Questions tagged [telescope]
Questions related to the physical instruments for astronomical observations.
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Why are telescope mirrors nearly flat?
My understanding of telescope mirrors is that they are (generally speaking) a slice out of an imaginary sphere. The center of this sphere is the focal point of the telescope, where the detector is ...
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Difficulty in using the telescope as a projector
I have been trying, but completely failing, to copy the arrangement for viewing the sun mentioned on this website: https://astronomyconnect.com/forums/articles/2-three-ways-to-safely-observe-the-sun....
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Can equatorial mounts be used at lower latitudes?
I wanted to order a Celestron 127EQ and I was going through the manual online and just noticed that the manual says that latitude is adjustable in about a 20-60° range.
The PowerSeeker equatorial ...
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Eyepiece recommendation for Orion XT8
I am looking for some eyepiece recommendations for my Orion XT8. There are so many kinds out there, and I am not quite sure what to get as recommendations vary wildly. Here are some Q&As that ...
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What will succeed the Arecibo Observatory?
Just a few minutes ago, I got a notification from Space.com stating that the Arecibo Observatory will be, sadly, decommissioned due to extensive damage to its structure. So, with the loss of one of ...
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How long would it take to first detect a new object in the night sky given its apparent magnitude?
If an object as bright as the star Polaris (Apparent Magnitude +1.8) showed up in the night sky, it would be detected almost instantly by stargazers. If an object as bright as Pluto (Apparent ...
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What's the farthest point humans have explored?
By using powerful telescopes on land and space, what's the farthest point humans have explored or viewed?
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Eyepieces and accessories recommendations for a Starblast 4.5-inch scope in a city as well as darker suburbs, and kid friendly?
For the Starblast 4.5 Telescope I currently have an Orion 7-21mm Zoom eyepiece attached on top of a 2x Barlow lens. I like them because of the magnification they give stacked together and the zoom ...
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Please check my Mars photo
Hi built my own newtonian telescope for the first time. Up until that point I had never used a telescope.
Can you please look at the photos attached and tell me if this is what Mars should look like ...
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How to use an app to help find deep sky objects in general, either attached to a telescope as a finder scope or held on hand?
A friend with a young child asked me for a beginner scope recommendation of less than $300 to see the planets as well as some brighter deep sky objects in a relatively dark suburban location. My first ...
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What is an Ideal apparent field of view for viewing planets through a zoom eyepiece?
I was reading the specs of a few zoom eyepieces, and in every eyepiece, there is a term called 'apparent field of view'. I looked up and searched about it and figured out that if you divide this by ...
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Shouldn't this cause a fire?
This website shows a telescope projecting the sun onto a blackboard: https://astronomyconnect.com/forums/articles/2-three-ways-to-safely-observe-the-sun.21/
Why isn't the board catching fire? You ...
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Mars is dark, surrounding is bright, what am I doing wrong? [duplicate]
I just got a Celestron 8 and I'm a complete rookie: set up scope early so it would acclimate to the temperature. No difficulty locating Mars, but I see a dark planet with its circumference slightly ...
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Would alcohol wiping damage multi-coated eyepiece coating? How else can I take COVID precautions on the eyepiece?
My small group of friends will be wearing masks. But could COVID-19 be spread by eyes/eyelashes touching the eyepiece? If so, what precautions should I take?
I have a small Starblast scope with an ...
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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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What exactly is a Hamiltonian telescope? Is this one?
This comment on the current answer to Why is this telescope so short? How hard is it to make such a fast primary? says
In this forum topic Borisov appears to call it an f/1.5 Hamiltonian.
Wikipedia'...
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Is there a more permanent way to set up an Artificial Horizon?
For the last few months we have been constantly setting up an Artificial Horizon (Davis Instruments) using motor oil as the liquid. We discovered that it is very hard to take a reading off of it ...
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Which is a better way to increase magnification - by choosing an eyepiece of lesser focal length or by choosing a telescope with higher focal length? [duplicate]
Magnification of a telescope = (focal length of telescope / focal length of the eyepiece being used)
$$M=\frac{f_{objective}}{f_{eyepiece}}$$
If I want 75 X magnification and the following are the two ...
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What are the deciding optical factors between a refractive and reflective space telescope optics as a function of aperture? (visible light)
Reading Yale News' Lighting a path to Planet Nine:
To detect objects that are otherwise undetectable, Rice and Laughlin employ a method called “shifting and stacking.” They “shift” images from a ...
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What are Native coordinates in the World Coordinate System?
i am writing my first paper about our solar telescope, and i need to explain the optical transformations in terms of World Coordinate Systems. I am not sure if i got the following right, and would be ...
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What would a red giant Sun look like from Proxima b?
As of now, Proxima b is the only confirmed planet (or dwarf planet if it didn't clear its orbit - sorry, couldn't resist) around Proxima Centauri, the nearest-known star to the Sun about 4.2 ly away. ...
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TASCO 49060700 60x700mm Spacestation Refractor
So, my grandfather so graciously gave me his TASCO 49060700 60x700mm Spacestation Refractor Telescope, which is extremely wondrous. Any way, I found this answer to my 3x barlow lens, which I believe ...
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How did Michelson measure the diameters of jupiter's moons using optical interferometry?
In Betelgeuse: How its Diameter was measured (Chant, C. A., Journal of the Royal Astronomical Society of Canada, Vol. 15, p.133, Bibliographic Code: 1921JRASC..15..133C) the author says:
The paper in ...
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How accurately could late 50s - early 60s humans have mapped the solar system?
What if early SETI investigations had focused on our own solar system, rather than distant stars?
Given the technology that existed around the 1950s, how much surveillance would humanity be able to do?...
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How to view the surface of Mars with a 130 mm Newtonian?
I bought a Celestron AstroMaster 130EQ telescope, but I am not able to see the surface of Mars through using the 10 mm eyepiece. Instead I only see a glowing dot.
What should I do to view the mars ...
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What is a good focal length for DSO
I found two telescopes that i'd like to buy, but one has 900mm focal length ((Skywatcher Newton 114/900 EQ1)) and the other has 500mm focal length ((National Geographic Dobson N 114/500)).
My ...
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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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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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Eyepiece::Astromania or Meoptex
I am looking into getting a zoom eyepiece for myself, and not sure on what basis to evaluate and compare various options.
For some background on the type of observing I plan to do see my earlier ...
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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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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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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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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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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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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 ...
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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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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 ...
user35183
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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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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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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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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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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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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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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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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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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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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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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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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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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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