alacant

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

Not so much the primary mirror, rather the silly backfocus; more that half the focal length comes after the secondary. Imagine trying to hold a camera, no matter how light at this distance from the tube, let alone balance the same! Hopefully the sw doesn't have this problem. Yours is looking promising. Good luck and do report back.

Hi Lovely shot. The amount of detail is superb. Love it. Just a thought... With the 533, are you sure it's necessary to introduce more glass? The field is easily corrected in software. Don't know about ps but very easy in StarTools' lens module:

The one you need to begin with is an ir cut. These usually include a UV cut off too. The latter is not needed for your reflector, but neither will it do any harm. Rather than Ha, which will give you monochrome (process in shades of any single colour you like), try a UHC. Links to ir the filters here. UHC from the same source. HTH

Either a clip in filter for your camera or 2" filter + double sided tape:

Hi As @barbulo comments and confirmed on the ground using Siril: drift along DEC. Over 5 minutes, the mount needs to be mechanically perfect, correctly adjusted and with both -very- accurate polar alignment and tracking. Maybe take more say, one minute frames instead? Or you could guide the mount. Cheers and HTH.

Hi We can't tell because we don't know which which adapter you are using. The 200p comes with both 1.25" and 2" adapters. So either This or this.will get you there. HTH

Some ideas: Drill the dovetail plate where you want the bolts to fall Fit a wide Losmandy dovetail plate or. simply... Cheers and HTH

Our cat guy says something like this... Assuming you're in focus with an eyepiece, the camera needs to be between 10cm to 15cm from the rear face of the telescope, probably nearer the latter. You may need an extension tube. HTH

Hi Given the mechanics of an 80ed, I'd say very good. Adjusting from here may make matters worse. For values as close as this, simply reseating the camera or any other part of the train would most likely result in different tilt. If anything, maybe the focus is a little wayward. Best not to use a focusing mask as not all colours coincide in the focusing pattern. To get you close, choose a -not too bright- white star. Look for the minimum hfd value as you rack the focuser.. Now adjust focus -a tiny amount- until the blue halo just begins to disappear.

Hi Amazing amount of detail for such a short exposure. Love it. We'd recommend dithering between frames. If you've around 20 or so, you then stand a good chance of the trails being removed by stacking; use a decent clipping algorithm. Cheers and HTH