Questions tagged [telescope]
Questions related to the physical instruments for astronomical observations.
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If 42000 Starlink satellites interfere with telescope observations from Earth would someone observing from another solar system detect them too?
SpaceX's Starlink constellation could place up to 42000 satellites around the Earth. Would aliens with their own telescopes notice them? They would be about 150 km apart and could reflect light of ...
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Which place in the world should be best for astronomy with an optical telescope?
Would it be somewhere in a desert a long way from water and mist, or high on a mountain above the lower atmosphere? Where is the best location in theory or in practice?
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Are there plans to detect life on Earth from the outer solar system?
This has been kicking around in my head for a while. We've been detecting planets for decades by observing regular dips in starlight from many light years away as a planet transits its host star. I've ...
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How do eyepiece mm values equate to telescope tube extension mm values?
I'm trying out a DSLR on my Celestron 70EQ refractor telescope with a DSLR T-ring.
The first try didn't magnify very much, and I learned that I need to extend the focus length to magnify the image; I'...
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Would it be possible to use existing radio-telescopes to do spot measurements of CMB?
With CMB peaking at roughly 158GHz would it be possible to create a more precise map of CMB just by sampling 'points' using existing Earth-based radio telescopes? I understand that large dish ...
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How can telescopes see anything at all?
I'm impressed that we have any telescope imagery at all. Take the images we have from the "Pillars of Creation".
The Pillars of Creation is in the Eagle Nebula, some 7,000 light-years away ...
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Can telescopes under $200 help you see saturn clearly by eye without editing the image on a computer?
I had a telescope that only cost 50 dollars for viewing the moon and it was good for that but the planet's were always badly out of focus. I am thinking of getting a better telescope for up to $200 ...
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What kind of telescope would be needed to image a 10m dim object 1 million km away?
There's a 10m diameter object 1 million km away from you, stationary with respect to you. The object is dim: it is at 3K and is not reflecting any light towards you. So you have to pick it out by the ...
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How to spot Andromeda in a 130mm telescope?
I have no problem to spot orion nebula, I mean the blue splash caused by the gas on my 130mm reflector telescope but I can’t see the same on Andromeda, what I am missing?
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Why are segmented mirrors lighter than monolithic mirrors?
Everywhere I look, it is recited as a quasi-mantra that "segmented mirrors are much lighter than monolithic mirrors", and I can't manage to find an explanation anywhere no matter how hard I ...
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General process of calculating what a telescope's diffraction spikes would look like?
I was reading this question about the JWST's diffraction spikes, and I was rather surprised by the magnitude of the 4 sets of diffraction spikes.
The large hexagonal spike pattern I believe is formed ...
CommunityBot
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Is there a maximum practical telescope aperture for viewing (through a filter) a solar eclipse?
I grew up stargazing through various telescopes of increasing aperture sizes, and now that I can afford it, I'm about to invest in a more serious telescope to suit me for decades to come. My primary ...
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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 ...
CommunityBot
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Why do planets just look like a dark ball in my telescope
I bought a Matsukov Cassegrain many years ago and now wanted to dust it off and use it. I had two young kids at the time so couldn't really find the time. Last night Jupiter and Saturn were both ...
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What instruments do amateur astronomers use in their ground based telescopes in order to avoid atmospheric absorption/telluric contamination?
What instruments do amateur astronomers use in their ground based telescopes in order to avoid atmospheric absorption/telluric contamination? For example, when an astronomer observes a celestial body ...
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Attachment for viewing the sun with a telescope
In 2016 I got to see the transit of Mercury thanks to a group of volunteer astronomers. The astronomer had a device attached to the telescope eyepiece that allowed the light to project onto frosted ...
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Mauna Kea versus Mauna Loa: Astronomy ethical considerations
There have been controversies and conflicts related to telescopes/observatories developed on Mauna Kea, as described here. However, there does not seem to be controversies related to observatories on ...
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What eyepiece or other optics might improve image quality or observing experience for my Shilba Eclipse 60900 telescope?
I have an old Shilba Eclipse 60900 telescope.
Specs:
Object diameter: 60mm
Focal Distance: 900mm.
Optics:
Barlow 3x
1.5x Erecting Eyepiece
4mm and 12.5mm eyepieces.
I'm aware it's a basic one, ...
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How are the Extremely Large and Thirty Meter Telescopes coming along ("planned 2027")
The graphic above is oft-cited in SE questions and answers. I was (a little) sad to see in it that the 100 meter telescope-engineering wunderkind Overwhelmingly Large Telescope or "OWL" has ...
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Is there a reflecting telescope like as a Newtonian telescope but with a negative lens before the diagonal mirror?
A Cassegrain reflecting telescope contains a negative optical element between the main mirror and its focus. This increases it's focal length.
Is there a reflecting telescope like as a Newtonian ...
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Why aren't reflector telescopes built with an offset secondary mirror?
Reflector telescopes (normally?) have a parabolic primary mirror that reflects the light to a secondary mirror which is placed at the center of the telescope. The construction holding that mirror and ...
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Getting good images only when I cover the part of telescope opening
I have recently built a 4.5inch reflector telescope. The primary mirror is of 900mm focal length. The issue is, when I try to observe Saturn I am not getting good images. It looks like kind of double ...
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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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If the universe were infinite, how would it look through a telescope?
I assume there is some limit to how far our telescopes could actually see, and that this distance would be about the same in all directions. So, as a layman, I would assume that an infinite universe ...
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Apart from higher costs, drawbacks of catadioptric telescope vs Newtonians?
From what I've read, catadioptric telescopes seem to be superior to reflectors. They tend to require less frequent collimations, are generally shorter in physical length, and the combination of lenses ...
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Is seeing the Apollo Moon landers via an Earth-based telescope that hard?
There are interferometers that fuse the images produced by multiple telescopes and achieve a resolution of 0.001 arcseconds. With changes, couldn't these observe the Moon landers? Is the reason why ...
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Is there any telescope on Earth that can see the lunar rovers on the Moon?
If I have the right numbers, it seems to me that even the Hubble telescope might barely be able to make out a carcass of a blue whale on the surface of the Moon, which puts objects as small as the ...
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Can the interferometer called "Gravity" measure "a few centimeters on the Moon"?
Phys.org's Very Large Telescope sees star dance around supermassive black hole, proves Einstein right links to several ESO videos, including Interview with Reinhard Genzel (in English). After ...
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What telescope is Polish astronomer Kazimierz Kordylewski holding in this April 1964 photo at the Jagiellonian University Observatory in Krakow?
The following questions touch on Kordylewski clouds
Can dark matter accumulate at Lagrange points?
Are dust-dust collisions necessary to explain Kordylewski clouds at Earth-Moon L4/5? Aren't the ...
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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 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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Is moisture harmful to a Newtonian Reflector?
It is often cold outside, especially in the evening. So when I take my Newtonian Reflector back in my house, it starts condense.
Can the water destroy my telescope? or the mirrors? Do I have to clean ...
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Planets looks like normal stars when I see them using telescope
I've been trying to see planets using my 114 mm (aperture) f=900 mm telescope. For the moon, I got very good quality pictures, but when I try to see planets they just appear to be as if I'm looking at ...
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2001 VB - when will it be reacquired?
2001 VB's orbit is poorly known but has a two-in-a-billion risk of a collision with the earth in 2023.
Assuming that it were on a collision course, when would it be likely to be reacquired? Which ...
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Why did it take so long to invent telescopes given glass was used 4000 years ago in Mesopotamia?
Is a telescope difficult to make? Does glass have to be polished and shaped very precisely? Or is a device using two or more lenses to magnify things just not obvious?
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How did people in Mali know that there were two stars appearing as one in Sirius before telescopes were invented?
Did they invent a telescope and keep it quiet?
Given that glass has been around for 4000 years (made in mesopotamia in 2000 BC) was it technically possible to polish it and make convex shapes from it ...
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Why aren't concentrated solar power plants use for astronomical observations of some type?
Concentrated solar power plants use reflecting surfaces to gather the sun rays for energy production.
Currently they sit idle at night and are not used for anything.
These have huge collection areas, ...
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Claim that 30-m class telescopes will have resolution far superior to Hubble: true?
This article makes the claim that the Giant Magellan Telescope (GMT, number 4 in the list) will have resolution 10 times better than that of Hubble, while the Thirty Meter Telescope (TMT, number 3 in ...
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Trouble seeing Mars and Venus more than specks of light
Finally been breaking out the telescope to get a better look at things recently, and have been attempting to take advantage of Mars's and Venus's positions in the sky, but I haven't been able to see ...
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Which telescope(s) did Charles Messier use to catalog his 110 objects?
Charles Messier is known for (among other things) a catalog of "Messier objects".
Neither article shows an image of "Messier's telescope", though the latter includes:
Since these ...
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Which value of the apparent magnitude do I use from a Supernova light curve
I am trying to get the distance modulus from a light curve of a supernova and obviously the apparent magnitude changes with time. Not only that but there are so many filters with different mags.
So my ...
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Was Galileo expecting to see so many stars?
Beginner amateur here. I see mentioned many times that Galileo was surprised to see the moons of Jupiter and all that their existence proved, i.e. the Earth not necessarily being the center of ...
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Ritchey–Chrétien telescope with a short back focus
I have an observing project that requires a 30 -- 40 cm (12 -- 16 inch) diameter primary and no refractive/transmissive elements (i.e. lenses).
Telescopes like this Ritchey–Chrétien has a back focus ...
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How can I observe Sgr A* with itelescope.net
I've been experimenting with itelescope.net and tried to observe Sgr A*.
I was wondering if there are any suggestions as to how I can best observe the surrounding stars?
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Right ascension of a star and local sidereal time
If I'd like to watch star like Betelgeuse that has coordinates - right ascension 05h 55m 10.30536s and declination +07° 24′ 25.4304″.
If my local sidereal time is 05h 55m 10.30536s does it mean that ...
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Telescopes with equatorial mount and "catching" stars
I have a misunderstanding of principles behind using telescopes with equatorial mount (I don't have it yet, only trying to grasp the idea). For example, I would like to watch Betelgeuse in the ...
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Is rayleigh's criterion only applicable to refractive telescopes?
Can we apply Rayleigh's criterion for the resolution of a primary mirror of a reflective telescope?
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Why can't we build a huge stationary optical telescope inside a depression similar to the FAST radio telescope?
So first we'll have to find a natural depression or we should create one. I understand you can only see a single portion of the sky since it can't be moved, so my money is on creating an artificial ...
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Advantages or disadvantages of a photometer versus a CCD-camera?
The Wikipedia article on photometry says this about photometers:
These have largely been replaced with CCD cameras that can simultaneously image multiple objects, although photoelectric photometers ...
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Calculate Dec and RA of a star from Euler angles and GPS data
I have 9DOF sensor (accelerometer, gyroscope, and magnetometer) that gives orientation via Euler angles (yaw, pitch, roll). Along with GPS data (latitude, longitude, elevation, time) this is passed to ...
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