Peter Drew

For housing Dobsonians over 14" aperture I use fixed buildings and the telescope rolls out on rails. 🙂

I've had pleasing solar views at 80x using a C8 with a full aperture white light filter. Just pick a good day/time of day. 🙂

Probably someone has but not worth doing seriously, you would lose the benefits normally obtained by binoviewing.

I think most amateur available mirrors are overcoated with silicon dioxide as a protection for the softer aluminium. Mirrors, like star diagonals, can be dielectrically overcoated for greater protection but the process is very expensive. 🙂

We get several requests each year for recipients of stars etc to help them with the location and the possibility of visiting to have a look at them through one of our telescopes. Almost invariably, the star is far too dim or badly placed for little to no chance of a view. I have often asked whether they had any input with the choice as the high magnitude numbers suggest inexperienced selection, apparently not. We were able, on one occasion to show someone their patch of land on the Moon thanks to the services of Quickmap which zoomed to show that it even had its own small crater. I know that many astronomical groups, including our own, to a degree frown on these star naming sites but it does give pleasure or condolence depending on the circumstances, I just wish that, as mentioned by the OP that the vendors would pay a little more attention to the reality.

Another vote for a zoom eyepiece for single unit use. I use binoviewers these days though. 🙂

Pity about the distance to Oz. I could fix it in less than 15 minutes if down your street. I would just pop it in the lathe, drill out the remaining bit of thread, re-tap it with the correct thread and screw in a new length with some threadlock. Surely someone close by in Oz could do this for you? 🙂

Open a bag of salt, take a large pinch ...........etc,etc. 😀

I'd rather have an achromatic doublet lens made by Skywatcher than a Flourite doublet lens made by me! It's not always just about the glass. 🙂

By contrast, I have a 4" Flourite and a 5" triplet that I've used probably no more than twice in the last 5 years. I also have a 150ED that gets used frequently as it's mounted on a larger telescope as a finder/general purpose telescope. I don't need to G & G and I rarely take a telescope anywhere else, usually once a year to Kelling. 🙂

@Goldenmole. Your telescope has an erecting prism diagonal, the prism will show a bar across the middle when used at night, if you plan to replace it make sure you get a standard 90 degree star diagonal. 🙂

Some years ago now Nigella, life still goes on though. 🙂

Of the many PST etalons that I have used, all were good enough, quite good and a couple were exceptional. One of the latter couple was stolen along with the modded 6" refractor and its full aperture ERF, the other is in my 6" replacement. 🙂

Just been reading a thought provoking thread on another forum about the distance of the Andromeda Galaxy. The OP asked, being as the galaxy is accepted as appearing as it was 2.5 million years ago, how much nearer to us is it now. It appears that at its speed is 110 kilometres/sec it will be 917 light years nearer, in other words not a noticeable amount. It was then said that if scaled down to the galaxy being equivalent to a human being the distance would be 1/2" in 2.5 million years and the distance to the galaxy about 7.5ft. A further thought was that due to its supposed diameter of 200,000 light years, light observed from its nearest edge reaches us 200,000 years sooner than light from its furthest edge. Something to think about when you next observe it. 🤔

I think it's a real but frustrating issue that some people just don't get on with binocular vision, be it binoculars or binoviewers. You have already tried the obvious experiment, adjusting the IPD as this is often the problem. I can't think of any further advice unfortunately. ☹️

The "tuner" is a pressure chamber. Screwing it in compresses the air which in turn increases pressure on the Ha etalon. The etalon is two glass discs separated by a precise air gap, the increased pressure varies the air gap which varies the bandpass width of the etalon. The bandpass determines what Ha detail is optimised. 🙂

Despite the mew in Mewlon, it's not a CAT it's a Dall-Kirkham Cassegrain. 😀

I don't think this will work. The optics in the Hyperstar correct the aberrations from the F2 primary much as the corrector plate and secondary mirror combination do for the native F10 system. Without the Hyperstar the images are likely to be horrible. 🙂

I don't have these details but presume so. I do know that the equipment was insured so hopefully that will soften the blow.

This is exactly what I used to do when I made Maksutovs commercially. The screw -on larger disc was used for terrestrial purposes where contrast reduction due to sky flooding would be noticeable with a small obstruction. The only practical way to eliminate this problem for both astro and terrestrial use was to employ the Dall modification that included an erector transfer system into the primary mirror support baffle tube. This enabled a much smaller CO without any sky-flooding. 🙂

I thought I said "decent size" that's only a 16", can't Takahashi make big telescopes? 😀

For visual I would go for the extra aperture of the 9.25" 🙂

Probably best me via a PM and I can pass the info on.

A local astronomer had his observatory broken in to recently, the following items were stolen:- TV NP101 with 90MM CORONADO ETALON ATTACHED 80mm REFRACTOR with 40MM CORONADO ETALON ATTACHED STARWAVE 102 CANON 20D CANON 20DA Please be on the lookout for such items being offered in unusual circumstances.

The further away from the eyepiece is from the diagonal then the further into the focal point the diagonal will need to be to achieve focus. Therefore more of the diagonal optical surface will be in use and better the diagonal quality needs to be. 🙂