Peter Drew

Apologies for multiple posts, don't know what went wrong there? 🙂

I've built more than 20 binoscopes over the years, both reflecting and refracting so have no qualms about building any size, the main limitation is cost!. I do have a spare 18" F3.6 mirror, it's tempting to get another made. I have not found it necessary to use coma correctors on my 12" reflecting binoscope despite the off axis images being compromised. When you use a binoscope you generally concentrate on the central image and the periphery is just a perception, the eye has a very small field of definition and resolution. Try looking at a page of text without moving your eyes and you will find that it is difficult to read more than an extra word either side of it, the same goes for stars in a binoscope. 🙂

I've built more than 20 binoscopes over the years, both reflecting and refracting so have no qualms about building any size, the main limitation is cost!. I do have a spare 18" F3.6 mirror, it's tempting to get another made. I have not found it necessary to use coma correctors on my 12" reflecting binoscope despite the off axis images being compromised. When you use a binoscope you generally concentrate on the central image and the periphery is just a perception, the eye has a very small field of definition and resolution. Try looking at a page of text without moving your eyes and you will find that it is difficult to read more than an extra word either side of it, the same goes for stars in a binoscope. 🙂

I've built more than 20 binoscopes over the years, both reflecting and refracting so have no qualms about building any size, the main limitation is cost!. I do have a spare 18" F3.6 mirror, it's tempting to get another made. I have not found it necessary to use coma correctors on my 12" reflecting binoscope despite the off axis images being compromised. When you use a binoscope you generally concentrate on the central image and the periphery is just a perception, the eye has a very small field of definition and resolution. Try looking at a page of text without moving your eyes and you will find that it is difficult to read more than an extra word either side of it, the same goes for stars in a binoscope. 🙂

I've built more than 20 binoscopes over the years, both reflecting and refracting so have no qualms about building any size, the main limitation is cost!. I do have a spare 18" F3.6 mirror, it's tempting to get another made. I have not found it necessary to use coma correctors on my 12" reflecting binoscope despite the off axis images being compromised. When you use a binoscope you generally concentrate on the central image and the periphery is just a perception, the eye has a very small field of definition and resolution. Try looking at a page of text without moving your eyes and you will find that it is difficult to read more than an extra word either side of it, the same goes for stars in a binoscope. 🙂

Here's another related thought. It is usually advised that if the telescope's exit pupil is larger than that of your eye, then the aperture of the telescope is effectively reduced. On that basis, when observing a bright Moon, presumably the iris in your eye stops down to its minimum aperture, surely this could be effectively stopping down the aperture of the telescope? 🙂

Welcome to SGL. Sounds as though the tube is unbalanced and front heavy, the higher the tube is raised, the less the effect is. Have you left the cover on the front for this test? 🙂

For imaging, yes. For visual, probably not. 🙂

Send yourself an email congratulating you on winning a (telescope of choice) and keep the ensuing expense secret.

Poor seeing is better than no seeing. ☹️

The largest Dob I've heard of in Europe is around 40". VCSM in N. London can coat mirrors to at least 30" as they have done ours a couple of times over the years. 🙂

The camera is underwater, hence the mushy image. 🙂

Definitely in OOUK livery rather than OOUS. The length of the tube suggests that the "L" could stand for long focus. 🙂

That's bad luck. You might find that you have a broken small bearing that the focus tube rides on, they can be quite brittle and a sharp blow could split one. They are replaceable if necessary.

I don't see why not. As long as you can mount the encoders central to the rotational axes, the encoders have no idea what telescope they are being used on. 🙂

There is a VX200, perhaps someone spelt it incorrectly. 🙂

I would suggest a long arm be fitted to the mount, it gives better control and avoids touching the telescope. This method has been used successfully for tracking and photographing the ISS. 🙂

A suitable mount for the purpose is likely to be a challenge. 🙂

I quite like looking at high altitude aircraft now and again and have used all manner of telescopes up to 30" aperture. It's difficult to give a recommendation as to the best telescope for the purpose due to their different characteristics. If a refractor it needs to be at least an ED version, objects against a bright sky are very unforgiving concerning CA and you need the optical quality to stand the high power. Probably a 80ED or a 102 Mak would be adequate, they both have adequate light grasp for, presumably, daytime use. A zoom eyepiece would be a good choice and a 6x30 RACI finder would help with target acquisition.

There seem to be some significant extensions to the rear on some of these setup photos. I would have thought that the usual caveats regarding correction on Cassegrains when far from the design optimum would apply also to this model? 🙂

I have a XT8i Intelliscope. I bought it second hand based on the excellent planetary views it gave. The push to system worked well if set up carefully. There is an "urban myth" that Intelliscope optics are cherry picked (?). I have dumbed down my Intelliscope by removing the push to system and re-installing it on a 20" Dobsonian. 🙂

Assuming it's a Crayford type focuser, there will be an adjustment facility to address the slippage, the locking screw shouldn't be needed for this. The adjustments are usually underneath the focuser body, either Allen head screws or thumbscrews depending on the specific model. 🙂

🙂

Think of levelling this way. You level your mount, go through the alignment sequence and your goto works fine. At the same time, a user 10 degrees South of you does exactly the same thing and the goto works fine. Yet the level of the second telescope is 10 degrees out compared to yours yet still provides the same result. No harm in levelling an alt-azimuth goto mount but as long as it doesn't fall over, the goto will work. The star positions relative to each other, the basis for the alignment, are not variable. 🙂

Offer the seller your lottery win in exchange for the telescope. 🙂