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Questions related to the physical instruments for astronomical observations.

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3answers
86 views

What's the difference between a Newtonian telescope and a regular telescope

So, recently I was shopping for telescopes and I decided on the following telescope: https://www.amazon.com/Celestron-21049-127EQ-PowerSeeker-Telescope/dp/B0007UQNKY/ I had exactly $180 to spend, ...
6
votes
2answers
546 views

Which telescopes model is being shown to Albert Einstein in this file footage? What event might this be?

In the Economist video Why does time pass? there is some file footage of Albert Einstein attending some event where a model of a large telescope is on display, and being described to Prof. Einstein. ...
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1answer
49 views

I am beginner here.Could any one please suggest telescope on AliExpress [closed]

I am beginner and eager to buy telescope for viewing planets and deep sky objects. I have gone though several posts here and found that only magnification is not so important but along magnification ...
3
votes
0answers
28 views

Things to be aware of when designing a custom equatorial fork mount

I'm still relatively new to amateur astronomy, and I would like to get into astrophotography. I've looked at different equatorial mounts, and I think I like the benefits of fork mounts. I'd like to ...
5
votes
1answer
46 views

What is the meaning of “bright unresolved sources”

In many articles talking about telescopes, they talk often of "bright, unresolved sources". "bright" usually mean that the magnitude should be less than a certain threshold, (or that the signal to ...
5
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2answers
139 views

Why can’t I see any detail on planets?

I really want to know why I can’t see detail on planets. This summer my Dad and I went on a trip to Utah I went outside to look at the planets and couldn’t see detail on Mars, Saturn, and Jupiter. ...
1
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1answer
22 views

Air temperature range recommendation for observations in a summer night with an entry level telescope?

Recent nights where I try to make my first observations with the entry levell telescope Seben with 114 mm mirror it seems that for lenses less than 6 mm details go lost due to warm air refraction (as ...
2
votes
1answer
48 views

Can this mirror be cleaned?

I dug up my old 6" Dobsonian telescope from storage and the mirror looks like the following: The picture is down the tube, so you can see the spider holding the secondary. To my eye, the spots look ...
2
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1answer
36 views

First Telescope SkyWatcher Heritage 5" Tabletop Dobsonian Telescope

I have been star gazing for awhile with a pair of binoculars and now I am ready to step it up a bit and purchase a telescope. I have been looking at the SkyWatcher Heritage 5" Tabletop Dobsonian ...
2
votes
1answer
56 views

I have a Model 36050 telescope

My Model 36050 telescope came with the H6mm, H20mm and the green filtered moon lenses. It has a 360mm focal length and a 50mm diamiter. What can be seen with it?
2
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0answers
68 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 ...
2
votes
1answer
41 views

Beginner looking for extra eyepieces for telescope

I have a Bushnell Voyager Reflector telescope. It came with 2 eyepieces: k4mm and k20mm. And I am trying to find additional eyepieces to zoom in further on planets and stars, but the bushnell website ...
1
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1answer
62 views

Struggling to use my new telescope

I recently got my first telescope, a Bushnell reflector telescope. I spent a good while setting up my alignment. And I can see the moon perfectly! I went to look at another, Mars. I got it aligned in ...
1
vote
2answers
119 views

Does the size of the atom limit the focal length of telescopes?

Does the size of the atom place a theoretical limit on a telescope's focal length (and thus, resolution)? It seems to me that that the allowed margin of error for parabolic mirrors drops with an ...
6
votes
2answers
109 views

Do we know at which angle the Event Horizon Telescope will look at the accretion disk of Sagittarius A*?

Do we know at which angle the Event Horizon Telescope will look at the accretion disk of Sagittarius A*? Additionally, would it matter if we are exactly in the plane with the accretion disk, i.e. ...
4
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1answer
117 views

Orion Skyquest xt8i Intelliscope Dobsonian Telescope Lens

I have the telescope in the title, which camps with 10mm and 25mm eyepieces. Both cannot really see anything in detail past the moon. All planets look like stars. What are good eyepieces for seeing ...
35
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4answers
8k views

Why are we building larger land-based telescopes instead of launching larger ones into space?

This question is a follow-up to Do bigger telescopes equal better results? How much bigger does a ground-based mirror have to be to match what a space-based one can do? I guess I'm asking primarily ...
2
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4answers
167 views

Is it practical to build a giant telescope in Moon? (Considering the fact that the atmosphere of moon is very rare)

China's FAST (Five-hundred-meter Aperture Spherical radio Telescope) is the largest radio telescope in the world.(This is huge!!!) As we all know Space Telescopes are better than Earth-Based ...
4
votes
1answer
80 views

How many galaxies can be seen in a given patch of sky

Similar to the question asked here, but my question is not about what can be seen with the naked eye but rather what might be seen if pointing my Newtonian reflector (full specs outlined below) at an ...
5
votes
1answer
51 views

Surface brightness of deep-sky objects and telescope specs

I'm new to amateur astronomy, and I recently acquired my first small telescope. I've just learned a bit about surface brightness after an unsuccessful night of trying to locate a few nebulae that were ...
2
votes
1answer
60 views

How to understand Kepler telescope under large aspherical wavefront

To my understanding, a Kepler telescope is designed to conjugate one plane to another. For example scale down/up the incoming wavefront onto a wavefront sensor for measurement. It works well for small ...
4
votes
3answers
148 views

Relation between angular resolution and aperture?

The angular resolution of a telescope is given by $\frac{1.22\lambda}{D}$. This should mean that the smaller the aperture D, the higher the angular resolution. But it is exactly the opposite - why?
4
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3answers
108 views

Why do we use solar filters instead of simply reducing aperture of the telescope?

Everywhere I read that to view the Sun in the telescope, one has to use a solar filter. The filter must be handled carefully to avoid any holes in it and even mustn't be stretched so as to avoid ...
3
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2answers
95 views

Need help in creating telescope

I have 100cm F.L objective and 10cm F.L eyepiece 10cm in diameter and double convex both. what are the planetary objects I can see with telescope made with these lenses. I also have a double convex ...
5
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2answers
79 views

Names of specific galaxies in Hubble's XDF

I'm working on a little side project that traces and identifies galaxies in Hubble's XDF using OpenCV. This is my current progress with tracing the more prominent galaxies: I was wondering if there ...
1
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1answer
36 views

Best locations for large telescopes at high northern latitudes

Large optical telescopes want to be located at high altitude (get above as much of the atmosphere as possible). I get the impression that there is also a preference for low latitude (see as much of ...
5
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0answers
26 views

Meade LX200GPS electronic RA movement very slow

I use a Meade 200 LX GPS. Last night between viewings it was placed in Sleep mode. On return the scope was making noises as if the motor was running. The scope was stationary, but had moved to what ...
4
votes
3answers
199 views

My first pictures of Jupiter

Well, I'll start off by saying I am certain I am doing it wrong! Now that I got that out of the way here is my image: I have a feeling I can't see the planet because I need a filter to block out the ...
1
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3answers
66 views

How do I obtain the brightness of a star in the night sky?

I am planning to conduct a research which involves observing the brightness of a star. So far, I haven't been able to obtain much information as to how I may go forward with the observation process. I'...
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1answer
66 views

About bigger resolution of telescopes [closed]

Any idea about the design of new better telescope having small length of diameter and having more resolving power.
1
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3answers
173 views

Photographing Venus with a phone through a telescope

I took a picture of Venus through my telescope (Celestron Astromaster 130eq) using a 10mm lens with a Barlow lens. The picture isn't really good since I took it with my phone and I still don't have a ...
3
votes
2answers
121 views

Can a telescope detect a blackbody?

I'd like to determine the distance at which a telescope with a certain set of parameters (sensitivity, collector area) can detect a blackbody with certain other parameters (temperature, emitting area)....
1
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1answer
114 views

How can I find out the maximum magnification of my telescope?

I have a Meade DS-2080AT-LNT. It's an inexpensive scope that I've had for several years. It has a couple of eyepieces with it, but nothing that will let you get a really good look at planets. I doubt ...
2
votes
1answer
50 views

South or North Celestial Pole

I'm really confused with this one. Almost all documentation says you must start with your telescope pointing to the Celestial Pole and for the lucky ones who live in the north you can use Polaris. ...
0
votes
2answers
85 views

Need help with telescope mount; stars have tails

If I take a shot longer than 20 seconds, the stars get a tail. I have a Celestron Advanced GT mount with starshoot autoguide scope. I use a cannon can on a 9" Celestron scope. I can't get a picture ...
0
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0answers
23 views

Non-typical Secondary Mirror in 20" RC telescope?

We recently discovered that the secondary mirror of our 20" RC has a hole that runs through the center. On the side of the secondary facing the primary there is a metal tube (for lack of a better ...
3
votes
1answer
71 views

Newtonian reflector collimation question

After an initial collimation, I took my scope (150mm/750mm) out for a star test. While I could see concentric circles when the bright star is at the centre of the video, when the star is on the side ...
3
votes
1answer
59 views

Is it possible to calculate the focal length of a refactor I built?

I am trying to build a very low cost refractor telescope. It's for a project, so I need to be able to provide "data" about the telescope. But it seems I can't calculate anything (magnification, to be ...
0
votes
1answer
56 views

Which telescope to choose and some general questions [duplicate]

I'm playing with the idea to buy a telescope for years now and finally decided to do so. There are two which I consider: The Celestron NexStar 127 SLT Mak and the Celestron NexStar 130 SLT I ...
5
votes
1answer
104 views

Which space telescope is the most distant?

From the earth, and from the sun. Only interested in active, operational ones.
1
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1answer
23 views

Focusing with Meade Audiostar

I recently upgraded from a Meade ETX-RA to and ETX-EC and bought a used Audiostar controller. My EC came with a Meade autofocuser and one of the old (I think it’s 494) controllers that has the focus ...
3
votes
1answer
53 views

What is tilt anisoplanatism for Laser-guide-star usage in adaptive optic systems?

How does tip-tilt mirrors correct such issue? What is the physical origin of the error?
1
vote
1answer
60 views

What allows WFIRST to have similar resolution to Hubble over a 100x larger solid angle?

In the video linked in the Space.com article What Would It Mean for Astronomers If the WFIRST Space Telescope Is Killed?, (available in YouTube as WFIRST: The Best of Both Worlds) after ...
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0answers
50 views

Detecting the Chicxulub impactor, right now [duplicate]

Say an asteroid identical in all ways to the Chicxulub impactor (size, mass, materiel, orbital type, etc) was about to hit us. (Again!) As of exactly early 2018, given our known instruments and ...
1
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1answer
129 views

Replacing Meade ETX with computerized mount

I've been using a Meade ETX 90 for a few years now. Since it doesn't have the new computerized mount (with goto), I am looking into buying one to swap out. Where might I find this and is there a more ...
1
vote
2answers
209 views

Can I build a telescope with a lens from a CD-ROM as eyepiece?

I saw some article on the web about making an eyepiece of a telescope with the lens from a CD-ROM. Will this really work? I have an objective lens of 100 cm focal length. What will be the ...
2
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0answers
34 views

Webcam set up small circle tunnel vision type view

I've just adapted a webcam for my telescope. I'm new to astronomy so I'm not sure if the view I get is right. When I attached the webcam to my Barlow lens, the view on my laptop becomes a tiny ...
1
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1answer
78 views

Thinking of buying a new telescope. What aspects should be considered? [closed]

I'm new to astronomy and I have a Celestron 50Z but I'm thinking of buying a better telescope. I see that there are many options out there but I'm not really sure as to which aspects I should ...
3
votes
0answers
43 views

Is it possible to model a solar thermal concentrator using Zernike polynomials?

This question might seem a bit off-topic, but I guess there are a lot of people here that know about optics, telescopes, etc. I would like to simulate solar thermal systems that focus solar ...
1
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2answers
118 views

Planetary observations: what to expect from the Powerseeker 50AZ?

I bought the Powerseeker 50AZ, which has D=50mm; F=600mm F/12 which comes with 3 eyepieces: 20mm, 12.5mm and 4mm. As far as I can tell it's not possible to colimate this telescope. As suggested here ...