michael.h.f.wilkinson

Sometimes slightly different design decisions in terms of distortion correction are made in spotting scope EPs compared to astronomical EPs, but I doubt there would be any major problems. There are several zoom EPs originally intended for spotting scopes that have gained a high reputation in astronomy (Leica and Pentax spring to mind)

Superb images, especially given the turbulence

Of course, but a fast APO refractor makes life a lot easier, and for visual there is no substitute for a real wide-field scope. Even if my C8 working at F/4 replaces the 6" F/5 Schmidt-Newton for imaging with the ASI183MM-Pro, the latter scope will still be a great comet sweeper, and allow the use of bigger cameras., capturing more photons in its wider field.

Not ideal for wide field, however. I would say the sweet spot is with the C8. It isn't much heavier than the C6, but has the much bigger light grasp.

Just pulled the trigger on the Starizona Night Owl 0.4x reducer. Couldn't resist (or to quote Oliver Hardy "Now look at what you have made me do!" )

Very nice indeed, especially for such a short exposure time. What telescope and camera did you use?

That was my impression too. They looked like a fairly close but still clearly resolved binary with near equal components in my 16x80 bins

Solar heat tends to shatter or melt things at the EP end, i.e. near the point of focus, not at the objective, which isn't exposed to any unusual concentration of sunlight. So indeed, this is more a case of "blunt-force trauma"

Just had a look at the nova, and definitely spotted it with the big 16x80 binoculars. Initially M52 was quite hard to spot, but as my eyes got more dark adapted, it stood out quite distinctly in averted vision. I could clearly spot the nova nearby, with the aid of a couple of the images in this thread. That's my third nova bagged

I have never noticed any temperature related issues like tube currents in the APM 80 mm triplet, unlike in my C8. I do store the telescopes in a fairly cool garage (there is a radiator there, but that is only switched on enough to prevent things freezing), so that might be the reason. I only get some reduced sharpness due to tube currents if I observe the sun with Herschel Wedge or Ca-K module without my tri-band ERF. The ERF clearly keeps the air in the tube cooler, and cuts back tube currents.

I have an APM 80 mm F/6 triplet (same as the earlier TS version) which is a lovely lightweight travel scope, and really nice imaging scope.

Really interesting. They don't seem to be in stock in many places

The M51 must be a crop, given my image of M51 at 762 mm focal length and the same sensor

That should work. The Starizona is better, but this is doable. You could even let everything hang out at and bin in software later if you don't like it

The 0.63x reducer would certainly work in a C5, in combination with an ASI178MM. The 0.63x reducer is a lot cheaper, and doesn't require a 2" visual back, which the Starizona reducer does require. Note that the image of M13 was taken at just 384mm focal length, whereas the C5 with 0.63x reducer has more than twice that at 788mm. Even with the 0.4x reducer you end up with 500mm. If you invest in something like the Starizona 0.4x reducer, and a 2" visual back, costs all adds up and I would wonder if a small refractor might not be the better investment. You might be able to find the 0.33x reducers solely intended for imaging with small sensors that can be had for very little, but I do not know whether the image quality is sufficient for the small pixels of the ASI178MM.

Hadn't seen that reducer yet. That would work rather neatly in my C8 combined with the ASI183MC and ASI183MM-Pro I have (15.9mm diagonal). This would mean serious competition for the 6" F/5 Schmidt Newton (762 mm focal length at F/5 vs 812 mm at F/4).

I have done some DSO imaging with the ASI178MM I have (mainly used for solar white light and Ca-K), but at a much faster focal ratio than the F/10 of the C5. I would certainly get a 0.63x focal reducer, which will make life a lot less difficult for DSO imaging, first of all because more photons hit each pixel, and secondly because guiding errors are reduced. The image below was with am APM 80mm F/6 with 0.8x reducer, LRGB image using a filterwheel.

Nice one! I have been targeting this area recently. Fingers crossed might get some more data tonight (even with a bit more moon, but as you say, beggars can't be choosers).

It is not so much a matter of resolving power, but limiting magnitude. I never catch even the brightest stars of M13 or M22 with my 80 mm, could make out a fine "diamond dust" effect in my old 6" Newton, and clearly see a mass of stars in my C8. Aperture is king. The view of these clusters with Olly's old 20" Dobson was absolutely amazing.

Very nice result indeed

It is far more extensive, when skies clear again I hope to get a lot more data, and when our curfew ends I can even get the data from a properly dark site.

Clouds here, alas. Will give it a shot with the 16x80s when they decide to buzz off

Managed to get about one hour's worth of luminance, and 30 minutes in R, G, and B, each (2x2 binned), and added this to the data from Wednesday night, with the stallwart Meade SN-6 6" F/5 Schmidt-Newton and ASI183MM-Pro and ZWO 8-position EFW. The result is a clear improvement on the earlier attempt. Still a long way to go however. I found the best way of adding the colour into the luminance data was to decompose the RGB into HSL channels in Gimp, and replace the L channel with the Luminance data. I could perhaps create a weighted sum of t he L channel of the HSL decomposition of the RGB data and data captured with the L filter. This is the first time I combine luminance data with 2x2 colour data.

Just 1.5 hours of L data, but it is a start Data grabbed with the SN6 6" F/5 Schmidt-Newton with ASI183MM-Pro. Stacked in APP, tweaks in Gimp. I hope I can get more L and R, G, B tonight. Much more data needed

Would have loved to see those