Questions tagged [telescope]

Questions related to the physical instruments for astronomical observations.

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3
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2answers
114 views

How come I can point to two places with telescope and have the same coordinates?

Absolute beginner here. I read through the telescope manual, watched many videos, and got a pretty decent understanding of DEC and R.A. However, I don't understand one thing (where theory doesn't ...
5
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1answer
50 views

Advice for next steps with astrophotography

Over the last year, I have started to take up the hobby of astrophotography. At the moment I have been focused on planetary astrophotography. Up until now I have been using a Celestron 5SE telescope (...
2
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1answer
87 views

If Proxima Centauri was replace with a quasi-star, would our telescopes be able to see it in fine detail?

Quasi-stars, if they ever existed, were stupid big and stupid bright; many times bigger, brighter, and more massive than any star supported by fusion can be. There's no question that it could be seen ...
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2answers
1k views

What is the highest resolution image of the moon taken from Earth's surface?

According to this article: https://www.theguardian.com/science/2018/jul/26/star-spotted-speeding-near-milky-way-black-hole-for-first-time the Very Large Telescope is "powerful enough to see a tennis ...
16
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3answers
5k views

Can large scientific telescopes observe the Moon without being damaged?

When I look at the full Moon through my 10cm telescope, it is so bright that it hurts. Can large scientific telescopes observe the moon at all? Does that require special protection equipment? Or ...
1
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1answer
54 views

How to determine the color term for a filter with a systematically bluer offset than the standard

This is a hypothetical scenario in an attempt to test my understanding of the color term when performing photometric calibrations: Imagine we are observing stars through a B filter with an offset ...
0
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1answer
142 views

How to make a 65 cm lens with a 20 cm hole in it for a Hamiltonian telescope?

This answer to What (the heck) is a Hamiltonian telescope? Is this one? confirms that the telescope in the question linked there is indeed as described and that the first lens is a full 65 cm aperture ...
3
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2answers
296 views

Why do we use filters in telescopes for astronomical imaging?

I have read that if we image without a filter we get no information about the color or SED of objects. Can anyone elaborate the reasons for using filters for imaging/photometry? What happens if we ...
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1answer
76 views

Tracking deep sky objects

I have a Celestron Astromaster 130Eq. I saw all the planets in our solar system and quite satisfied. Now I am in the hunt for DSOs, but living in a city is a disaster for tracking some good-for-...
1
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1answer
142 views

Not getting quality images in telescope

New to astronomy, I have a Newtonian telescope (Celestron 130 eq) with 5.2 inch (~132 mm) aperture with 650 mm focal length, Spherical mirror. And having 4mm, 10mm, 12.5mm, 20mm,20mm (erecting ...
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1answer
44 views

Schmidt corrector plate on a Newtonian = Schmidt Cassegrain?

Went on with a wide range of telescopes and its mechanics. To my understanding, the only change in the optical function in Schmidt Cassegrain telescope is a Schmidt's corrector plate in front of an ...
2
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0answers
35 views

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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0answers
33 views

Would Atlas Pro's prediction about the color of plant in Kepler-186F work as a biosignature to search for life?

The Atlas Pro video that prompted this question is this. Tl;dr: it is argued that due to the different spectrum of radiation emitted by Kepler-186 and what is known about the evolution of ...
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0answers
33 views

Can you advise on the construction of a large segmented primary mirror (hobbiest)?

I am interested in experimenting with the building of a large parabolic primary mirror constructed from 4" hexagon mirrors mounted on a "rough" parabolic surface with either 3 screw ...
9
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2answers
145 views

What visual artifacts are expected from the JWST?

What visual artifacts should we expect from the images that will be released from the James Webb Space Telescope? Specifically, do we expect 3-pronged diffraction spikes (any preview how they would ...
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0answers
16 views

Database capable of determining or predicting tumble of space debris

The tumble of space debris will need to be understood before large scale, active debris removal missions can be carried out. Tumble is really hard to precisely determine because most debris has lost ...
4
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3answers
94 views

Do telescope measurements (in meters, usually) measure in a straight line, from edge to edge, or follow the curve of the mirror?

Somehow, no site or book or magazine has clarified this question for me.... Perhaps I am an idiot, but, Is the parabolic primary mirror on the new James Webb Space Telescope (JWST) 6.5 meters from ...
4
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0answers
65 views

A new (radio) neutrino telescope in Greenland?

I just stumbled upon ScienceMag news from July 14th, 2021 which says: By placing hundreds of radio antennas on the ice surface and dozens of meters below it, they hope to trap elusive particles known ...
32
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4answers
3k views

What will succeed the Arecibo Observatory?

Just a few minutes ago, I got a notification from Space.com stating that the Arecibo Observatory will be, sadly, decommissioned due to extensive damage to its structure. So, with the loss of one of ...
5
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1answer
67 views

If the visibility function is the Fourier transform of the sky brightness distribution, why do you need the dirty beam and dirty image to find it?

In radio astronomy, the dirty image is equal to the inverse Fourier transform of the uv-plane coverage times the sampled visibilities. The dirty image is also equal to the convolution of the "...
4
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1answer
81 views

Is there a complete guide on how to use telescopes?

tl;dr As said by @uhoh in the comments, is there A Big Book of Telescopes? i.e: Is there some kind of media that gives a complete treatment to telescopes? I am relatively new to Astronomy.SE. I wanted ...
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2answers
748 views

What can I see with different apertures?

I'm looking to buy a telescope, and every mainstream website says that aperture is the most important factor, and buy the largest telescope your budget can afford. However, a website I found offering ...
4
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2answers
2k views

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. ...
4
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1answer
68 views

How common are telescopes with the finder scope on the right side?

Are there telescopes where the finder scope is mounted on the (upper) right of the body? Are they common? If not, are there any ways around this (e.g. can I mount a lightweight telescope "...
2
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2answers
86 views

Using a refractor telescope 5" aperture, 900mm focal length for terrestrial viewing

Can I use a refractor telescope 5" aperture, 900mm focal length on an equatorial mount for terrestrial viewing.
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0answers
38 views

Batteries for a StarNavigator 90 motorized mount?

I was given a StarNavigator 90 (DS-2090) with a motorized mount (Single-arm, motorized Alt-Az) which works with 8 AA batteries. Only issue is that it eats the batteries, so I am wondering what kind of ...
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3answers
2k views

Could we parallax measure stars just based on the Earth's size?

Imagine two major surface observatories, perhaps the "northermost" and "southernmost" such (ideally on a similar longitude). For nearby stars, could they each take a photo at the same time, and ...
0
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3answers
112 views

Can a hydrogen bomb explosion be seen from every distance?

When we use the strongest optic telescope available, how far from Earth can a hydrogen bomb explode in space and be visible for this telescope? Is there a fundamental limit to this distance? Even for ...
3
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1answer
66 views

Any method to apply inverse TPoint model?

I have an automated telescope that I have written some software for. I am currently using TPoint to compensate for some of the irregularities of my system. However with TPoint you apply an offset (...
2
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1answer
47 views

2001 VB - when will it be reacquired?

2001 VB's orbit is poorly known but has a two-in-a-billion risk of a collision with the earth in 2023. Assuming that it were on a collision course, when would it be likely to be reacquired? Which ...
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1answer
75 views

What eyepiece to use for moon?

I'm using a 95mm f/8.4 telescope. What's the best eyepiece that I can buy for a very close look at the moon or even planets? I'm a beginner in this field so please help me. Thank you.
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3answers
387 views

What is it about the layout of the three gratings in a Bahtinov mask that makes its indicate focus in this way?

The question Lucky imaging with Celestron 14 - is this result reasonable? includes a beautiful example of a focus test using a Bahtinov mask and the image below from Deep Sky Watch's Home Made ...
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0answers
62 views

Would a possible accretion disk around a primordial black hole 500 au from the Sun be visible in present telescopes?

If the hypothetical two-inch black hole 500 au from the Sun had an accretion disk, might current telescopes detect it already or do we have to wait till the Vera Rubin Observatory starts work?
5
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2answers
102 views

Can the transit of satellite in front of Sun be visible in 10-inch telescope?

I have 10 inch Sky-Watcher telescope and I would like to know if a satellite passing in front of Sun can be visible. Suppose that satellite's angular diameter is 1˝. Yes, I know the formula $\theta=\...
7
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1answer
118 views

Where can I find Arecibo's data archive?

Does anyone know where I can find Arecibo's historical data? After much searching, I can find neither hide nor hair of it. It doesn't help that the search results are completely dominated by the news ...
1
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1answer
44 views

Why did the famous Multiple Mirror Telescope (MMT) get rid of them and become the Massive Monolithic Telescope?

Popular Science's 2016 article The silliest names scientists have given very serious telescopes... Ranked! says: Arizona’s MMT Observatory used to house the Multiple Mirror Telescope. In 1998, ...
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1answer
86 views

How much of M87 can i see with an amateur telescope?

I was reading about M87 and how it is possible to see it's relativistic jet with an amateur telescope. About a year ago i impulse-bought a telescope (model: Celestron CE21049 powerseeker 127EQ). I'm ...
4
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1answer
92 views

Can we get a picture of Oumuamua with Hubble Space Telescope?

Can we get a picture of Oumuamua with Hubble Space Telescope? If not, what are the reasons? Answers why other telescopes might fail to get a picture of Oumuamua are welcomed as well.
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1answer
112 views

How do I design a good telescope to observe nebulae and other deep sky objects [closed]

How can I make a good telescope that is powerful enough show nebulae and other deep sky objects ? (consider low budget build)
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6answers
915 views

Edu-Science telescope

I don't know much about astronomy, but my kids are asking for telescopes to view planets, stars etc. Could anyone tell me if this Eduscience telescope is any good? This kit contains a 40x with a ...
3
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1answer
69 views

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 ...
3
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1answer
3k views

Challenges when trying to build a telescope using two lenses

I have some lenses - a 10 cm and 7 cm convex lense and a 4 cm and 1 cm concave lenses. I am trying to make a telescope by combining one of convex and concave lenses, but I am struggeling to do so. The ...
8
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1answer
895 views

Which type of telescope should I make?

I am not very much interested in observational physics but I just like to look at the night sky. It gives me a lot of inspiration. So, i was thinking about making a telescope for basic observations. I ...
3
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0answers
69 views

Combining lenses from two telescopes to build a more powerful one?

I have two Galileo 700mm x 60mm Astro/Terrestrial Refractor Telescopes. Can I take the lenses out and make one powerful telescope, something like an optical series circuit?
0
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1answer
56 views

Safety while using a telescope to view a total solar eclipse

I have an 8-inch reflector telescope and a solar filter that goes on the front aperture to view the Sun (most recently to view the transit of Mercury). If I were to use this telescope during a total ...
3
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1answer
67 views

Do telescopes exist that reflect the incoming light more than three times along their length?

Refractors only use the length of the telescope once, reflectors twice, catadioptric telescopes like those of the Schmidt-Cassegrain design three times. Have telescopes been built that reflect the ...
8
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5answers
23k views

Can an astronomical telescope view objects on Earth?

I am new to telescopes and I'm planning to buy an astronomical telescope like the "Celestron AstroMaster 114 EQ Reflector". Just curious to know whether it can be used to view objects on Earth (e.g. ...
2
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1answer
72 views

Do triple or more times reflecting telescopes exist?

Refractors only use the length of the telescope once, reflectors twice, catadioptric telescopes like those of the Schmidt-Cassegrain design three times. Have telescopes been built that reflect the ...
3
votes
1answer
156 views

It is possible to combine a reflector and a refractor telescope together?

I know it sounds crazy, but is it possible to connect a reflector telescope and a refractor telescopes (like monocular for bird watching) together to build a better telescope?
4
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1answer
283 views

Why are solar telescopes built on lakes?

The telescope big bear is located in the Southern California. According to the wikipedia page, water can cool the observatory. Is it better to build it on a cold high mountain with stable and clear ...

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