST manual, that is: "Giving StarTools virgin data is of the utmost importance. For example, if you are using DeepSkyStacker, make sure 'RGB Channels Background Calibration' and 'Per Channel Background Calibration' are set to 'No'." Also, don't mess about with the curves in DSS, just use the straight 'auto' output file. Use the FITS file format, which is set in "Stacking Parameters", "Intermediate Files" tab. ST should open those. Don't use other manually output files. Now I rarely see colour in a single sub other than sky background, a bit of a sickly orange, unless it's a particularly bright object like M42. Quite often, I don't see colour in the stacked image either. If I auto develop, followed by wipe, what I get is generally B&W. It's only after I do a further re-stretch do things become apparent. But by the time you get to developing then at least the stars may take on colours, and in any event, there will be after using the colour module! As Neil says, you can select subs (i.e. "check") based on the star score, but as he says, this is really a measure of how round stars are, I don't think it'll account for cloud. I think you'll have to go through manually and "un-check" those. Oh, it helps when you've finished selecting your files to "Save the File List" so that at least you can return to your selection later. But whatever, don't give up. Ian

Well done Jon, a successful first attempt with Alt-Az imaging. Your stars are point-like, which is great. M31 looks a little odd to me though, as though you've used a mask for the central area. I feel that with the tightness of stars and the number of subs, this image should have a lot more to give, even with StarTools. It does take quite a while to get familiar with it though, so don't give up on it. PI is I'm sure great, but it comes at a significant price and by all accounts demands an even greater learning curve than ST. Give it a try and see what you think, but either program will take some while to master and give you what you want. Ken (Filroden) has gone down the PI route. If you were interested you could perhaps post the FITS file from DSS into a drop-box for others to see what lurks in your data. From looking at many of the offerings on this site it does seem to me that the image processing is as critical a part as getting the data in the first place, so it would be a pity if you are not getting the most out of your image. Knowing what is achievable is part of the mind-set. Ian

I'd be very happy with that Herzy. Good luck with the house move! Ian

There are some StarTools video tutorials here: https://www.youtube.com/user/StarToolsAstro?feature=watch Ian

Well done, that's a great start! Yes there is plenty unexplained , but we muddle through and get there in the end. It is remarkably powerful software and can seem to extract a surprising amount of information from your data, but as ever, it works best when you feed it with good data, and of course that is something us Alt-Az imagers struggle with, so don't always expect a good result! I know, I've been there!! At the bottom of the StarTools web front page, there is a link which says "PDF Document". I don't know if you are aware that that is an "instruction" manual, which provides a good background. I put it in quotes because it has its limitations and is supposed to be a work in progress. Ian

As you know Jon I have the same mount as you and for operational reasons I've stuck to a maximum of 30s exposure times, but I haven't had serious star trailing, even less so when I'm using my 0.79x reducer (bringing the effective focal length down to 565mm), so with your even shorter focal length the mount should easily give you 30s. Don't expect to see no star trailing though; I find a percentage show it to a greater or lesser degree. Alt-Az mounts I think are a bit cruder in their movements as they are primarily designed for visual use. DSS calculates a 'score' for each frame and you can decide on this basis, if you want, what frames you want to include in the stack (to do this you'll need to un-tick the box in the registration set-up to preclude stacking straight after registering). I've not tried longer subs but I think all the others have pushed it up to a minute or so, with varying degrees of success, when field rotation allows. As happy-kat says, many of us use StarTools. It's not too expensive (60 AUD, or ~£37), has a good user group, but is rather a 'black box' though and make no mistake there is a learning curve with that. If you really want a challenge, and empty pockets, then go with the purists and get PixInsight! Either way, I think that astro images demand rather more than conventional photo-processors can provide. As I said before, processing can make or break an image, so it's worth using tools that'll get most out of the data. Ian

That's an excellent and encouraging start Jon. You've got nice tight stars so your focus looks spot on, not schoolboy at all. All you need now are some clear nights, photon collection is a priority! I've not used gimp so I don't know how easy it will be to extract all the detail, but in my view the processing is everything (well, almost ). A lot of folk use it though I think. Ian Edit. I see that you're not keeping the camera strap on, but a number of us do and use it as a 'safety harness' for the camera, should it decide to drop out! I know it is recommended to remove it so as to minimize any 'scope movement in any slight breeze, but your call . I've not noticed it being a problem.

Thanks Nige. Ian

Doh! Yes, they're not purple stars are they. I guess it's a mixture of the blue with the red H-alpha. I had a look on the Messier Objects website and it confirms it. Thanks for your comment, much appreciated. Ian

That's brilliant Nige! That's a good way of showcasing your images. Ian

Last Monday I had a go at imaging M33 (Ken, you're to blame for that ). The trouble is, I'm not good at this late night thing, so I didn't really image at the best times. Still, this is what I got. I was debating whether or not to image using my 0.79x reducer/flattener, but in the end I went with the native FL as I reasoned it would cover more of the sensor and thus require less cropping. Put it in to DSS and it threw up scores of between -5.25 and 567! With my reducer they normally top the 2000's, but hey ho. So I stacked all with a score >50 (234 x 30s subs), and after doing what I could in ST, I was just not happy. The image looked a bit out of focus, though it has to be said that individual subs looked fine. So this time round, I went through the subs one-by-one and weeded out those where I thought there was a bit of trailing. That brought it down to 199 subs. I registered and stacked those, and this is the result of that. It was quite interesting going through them in time order, because they started out with a coffee colour at about 8.30pm and ended up a dark grey by 11.20pm. I really needed to have started and finished imaging later. Perhaps I'll have another go in a few weeks time, when it is better placed earlier in the evening, and use my reducer. Let's hope for some clear skies when the Moon's not up! I feel that I'm pushing the data a bit too hard here, but needs must! Not sure what to do about magenta stars, always get them*. Ian *Edit. I've found I can either reduce their saturation to zero, or turn them blue, in Lightroom.

Nice ones Nige! Plenty visible in the arms of M33, and your M31 core looks nicely processed, revealing stars within it. I don't know about you but I find it quite hard to predict which images are going to be the easier to process in ST. Hope all goes well with your re-reassembly! Ian