Martyn87

@Ags you win!

Bit of a leftfield choice for me, this one. I wanted something considerably shorter than my C6 but didn't want to shell out on another scope or Hyperstar just yet, so figured I'd try a telephoto lens on the DSLR. Didn't quite intend to go this far back in time... It's a 200mm Soligor prime lens, and from what I can gather online, it was manufactured by Tokina in Japan in 1967! It's not in perfect shape, but cost less than £18.50 from ebay... Obviously, it looks stupid mounted on top of my EQ6-R...

On the canon, it will have a sensor clean function which may be enough to shake some debris loose. Other than that, stick to the tried and true "least contact to most contact" method. Use a rocket blower to remove as much loose debris and possible, followed by a soft brush, then move on to the single use swabs as mentioned above. Remember on a DSLR, unless it's been modified, you're not cleaning the actual sensor, but the filter stack in front of it.

Hi all, After recently astro-modding my DSLR, I wanted to test it out last night on and spent a couple of hours on the Crescent Nebula (NGC 6888). I've been messing about with processing in PixInsight (currently in the trial) and have got the nebula itself with the stars removed to a point I'm happy with, but once I add the stars back in, LOADS of detail is lost. I've tried desaturating the stars, lowering the luminance, but this either doesn't do enough, or causes weird artifacts. Any suggestions on what I could do to improve this? Thanks! Without Stars: And with:

I've also got a pack of 5 of the MyRotator PCBs to use with a DRV8825 if anyone wants one!

@Elp believe it or not, I think you've hit the nail on the head with the saddle knobs! I've had literally everything off, had the OTA back on its original dovetail, still not balanced, and I figured, while I'm here, let me just check... I've now been able to balance it perfectly (only with the OTA, still putting everything back together) with the help of my make fix counterweight made up of some M10 washers and a velcro strap. Time for some stick on weights I guess! PXL_20240904_213502757.mp4

Yep definitely not good. I think I'm right in saying that all north/south and east/West points should be somewhere along the dec/RA axis', at 90 degrees to each other, but the position on the graph is just related to camera rotation? I think I've solved the balance issue now, although it does mean I'm temporarily back to manual focusing while I wait for some longer belts.

Looking at my calibration graph, I do have a number of South points that are a long way from where they should be:

Thanks @michael8554. I don't remember exactly what the error itself was, but dec balance was definitely mentioned in the description. This is the only reference I can find in the PHS2 documentation "the GA (guiding Assistant) will try to compute an accurate estimate of the backlash amount, corrected for Declination drift. This won't be done if the mount never established a consistent rate of south movement that was at least 90% of the measured rate moving north That situation usually indicates binding in the Dec axis or substantial imbalance, in which case a simple estimate of backlash will be inaccurate and probably irrelevant."

That was my thought too. It does 'hang' with the focuser side at the lowest point so it sort of makes sense. Now I've reattached everything on the back, it is worse, so it's obviously not perfectly balanced at the back which is hardly a surprise. The losmandy bar is mounted in the same place as the original dovetail, I only replaced it as I couldn't move the scope far enough forward to get balance on the vixen dovetail. Ill see how it goes, and if it's an issue I'll find a way to move some weight to the other side. Thanks @Elp On the plus side, at least I've eliminated any stiction in the dec axis!

So I've stripped everything off now except the OTA and it's landing in exactly the same place (when balanced in the rest of the rotation). If I move the balance back far enough, it sits where I'd expect it to. Is it maybe the focusing mechanism? I think even with the imbalance, it's better than it was before, so I think I'll have to do more testing to see if its still an issue before I mess too much more.

Thanks @Elp, the cabling is a bit of a mess as if had this in bits so many times today trying to figure it out. The bits sticking out if the back are EAF, OAG etc. I had wondered if these were the issue so I've printed a new bracket to move it more towards the centre but it seems to have made no difference. I think I'm going to have to strip everything off and check. It seems odd that it seems to balance fine through most of the axis, other than when it gets too close to that balance point.

Bit of a weird issue here, I've been having trouble guiding and PHD2 was complaining about declination balance (amongst other things), so I've followed a YouTube tutorial to free up the DEC axis a bit. This has exposed that I was indeed out of balance, but not that it's more sensitive, I'm having a weird issue, the video below might explain better than I can. Any suggestions what might be going on here? PXL_20240902_180843407.mp4

Thanks @Mr Green, I've been looking at dedicated cameras for a while but can't justify the outlay at the moment, but I'm planning on modding my DSLR at some point soon to see if I can get rid of the IR filter without killing it... I've found myself looking through Stellarium for "blue things" just to give myself a bit of a fighting chance!

Thanks! I bought a "cheap" C6 and DSLR from ebay, followed by an EQ6R that cost 3 times the rest of the kit. It's funny how this hobby seems to always cost more than you planned 😂

Well guys, I just wanted to say thanks for some of your suggestions, I had another go at the Dumbbell last night and I'm so much happier with the result this time. Dithering has made a huge difference to the image noise and I made a much better job of calibration frames. Flats still seem to be a weakness though! This is 30 x 120s at ISO 800. Still far from perfect but it's a step in the right direction!

EDIT: Apologies, it's early and I didn't look properly at the scope in the link. It's a Maksutov Cassegrain which I know very little about, so ignore my previous response! Had you thought about looking at the used market? As an example, I picked up a 6" SCT on an AltAz mount for £260 which retails at around £660 online. There are definitely some bargains to be had.

Honestly I mainly started this hobby to get a bit of time alone and and excuse to sit outside all night on my own! We do have a (very new) astronomy club locally, but it's still small and I don't really feel like I have much to add, especially as a complete novice. Besides, places like SGL are such fonts of knowledge, there's a much better chance of me finding any help I need here. I also wouldn't like to manage my imaging rig without my PC!

Schroedingers RedCat?

Do you mind me asking how old the kids are? Elp mentioned patience, I run into this regularly with my 8 year old who is always keen to get out in the garden to look at the moon with me, but can't even wait long enough for me to point the telescope in the right direction.

Haha funnily enough, I had already 3D printed brackets for a DIY focuser too and fully intended to go down that route, but as you say, this way is cheaper! I actually bought the SCT bracket to go with it but the supplied coupler doesn't fit on the motor end, although it's perfect on the scope end. I had the brackets printed and belts here already though so the printed option worked out great. I've not had chance to try it out yet other than getting NINA to move it, which worked great. Cuiv the Lazy Geek reviewed it a week or so ago though and was pretty happy with it!

My latest AliExpress purchase turned up today... I wasn't prepared to pay over £200 for a ZWO EAF, so went for the Genesis equivalent at around £75 instead. Came with a temperature probe and IR remote that I probably won't use! The back of the C6 is getting a bit cramped now...

@TiffsAndAstro looks great, the pillars are definitely visible! What's your setup?

Thanks for the replies both. I have read through what I thought were the relevant bits of the user documentation, although I'm going back through it again now (with a bit more understanding, as last time I read it I don't think I'd even taken a single exposure yet) and think I might have found the answers to a couple of my questions at least. The scope is indeed a Celestron SCT, C6 to be precise, so about 1060mm focal length. I'm hoping to be able to do some testing on stars soon but I've been able to get an image at least, so I'm hopeful it should work ok. The guide camera is an IMX 290 Mono so I'm keeping my fingers crossed!

I've a couple of LED street lights in close vicinity of my back garden, but luckily I can position the scope in such a way that one is blocked by my house, and the other by next doors shed, although it would be useless for visual observing as it's much too close to the house. Might have to try getting in touch with the council about them though, seems people have been quite successful in getting the shields fitted!