Questions related to the physical instruments for astronomical observations.

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2
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0answers
35 views

What is the bluest narrow band filter mounted on ground based telescopes?

If we want to check a QSO's lyman alpha narrow band image, could a ground based telescope do that? I mean under the circumstance that its lyman alpha shifts to 3300A.
1
vote
2answers
29 views

What is meant by Electronic Beam Steering and how is it achieved?

I recently came across an article about the Murchison Wide Field Array which said directivity is achieved by Electronic Beam Steering and not by Mechanical methods. It would be helpful if someone can ...
3
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1answer
49 views

Build a high quality telescope from scratch

I am interested in building a high quality portable telescope from scratch in an attempt to better understand how telescopes work. What kind of materials do I need? How would I go about putting the ...
2
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0answers
17 views

need data-point: actual counts per second with APD (avalanche photodiode) detector

I'm designing a sensor system to perform specialized [astronomy and space-sciences] experiments, and need a "reality check" to support or adjust my theoretical calculations. What I need is the ...
2
votes
5answers
185 views

Why can't I see Mars clearly?

I just bought my first telescope - a Celestron CDC 1100. It came with a 40mm lens so with a primary focal length of 2800mm the power should be 70x. My problem is that I've looked at Sirius and Mars ...
2
votes
1answer
111 views

Do telescopes harm while observing sun through them?

I don't know whether we can observe a sun through a telescope. But if we can then will it harm our eyes and if such telescopes exists what is their configuration?
5
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1answer
53 views

What's a good step up from 7x50 binoculars?

I own a Nikon OceanPro 7x50 pair of binoculars, but I find that when I look at the moon, I would like more magnification. My requirements are: costs less than $400 weighs less than 10kg the length ...
4
votes
2answers
38 views

Is there an oxide layer on aluminum reflectors for telescopes?

I was watching a Nottingham Science video linked here (periodic videos) and they mention modern reflectors are made of aluminum. I can understand why mirrors are preferred over lenses, but what ...
4
votes
1answer
61 views

Pictures of large galaxies

The Andromeda Galaxy is tens of thousands of light years in diameter. That suggests that the most distant stars in the Andromeda galaxy is up to tens of thousands of years "behind" in their orbit ...
-2
votes
1answer
75 views

Can you identify this telescope in a desert? [closed]

It should be in a desert. 5-15 similar lens cones are binded together,small size(about 30 cm?),same direction. The purpose is to find exoplanet? It is like WASP below. It is in a desert and lower ...
5
votes
2answers
61 views

How does a telescope measure parallax angle?

I know how stars' distances are measured by using parallax, but I want to know how the actual telescope measures the parallax angle. Any helpful links/ explanations are needed.
3
votes
1answer
84 views

Telescope buying guide for a beginner in India

I am located in the southern part of India and am looking forward to buy a telescope to gaze up to look ay farther planets, moons in our solar system and take pictures. How should I go about getting a ...
8
votes
1answer
256 views

Is there any telescope on Earth that can see the lunar rovers on the moon?

If I have the right numbers, it seems to me that even Hubble telescope might barely be able to make out a carcass of a blue whale on the surface of the moon, which puts objects as small as the lunar ...
0
votes
1answer
279 views

How to build a powerful home made telescope [closed]

Simple, I fell in love with the sky when my parents were constructing our new house I was a kid then and one day I ventured out on the terrace, to my amazement it was a full moon, ever since I've felt ...
3
votes
1answer
91 views

How does a Bahtinov mask work?

For focusing the image of a telescope, one can use a Bahtinov mask. How does this mask work, and how did Mr Bahtinov get the idea to cut such a peculiar shape? Is it possible for me to design my own ...
4
votes
1answer
116 views

Colossus telescope, trying to outsmart aliens?

I was listening to Jeff Kuhn's talk on SETI's Colossus telescope project. Background: He explains his theory that a civilization living somewhere the galaxy would want to hide, and thus would ...
5
votes
1answer
79 views

Planned telescope to detect alien waste-heat

I remember watching a talk by someone who designed a telescope to view a single star at a time. The purpose of the telescope was to detect waste-heat which would presumably be emitted by any ...
4
votes
1answer
50 views

What are the next planned space telescopes?

We've had hubble for two decades. Its become the most famous space telescope, and lately Kepler seems to be running for the second place. Are there any more powerful, better telescopes planned for ...
4
votes
1answer
99 views

Most important feature of a telescope

I was taking an astronomy test, the following question came up: The most important function of the astronomical telescope is: Resolving power Light gathering power magnifying power ...
5
votes
1answer
77 views

Are Barlow lenses stackable for bright objects?

I'm back to the refractor that I own, and I want to maximize the zoom capacity. I realized today that I own more than one barlow lens, and I was wondering if I could stack them together for looking at ...
7
votes
1answer
32 views

Does the Reflection Method for Looking at the Sun Work For Refractors?

I own a newtonian reflector and occasionally use it (using the reflection method with paper) for looking at the sun. I happen to also own a refractor, but I'm not exactly sure if the reflection method ...
9
votes
1answer
85 views

How Does a Refractor Telescope Work?

As I understand it, the difference between a reflector and a refractor is that a reflector uses mirrors on the back to reflect the light to the secondary mirror then the secondary mirror reflects the ...
21
votes
3answers
891 views

How powerful a telescope would allow me to view the astronauts aboard ISS do a space-walk?

This arose from a comment posted against a question elsewhere on the stackexchange How powerful a telescope/binoculars would allow me to view the astronauts aboard the ISS do a space-walk? Aperture? ...
3
votes
1answer
86 views

Periodic error correction in automatic telescopes

I am starting a study on automatic telescopes and the correction of their periodic error. I found two ways of correcting it : with a CCD camera and manually by recording the error. I was wondering if ...
11
votes
3answers
228 views

Should I focus more on Aperture or Focal Length for a telescope?

Let's assume there are three types of telescopes with the following specifications: ...
5
votes
1answer
72 views

Why does squinting make hard-to-see objects clearer?

So I, like most other astronomy enthusiasts, have, at some point, not been able to see something clearly, such as a star, and have had to squint to be able to see it better. When this happens, the ...
8
votes
3answers
77 views

What limits the usable focal length of telescopes currently?

What barriers - of technology, physics and possibly economy (things that would be possible technologically but are simply too expensive) sets the upper bound on quality of telescopes for observation ...
0
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0answers
32 views

What are right ascension and declination? [duplicate]

I'm trying to learn how I can use my amateur telescope, and I was reading a tutorial that talked about right ascension and declination. I have looked around a bit online, but most of the answers are a ...