Questions related to the physical instruments for astronomical observations.

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3
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1answer
33 views

Is remote measurement of isotope ratios possible, or must a sample be aquired

Is it possible to measure to measure isotopic abundance of remote astronomical objects - ie measurement without having a sample to feed into a mass spectrometer? Do different isotopes show any ...
3
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1answer
147 views

Do primary mirrors in large observatories undergo regular removal and re-coating of the aluminum? Why?

Performance of astronomical mirrors that are exposed to the environment for long periods of time can experience a slow degradation of performance. They usually need to receive some kind of regular ...
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3answers
140 views

Do bigger telescopes equal better results?

There are many large reflecting/optical telescopes around the world, just to name a few: the Very Large Telescope, Large Zenith Telescope, and European Extremely Large Telescope. My question is does ...
3
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1answer
44 views

When did “resilvering” large telescope mirrors actually refer to aluminization, and why was it necessary?

This answer nicely summarizes the general picture of historical use of silver for mid to large size telescope mirrors, and the shift to aluminum once good quality vacuum pumps and chambers suitable ...
5
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1answer
70 views

Was the use of silver on 'optical' telescope mirrors more common in the past? Why?

In the past, weren't many astronomical telescope mirrors periodically removed and 'resilvered', and wasn't this actually done using silver? I'm guessing that this is much less common now - new ...
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1answer
64 views

UTC to UT1 time corrections

Astronomic observations in geodesy. It is well understood that sun and star positions may be expressed in Greenwich hour angle and declination. Or Right Ascension Declination. And may be published ...
3
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4answers
135 views

Would space-based telescopes need to remain in the shadow of Earth to avoid light interference from the sun?

So I am thinking about orbiting telescopes tonight and I was thinking that it would probably be beneficial to keep them in the shadow of the Earth or some other space body to avoid light interference. ...
0
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0answers
25 views

Replacing the tripod on a Celestron Travel Scope 70

I have a Celestron Travel Scope 70. The tripod seems incredibly wobbly, making it very difficult to view anything without the whole system bobbing up and down. I was thinking about replacing it with ...
5
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2answers
15k views

How much magnification is needed to see planets of solar system?

I have a 3inch Newtonian reflector telescope with 300 mm focal length. I can use highest magnification of 75x using a 4mm eyepiece. But in 75x I can't see details of Jupiter what was expected. Instead ...
3
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1answer
51 views

Does the summit of a small mountain offer better seeing?

I have a small amateur telescope, and would like to defeat the atmospheric seeing conditions as much as is possible. Fortuitously, I happen to live fairly close to this lovely patch of bare elevated ...
1
vote
1answer
48 views

How useful are filters for spotting nebulae?

Recently I've been trying to spot a couple of nebulae, IC59 and IC1318. The skies at the site are modestly dark (4.5 on the Bortle scale), I'm using an 8" scope, and I've slowly scanned around the ...
8
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2answers
111 views

Why do we use FITS format for scientific images especially in astronomy? How is it different from formats such as JPEG, PNG etc?

I am new to astronomy and I found that the telescopic dataset can be stored in the FITS format instead of JPEG. Why do we have a special image format just for scientific images?
4
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1answer
154 views

Is it possible to steer the sight of a Liquid Mirror Telescope using a plain mirror scheme? If yes, why hasn't it been done?

I have read about Liquid Mirror Telescopes in a number of places, and according to these sources, a major disadvantage of these telescopes is that they can only "see" straight up. In a nutshell, the ...
6
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1answer
87 views

What is a quaternary mirror and why does the E-ELT need one?

In this recent BBC article I read the one-sentence paragraph: "Development on the mirrors - in particular, a very complex quaternary mirror - continues apace." and became interested in the ...
-1
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1answer
83 views

Communicating with distant planet with life possibility

So, telescopes are like time machines. If we get an image and data for analysis from a planet say 1000 light years away, we are essentially looking 1000 years back in time. Now, if we notice presence ...
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2answers
73 views

Tripod mount missing!

I have received a new Celestron Powerseeker 127 (a 5' short Newtonian), however it came without a tripod mount. Ideas or suggestions on how to procure the right mount our a suitable alternative ...
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2answers
156 views

Why don't Australia/Russia have large optical telescopes?

Australia and Russia have large land areas. However, I am only aware of one 3.9m telescope in Australia. As far as I know, there are lots of mountains in Australia and Russia. So why are there not ...
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2answers
116 views

Why does the Southern hemisphere seem to be short of radio telescopes? [closed]

In northern hemisphere, we have GBT, Arecibo, Parkes, Jodrell and VLA, while in southern hemisphere, only Australia has big radio telescopes. ALMA is in Chile, but it is in sub-mm. Is not ...
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2answers
146 views

How to make a telescope for viewing planets, moon and DSOs using a convex lens of aperture 100 mm and focal length 200 mm and other lenses at home?

I wanted to make a telescope with DIY things lying around in home. I read up that the aperture was a very important aspect and thus bought a convex lens with 100mm aperture and 200mm focal length, to ...
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3answers
75 views

Would a telescope that uses Fresnel lenses be more practical than using regular lenses?

If we were to make telescopes with Fresnel lenses instead of regular lenses, would it be more practical? Would this also allow for much bigger telescopes to be made? Here is an example of the type ...
0
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2answers
129 views

How do I see more than just points in the sky?

I just bought a new telescope with these specifications: Aperture: 203 mm Focal Length: 1200 mm F/ratio: f/5.9 I usually use a 28 mm eyepiece, giving me about 42.5x magnification, but I also have ...
4
votes
1answer
102 views

Focusing light through fiber optic cable to extend telescope viewer

I want to build a system to view my telescope without being uncomfortable. Currently I have to stand up and bend over to view the eye piece. I want to build a system that allows me to 'pipe' the ...
8
votes
1answer
123 views

How much competition there is for jobs in astronomy compared to other fields of science?

I will soon finish a master's degree in computer science. I have been interested in astronomy for some time, which has included playing around with a Newtonian reflector telescope and reading about ...
3
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1answer
65 views

Moving from computerised to normal amateur telescope?

A few years ago I purchased a Celestron Nexstar 130 SLT computerised telescope thinking that it would be a perfect to get me into astronomy. The issue is the computer doesn't work at all and manually ...
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2answers
38 views

Tunnel vision while viewing through a reflector

I have a Celestron astromaster130 eq. While viewing through its eyepiece, or using a smartphone camera for photography purpose there is always a definitive no light region( it is circular in curvature)...
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0answers
18 views

Telescope optical tolerance from central axis

I sometimes encounter telescopes/binoculars with a decent objective diameter but are very difficult to use because they only work when the eye is looking down the central axis (i.e. in the centre of ...
0
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1answer
77 views

Jupiter appearing odd through a 6" reflector

Recently I have been trying to get a good look at Jupiter through my 6" Orion reflector, but the image seems to always come out as an oblong white streak. I've tried changing the lenses I'm using, but ...
0
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1answer
48 views

How do I see DSO's in my telescope? [duplicate]

I just bought a new telescope. I tried it out, and I even woke up at 3am when the moon set so there was light pollution. I have an 8 inch dobsonian telescope with a focal length of 1200 mm. For some ...
0
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1answer
107 views

Why would astronomers want to eclipse the Sun?

I've heard that some astronomers are building an artifical solar-eclipse ship, that should help us to dim the diffraction of the Sun. Why don't we just wait till night? What is the function of the ...
2
votes
1answer
68 views

Given a collection of pixels, how to deduce the flux from them?

I've obtained the coordinates of brightest pixels from different images (.fits files) using Python. I want to get the flux of each pixel. How do I go about finding out the flux?
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2answers
38 views

VLT interferometry vs E-ELT?

If the VLT (very large telescope) can use interferomerty to act as a 200 meter mirror, then why are they trying to build the 39 meter E-ELT? What advantage does the E-ELT have, if the VLT can act as a ...
1
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1answer
77 views

Telescope choice

Which one is better? Features: 1)Magnification: 18x - 90x Eyepiece Diameter: 5mm (18x), 10mm (60x) Objective Diameter: 50mm Focal Length: 36cm Tripod Height: 38cm Main tube Color: Silver Net ...
5
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3answers
109 views

Could mirrors be replaced with CCDs?

Why do telescopes use mirrors that simply reflect photons, when they instead could be covered with large sensors to register them? Reflection is all good and well, all thanks to silver and beryllium ...
7
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0answers
128 views

Method to determine the amount of reflected starlight necessary for an exoplanet to be visible from a given distance/angle?

What is the method to determine the amount of reflected starlight necessary for an exoplanet to be visible from a given distance/angle? (Not from occlusion but actually visible on its own.) Further, ...
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1answer
54 views

The moon: how to determine its size, speed and distance from earth using a simple telescope?

Assuming I only have a simple telescope, how can I determine the size of the moon, its angular velocity and distance from earth?
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0answers
90 views

Buying telescope online [duplicate]

I'm trying to buy a telescope online but I'm afraid of scams. What is the minimum magnification required to view celestial objects like the rings of Saturn or the asteroid belt? Here are the details ...
6
votes
1answer
43 views

Infrared Region Telescopes

Why do we need to build telescopes that can view in the infrared? What exactly do we need to see in the infrared region? I know this seems like a really broad question but I'm just curious about it.
2
votes
1answer
146 views

Power of the James Webb Space Telescope [duplicate]

I have heard that the JWST will be capable of looking at the early stages of the universe. However I have also heard that it won't be capable of detecting the Oort Cloud that supposedly provides ...
4
votes
1answer
48 views

Has THC been detected in space?

I was wondering if and how astronomers have/had detected the molecule Tetrahydrocannabinol (THC), commonly known for it's effects in marijuana, in space. I had previously seen a hoax regarding the ...
4
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0answers
56 views

3000th Question: What does the future of astronomy look like with the next generation of telescopes? [closed]

What will the benefits and advantages be of the upcoming generation of telescopes such as LSST, E-ELT and JWST? And more broadly where will this leave astronomy in 10-20 years time? This isn't a ...
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2answers
55 views

What is the longest observable wavelength of light using an optical telescope?

How far outside the visible spectrum could an optical telescope feasibly operate?
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2answers
182 views

Dish antenna as parabolic mirror for OPTICAL telescope?

Can i use a chrome painted dish tv antenna as a parabolic reflector for my Optical telescope ? Given that glass mirrors are quite expensive, i am thinking of using a Dish TV antenna and coating its ...
3
votes
2answers
155 views

What are the advantages and disadvantages of a 2-inch eyepiece versus a 1.25-inch eyepiece?

I'm considering picking up some new eyepieces for my telescope and am interested in comparing 2-inch and 1.25-inch eyepieces. Are there any disadvantages to 2-inch eyepieces? Are 2-inch eyepieces only ...
2
votes
1answer
36 views

Can angular information be known more precisely than the diffraction limit?

The diffraction limit deals with the ability to determine if two things are separate. I am interested in the ability to find the the centroid of a single object. Imagine a star with no near ...
5
votes
1answer
56 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 ...
3
votes
1answer
37 views

What is the formulat to compute King tracking rate for a given set of topocentric coordinates?

Canbury Tech has a good background on King tracking rate, which approximates the average sidereal motion of a refracted star across the sky. Most amateur telescope mounts have some sort of notion of ...
5
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2answers
170 views

Why when we look through a telescope in space, do the billions of stars not block our view from seeing further?

I know that we are able to "see back into time" by looking very far away through telescopes such as the Hubble telescope, but my question is, wouldn't you run into at least a couple of stars that were ...
9
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1answer
203 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.
10
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4answers
362 views

Using the Sun as a Gravitational Lens

Can the Sun be used as a gravitational lens to achieve better telescopic viewing? Can this effect be practically used to view celestial objects?
0
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1answer
63 views

Identify this 2 axis motorized tripod

I am NOT an astronomy person, so this may be a dumb question, however I have recently found a tripod that appears to be for star tracking as far as I can guess. I would like to know the type of tripod ...