Posts Made By: Nicholas Seiflow

If I understand things clearly (always a risky proposition) the state of mainstream telescope supply and manufacturing is in a parlous state.

The world's largest telescope manufacturer is Synta: Synta owns Celestron: Synta has for a long time been Orion's major supplier.

So, now you can buy a Synta SCT from Skywatcher USA (Synta), Celestron (Synta) or Orion (Synta). The different badges will fool some but not all buyers.
You can also do similarly with accessories, and of course you can do similarly with collapsible dobs and ED refractors etc. The Model T Ford: any color you want as long as it's black.

It seems odd that Synta should essentially be competing against itself, at least on paper. My guess is that this state of affairs cannot last: this might, for example, be a spur to the re-vivification of Meade, something most of us would like to see (I hope)

Let it be said that I don't have any problems with the quality of Synta products; we are spoiled as never before for good-quality inexpensive equipment. But when suppliers become retailers I think things get interesting, to say the least.

My suspicion is that this dynasty has grown so large that it has to implode somewhat, and this will be to the benefit of consumers - I am an optimist I suppose - and that we'll be even more spoiled for choices in the future. None of us likes a monopoly (unless we own it) and neither do retailers for obvious reasons.

Exciting times ahead?

(If it's OK with the powers-that-be I'm going to post this question on The Other Forum Group. It will be interesting to compare responses...)

As a long time user of SCT's I (like many) am constantly aware of two thermal issues. Firstly, cooling the optics to a state of equilibrium with the ambient temperature, and secondly, dealing with currents INSIDE the tube.

The first problem is solvable, either by patience or by fan cooling (Lymax e.g.), but the second seems more problematical. Many times the SCT seems more prone than other designs to thermal problems inside the tube: I can only surmise it has to do with the fact that not only is the tube uninsulted, but also that there are two operating reflective surfaces, the light passing a total of three times inside the tube before it reaches the eyepiece, and that the secondary magnifies the image (and perhaps the instability?) by a factor of around 5X. Whatever the cause or causes, I am constantly nagged by the feeling that the system is operating under par.

I am contemplating two attempts at a solution: lining the inside of the tube with cork, blackened of course, and an aggressive fan or fans, most probably mounted at the rear, but maybe at the side of the tube, so as to "scrub" the primary mirror. Peltier cooling seems an interesting alternative also.

Has anyone attempted, successfully or not, to do these things? I would love to hear from others with their experiences.
P.S. The tube in question is a 9.25.