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You'll always get some astigmatism in the corners over aps-c with the Baader mpcc anyway and the corner elongation should respond in going to ~60mm spacing. Apart from the points above, the new m27 stars look fine to me. Guiding at 1000mm is never going to be easy and you'll need nights of very good seeing to be able to do it justice. For other nights, maybe invest in something like a 130pds? Oh and a GPU cc;) Cheers and HTH

Most of the errors with the silicone are caused by pushing the mirror back into the cell instead of leaving it to cure under gravity. You need at least a 2mm thickness to allow for thermal expansion and contraction. Try reseating the primary. If not, next you'll need a secondary of known performance. HTH

Hi All the three frames display astigmatism. We need a shot without a filter to eliminate the same, although I doubt they're the cause. Next would be a shot without the cc. Then substitute the secondary. Then remove the mirror clips... etc. Or simply leave it as it is and correct in software. Cheers

So it's not the cc then;) Do you have an L frame without filter?

Hi There's quite pronounced astigmatism across the whole field. I'm guessing the Baader cc and/or filters. Could this have fooled the focuser? Cheers

Hi m27 shows triangular stars and there is constant elongation in your star tests. Our bet is that the 1º mirror is distorted. Either the sealant isn't thick enough or it has hardened, preventing the movement of the glass as the temperature changes. You probably pushed the mirror against the cork when you refitted it. If you're using an OAG, you don't need to modify the cell. It's only needed if you're using a separate guide telescope or if you've unacceptable diffraction patterns around stars. As it is, your stars look to have the potential to be superb, so stick at it. Strange diffraction from the secondary spider too, as if you've used an altitude-azimuth mount. Any ideas? In any case, you're going to need more space between the sensor and the shoulder of the m48 connection. We find that most of the 2 element Baader ccs need closer to 60mm. Our first call would be: 1. to set the mpcc at 60mm and go with the OAG. Or... 2. stiffen the tube with a longer Losmnady dovetail with the guide telescope mounted on a stiff top rail. Both will need the mirror removed, silicone cleaned and replaced with the correct type and amount. Guidelines which work for us, here, the main part being [1] Seal the mirror to the cell using neutral silicone sealant, generous blobs to coincide with the gso cork. Leave the mirror to settle under its own weight on a horizontal surface, that a blob of the same sealant under the same ambience returns to its original form when distorted. Only then refit. Cheers and HTH [1] gso used but also tested with a 200pds, 130pds, bresser etc; the same applies to any low end Newtonian.

Hi Love it. Great result for such a short time. Superb star field showing loadsa structure and nice colour in the nebula. Well done.

Yes. Absolutely. There's loadsa detail already: But be careful with the camera orientation. Best to leave the camera attached to the telescope to avoid rotation..

Probably, yes. I'm certain that will be down to differences in eyesight and patience. For inspiration, we looked at Google images. It seems anything goes. Take your pick!

Hi We don't think the equipment counts that much. Far more important is to have clear nights with steady seeing so that you can get accurate guiding. The filter is certainly not needed; we prefer as little glass as possible, but in this case, the UHC seems to concentrate the blue/green of planetary nebulae without it looking unnatural. Certainly better than the new generation (read €silly!) multi pass filters. It also allows you to isolate and recombine the colour channels. To get any red though, you'll need to remove your 550d's hot mirror. Otherwise, wait for good seeing and just keep adding frames. The longer, the better; the detail will begin to emerge. IIRC, we used ~8 minutes. Cheers, thanks for posting and do post back your results.

Hi everyone The Dumbbell with a bit of the outer halo showing. This is around 3 1/2 hours using a UHC filter and processed HOO. Not sure if there's much more to be had; DSLR users, do post if you have any experience of what to expect. Almost tempted to hit the ruin denoise button, but managed to resist! Cheers and thanks for looking. 700d on pn208 siril 1.1.0 startools 1.8.525-2

We use the GPU. Anywhere between f5 and f3.9, we find it -far- superior than any of the affordable ccs. Dunno. Try L and hope they're a little more par-focal? Cheers

? All seems well apart from the colour. I think R may be out of focus. The only other glass the light traverses is the cc. Borrow one you know to be good to eliminate that? But hey, for just 1 hour, this is good. Cheers and HTH

Hi Nice image. Could be cc, filter, focus... Post an unprocessed link to it if you like. That will help us.

Hi everyone Any other attempts at dark stuff with a DSLR, do please share your methods. TBH, i don't think there's much you can do, apart from keep snapping until the noise in the dark stuff disappears. Oh, and there's enough signal to colour-balance away the brown muddy stuff which otherwise gives the impression of the bad old 589 light pollution days. Thanks for looking. 700d on ES208 ~4h @ ISO800 revelado: siril-1.1.0 + st-1.8.527-2

You can scan a frame taken in darkness at 1/4000s in the siril window: hover -> statistics. Average the pixel values to the nearest power of 2. You'll find that the offset on a 600d is 2048. No need for bias frames themselves. But try for your self of course and do post if you see any difference. Cheers and HTH

Hi everyone Mediterranean haze, wildfire + local fiestas' smoke and gibbous moon notwithstanding, and with our clip-in filter doing the rounds elsewhere, an old 2" UHC on the end of the cc did a good job of getting something from nothing. But enough excuses... Processed HOO using StarTools' L + Synth L From R(2xG)B, R(GB)(GB) option, this worked better than expected, despite including the -noisy- blue channel. Thanks for looking and do please post your filtered DSLR shots. 700d on ES-208 ~3h @ ISO800 Siril 1.1.0, StarTools 1.5.7-2

Hi 600d, so lose the dark frames. Instead, simply subtract a constant bias value and use flat frames. +1 for doing this in Siril. Download here. Cheers and HTH.

Because with a DSLR, the light from the mirrors is not projected far enough out from the tube. Yes. Both of those telescopes will reach focus with a 550d. Yes. To fit the camera you need this and this. HTH

Hi Love it. Sorry, just couldn't resist an in-your-face HOO, as there's so much detail. But with the stars:) Cheers and clear skies.

We use DSLRs with sensor temperatures well above 30º. The images turn out fine. Cheers

Hi I'm guessing you're using the Baader cc. Cheers

Hi 6 minutes. The UHC allows you to go much longer, especially if you're light polluted. Moon or otherwise. Cheers

Hi everyone Almost full moon so a UHC filter to help with the glare and the noise. Split and recombined to HOO, so not sure about the colours, but judging by Google's image serch, anything goes. Background: stuff everywhere. Impossible. Thanks for looking and do please post your dslr versions. eos700d on ES pn208 ~4h @ ISO800 calibración: siril. revelado: startools 1.8.527-2

Hi Careful. The 'white ring' is the tube aperture reinforcement which forms part of the structure of the tube and secondary spider support. Unless you plan upon reinforcing the tube around the four knurled secondary spider thumb screws and focuser, it must be left in place. Cheers and HTH