alacant

Hi I had a go with a refractor but it takes ages; 6 hours. I don't think an hour or so would get much detail. Do post your image and prove me wrong though! I think that's important. Even with just 72 minutes, it's tempting to push beyond what's really there. When to stop? Having to continue processing to combat artefacts -not just noise- you've introduced is perhaps a good time to decide where processing ends and over-processing begins.

That's the Crayford-friction model as fitted to the Quattro range. It works without introducing tilt and holds the position at which it is locked. Out of the box, usually. HTH

Neither focuser is of rack and pinion design.

Thanks. Indeed it is such a pity. It seems to be down to luck as to which focuser is supplied. JTOL... The closest we got from our local dealer was the distinction between Quattro and Black Diamond. Evidently, SW Europe carry both. Here for example is a black diamond. You can see that it has the inferior quality focuser. I wonder if that's it? Still thinking....

Hi everyone Upon our recommendation, a visitor brought over their newly acquired Quattro 150p. One of the main recommendations for it was that it had the excellent Quattro monorail focuser. Alas, this example had the awful sw ds focuser. SW can't/don't know or help, Does anyone know the policy for what is supplied to where? It seems that Spain sourced models have the proper monorail focuser whereas (guessing non EU?) countries have the cheap ds model. Is it possible to convert between focusers? Is the Quattro focuser available separately anywhere?

Hi everyone Trying to decide if loadsa short frames are better than fewer longer frames. Any ideas/examples most welcome. m45 en tauro, 72 x 1 min ISO800. Looks quite promising. The noise seems to be under control, even for a short exposure time. Cheers and thanks for looking.

Hi everyone Anyone ever forgotten the moon may rise close to the target whilst asleep? I thought that Ursa Major would be relatively safe, but what a mess. Lesson learned. What I anticipated to be an interesting and unusual galaxy, became a rescue mission. Big call out to StarTools' wonderful Wipe module for getting us anywhere near. Thanks for looking and please do post your -hopefully moonless- images of this. It seems impossibly faint. nt150s ~5h, ISO800

Hi Unless you really do want to do wide sky shots, there's one on your list which stands out several kilometers above the rest;)

From the end of the FF closest to the camera to the plane of the sensor. The latter is marked on top of the camera: ø What adapter do you have to attach the FF to the camera bayonet? How thick is it?

Which FF is it and how far is it from the sensor of the camera? The image suggests it's too close.

Hi If you're using a telescope, fit a field flattener (FF) and ensure that the camera and FF assembly are held fair and square to the focuser. We don't know which telescope or lens you are using (or maybe it's in the signature which I can't see) so it's difficult to offer specific help. But hey, well done. A worthwhile image no matter what. Cheers

We neither.

LOL. At the risk of putting Optolong out of business, I'm sure the craze will pass. Take butter for example. Next year, it's bad for you. Cheers and with my sincerest apologies to the OP, but please keep the reds coming, do.

Hi. Sorry. English isn't my first language and I've learned how to write the technical form of it on this forum, so that's me just attempting to be pompous. And failing! offset: a number derived from the bias which prevents negative cold pixel values. But please see below. WHY: What Have You It isn't, or at least there's less of it and other artefacts, but I've no idea why. Everything we post is from hands on experience. We gave up on trying to explain anything to do with astrophotography many moons ago! HTH

Well worth a go. The 2" version is around €30. Not sure where you are but they also have a European warehouse. e.g. ~5 days to Spain.

Hi I don't much care for false colour, but if you want to have a go with osc data, this Siril video makes it easy. If you're into this on a regular basis, you may wish to consider StarTools which has a dedicated composition module. BTW, you'll probably find that a UHC filter gives better results than a duo band; prominent colours, you get to keep the blue and far gentler on the finances! Here is some UHC HOO stuff we did. Cheers and HTH

I'm guessing the darkest oif the frames is the bias, the next lightest the dark... (?). Here is the calibration using only the bias and the flat. Gradient notwithstanding, relatively clean. Now with -what I guess is- the dark. Much noisier. I next try to find the offset from -what I guess is- the bias, so as to obviate the need for in-camera bias frames. It seems very low. Thoughts I don't know where the noise in your -what I think are- stacked images (this post) originates. So... Keep`it simple: Take a bias frame at 1/4000s in total darkness. Use Siril or WHY to find the offset as in the example above. Lose the dark and in-camera bias frames Calibrate the flat and light frames by subtracting the offset you found above. Clean the sensor Remoive any sd card from the camera. Download directly to your 'phone or a computer. I've lifted this mostly from our dslr guru's recommendations: ,https://linuxcb.blogspot.com/2023/09/siril-dslr-processing.html Cheers and HTH

Hi The files don't seem to be equivalent or linear. Originals: Anyway, there is an almost impossible gradient and a noise pattern which suggests lack of correctly exposed flat frames, circular pattern walking noise or electrical noise; the sort you get when recording to in-camera sd with a mains fed dummy battery. Perhaps send more details of the image acquisition at the telescope and what you did to process up to the point of posting the frames here? Otherwise, we can only guess the cause. Here for example is the red: I don't feel confident pushing any further than this: But hey, there is some nice detail emerging. Cheers and HTH **EDIT... Ah... Just seen. DSLR? So best without dark frames of any kind. Simply subtract the bias from each frame you take. Siril makes this easy. That may well explain the noise artefacts.

What you are quoting there is the guide camera exposure. It was the guide rate -as a function of sidereal- which I thought may need attention. Before substituting the focuser, (expense!) dismantle it and remove any rubbish along with flexible components . That should help. Cheers

Hi Small sensor notwithsatnding, to get stars that consistent under poor seeing using the sw ds focuser and a budget cc is pretty good. If you want to take it further without upgrading the cc, maybe have a look at the (7 off) rubber rings in the focuser. They distort and perish easily giving rise to wobble, tilt and slip. Increase the guide speed. This may help the PE blip at around 12s although I doubt this can be removed by guiding. Otherwise, perhaps simply stay as you are and hope for better atmospheric conditions. Full sized .jpg of the images attached. Cheers and HTH

Hi Excellent shot. It's slightly tilted, but nothing bad. Usually simply reseating the camera/ff/focuser assembly is all that's required. Processing: perhaps go with a less-is-more approach? Especially with the background. There's loadsa detail emerging and the stars are wonderful. Cheers and HTH

Hi I think you're trying to pre-process frames of different sizes. AFAIK, the aligning/coalescing/distorting/rotating has to be done in the registration step. In Siril: Pre-process each night separately then make a new sequence of all the pre-processed files. NOW you can register. HTH

JTOL and I'm hoping that YMMV... Have you checked to see if the focuser is capable of holding the camera/cc/fw assembly at the required distance? Even with a quality 2-1/2" r&p, we gave up with a similar specified ES. Here we are at 80mm with a DSLR at the focal plane:

We can't advise because we don't know the diameter of your spacers. m48 gives you the option of clamping anywhere along the length. Unfortunately, zwo supply only m42. The main problem with the gso is retaining stability and balance with the focal plane so far from the tube.

Hi Yes. Indeed... Nothing. Fortunately, it would never be deployed in such configuration. The GSO has m48 threads, so as long as you have allowed for any adapter 48 to 42, the 75mm would be a good place to begin the positioning trials. IIRC, over aps-c, you'll probably find the best correction is however nearer 80mm; there is usually a 5mm m48 to m42 adapter supplied already fitted. Cheers and HTH