Questions tagged [telescope]

Questions related to the physical instruments for astronomical observations.

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3
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0answers
184 views

Angular magnification of three lenses telescope?

What is the magnification of a three-lens telescope? As a child I built a "telescope": objective lens $$f_1 = 20 cm$$ middle lens $$f_2=5cm$$ and eye lens also $$f_3=5cm$$ My drawing of my ...
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2answers
141k views

How much magnification is needed to see the 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 the details of Jupiter what was expected. ...
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111 views

Powerful-enough telescopes to observe the Lunar Roving Vehicle from Earth?

Apparently, not even the Hubble telescope (which is actually in orbit, not even on Earth) is powerful enough to observe the LVR... will we ever have the technology to observe the LVR from Earth? (it ...
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2answers
194 views

Astromaster Celestron 130 EQ

I brought a new Astromaster 130 EQ and collimated it using a laser. However, whenever I try to observe moon I get a perfect picture but with other planets I see only a bright glowing ball which ...
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1answer
64 views

Is the LSST (Vera C. Rubin) telescope going to change position every 20 or 35 seconds?

This is a very particular question, I realize, but I am still curious... The Vera Rubin telescope is supposed to take a 15-second exposure, then take 5 seconds to move to its next spot... But I also ...
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1answer
445 views

Which eyepiece should I use to view planets with a Slokey Skyways 50080 telescope?

I am new to Astronomy. My husband bought a Skyways 50080 for me for my birthday. It's an f=500mm refractor made by Slokey. The 80mm aperture makes it a fast f/6.25. It came with three eyepieces; 25, ...
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1answer
102 views

When did telescopes become available?

The History of Science and Mathematics stack exchange has a question "When Did Telescopes become Affordable?" asking when telescopes became available to members of the general public instead ...
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5answers
9k 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 ...
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1answer
45 views

What do 5-sigma, r, and lowercase-delta mean in the physical descriptions of major telescopes?

The typical 5σ point-source depth in a single visit in r will be ∼24.5 (AB). The project is in the construction phase and will begin regular survey operations by 2022. The survey area will be ...
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102 views

SpaceX's Starlink Megaconstellation and its Effect on Earth-Based Astronomy [duplicate]

SpaceX's Starlink project is already greatly impeding scientists ability to make good Earth-based observations. With the planned launch of 12,000 satellites total, the future is uncertain. Is there ...
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144 views

Is it possible to generate random numbers from images of the sun? [closed]

If this is off topic, please change it to world-building. Is it possible to make a low cost heliography telescope, which is not digital, and which can be used to generate an worldwide numerical ...
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1answer
136 views

I saw a weird thing around Venus

I pointed my telescope (50mm aperture, 500mm focal length, 4mm eyepiece, image taken through a window) at Venus and saw this: What is it? I don't think this is Uranus or Neptune as my telescope is ...
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2answers
523 views

Why does this large Newtonian telescope's front cover have two or three holes in it?

The Michael Bernardo video How to use an Equatorial Mount for Beginners shows a large Newtonian telescope on an equatorial mount. The cover of the telescope's large aperture shows what looks like ...
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2answers
355 views

My local night sky is so bright that I can only see the Moon, so would a low-cost telescope be any use?

Light pollution is so bad near our home that we can't see anything other the Moon in the night sky. For instance there is a street light on all night right in our lane and there are many other housing ...
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1answer
84 views

What Crayford focuser to buy for a B&L Criterion 8000?

I'd like to get a dual-speed Crayford focuser for my newly acquired a B&L criterion 8000 (8") as the mirror shift is pretty bad. I'm really not sure which one to buy because I'm quite ...
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2answers
78 views

What are the effects of using non-spherical lenses in refracting telescopes?

Non-spherical (or non-circular) mirrors for reflecting telescopes are common and discussed in many places... But what about elliptical, parabolic or hyperbolic lenses?
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1answer
107 views

Number of actuators in adaptive optics

It is well known that diffraction resolution of a telescope depends on the exterior radius of aperture: One can, for instance, use just a narrow outer ring of a parabolic mirror and the resolution ...
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2answers
2k views

How do satellites impede current telescopes?

As we send up more and more satellites, it stands to reason that our view of the universe becomes more and more obscured. I would certainly expect for example that a large telescope such as the LSST ...
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1answer
80 views

Problem with making telescope

I am using a convex lens with $f=5$ cm and $5$ cm aperture, a concavo-convex lens with $f=100$ cm and $5.5$ cm aperture. I am trying to make telescope and it should have magnification of 20 x. But the ...
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2answers
96 views

How close would a Sunlike star have to be in order to be dangerous to look at it through a spyglass?

Alpha Centauri A which has an about 50% higher luminosity than the Sun is obviously undangerous to look at through a handheld telescope, at about 4.4 ly distance. How close would a yellow dwarf have ...
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3answers
320 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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1answer
237 views

Lucky imaging with Celestron 14 - is this result reasonable?

I attempted to do some lucky imaging of Jupiter using a permanent installation (Celestron $14$" SCT + Paramount ME II) and Nikon D5600 attached directly to a Baader Hyperion 8-24mm eyepiece (...
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1answer
202 views

Celestron C14 collimation and cleaning

When checking the collimation of a Celestron 14" SCT I took this image: My question is: how much will the particles causing the local aberrations affect the image quality? (i.e. do I need to ...
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1answer
117 views

How to see Mars and Venus in color?

My telescope is Arsenal - Synta 70/700 AZ2 (refractor model). 140x max zoom (10 mm with Barlow). I could clearly see Jupiter and Saturn in color. I even saw brown stripes on Jupiter. Yet, when I tried ...
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1answer
132 views

Can a telescope ever increase the apparent luminance of an extended object?

From what I know about common telescope designs, telescopes don't increase the apparent luminance of extended objects compared to the luminance seen with the naked eye. In this sense extended objects ...
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3answers
174 views

Practicality of Dobsonian telescopes

I've been using binocular for more than a decade for visual observation. I'm thinking of upgrading to a telescope. The Dob caught my attention due to its simplicity in setup and also cost ...
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1answer
426 views

Trying to use Canon 60D DSLR with Skywatcher 130P. Can't focus image

I have a Skywatcher Heritage 130P FlexTube Dobsonian Telescope. It works well, I can see lovely stars, planets, moons of Jupiter etc. It came with two eye pieces (1.25 inch): 10 mm and 25 mm. I also ...
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1answer
102 views

50mm f1.8 for Astrophotography

I am considering using a 50mm f1.8 maybe even try aN 85mm f1.8 on my Astro FI 102MM Telescope have you any thoughts or suggestions? I have never taken images via a telescope so this is a whole new ...
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2answers
1k views

Jupiter with a mobile phone and Celestron Astro FI 102mm Maksutov

My name is John, I am new here and now that I am retired I decided to get myself my first ever telescope, why I never got one before I have no idea...probably too busy. So I thought I would try and ...
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2answers
594 views

A smudge near Jupiter

I was looking at the Jupiter for the first time today and I have noticed a smudge near it. Could someone explain what it is, please? I was looking online but did not find anything. So I thought that ...
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89 views

Is there a good replacement finder scope for the Celestron 127EQ?

I've had a Celestron 127EQ for a couple years now and have only used it a couple times. One of the reasons I haven't gotten much use out of it is that when I do use it I spend all of my time aligning ...
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0answers
43 views

Can telescopes determine whether Hygiea is in hydrostatic equilibrium?

10 Hygiea is a spherical body in the main asteroid belt. With future telescopes like the Vera Rubin LSST or the James Webb Space Telescope, can we determine whether Hygiea is actually in hydrostatic ...
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1answer
184 views

Help stabilizing telescope

First time astronomer here... (pardon any less than accurate terminology) My son received a secondhand telescope, a Celestron Powerseeker 114AZ. Last night I calibrated the Starpointer, and was able ...
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1answer
72 views

What are these three black cap-like pieces?

My son received a secondhand telescope for his birthday. It is a Celestron Powerseeker 114AZ. I found these three black cap-like pieces separate from other parts. I can’t find what they are or what ...
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2answers
2k 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. ...
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1answer
65 views

Can the electromagnetic counterpart of a gravitational be seen by 'small' telescopes?

As follow-up question for my previous question I'm thinking about the search for the electromagnetic (EM) counterpart of a gravitational wave (GW). Is it possible to search for those events with '...
3
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1answer
157 views

How can I improve the Field of View of my home-made telescope?

I made my telescope, with two convex lens of focal length 1000mm and eyepiece (plano-convex) with 25mm focal length. But I can see only a very small field of view, with inverted image. Do I need to ...
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1answer
153 views

Distance between objective lens and eyepiece

I am trying to make home telescope, I have a convex lens of focal length 1000mm and eyepiece (plano-convex) with 25mm focal length. What is the ideal distance between objective and eyepiece to see ...
4
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3answers
3k 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 ...
2
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1answer
139 views

What is the magnification of my new telescope?

I just bought a Skywatcher telescope with a diameter of 60 mm and a focal length of 900 mm. I have a 2x Barlow lens and two eyepieces with focal lengths of 10 mm and 20 mm. How can I calculate the ...
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2answers
384 views

How to install the Barlow lens on this telescope?

I've brought a 4.5inch astronomical telescope recently which has an aperture of 114mm and a focal length of 1000mm, and two eyepieces. The two eyepieces were of 25mm and 10mm. I enjoyed stargazing ...
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1answer
100 views

What to expect to see

I have telescope with a diameter of 60 mm and a focal length of 900 mm. I have a 2x Barlow lens and eyepieces with focal lengths of 10 mm. Can I see any details of any galaxies? Andromeda for an ...
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0answers
325 views

Which Barlow lens should I choose, 2x or 3x?

I recently bought a 6-inch reflector, 750 mm focal length and I want to get a Barlow lens to get better observations. I have 2 eyepieces, one 9mm and one 25mm. My question is: Should I go for a ...
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0answers
43 views

Telescope focal length, reducer and/or Barlow

Say I have a scope with a given diameter $D$, a given focal length $f$, and a given exit barrel diameter $B$. It has a maximum true FoV of $B/f$ (supposing $B<<f$). Would adding a 0.5x focal ...
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2answers
944 views

What is the maximum distance measurable with parallax? [duplicate]

What is the furthest star or celestial object whose distance has been calculated with parallax and how does it compare to the theoretical limit using today's telescopes? And how exactly does telescope ...
11
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3answers
707 views

What was the largest telescope ever fitted with an eyepiece

Serious modern telescopes use CCDs to capture the results. This makes it convenient to process or display the results halfway around the world. However, there is something visceral about looking ...
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2answers
416 views

I can't see any detail through my telescope

I have a AILINK 114mm diameter, 900mm focal length, reflector telescope. I'm able to see the moon very well however, I can't see Planets very clearly The first two images are what I can see and the ...
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3answers
116 views

Frames per second capabilities cameras currently installed in Modern Telescopes?

What are the present real-time capabilities of various modern telescopes as video cameras? How do these compare with the capabilities various of space telescopes? For example, if it was known that ...
4
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1answer
1k views

What's the rationale behind the false colours in solar observation photographs?

Images from SOHO, SDO and other sun observatories are often coloured differently for different wavelengths or temperatures: http://www.nasa.gov/mission_pages/sunearth/science/Sun-Wavelength-Chart....
3
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1answer
83 views

Which telescope would be better with a DSLR?

I'm interested in astrophotography and since I haven't left my home in six weeks, my interest in photographing the skies has been growing. I'm on a tight budget and I've found these two options: A ...

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