ollypenrice

Hard to like it, I agree! Olly

You switched them off, Maurice! (Don't worry, nobody on here will tell the Police!!!!) Olly

This started years ago for me when I was cooking for a group of Dutch guests. I asked if they had any specific likes or dislikes and they said, 'We all hate tomatoes!' I looked a bit blank since hating tomatoes is unusual. With a grin one of them turned his PC towards me with a picture of a vivid orange glow above about 50 square miles of illuminated tomatoes... lly

Both, I guess!

The tomato problem does exist in astronomy! Ask any of our Dutch members... Olly

My main setup hasn't changed in two years. What could go wrong next time out? Everything! lly

Indeed we did. The Taks (now a pair) have moved into a block built observatory on the other side of the path.

Steve Richards got me with the same observation a few years ago! At the risk of responding too solemnly to a good joke, the essence of the Mesu is the extremely fastidious manner in which the friction drive is engineered. Above all the choice of materiel for the driving and driven surfaces is critical. The Mesu does not use smooth anodized aluminium on either. You could suggest to Lucas Mesu that he try it but I'd be inclined to stand well back as you do so! This is why Baader have invested so much time in finding the right material for the driven part of the drawtube and why Moonlite should, in my view, do the same. Their product could easily be modified accordingly. Other aspects of their focuser are excellent but there are more than enough posts in this thread to confirm that it can lack the grip needed for heavy-camera imaging and even, it seems, for supporting heavy eyepieces. I think mine would support heavy EPs but, so far, we've only tried it with a camera in a motorized focus application where it failed due to slippage. Olly

Quite so!

I don't know but it looks like a soft tipped pressure screw on mine (pressing down from the opposite side to the R and P mechanism.) I tend to give it a slight tweak after each focus iteration before looking at the FWHM since it always affects the value if I focus first and then tighten. Crayfords seem to have an assortment of ways of making the lock screw press on something - and not always the same thing. Olly

To take the conversation in a different direction, I often wonder why focus locks are designed as they usually are - which is to use a screw pressing on the draw tube. To avoid their damaging the drawtube they usually have nylon tips which are, of course, not very effective at holding the drawtube in place. They also push the drawtube from one side which is not good for the friction in a Crayford design or the mesh in an R and P. Nor is it good for the drawtube bearings since it enourages play over time. An alternative method would be to have a flat strip of low-expansion material attached to the rear of the drawtube and passing through a small clamp at the rear of the main tube. Either the entire focuser including clamp could rotate (the 'Captain's wheel' design) or a rotator could be added at the rear of the draw tube. No pressure would be applied to the draw tube and the strip-and-clamp would be doing what they were designed to do, which is be clamped. The conventional system has a drawtube being asked to do the opposite of what it was designed to do, which is move freely. A scribble: So what we're trying to do here is uncouple the holding still of the drawtube from the quite different problem of driving it smoothly while retaining sufficient tension for it not to slip until fixed. Olly PS I suspect, but don't know, that such a clamp would have less effect on fine focus than the present methods. As all imagers know, locking the draw tube does affect critical focus. PPS Oops, no good for remote operation!

I also have four... Olly

Of course you are! I for one have never said otherwise, nor would I.

Putting words in my mouth by implication? I wouldn't dream of denying anyone the right to own and like them. I own one and would like it for visual use. I'd like it even more with a strip of grippier material for the spindle to drive and I wouldn't be in the least surprised to see this introduced. Note that Baader are now on their second generation of 'grippy strips' which suggests that there are engineers out there (and Baader are certainly engineers) who see it as a key issue. BTW, as I said at the outset I think that the Moonlite design has it over the competition in terms of the effectively self-orientating drawtube/spindle. Many of the solutions to this problem are vastly over-complicated and difficult to adjust. Olly

For me too, with my older 10 inch. This one is staying just as it is! Olly

I thought I was being rather balanced here! I have made a clear distinction between good and bad Crayford practice, 'bad' being driving a smooth anodized drawtube directly with a steel roller. It just is bad, in my book. I think my Moonlite is poor for this very reason. (Poor for imaging. It would make a nice visual focuser on a Dob. Very smooth.) Olly

Sadly not. The electronic focuser holds the focus knob reliably but the Crayfoprd design relies on friction between the focuser shaft and the draw tube to hold the payload. That is why Baader insist on the nature of the driven surfaces in their naming. There's the Steeltrack which has an unpolished steel driven strip and the diamant which has a grippier industrial diamond driven strip. Having the steel shaft drive a slippery anodized aluminium drawtube is just not good practice. Sure, they often work - but they sometimes don't. Why not just get it right first time? If an imager's robo focus works by counting motor steps it needs to know that a step is a step and not a slip. Olly

So, some finishing touches. Steve's cable with low profile 90 degree jack: New cladding on the roll off. Note that the pod on the side is now an eyepiece pod rather than a PC pod! And last but not least... Olly

Good idea on slew speeds. I'll do that. I don't have to worry about the noise but wear on the gears is best avoided. Thanks. We found no need to re-synch during our first night out but, yes, it's an option. To everyone's surprise the GoTo was bang on all over the sky. Given a simple two star alignment we found this remarkable. I guess the mount's measurement of its own tilt plays a large part in its success. Pity we can't do GEM polar alignment this way! Olly

Awe, you're most kind Steve. I was expecting it to be a great pleasure to meet you and Jane and, of course, it was. In spades. My robotic client was also delighted that you could fix his autofocus. I guess I had the wrong steam pressure going... I'll post a bit more on the Meade 14 inch once its brass plaque arrives (naming it for Alan and currently in the post). Your cable will need honorable photographic mention as well. And there will also be, thanks to Jane, the floral connection between the Chanconbury Observatory and Les Granges.... I just need to find a competent daytime photographer for all this. Sincere thanks for giving us a great couple of days. Olly and Monique.

How frank should I be? Very? Then the Moonlite is a joke, albeit a pretty joke. It has one nice design feature, which is that there is no need to align the drive shaft to the drawtube. It is the interaction between the two which defines the rotational angle of the drawtube. This is good. What is dismal is that the roller drives the smooth anodized surface of the drawtube. This is fine on a Dob, where the focuser is always horizontal and carries no weight. It may also be OK on Cats and refractors for visual when it only has to resist the pull of an eyepiece. But hang a camera on it and it is soooo likely to slip. Sorry, it doesn't make the grade. We did heavy camera CCD imaging with a Baader Steeltrack without difficulty here for two years but one of our robotic Baader Steeltracks cracked a ballbearing. Feathertouch rack and pinion? That would be my choice. I have all three so have no axe to grind. Olly

The 'adjustable cell' shouldn't be overlooked lightly. If a refractor has a properly designed cell it can be recollimated if necessary. Olly

The collision is worse than it looks in the picture. Olly

A thing of beauty is a joy forever! Warmest thanks, Steve. Olly