Questions tagged [telescope]
Questions related to the physical instruments for astronomical observations.
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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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How are the aberrations seen in early JWST images corrected?
I found this image on space.com and it can also be found in NASA's JWST blog. This is one step in the process of aligning the 18 mirrors on JWST. A single relatively-isolated star has been selected. ...
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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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Why did the Event Horizon Telescope take so long to take a photo of a black hole?
The Event Horizon Telescope is in the news now because they are about to release the first ever picture of a black hole. They have been working on this since 2006. Why did it take 13 years to produce ...
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A new (radio) neutrino telescope in Greenland?
I just stumbled upon ScienceMag news from July 14th, 2021 which says:
By placing hundreds of radio antennas on the ice surface and dozens of meters below it, they hope to trap elusive particles known ...
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What to do in case of concentric circles that are not aligned with the cross after collimation (Picture inside)?
I have been collimating my newly bought first Newtonian telescope for a few days now, but I can't get the center of the circles to align with the intersection point of the spider's reflection. I have ...
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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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How was astronomical data meant to be handled on HST precursors?
The first drafts for a large space telescope such as Hubble were made in the 60's, and the idea of a space observatory originated long before that. From Wikipedia:
In 1968, NASA developed firm ...
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Meade LX200GPS electronic RA movement very slow
I use a Meade 200 LX GPS.
Last night between viewings it was placed in Sleep mode.
On return the scope was making noises as if the motor was running. The scope was stationary, but had moved to what ...
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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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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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How does SDSS estimate photometric redshift of sources?
I'm looking through the data in SDSS DR 12:
...
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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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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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Things to be aware of when designing a custom equatorial fork mount
I'm still relatively new to amateur astronomy, and I would like to get into astrophotography. I've looked at different equatorial mounts, and I think I like the benefits of fork mounts. I'd like to ...
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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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Metric to estimate measuring accuracy
I need help/suggestions on which metric/approach to use.
I am trying to estimate pointing precision by measuring the offset of the experimentally measured values from the real, theoretical values, ...
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Can you advise on the construction of a large segmented primary mirror (hobbiest)?
I am interested in experimenting with the building of a large parabolic primary mirror constructed from 4" hexagon mirrors mounted on a "rough" parabolic surface with either 3 screw ...
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Can the "haze" of a mirror telescope be quantified?
When reading Why was StDr56 discovered only now? and its answers and comments, I realized that refractor telescopes, and in particular the Dragonfly Telephoto Array are a great tool to find nebula and ...
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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 ...
user35491
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Is it possible to build a ground-based telescope that can directly image Earth-like planets orbiting in the habitable zone of sunlike stars?
In the following discussion I will refer to Earth-like exoplanets planets orbiting in the habitable zone of sunlike stars simply as “Earth-like exoplanets."
NASA is currently developing or ...
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Does it make more sense to upgrade our existing telescope or to buy a new one?
We're at a bit of a crossroads here, since we're faced with what appears to be a tough choice.
We've got a Celestron 11" SCT tube with a Losmandy G11 equatorial mount, all bought in 1996. The mount ...
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Combining lenses from two telescopes to build a more powerful one?
I have two Galileo 700mm x 60mm Astro/Terrestrial Refractor Telescopes. Can I take the lenses out and make one powerful telescope, something like an optical series circuit?
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Is it possible to model a solar thermal concentrator using Zernike polynomials?
This question might seem a bit off-topic, but I guess there are a lot of people here that know about optics, telescopes, etc.
I would like to simulate solar thermal systems that focus solar ...
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Is there a Free repository of pictures taken everyday of the night sky?
I'd like to know if there's a repository out there of pictures taken everyday of the night sky. Not looking forward to anything fancy. Maybe a group of people out there have set up something out of ...
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Radiometer Equation for Flux Density
In Duncan and Lorimer's Handbook of Pulsar Astronomy, the equation for the flux density using a radio telescope is given as (for a top-hat function):
$$S=\frac{\beta\,\mathrm{SNR}\, T_{sys}}{G\sqrt{...
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Batteries for a StarNavigator 90 motorized mount?
I was given a StarNavigator 90 (DS-2090) with a motorized mount (Single-arm, motorized Alt-Az) which works with 8 AA batteries. Only issue is that it eats the batteries, so I am wondering what kind of ...
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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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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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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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Can JWST be damaged by looking at a bright star?
Can JWST be damaged by looking at a bright star?
The Sun as well as particularily bright solar-system objects like Jupiter, Venus or the Moon not meant with this question.
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What are the technological advancements that made it possible for modern large telescopes to work with alt-az mounts instead of equatorial mounts?
The video Earth's Rotation Visualized in a Timelapse of the Milky Way Galaxy - 4K (linked below) and discussion below this answer to Why does a timelapse video of a stationary Milky Way make the ...
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What is the difference between a Cassegrain telescope and a Gregorian one? Which one is better?
Of the three giant (or 'Extremely Large') new telescopes being built, the Thirty-Meter (TMT), the the Giant Magellan (GMT) and the Extremely Large Telescope (ELT), only the Magellan, from what I ...
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Would Atlas Pro's prediction about the color of plant in Kepler-186F work as a biosignature to search for life?
The Atlas Pro video that prompted this question is this.
Tl;dr: it is argued that due to the different spectrum of radiation emitted by Kepler-186 and what is known about the evolution of ...
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Would a possible accretion disk around a primordial black hole 500 au from the Sun be visible in present telescopes?
If the hypothetical two-inch black hole 500 au from the Sun had an accretion disk, might current telescopes detect it already or do we have to wait till the Vera Rubin Observatory starts work?
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Size of crosshair
TL;DR: Does anybody know the width of a single crosshair as a fraction of the full field of view on a Skywatcher 1.25 inch 12.5mm illuminated reticle?
Explanation (in case there's a different question ...
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Tradeoffs "upgrading" from a 60/900 refractor to a 150/1200 Dobsonian?
My current/previous telescope is a Skywatcher 60/900 refractor on an equatorial mount. I am now looking at a SkyWatcher 150/1200 "Classic" Dobsonian reflector.
How can I compare the two in ...
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Convert Object Intensity to Pixel Intensity
If I have an object of some size and spectral radiance, and it's some distance R from a camera, how would I calculate its digital count value in an image? I'm sure there's an equation out there, but I ...
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Celestron uncommon DC long barrel connector
I have tried to connect a 12v DC adaptor and also a battery pack to my telescope unsuccessfully. Sadly it seems Celestron DC jack needs to be around 2mm longer than common 5525 DC ports.
I was ...
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What are recent discoveries with Earth-based radar telescopes?
The Wikipedia article on radar astronomy lists a few important discoveries using radar technology in general, i.e. also using space-crafts:
The following is a list of planetary bodies that have been ...
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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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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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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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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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Why look at an infrared telescopes's mirror with ultraviolet light? (Herschel Space Observatory)
While link-clicking for Where did Herschel Space Telescope go in 2013? I ran across the 2009 Time Magazine article Two Telescopes to Measure the Big Bang which shows the file photo below with the ...
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How was the astrometry of the famous 1919 solar eclipse confirmation of General Relativity calibrated and verified?
The new New York Times article The Eclipse That Made Einstein Famous describes several events and discussions on the hundred year anniversary of the the 1919 solar eclipse and verification of the ...
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Within a given image of a multiple-image producing gravitational lens, does Fermat's principle apply?
The question Does gravitational lensing provide time evolution information? is excellent!
When we see multiple images of the same object because of the phenomenon of gravitational lensing, do all the ...
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Webcam set up small circle tunnel vision type view
I've just adapted a webcam for my telescope.
I'm new to astronomy so I'm not sure if the view I get is right.
When I attached the webcam to my Barlow lens, the view on my laptop becomes a tiny ...
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Finding individual band magnitudes: Why and how is the integration of individual flux values for each wavelength used?
What differentiates the distance modulus equation to find the difference between two apparent magnitudes? For example,
$$ m_1 = -2.5\cdot log_{10}\left(\frac{F_1}{F_2}\right) + m_2$$
leads to the ...
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Visible Light Ground-Based Solar Observatory Data Archives?
I'm mainly searching for the best(or good/significant/important) solar data archives via ground-based telescopes. If I'm not being very straightforward...
Say if I wanted high quality/resolution ...
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