alacant

Hi 10" Quattro, so 1.6 x 15 x 20mm from here. Specify the size in the comments section at the checkout. +1 for the three passive springs too; six in total. Besides the springs, perhaps the best upgrade on a Quattro is to seal the mirror to the cell using neutral silicone sealant; a generous blob coinciding with the existing contact points. This prevents lateral movement of the mirror whilst still allowing for thermal expansion and contraction. If you have the steel tube, this benefits from a longer Losmandy dovetail plate. Complete the tube stiffening by fitting a rigid box-section aluminium profile to tie the top of the rings If you're aiming for the best possible stars, use an OAG too. Conclusion: a Quattro which holds collimation at all angles. Not just the one at which you collimated. Cheers and HTH

OK, post a shot of the train with the 294. Guessing: the camera is screwed directly to the fw. As the spacing doesn't matter on the 51, you could try e.g. adding a tube on the camera side. Same using a different spacer on the telescope side. Trust the orthogonality of nothing! Cheers

Much better. The bloat introduced when the fw is attached is probably a combination of astigmatism and tilt. Without the fw, it is visible top right. But hey, almost nada and easily corrected in software. fw and attachments: Clean the threads with very fine emery cloth whilst in the proximity of a vacuum cleaner tube. Cheers and HTH

Hi Before suspecting the camera, perhaps better to dismantle, reassemble and have a look at the tilt again at various camera angles. Often, simply screwing stuff back together will cure (or change) the tilt. Cheers

+1 for all the above. Here are the frames. The flat frame is of no use. It is saturated and will not correct the light frames. Aim for around 20000. Redo the flat frames correctly and try again. It should get you closer. This will make it much easier to diagnose. Next, remove the filter and take another flat frame. Otherwise, it's probably local to the session. Cheers and HTH --- --- --- flat: dark: bias: light:

Hi You need around 35mm further from the telescope. Just get a set of extension tubes; https://a.aliexpress.com/_ExGd4cp Specify 'm42' at the checkout. Cheers and HTH

Maybe it would be easier for us to troubleshoot if we had -links to- a light frame and one each of whatever calibration frames you used. Cheers

Agreed. We have visitors bringing all manner of cameras. It's the only way we've found to host client-server reliably. .For free. All night, every night. I doubt whether you'll find a Pi though ATM,. instead we use mini pcs running Ubuntu at the telescopes. These are faster and significantly cheaper than both Pis and Airs. Otherwise, just go with your laptop. Here's an example under it's high-tech vegetable rack dew shield. 5GHz wffi to the router. Then wherever you like. Cheers and HTH

+1 This is our observation too, except we'd substitute 'gone' for 'changed'. Threaded or not, low end focusers on low end telescopes will introduce tilt. Simply re-seating the camera will change the tilt, as will moving the telescope to a different angle. Cure it at one angle, and it's gone for the next. Perhaps don't stress too much over numbers. rather look at the averaged out final images. Just our hands on but HTH anyway. Cheers and clear skies.

Hi Nice data. There is some good detail emerging in the big galaxy Our PI trial expired some while ago but we came to the conclusion that it deals well with data which is perfect or near perfect, but needs hours in front of a computer otherwise. Disclaimer: that is almost certainly down to our lack of both skill and patience! A few pointers: - go through the frames and remove any which have cloud - apply matched flat frames I'll leave it to the PI gurus to advise exactly how to tackle stuff like this. We never found a way. Maybe do the heavy lifting elsewhere and come back to PI for the finishing touches? Dunno. Anyway, 10 minutes in a different app but with no finishing touches gave... Cheers and HTH

Hi 60d, so lose dark frames of any type. Instead simply subtract a constant offset of 2048. ISO 800 throughout. Cheers and HTH.

Hi Almost certainly this. Simply removing and reseating the camera on an unmodified sw-ds focuser will cause tilt to change. Before suspecting sensor tilt in the camera (rare), as a minimum, remove the focuser rubber washers and set push-pull adjusters correctly.. Then try tapping a third m4 hole at 120º, then... etc etc. HTH

Hi Correct😀 We believe that they ought to be made compulsory but, if you really must, you don't have to have them: https://garyseronik.com/how-to-build-a-curved-vane-secondary-mirror-holder/ Cheers

sw72 Cheers

Yes, that's fine. You can't really do a star test with just a camera. An afocal 10mm may get you there, but perhaps the best method is by examining single frames of a star field. Anywhere in Cygnus is good for this ATM. It's just our philosophy when troubleshooting to strip to the bare minimum before replacing items singularly, especially in this case where focus is critical and there's a focuser in the mix. But hey, you've a relatively good example, so our initial recommendation remains: leave it as it is;) Cheers

Remove/disable the EAF and go again. They're great on reflectors and top end refractors, but will most likely need a carefully calibrated offset with an 80ed. Cheers

Sorry. English is not my native language. Whatever it means it is that the cell is not sitting square to the tube (dirt/poor threads/swarf) and/or the lenses themselves have not been allowed to seat parallel to each other before being tightened. Usually just loosening and retightening everything GENTLY is all that is needed. Yes. All the ones we've seen have been push fit. Well done for persevering.

it's not threaded. Hair-drier for a few moments around its base, then wobble and pull rather than unscrew. You're going to remove the lens cell anyway but its easier to remove the lens shield with the cell still attached. HTH

We only realised after the hassle of the brushed aluminium collar and focuser alignment. It takes only 5 minutes to set the lens square, so almost certainly worth a try. BUT: bear in mind, any adjustment you did at the focuser end will almost certainly have to be undone. We found on the two examples we had that setting the collar back to it's original position was all which was needed. If you didn't remove the flexible rubber in the focuser on your first attempt, now is the time to do it. Cheers and HTH

+1. Rock solid all night, every night. OK here over 5GHz WiFi. Maybe too, store on the telescope computer? Transfer the image files as a single batch via scp the next day; almost compulsory if you're hosting remote over Internet. Cheers and HTH

Hi everyone Full moon last night to illuminate the high altitude Mediterranean haze. We could just about make out Cygnus and Cassiopeia. The gradient was such that the immediate reaction was not to bother, but armed with a moderate hammer, you really don't need to reserve these sort of nights for testing. Clusters seem good targets to choose. Cheers and thanks for reading. Anyone other dslr imagers out last night? eos700d 2 1/2 hours

We see so many images with so few stars, they look unreal. So much texture and context is lost without them. It's such a pity that star removal seems to have become a routine part of processing. If you really must, a big +1 for @carastro's take on this; don't over do it! Cheers

Hi We've yet to see a 72ed emerge from its tissue paper correctly aligned. Apart from the infamous impossible-to-adjust grub screws on the focuser collar and the rubber washers in the focuser, another popular cause of misalignment is the lens itself which is jammed into the end of the tube at an angle and tightened to death at the factory. Or conversely, loose and not threaded home. The latter can easily be rectified by loosening the slotted retaining collar until the lenses rattles upon agitation of the tube. This allows the lenses to re-seat. Then, keeping the tube vertical, gently tighten the collar until the rattle just disappears. Finally, remove the lens cell (it unscrews) and clean any swarf or plastic bits which would otherwise prevent the cell from seating correctly. Now go back and realign the focuser. You'll probably find that it will be back to its original position. Cheers and HTH

So we can eliminate the camera too. Ah well... Dunno. Borrow a mirror set of known performance? Try the secondary to begin with. You have now blackened the edges of the same, yes? Or just accept it? It's not often you'll have a star bright enough to cause reflection after all. Otherwise, out of ideas:(

I thought it was international. Entirely my fault. Please accept my apologies.