Questions tagged [telescope]
Questions related to the physical instruments for astronomical observations.
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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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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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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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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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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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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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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?
user50918
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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 ...
user50918
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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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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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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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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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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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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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What is the diameter of a telescope lens that will capture the surface of Proxima Centauri b?
I been trying to find the way I can calculate the telescope lens diameter needed to see a star by the distance of the star or the planet from the earth. Is there any mathematical relation we usually ...
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Can we see the colorful patches or the strip of milky way galaxy with reflector telescopes?
As reflector telescopes gather light and make dimmer images brighter, so if I viewed through telescope with 1x magnification or viewed the horizon ,would I see the strip of milky way?
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Can we use plain mirror as a secondary mirror in cassegrain telescope?
I was planning of making a telescope like JWST, just with plain mirrors, as bigger concave or convex are much expensive. The primary mirror would be totally made of plain mirrors configured like JWST. ...
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For lenses, what is the practical difference between plano- and bi-?
I don't know if this is a trivially obvious question for astronomers. If so please forgive my ignorance.
I've looked around at a lot of diagrams of lenses in telescopes. The plano-convex and bi-convex ...
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Why does the altitude-azimuth mount have a blind spot near zenith?
I understand the subject mathematically. Azimuth of the celestrial object under track changes a finite 180 degrees instead of a infinitesimal amount as the body passes zenith. This would require ...
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Could two-way mirrors be used to completely eliminate obstruction for a reflector telescope?
The secondary mirror on a reflecting telescope obstructs some of the light coming in and the spider vanes that hold up the secondary mirror cause diffraction spikes when imaging. Some people prefer ...
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What is the probability that a photon that enters the aperture is registered?
If I want to derive the probability that a photon that enters the aperture of a telescope is detected, how do I do that?
This should be closely related to the quantum efficiency of a telescope, but ...
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Is my TAL-1 telescope too old to be useful
I have a TAL-1 4.3” Newtonian reflector. It is old, gifted to me by my dad and was gifted to him many years ago.
Last year I spent some time cleaning it, calibrating and getting it in a good state. It ...
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Could we detect the light of cities at night in other solar systems?
Would it be possible to see electric lights on distant planets using current telescopes?
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Can a Panasonic Lumix DMC-FZ2000 be attached to a Celestron StarSense Explorer DX 130AZ
We recently bought a Celestron StarSense Explorer DX 130AZ for our children and we like to take some pictures of what we are seeing through the telescope. We know that's a beginner telescope and not ...
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Need help in choosing a used telescope for a beginning observer [closed]
I am a beginner when it comes to telescopes and have been doing research online for a week with which one to buy. At the moment I’m interested in a pre-owned telescope. My priority is planets but also ...
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How does one convert between Modified Julian Date (MJD) and a standard (mm/dd/yr, hr:mm:ss)
I looked online and couldn't see an actual formula or anything, so I figured I'd ask here.
If I had an MJD like the following: 59145.6678
How would I convert that to a month, day, and year with the ...
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How does the James Webb Space Telescope achieve a focal length of 131.4m?
How does the James Webb Space Telescope achieve a focal length of 131.4m ?
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Does JWST have the largest bandwidth of any telescope?
If the longest and shortest wavelengths that JWST can focus are 28.3 and 0.6 microns respectively, then it has a bandwidth (max/min) of a factor of about 47.
That's a lot, and of course it needs ...
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How would images with an overextended focal length look like?
If one stacked many Barlow lenses/used several focal extenders, what would the resulting image look like?
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How do I know that I’ve found Neptune?
So, recently I went out for a look at Neptune with my telescope and I found the general area of where Neptune was. However, when I took a see for myself, there were a ton of blue stars everywhere and ...
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Recommendation for green laser pointer for 6" Orion SkyQuest; one integrated with finder or a separate laser added to current configuration?
I would like to replace the default finder scope on my 6" Orion SkyQuest with one that incorporates a green laser.
Do such things exist, and if so, what should I look for in the laser ...
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The Interpretation of Uncertainty Map of NEO in Minor Planet Center page
I am an observational astronomer. I have just started with the observations. If any of you use MinorPlanetCenter website to get the ephemeris of a possible NEO in the NEO confirmation page, there is ...
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How to polar align equatorial mount if I see only small part of sky at south-east?
My mount is located on balcony where I can't see the polar star. I have only one window here which points to the eastern south. I limited by small piece of sky near the ecliptic plane between 120 ...
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Can a very powerful telescope show a person standing on the moon from the side rather than from directly overhead?
If we had a very powerful telescope with say a 150-meter diameter, placed in orbit around earth, would it be possible to get a side view rather than a top view of a person standing on the moon?
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Why are almost all modern telescopes reflectors?
I've noticed lately that reflector telescopes are used much more than refractors. The majority of telescopes I see in telescope shops or featured by people online are reflectors. Even the Hubble and ...
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Does an umbrella reflector telescope exist?
I searched for use of an umbrella mechanism for a reflecting telescope but have not found anything. I was imagining that use of enough actuators on enough umbrella arms would allow fine tuning an ...
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Which mobile/computer application can help me understand celestial coordinate systems better? [closed]
I wish to understand Equatorial and Altazimuth coordinate systems much better. Any applications or softwares which can help me out with the same?
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Would it be possible to create a telescope from a hanging reflective cloth?
A chain suspended on two points hanging under gravity forms a curve called a Catenary, which can look pretty similar to a parabola. I'm not sure if this generalizes to the two dimensional case where ...
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Are magnetic vortices capable of providing magnetic lensing when observed away from the poles
Magnetic vortices-(ESA cluster mission from observations November 2018)(article, ESA, science & exploration: 'Magnetic Vortices explain mysterious auroral beads'. An observer during Saturn's ...
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