Peter Drew

I don't think you are basically doing anything wrong. You are really up against it having to operate in the circumstances you describe. Even if you are viewing through an open window, the warmer air from inside will be flowing to mix with the colder air outside which will help to make the image blurry. A Maksutov needs a fair amount of time for the air inside it and also the optics in order to match that of the outside before the telescope will work well. The things you can do to improve matters are 1) Try to use it outside, 2) allow the telescope to reach equal air temperature and 3) Practice, practice, practice. You will also need a lucky night when the seeing conditions are good. Astronomy calls for a lot of patience, we've all been through this!. Welcome to the SGL "Helpline". 🙂

With an eyepiece you will need to focus even further out than with a camera. The telescope is most likely to need a diagonal for visual use. 🙂

I've been involved in this "game" longer than most but my main take from all this is ("Thank my lucky stars that I couldn't afford to buy a telescope!"). Why?, because it forced me to make my own which lead me on to being a telescope maker both as an amateur and a professional. 🙂

Just had a look. Same lousy seeing conditions, still better than no look!. Plenty to look at all round. 🙂

My interest level in equatorial platforms keeps coming to the surface. When the original Poncet design appeared I ended up making one to try and get my head round as to how they worked. This idea has gradually been modified almost out of recognition by DIY experts and a few manufacturers although the end result principle is much the same, moving an alt-azimuth mounted telescope in an equatorial manner. I'm thinking of revisiting the original design as it is both simple to make and could be engineered to carry considerable weight. If I remember correctly, the main shortcoming of the Poncet was that the drive mechanism was tangential to the drive direction so not of a constant speed. This lead to all manner of modifications to help address this. The original design had the top moving surface confined by a plane angled to suit the latitude, it ran on bearings attached to either the running or fixed surface, apart from some form of drive system, that's all that was needed. My current thoughts have been in the direction of driving one of the bearings which should rotate the driven surface without loss of accuracy once the radius of operation and motor speed have been determined. The simplicity should lend itself to rugged construction and significant load bearing. 🤔

I used to truncate the tips of the worm threads when I manufactured gear sets for just that reason. How difficult can it be in this day and age to make gear sets properly?. 🙄

You've just reinvented the wheel! (You did ask). Fullerscopes, at one point, attached their worm brackets wit rubber bushes surrounding the attachment screws. This was intended to allow sufficient "give" to compensate for eccentricities. They also had back stop screws to limit the degree of movement. 🙂

There is a limit as to how deep you can go with the teeth on a fine pitch gearwheel. Despite the flimsy appearance they are very strong, any drive that could strip these would already have serious other issues. Think how much pressure you can bring to bear on hose clips which have similar shallow depth. 🙂

More a case of spot Sun here! ☹️

That's why I mixed it with 50% Castrol LM grease. The load bearing was retained but things didn't seize up in Winter. 🙂

This problem underlines the benefit of the secondary holder "mod" where a disc is introduced between the three adjusting screws and the top of the holder. This simple mod allows the holder to be turned without being wobbly loose and the tightening of the three adjusting screws doesn't readjust the collimated setting. Plenty of detail how to do this elsewhere on this forum. 🙂

A tin of Kilopoise would last you 3 lifetimes of constant DIY telescope building so is probably quite good value! The last time I bought some about 30 years ago Rocol sold it in small squeezy toothpaste type tubes for a few quid each, I still have a scraping left. (NB, don't confuse the tubes with your toothpaste!) 🙂

Welcome to SGL Stargazer10. Whilst I would be one of the last to deter anyone from embarking on an ambitious project, I think you will have to be very aware of the complexity of mirror making let alone mirror casting. The former takes a great deal of prior experience on smaller mirrors and the latter is a science in itself bearing in mind the accuracy of the annealing process which can take several days. In what way was the magnification of your 8" "not great"?. I have an 8" and a 20" and on most nights in the UK the maximum magnification possible with either is very similar, it's the atmosphere that's the limitation, not the aperture. 🙂

I'm not a fan of white grease and similar, too thin for my liking when used in high load bearing situations. I prefer a heavier sticky grease that clings to the bearing surfaces, rather like the Chinese "gloop" that many complain about. I always used Rocol "Kilopoise" for worm/wormwheel lubrication and a 50/50 mix of Kilopoise and Castrol LM grease on other applications where load bearing was important but needed to still turn in very cold weather. I never had backlash issues due to eccentricity of the worm or wormwheel as I made sure they were concentric when I made them. It's not "rocket science". 🙂

I would try retaining the pivoting worm bracket and spring pressure but introduce an adjustable stop to limit the amount that the amount that the bracket can back away from the wormwheel at the tightest spot. Hopefully the difference in the backlash inducing eccentricity will not be excessive. (Though I won't be surprised if you haven't already tried this.) 🙂

Baader solar film will give excellent white light images, don't dismiss it as a "poor man's" wedge if on a budget. It is the 200P of the solar filter world for value. 🙂

If the telescope is of reasonable size and relatively fast focal ratio the displaced shadow might well be showing the offset of the secondary mirror. 🙂

If anyone is unclear why there can need to be an offset just draw a cone with a centre line. Then cut through the cone with another line at 45 degrees to represent the diagonal mirror. You will notice that where this line touches the edge of the cone, the top radius is smaller than the bottom radius. Offsetting the mirror towards the wider radius makes sure that the full amount of the aperture is transmitted to the eyepiece. If the diagonal mirror is oversize then offsetting is not important. 🙂

It's very much to do with the sensitivity to brightness of the viewers eye. I can look at the Moon with a 20" without needing any filter whereas my wife would need sunglasses to look at a full Moon with the naked eye! 🙂

The best advice would seem to be to spend a while using the telescope "as is" after which you'll have a better idea of what you may need. 🙂

That's a pity. however you shouldn't need to lock the focuser for visual use. 🙂

Well worth looking at the Mars section blog for a great selection of images and sketches of Mars 2020. 🙂

The above is why the Moon is the hardest object for a goto to find. 🙂

The locking screw definitely needs to go through the misaligned hole to perform its function, at the moment it would be locking on to the fixed casting. It may be that there is a floating plate that the hole is in that can somehow be repositioned properly. However, as pointed out, this should have no affect on the focusing assuming that the drawtube actually moves in and out whilst turning the focus knobs. 🙂

Plenty of canals round these parts to practice on prior to the next opposition. 🙂