BirdForum is the net's largest birding community dedicated to wild birds and birding, and is absolutely FREE!

Register for an account to take part in lively discussions in the forum, post your pictures in the gallery and more.

Reply to thread

Message: <blockquote data-quote="Binastro" data-source="post: 3166522" data-attributes="member: 111403">Hermann, the one you have seems to be a late one made in 1992, may be post-Soviet, but it still may be good.I've had about four of these over the years with varying manufacturing dates. They generally do perform well up to 100 times, although I found that they have temperature stabilisation problems if used in cold weather or through an open window. Part of this is atmospheric disturbance, but also due to the instrument itself.The eyepieces that you have are probably very high quality.There was I think a variation, possibly called a Russar, which had a doublet corrector in the front, rather than the normal single corrector. Whether this was better or not I don't know, it may be better corrected off axis.Many mirror lenses have been made with doublet correctors and also complex relay lenses, and some use Mangin mirrors, where the mirror itself is used as a refractive element with the coating on the back rather than on the front.The 1000/F10 MTO is a fairly simple version, but of high quality.The filters supplied with it are usually of high quality and is the cheapest way of getting good quality filters 100 mm diameter.Both the Russian and Soviet 500 mm F/8 and 1000 mm F/10 are geometrically correct F numbers.However, the Japanese good quality mirror lenses such as Nikon, Minolta, Canon and the Optomax are 77 mm aperture instead of 62 mm or 63 mm for the Russian 500 mm F/8. The Japanese ones compensate for the central obstruction. However you cannot call them 500 mm T/8 as they are not further corrected for transmission losses. So there may be 500 mm T/9.5 unless they have enhanced coatings.The Tamron I think uses enhanced coatings, possibly a doublet corrector and maybe a back silvered mirror?This is usually very good and a bit better than the Sigma or Tokina versions.One really needs to try these lenses at high magnification on stars to see how good they are.The one that I have, mentioned above, is quite outstanding and was made about 1950, and has a special wooden box. It is about the best optical quality that can be made. It is made by a master craftsman and I've often wondered whether it was made by Maksutov himself, although I don't know offhand the year he was born. It is definitely better than two Questar telescopes that I have used. Bouwers in Holland independently invented the same thing, but during the war years they did not know about each other's work. But Den Oude Delft made fantastic quality optics, at least the ones I've seen.The Mirador 70 mm spotting scope is also essentially perfect and can be used up to 200 times magnification.I think it was a special manufacturers sample, as I have not seen another one.Similarly, the Pentax 100 mm F/12 top quality refractor that I had also seems to have been a special manufacturers sample.These are the optics to get, if you can get hold of them.The Russian small spotting scope that I have is maybe 65 mm or 70 mm aperture, I think called Astele? It is also very good and can be used at high power.Generally, Soviet and Russian mirror lenses and mirrors scopes are of high quality, although quite heavy.These types of telescopes are optically good at high magnification, although because of their long focal length they are not suited to low magnification and they don't have wide fields. If buying a goto telescope I would definitely not advise going for one of these long focal length instruments, but rather go for a short focal ratio, because the goto is often not accurate enough to find anything. Beginners buy these telescopes, get completely frustrated. The telescopes end up in the attic and the owners lose interest.Similarly, I would advise against any beginner buying a telescope with a flimsy Equatorial mounting and tripod. They are pretty useless. A simple sturdy altazimuth mount works and is a much better idea.Unfortunately, people nowadays think that electronics and digital is a way is the way to go. It isn't.</blockquote>

Verification