Questions tagged [telescope]

Questions related to the physical instruments for astronomical observations.

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1answer
263 views

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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2answers
4k views

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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2answers
316 views

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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1answer
57 views

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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4answers
7k views

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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1answer
248 views

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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2answers
251 views

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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1answer
147 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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227 views

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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30 views

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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92 views

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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0answers
29 views

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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2answers
151 views

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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1answer
47 views

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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56 views

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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2answers
202 views

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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1answer
541 views

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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3answers
472 views

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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0answers
233 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
115 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
461 views

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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2answers
257 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
700 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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1answer
80 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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1answer
74 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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3answers
201 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 ...
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0answers
103 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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1answer
159 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
762 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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1answer
105 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
105 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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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
95 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
109 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
394 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
129 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
279 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 ...
4
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1answer
241 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
213 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
652 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
117 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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1answer
2k views

Black dot visible when looking into the telescope

A few weeks a go I bought a telescope. The problem is I am a total beginner. I was able to setup the telescope correctly and I already saw the moon very clearly. Then I moved on to jupiter. When I ...
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0answers
129 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
45 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
210 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
73 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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4answers
1k views

Is there a website that shows equivalent views through different telescopes?

I'm trying to buy a beginners telescope. I have a Celestron TravelScope, but would like something better. When I look at other models, many users have posted images from their viewfinders. Is there a ...

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