Questions tagged [telescope]

Questions related to the physical instruments for astronomical observations.

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5
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1answer
82 views

Same area, different shape. pro's & cons

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 ...
2
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1answer
94 views

How does eyepiece exit pupil diameter affect image clarity and viewing experience?

This answer to Not Able to View Objects with Barlow Lens includes a calculation of exit pupil diameter as a way to address the limits of useful magnification when observing planets with a small ...
2
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1answer
71 views

Benefits to adding a 32mm Pössl to my Celestron AstroMaster 130EQ's eyepieces?

I am getting a Celestron AstroMaster 130EQ soon. I have heard that its eyepieces aren't the best, so I am considering a 32mm Pössl. For such a choice, what would be the arguments for and against? How ...
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1answer
52 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 ...
2
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1answer
70 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 ...
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2answers
47 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: ...
3
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1answer
51 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 ...
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3answers
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 ...
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0answers
30 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 ...
6
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2answers
103 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 ...
2
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1answer
26 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 ...
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1answer
78 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 ...
4
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2answers
1k views

How does making a refracting telescope very long reduce the chromatic aberration of an uncorrected lens?

Below are two cropped views of "Johannes Hevelius's 8 inch telescope with an open work wood and wire "tube" that had a focal length of 150 feet to limit chromatic aberration." from ...
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0answers
66 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 ...
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1answer
36 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?
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1answer
65 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?
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2answers
720 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 ...
4
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2answers
93 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 ...
2
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1answer
201 views

Not getting quality images in telescope

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 eyepiece), a 3x and 1.5x ...
8
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1answer
675 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 ...
7
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3answers
561 views

What range of exit pupils work for observing the full moon?

I'm observing the full moon, from a major city, with heavy light pollution and dust. The objective size is fixed, for this comparison, something between 4 and 6 inches. The question is about the ...
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1answer
59 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 ...
10
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4answers
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.
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1answer
164 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 ...
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3answers
4k views

Minimum telescope needed to see the rings of the Saturn

I am a total novice. My daughter, likes Saturn. Since Saturn is so close I thought it was a good time to view it with her. What are the minimum needed telescope specs? Update: Can answer answers be ...
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0answers
62 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, ...
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6answers
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 ...
8
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1answer
745 views

Will JWST be as durable as the hubble telescope?

JW Space Telescope is designed for a 5-10 year mission duration. Seeing as Hubble and other space missions have paved the way for JWST for reliability issues, It even has zero friction gyro's with 100+...
6
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3answers
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 ...
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2answers
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 ...
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2answers
134 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 ...
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4answers
236 views

How can Mercury's sodium tail be imaged?

I recently learned that Mercury has a sodium tail. Can this sodium tail be imaged with a ground based telescope? Is so, what is the minimum setup required to be able to take a picture of it? Do you ...
2
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1answer
306 views

Telescope light gathering power and resolution

I'm a little confused. Could you help me? The question is: if we increase the radius of a telescope twice, how much does the light gathering power change? What about resolution? Does it increase 22-...
6
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1answer
945 views

Telescope collimation issue

Recently, I purchased a Chinese 8 inch reflector telescope from local store. When I observing stars and planets I've been having trouble getting really sharp image from this telescope. I observe Venus ...
2
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2answers
75 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 ...
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0answers
33 views

Would a telescope substantially away from the ecliptic plane improve TNO detection?

There have been lots of new TNOs found in the last decade. Would a telescope far from the ecliptic plane be useful to image them, and spot new ones? What about planet nine, assuming it exists: would ...
4
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2answers
549 views

What's the difference between optical telescopes and solar telescopes?

Solar radiation is strong. Following problems for solar telescopes may be telescope site selection and temperature control. I wonder the telescopes themselves and their instruments are different?
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0answers
55 views

How has the price of an amateur telescope 8-inch, f/8 finished, aluminized mirror varied over the last fifty years?

During a discussion in The Observatory I was remembering that an 8-inch telescope mirror, polished and aluminized, cost something like \$100 to \$200 US in the mid 1970's. Just now I've seen an add in ...
2
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1answer
112 views

Not Able to View Objects with Barlow Lens

I am new to using a telescope and am having a hard time using a Barlow lens. I was able to find Jupiter multiple times using a 6mm lens with a telescope that has a D = 60mm and FL = 700mm. I am very ...
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0answers
28 views

How exactly does NEOSTEL's fly's eye telescope's secondary mirror array split the primary beam among sixteen cameras?

Wikipedia's NEOSTEL says: The Near Earth Object Survey TELescope (NEOSTEL - also known as "Flyeye") is an astronomical survey and early-warning system for detecting near-Earth objects sized ...
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2answers
112 views

I'm considering buying a telescope, which type should I choose?

I am considering buying a telescope for amateur viewing. I am planning to view the stars from my backyard, which is in an area with reasonable light pollution (most of Orion's primary stars are ...
3
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2answers
129 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
77 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
110 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 ...
11
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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
58 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 ...
3
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2answers
312 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 ...
1
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1answer
85 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
72 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 ...

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