Questions tagged [telescope]

Questions related to the physical instruments for astronomical observations.

Filter by
Sorted by
Tagged with
2 votes
0 answers
77 views
+100

How do you clean a foggy or dirty eyepiece of a telescope?

I'm wondering what the procedure would be to clean the eyepiece of a telescope when it looks foggy or there's dirt either on the outside or inside it. I can get rid of loose dirt with a camel hair ...
user avatar
2 votes
0 answers
45 views

Telescope's eyepieces got blurry over time

Right at the beginning: This is not a duplicate of questions involving blurry images through their eyepieces. I only get blurry images for 2 of my 3 eyepieces so it's not the telescope's fault and in ...
user avatar
1 vote
1 answer
93 views

Why not building a swarm of space-telescopes?

Haven't even James Webb telescope started doing science, - it's successor "LUVOIR" is being discussed already. However I got curious: humanity invested billions of dollars in developing ...
user avatar
  • 113
2 votes
1 answer
16 views

Where can I find data on SDSS filter profiles?

I've seen lots of filter throughput curves for the SDSS, such as this one: from the SDSS camera page, but I'd really like to produce my own from the data. Is the filter response data per wavelength ...
user avatar
  • 1,931
1 vote
1 answer
49 views

Can the Celestron Powerseeker 127EQ observe the moon during day time?

I am able to find the moon with the finder scope during the day. However, when I use my 20mm lense, it seems like I am unable to focus the moon at all. Is there a fix to this?
user avatar
3 votes
2 answers
77 views

Focus Problems when using Barlow 3x or 4mm lens

So I just recently bought a Celestron Powerseeker 127EQ 12.7 cm f/7.87 Cassegrain telescope and I inserted a 20mm eyepiece and the telescope with the Moon. That eyepiece seems to work fine, but when I ...
user avatar
1 vote
0 answers
45 views

Why does my 10mm eyepiece produce blurry images?

I own a tabletop Sky-Watcher Heritage 130mm tabletop Dobsonian with a f/5 130mm aperture and 630mm focal length. 25mm wide-field eyepiece and a 10mm narrow-angle eyepiece. Last night I took it out to ...
user avatar
4 votes
2 answers
390 views

Why are photos from telescope stretched at their edges?

You may know the issue that photos from (at least some) telescopes are stretched at the edges, so that the star locations do not fit compared to if this location would be on the center of the photo. ...
user avatar
9 votes
2 answers
3k views

Why aren't reflector telescopes built with an offset secondary mirror?

Reflector telescopes (normally?) have a parabolic primary mirror that reflects the light to a secondary mirror which is placed at the center of the telescope. The construction holding that mirror and ...
user avatar
  • 202
1 vote
0 answers
22 views

uvotdetect sometimes doesn't make valid .fits files for DS9 to read (Swift UVOT, Heasoft)

I have downloaded galactic center sky images from the Swift database (https://www.swift.ac.uk/swift_live/index.php#doSimpleSearch.php?catname=swiftmastr&searchpos=galactic+center&searchrad=10&...
user avatar
  • 11
3 votes
3 answers
327 views

How to choose eyepieces and other accessories for a Celestron 70mm f/5.7 portable refractor?

I have a Celestron Specialty Series Travel Scope 70mm refractor which came with 10mm (40x) and 20mm (20x) eyepieces. Specifications: Focal ratio: f/5.71 Optical Design: Refractor Aperture (mm): 70 mm ...
user avatar
1 vote
1 answer
136 views

How far can the best telescope see in outer space from Earth?

I was wondering what is the farthest the best optical telescope can see into outer space from Earth. What causes them to see so far?
user avatar
  • 135
2 votes
0 answers
50 views

Metric to estimate measuring accuracy

I need help/suggestions on which metric/approach to use. I am trying to estimate pointing precision by measuring the offset of the experimentally measured values from the real, theoretical values, ...
user avatar
9 votes
1 answer
211 views

How to determine the scale on astronomical images?

I've always been amazed at the many beautiful images of objects in the night sky. The Andromeda galaxy is a superb example. But it was only a few years ago that I discovered that Andromeda in those ...
user avatar
  • 1,224
4 votes
1 answer
161 views

General process of calculating what a telescope's diffraction spikes would look like?

I was reading this question about the JWST's diffraction spikes, and I was rather surprised by the magnitude of the 4 sets of diffraction spikes. The large hexagonal spike pattern I believe is formed ...
user avatar
  • 3,918
6 votes
0 answers
97 views

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. ...
user avatar
  • 1,224
6 votes
2 answers
138 views

JWST mirrors each can be "positioned in tip, tilt, piston, horizontal & vertical decentering and clocking". What does this mean?

This interesting paper by Robert Warden refers to each mirror segment on JWST as having six actuators providing six degrees of freedom in positioning (plus one more to tweak the curvature). These ...
user avatar
  • 1,224
5 votes
1 answer
139 views

Why aren't concentrated solar power plants use for astronomical observations of some type?

Concentrated solar power plants use reflecting surfaces to gather the sun rays for energy production. Currently they sit idle at night and are not used for anything. These have huge collection areas, ...
user avatar
2 votes
1 answer
124 views

Camera adaptor won't focus [duplicate]

I'm trying to use my DSLR camera (Canon EOS-40D) with my kids' Celestron First Scope. I bought a 3x Celestron 1.25" barlow, Celestron 1.25" T-adaptor, and the Canon ring. These things all ...
user avatar
  • 121
7 votes
1 answer
549 views

What does par. lines mean in relation to a telescope aperture in 19th century German astronomical publications?

I am trying to understand what is meant by par. lines in an 1867 article "The Aberration of the fixed stars after the wave theory" by Prof. W. Klinkerfues of Royal Astronomy Works of ...
user avatar
  • 63
1 vote
0 answers
55 views

Is it possible to observe the full Moon using this telescope?

I'm trying to solve this task: For amateur observations, a small telescope with a lens focal length of 120 cm was brought to the Byurakan Astrophysical Observatory. If this telescope is directed ...
user avatar
  • 1,017
3 votes
2 answers
110 views

Is a mirror cell only necessary for collimation?

I'm building a truss Newtonian, and I'm planning on achieving collimation using turnbuckle-style trusses, as demonstrated in this thread. If I'm collimating this way, is there any reason to support ...
user avatar
  • 185
2 votes
0 answers
145 views

Can JWST be damaged by looking at a bright star?

Can JWST be damaged by looking at a bright star? The Sun as well as particularily bright solar-system objects like Jupiter, Venus or the Moon not meant with this question.
user avatar
  • 793
5 votes
1 answer
110 views

Why orient a refracting telescope to the North?

I'm a french Guide of french military heritage. I have to prepare visit about "L'observatoire de la Marine, moulins du faouëdic" (Former windmill which served as an astronomical and ...
user avatar
1 vote
0 answers
67 views

How to find the aFOV of a eyepiece?

How do I find the apparent field of view (aFOV) of a eyepiece using simple math (if possible)? I need the aFOV to give as a value to Stellarium’s custom eyepiece I found a Q&A about this subject ...
user avatar
  • 11
4 votes
2 answers
100 views

How do telescopes avoid blurry images?

Telescopes rotate with the Earth. If a telescope isn't fixed on something like the North Star then everything in its field of view is moving pretty rapidly, yet photos from these devices are crystal ...
user avatar
5 votes
2 answers
150 views

Does a star shaped mirror present problems either optically, or in signal processing over a more nearly circular mirror?

Pure speculation about a future replacement for the JWST that I almost certainly won't live to see. The JWST's mirror (and then some) would fit unfolded and flat into the Starship's 8m diameter ...
user avatar
  • 49
2 votes
1 answer
77 views

Is it possible to take the same images in HST palette as the optic telescope but with radio telescope?

Is it possible to detect signal from SII, H$\alpha$, OIII using radio telescope and make the similar images as optic telescope? If no, can we use the different elements to take signal? What minimal ...
user avatar
  • 176
1 vote
2 answers
51 views

How much magnification would I get by this Dall-Kirkham telescope?

I'd like to know how much magnification I would get by this telescope. The main specs are as follows: Focal length: 2563 mm Focal ratio: F/7.2 Number of lenses: 2 Optical diameter of Primary mirror: ...
user avatar
  • 13
3 votes
1 answer
68 views

Improving portability of truss Newtonian

I'm designing a 10in f/6 truss Newtonian as a sort of big travel scope; something that I can break down into parts to fit in a backpack or similar but will still give me decent angular resolution. In ...
user avatar
  • 185
6 votes
3 answers
1k views

Trouble Seeing Distant Planets Such as Jupiter and Uranus

I am a beginner and I am using a Celestron AstroMaster 114 telescope. Whenever I try to view distant planets such as Jupiter I am presented with a black circle that has black lines leading from it. In ...
user avatar
  • 61
1 vote
0 answers
45 views

Maximum number of pixels across a synthesized beam in an ALMA image?

I have some ALMA data, from which I have created images using the TCLEAN task in CASA. I understand that with this type of data, it is necessary to have at least 2 pixels across the FWHM of the ...
user avatar
  • 1,189
2 votes
1 answer
38 views

How much do collimation and viewing conditions affect magnification and viewing?

Before I start this post, I'd first like to make clear that this account is an alternate of my SovereignInquiry account--at the moment, accessing this account is much more convenient, so if things I ...
user avatar
6 votes
2 answers
133 views

Will the James Webb Space Telescope need re-alignment of primary mirror segments?

I couldn't find an answer to this question. James Webb Space Telescope will align primary mirror segments and secondary mirror in space. Question is whether these will need re-alignment during the ...
user avatar
1 vote
1 answer
103 views

The most precise way to point the true north

Since all of my telescopes have equatorial mount and It needs to be placed with respect to North direction, what is the best way to point the North. Expecting answers that doesn't suggests methods ...
user avatar
3 votes
1 answer
81 views

Hoping to do some viewing and astrophotography with a large-ish Dobsonian and a DLSR, is this scheme workable?

I haven't put a camera behind a telescope since the lunar eclipse of 1975 except for a few experiments with a cell phone held behind a pair of binoculars. I want the occasional thrill of using a ...
user avatar
  • 31.4k
1 vote
1 answer
51 views

Can I use an achromatic focal reducer to reduce chromatic aberration?

I am using 75/1000 Plano convex lens to build telescope. Can I use an achromatic focal reducer to reduce chromatic aberration?
user avatar
1 vote
1 answer
76 views

Can I use 75mm Plano convex lens to build telescope [closed]

I want to see Jupiter with moon. So am planning to build telescope. Can I use 75mm Plano convex lens with 1000mm focal length?
user avatar
3 votes
2 answers
789 views

Will these simple 2 convex lens arrangement telescope see the moon clearly?

Hi readers, I am planning to build my telescope. Does this very simple 2 convex lens arrangement even possible to observe the moon clearly with high magnification? I am planning to buy 5 cm diameter ...
user avatar
2 votes
0 answers
71 views

What are the technological advancements that made it possible for modern large telescopes to work with alt-az mounts instead of equatorial mounts?

The video Earth's Rotation Visualized in a Timelapse of the Milky Way Galaxy - 4K (linked below) and discussion below this answer to Why does a timelapse video of a stationary Milky Way make the ...
user avatar
  • 31.4k
8 votes
1 answer
682 views

When might Rowan-Robinson's planet be discovered or disproved?

A month ago Michael Rowan-Robinson discovered three dots on old images of the sky which may or may not be an undiscovered planet (that's not identical to Brown's and Batigyn's hypothetical planet). I ...
user avatar
10 votes
4 answers
3k views

Why do satellites appear as streaks in telescope images?

Can you explain me in simple words why the satellite in this telescope image appears as a streak? The exposure time is 1 second.
user avatar
  • 111
2 votes
0 answers
64 views

What new fundamental knowledge could a very, very large optical telescope bring? [closed]

Very large baseline radio telescopes bring many mysteries of the cosmos to us. We build them because they are feasible. Say, in the future, we could build very large optical telescopes in deep space, ...
user avatar
26 votes
6 answers
4k views

What should I look for in a first telescope for a child?

I'm in a situation that I think many parents find themselves: my son has said that for Christmas he wants "a telescope so that I can see the planets". Which is cool, and I certainly would ...
user avatar
  • 373
4 votes
2 answers
104 views

New to Astrophotography

I just had a quick question on my telescope I recently purchased. I have a Canon Rebel XTi and I paired that with the William Optics Guide Star 61 Guidescope. The Specs on the Scope are: Guide Scope ...
user avatar
6 votes
3 answers
2k views

Could someone explain what is wrong with my telescope, and what should I be able to see with it?

In January of 2016, I received my first telescope, through Astronomers Without Borders. It was and is my first telescope: an AWB 130 Newtonian tabletop telescope with a 650mm focal length and a 130mm ...
user avatar
10 votes
2 answers
2k views

How big would a telescope have to be to get a good look at the nearest neutron star?

It's my understanding of observational astronomy that the size of a telescope limits its effective angular resolution, which is why scientists needed to use radio telescopes all over the globe to look ...
user avatar
  • 1,200
1 vote
1 answer
70 views

Which one is better for both the beginner dad and the 7-yr old? Sky-Watcher 130P or Celestron StarSense Explorer 114AZ

I am looking for a beginner scope for myself and my 7-yr old. She has been asking for a telescope for some time but I don't know how immersed she would be, once bought. So, I want something which can ...
user avatar
  • 13
-4 votes
2 answers
145 views

Telescope/s functioning from underground mines

Theoretically and Practically, Can a Telescope function for the astronomer observed from underground mines? By "telescope" I mean the instrument used by astronomers to observe stars, planets ...
user avatar
2 votes
2 answers
83 views

How is resolution defined?

So I'm looking at a 1 meter square object in my digital camera. What size of pixel is considered fine enough that the object is considered to be resolved? Obviously a pixel size of one meter squared ...
user avatar

1
2 3 4 5
13