Questions tagged [cassegrain-telescope]
Questions about reflecting telescopes that use a concave primary mirror and a convex secondary mirror, such that the focal point is behind the primary mirror.
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Is there a reflecting telescope like as a Newtonian telescope but with a negative lens before the diagonal mirror?
A Cassegrain reflecting telescope contains a negative optical element between the main mirror and its focus. This increases it's focal length.
Is there a reflecting telescope like as a Newtonian ...
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Can we use plain mirror as a secondary mirror in cassegrain telescope?
I was planning of making a telescope like JWST, just with plain mirrors, as bigger concave or convex are much expensive. The primary mirror would be totally made of plain mirrors configured like JWST. ...
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How are the aberrations seen in early JWST images corrected?
I found this image on space.com and it can also be found in NASA's JWST blog. This is one step in the process of aligning the 18 mirrors on JWST. A single relatively-isolated star has been selected. ...
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What is the difference between a Cassegrain telescope and a Gregorian one? Which one is better?
Of the three giant (or 'Extremely Large') new telescopes being built, the Thirty-Meter (TMT), the the Giant Magellan (GMT) and the Extremely Large Telescope (ELT), only the Magellan, from what I ...
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How did I flip some mirrors around in the dark at 3 AM and change the focal length of a 24 inch Boller and Chivens?
Current answer(s) to How do telescopes "zoom" and change angle of view? are "they don't", but traditional large genera-purpose observatory telescopes do sometimes (often?) have ...
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Are X-ray telescopes with glancing angle surfaces basically "funny-looking" Cassegrain telescopes mathematically?
In this answer I included the image below of a reflective X-ray telescope. It is made from two elements; the first is concentric shells of glancing (high incidence) angle paraboloidal surfaces, and ...
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What Crayford focuser to buy for a B&L Criterion 8000?
I'd like to get a dual-speed Crayford focuser for my newly acquired a B&L criterion 8000 (8") as the mirror shift is pretty bad.
I'm really not sure which one to buy because I'm quite ...
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Why are Cassegrain telescopes shorter than Newtonian reflecting telescopes?
Many websites say this is because the effective focal length of the objective is increased by making the secondary mirror convex. This allows a Cassegrain telescope to be shorter than a similarly ...
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Second Telescope: Maksutov Cassegrain vs Refractor
I bought my first telescope, a 3-inch refractor a few weeks ago. It has been a wonderful experience seeing the Moon, Jupiter, Saturn magnified and Andromeda, M33, M81 and much more for the first time.
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Under what situations can an aperture mask improve the resolution of a small/medium amateur telescope? Is this demonstrable mathematically?
@antlersoft's answer describes some of the challenges to seeing any details in the small disk of Mars in small amateur telescopes. In the case of reflecting telescopes, it mentions the use of either ...
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