michael.h.f.wilkinson

When I got up to make breakfast I noticed the skies were pretty clear, so I put on a warm coat and took the Helios LightQuest 16x80 bins out. Moonlight was a bit troublesome, but at least the moon was far away from Corona Borealis. After a few attempts, and getting out the bigger star chart and getting the position right (I first accidentally looked between gamma and delta CrB, rather than delta and epsilon CrB), I noticed a little ball of fuzz. Repeating the exercise a couple of times confirmed the little ball of fuzz, and checking the position on the map confirmed the sighting. No tail could be seen. This is my second sighting of this comet, but the first in binoculars.

Observing with the SC filter and Herschel wedge didn't ever cause me any discomfort with my 80mm F/6, as the wedge plus ND filter remove enough of the energy anyway. For bigger scopes there may be an issue. For imaging, you really need to insert a UV/IR cut filter. I must say the new SC filter looks an interesting proposition.

I am not claiming there is no market for this, I am claiming that this type of device is no replacement for larger telescopes, whether full-blown, go-to imaging rigs, or grab-and-go visual scopes or Dobsonians. It is just another tool in the box

Just to put things in perspective, the Rayleigh limit for a 24mm aperture is 5.75 arc seconds (way worse than the seeing disk), my 80mm boasts a 1.73 arc second limit, and the C8 0.68 arc seconds (only ever achievable with lucky imaging, of course). Stars will hardly be pinpricks in the 24 mm. Using the Dawes limit we get 4.83", 1.45" and 0.57" respectively

That's a wrong comparison, because it suggests a big scope cannot be equipped with a modern sensor. Besides, to quote Scotty: Ye cannae change the laws of physics, captain". A big instrument captures more photons and has a higher resolution than a smaller. My APM 80 mm F/6 triplet is optically outstanding, but cannot match the resolution the 8" C8 has on planets. There is simply no contest. A 30mm scope will not show as much detail as, and will capture 4 times fewer photons from the same area in the sky than a 60 mm, this means the S/N is half as good. Resolution-wise, a little 30 mm lens will not be able to capture the moon like this: Click for full resolution. No amount of AI-driven enhancement will change that, simply because the information isn't contained in the data. A colleague of mine showed a paper in which it was shown that a deep-learning-based sharpening method on astronomical data hallucinated several objects (i.e. created objects out of noise). Whilst adding some freckles, or misplacing hairs in AI super-resolution applications to old portraits is quite tolerable, in scientific or medical imaging this kind of creativity is unacceptable.

On my other monitor I notice a bit of a ringing effect on Jupiter in particular. Will do a reprocess later

Interesting, especially for large targets, but for smaller targets there is no replacement for aperture.

Had a quick bash at Jupiter before it got too low behind the trees, and was able to catch a bit of shadow transit Seeing wasn't brilliant, but at least I didn't get too much in the way of clouds I then turned to Mars, which was higher in the sky. The first shot, taken at 20:18 already showed some nice detail The second was taken almost two hours later, at 22:10: I think I can make out Olympus Mons and Alba Mons in the north. All pictures taken with my Celestron C8, with Siebert Optics 1.3x Tele-Centric and ASI183MC camera. The Jupiter shot is a stack of 20% of 9000 frames, the Mars shots 20% of 10000 frames and 40% of 20000 frames respectively.

That is really good. I am hoping to have a go tonight. Fingers crossed

Amazing stuff!

Indeed. The 183MM yields this with the same 135mm F/2 lens and an H-alpha filter The ASI183MC (non-cooled) yielded this with 4 h of data on my Meade SN6 6"F/5 Schmidt-Newton

I also have a cooled and a non-cooled ASI183, and rather like them. Might go for a bigger sensor at some time, but for now they will do. I also still have a modded 550D, which can produce some nice results, despite its age, especially when paired with the Samyang 135mm F/2.

Callig it a game changer is a bit much, I agree. At a similar focal length, and lighter weight, I will stick with my Meade SN6 6" F/5 Schmidt-Newton. It was also ridiculously cheap. Correction perhaps not quite as good as a top of the line apochromat, but at twice the light gathering capacity, and no diffraction spikes it makes me wonder why SN6 was discontinued. I am sometimes tempted by various Mak-Newts, as well

Welcome to the forum, Dylan!

I had a similar mount and telescope (4.5" f=500 Newtonian, now refurbished as mini-Dob). The mount isn't that stable, but after changing the aluminium legs with home-made hardwood legs, it was a lot better. More details here: I ultimately ditched the mount (which I didn't really need, as I had a perfectly serviceable Great Polaris mount), and put a mini-giro manual alt-az mount on it

In that case you'd better not practice the fleckerl in the Viennese waltz as I did yesterday

I just worked out that in the sixty years (and a bit) of my life so far, the earth has moved just over one third of a arc second in its orbit around the centre of the galaxy. Should I reach 85, that will go up to about half an arc second. Since Galileo's birth, the centre of our galaxy has moved just under 2.7 seconds of arc with respect to distant galaxies. A bit of a pale-blue-dot moment.

That is a lovely kind of set-up. I often use my APM 80mm triplet with a 2" Amici prism and the Nagler 31T5, yielding 5.3 deg FOV at 15.5x magnification. I did a comparison with the views in a pair of Helios Apollo 15x70 bins here: The bins have the definite edge in portability, but the 80 mm triplet beats them for visual impact

I can ask the people at the observatory

It actually is capable of fast imaging, and huge data throughput.

Had a bit of a struggle today, but at least got some result. Clear skies were replaced by clouds the moment the entire set-up was ready to go, but I persevered, and waited for the skies to clear. Indeed, 30 minutes or so later the sky was clear enough around Jupiter, so I decided to give it a go. Seeing was choppy, but I got a series of SER files before the next batch of clouds popped by. I waited some more, whilst doing a quick process of one or two files (with mixed results). Once the sky was clear again, I gave it another go, but the seeing was considerably worse, and with more clouds threatening, I gave up the idea of waiting for Mars to rise above the trees to my east. As it turned out, the first SER file I took was the best: Not brilliant, but better than nothing I suppose. Equipment: Celestron C8 on Vixen Great Polaris mount, with Siebert Optics 1.3x Tele-Centric, and ASI183MC camera

I don't think a regular Barlow would fit in HiPERCAM

An astronomer I know and I discussed the option of imaging Jupiter with the Gran Telescopio de Canarias (10.4 m, and he had observing time on it), with a very fast multi-band imaging device (HiPERCAM). He had observing time available, and all we asked for was 5 minutes, but the powers that be decided against it. The problem is that even with very short exposure times, freezing the seeing is not straightforward on such a big instrument, according to the technicians of the observatory, as you are requiring a much larger part of the sky to stay put. We were eager to try it in any case, but ultimately didn't get the green light.

Had a quick lunch break outside with the Coronado SolarMax II 60. Apart from quite a bit of activity on the disk, with some nice spots, plage areas, and filaments, a huge array of proms was visible on the right-hand (eastern) side of the disk. A smaller prom could be seen at the eight o'clock position. Several students joined me to have a look, so it was a nice little outreach event.

That is very nice. Very natural look with loads of detail