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1 vote

Why are segmented mirrors lighter than monolithic mirrors?

The bottom line is that an (active) support mechanism to hold a segment in the right position will be lighter than the (passive) glass required if the mirror were not segmented. There have been ...
Mark Morgan Lloyd's user avatar
17 votes

Why are segmented mirrors lighter than monolithic mirrors?

A telescope's precision mirror needs to be very large, to collect lots of light, and needs to be very precisely shaped. Holding that proper shape is based on the mirror's ability to resist stress on ...
Darth Pseudonym's user avatar
6 votes

Why are segmented mirrors lighter than monolithic mirrors?

When creating a mirror, you need to take a block of glass and grind and polish it until it has the desired shape. For telescopes this is typically a parabolic shape. So The thickness of the slab of ...
planetmaker's user avatar
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6 votes

Is there a maximum practical telescope aperture for viewing (through a filter) a solar eclipse?

If you want to see the entire Sun in a single field of view, your concern is with the magnification and field of view of your eyepiece, rather than overall aperture and focal length. Magnification is ...
antlersoft's user avatar
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5 votes

Why do planets just look like a dark ball in my telescope

Have a look at the images in these questions and the answers there as well: Help identify a bright and round object photographed through a telescope My first pictures of Jupiter Mirror telescope: ...
uhoh's user avatar
  • 31.6k
6 votes

Attachment for viewing the sun with a telescope

The device you saw was probably a "solar projection eyepiece". You can use any eyepiece for this, in theory, though eyepieces with cemented lenses can heat up in the sun and the glass can ...
Aaron F's user avatar
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4 votes

Mauna Kea versus Mauna Loa: Astronomy ethical considerations

While some of these questions might be better suited for astronomy history SE, Ill give brief answers here and end in your astronomy question. There have been controversies and conflicts related to ...
Daddy Kropotkin's user avatar
2 votes

What eyepiece or other optics might improve image quality or observing experience for my Shilba Eclipse 60900 telescope?

If the eyepiece holder has inner diameter 31.75 mm (1.25 inch), there are many eyepieces available in that size, also compatible with larger telescopes. As you may know, magnification is objective ...
Mike G's user avatar
  • 18k
3 votes

How are the Extremely Large and Thirty Meter Telescopes coming along ("planned 2027")

The ELT looks basically on track. It’s scheduled to start scientific observations in 2028 and is now half-completed. See The TMT’s fate is less positive, ...
Pierre Paquette's user avatar

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