alacant

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.

Dunno. Sybony stuff to Spain usually takes under a week. I believe AliExpress have European warehouses; the shipping is always from within the EU.

AliExpress don't ship to UK? I never realised that. Sorry. Not suitable for deep sky objects. Maybe someone on the ground in UK could reveal the secret of getting a simple everyday 2" ir cut filter to you. Cheers.

Flexible focusers? Not a good idea. Looking forward to when the new sw150 f4 quattro takes off. That really should be fun!

It allows for thermal expansion and contraction of the glass whilst at the same time retaining the mirror in the same place relative to the cell.

Of course, both will give halos on bright stars, but the halos will be of different shapes. A shot without either will confirm. The star is not central -causing two reflections- and there is tilt. Make certain that after collimation, the primary cannot slide around in its cell. Out of the box, they do. Do you still have the rubber o rings in the focuser? Cheers

Remove the cc and reshoot. The halo should be gone. My money is on reflection being caused by the glass surface(s) of the cc. We've seen this before when the telescope facing element has not seated correctly or when a filter is cross threaded and so not sitting perpendicular to the optical axis. A quick way to align the outermost element is to loosen the retaining ring until upon shaking the whole cc rattling can be heated. Retighten whilst moving the cc rapidly on a horizontal surface until the rattle just disappears. No mention of the primary cell, so I assume that's been addressed. Cheers.

Ah OK. What glass is there between the secondary and the camera? Has the primary cell been brought up to the standard required for astrophotography? Has the edge of the secondary been painted black? Anything other than mirrors of a shiny nature looking down the tube and into the focuser? Perhaps post a -link to- an unprocessed frame taken without the mirror clips so we can look further. Cheers

According to which criteria has it failed? You don't/can't choose. The spider on a 130pds is central. Have you moved yours off centre? Cheers

That will cut the vast majority of visible light; for dsos probably not what you want. The easiest and cheapest way to approximate the blue/yellow false colour stuff on an osc is to split and recombine the channels from a UHC filtered image. But if this is your first attempt at deep sky, perhaps better to go with a longer wavelength ir cut filter (links above) and treat the camera as a standard astronomically modified version. In so doing record all the visible wavelengths whilst eliminating the fuzz from the out of focus ir. Even then, as you can see from your image, stars are well focused and without blur so unless you're planning to use a refractor, to begin with you probably don't need one as colour is easily corrected in processing. HTH

Hi Here's hoping your re-install will work. If not... A good sq1 starting point would be to obtain concrete information upon the camera and its connection. It's possible the 'faulty' computer is trying to load the camera as a block device -such as a usb memory pen- to enable the client to download images, rather than for the same to be controlled as an imaging device. Anyway... Remove any storage from the 6d. Now, on the Mint box, tail the system log: tail -f /var/log/syslog Next, with the camera (+canon lens) turned off but set to 'M', plug it into a usb2 socket. Now power the camera. What do we see? Cheers and HTH