Posts Made By: Roland Christen

Unitron was always just a marketing firm here in the US. They imported scopes from Japanese companies who used subcontractors to make the lenses. Most of these were very small 1 man shops operating out of basements or small workshops all over Tokyo. Nihon Seiko was the main assembly company in Japan that actually built the finished scopes and mountings. We did some business with Nihon Seiko some time back and visited them along with Vixen and other companies when we took our trip to Japan back in the '90s. All these craftsmen and Nihon Seiko are long gone, so any telescopes that Unitron would offer now would probably come from China.

Rolando

The weight load on a mount is handled by the shaft bearings, not the worm gear. The bearings on a mount can usually take a very large load and they are not the limiting factors. The worm takes the torque load or the moment arm. If your scope is long and weighs 50 lb, it puts very much more force on the worm gear teeth than a scope that is short and weighs 50 lb.

Rolando

Very very nice!

Rolando

There's a black hole on the ore of that galxy, pulling all the stars apart as they get sucked into the vortex. Send it in to your local paper and tell them that you have discovered the beginning of the end of the universe and all life therein

Rolando

You have a wonderful deep sky image of this galaxy and surrounding region. There is really not much I would change. The only possible improvement would be to do just the right amount of unsharp masking to reduce the halos around the stars, which would increase the contrast a bit also (see attached).

Rolando

>>I've read somewhere (don't remember where) That no binocs (prisms) are diffraction limited. Is this true?>>

You can also read somewhere that the sky is really yellow and the earth does not turn on its axis - such is the internet.

Most Bviewers were adapted from microscopes. Microscopes have long F-ratio objectives, which means that the light beams are extremely narrow compared to those of a telescope objective. Narrow light beams means the prisms do not need to be very accurate.

The Baader MarkV Binoviewer was designed by Zeiss specifically to be used with their fluorite triplet refractors, which have focal ratios from F6 to F10. The prisms are all very accurate and the binoviewer is totally diffraction limited at F6. The viewer has a built-in a compensating lens which I designed for them to be used with all non-Zeiss lenses (the Zeiss lenses were corrected specifically for use with prism diagonals and prism binoviewers). This compensating lens can be removed for wide field low power observing, but should be attached for high power planetary (it adds 1.25x to the image). The downside is the expense of such a viewer - it just cannot be made cheaply and have high quality optical surfaces.

To get diffraction limited performance out of less expensive binoviewers with fast scopes, you would probably want to use a Barlow ahead of the viewer. In any case, it depends on how observant you are. I have an older model Binoviewer originally sold by Celestron that shows quite noticeable optical defects (astigmatism and color error), and yet when I demonstrated this viewer to amateurs at telescope meets, most cannot see the defects. This tells me that most people are not that sensitive to optical errors that are quite gross and obvious to myself. They are enjoying the view through the bino, and that is most important.

Rolando

1. No coating could ever make up a 2" aperture handicap.

2. No coating can ever "enhance" planetary contrast unless the inferior coating is old, worn and full of sleeks and scratches. A multilayer AR coating may have minor ability to enhance visual deep sky contrast under certain situations where there is a lot of local light pollution. At a dark sky site it will have no effect on deep sky contrast. For imaging, a multi-layer AR caoting may reduce or eliminate ghost images from bright stars in the field.

3. No coating will ever provide a "better" image, since this is strictly a function of how well the optics are made. However, a good mirror coating will not detract from the image, whereas an old worn coating with sleeks, scratches and pinholes will degrade the image. Two new mirror coatings, one enhanced and the other not enhanced, will look the same to you visually.

Rolando

verterons? Na, it'l be a mixture of excellons and ackenpucky

>>Actually since you seem to know something on it I'd like you to read the quote below and help me interpret it.>>

It is a simple single element field flattener element, which has no color correcting properties and has no bearing on the visual image. It is strictly used to control the field curvature for imaging. You would not notice it if it was missing, neither would you see any difference in color correction.

Rolando

As I said before, the spacer between the lenses is not precision enough. The elements need to be spaced equally to within 50 millionth of an inch, something that requires careful hand work by someone knowledgeable in optics. Otherwise you will get coma (bunching on one side).

Rolando