Questions tagged [telescope]

Questions related to the physical instruments for astronomical observations.

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1answer
138 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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0answers
11 views

Convert apparent magnitude in a filter to a luminosity

I have data in Johnson B & V filters and I would like to convert the observed magnitudes, m$_x$, into luminosities, L$_x$, over a passband where I already know the distance, d, to the object. x is ...
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0answers
53 views

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 ...
7
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2answers
22k views

I'm having trouble achieving sharp telescope focus

I've been having trouble getting really sharp focus on my telescope. Using Saturn as a reference, with a 20mm eye piece it is very sharp. But when I go to 10mm or 6mm, it gets bigger and blurrier. I ...
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1answer
46 views

How did I flip some mirrors around in the dark at 3 AM and change the focal length of a 24 inch Boller and Chivens?

Current answer(s) to How do telescopes "zoom" and change angle of view? are "they don't", but traditional large genera-purpose observatory telescopes do sometimes (often?) have ...
2
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1answer
43 views

Are X-ray telescopes with glancing angle surfaces basically “funny-looking” Cassegrain telescopes mathematically?

In this answer I included the image below of a reflective X-ray telescope. It is made from two elements; the first is concentric shells of glancing (high incidence) angle paraboloidal surfaces, and ...
2
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2answers
107 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 ...
2
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3answers
256 views

Does the size of the atom limit the focal length of telescopes?

Does the size of the atom place a theoretical limit on a telescope's focal length (and thus, resolution)? It seems to me that that the allowed margin of error for parabolic mirrors drops with an ...
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0answers
40 views

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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0answers
31 views

What happens to the Fourier Transform of the Measured Spectrum?

What happens when you double the width of the entrance slit of a spectrograph, in turn letting in twice as much light, would there be an improvement in the Fourier transform of the measured spectral ...
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0answers
15 views

Custom INDI client & Telescope control

I have started building my own INDI client library in dotnet standard C# to remotely control my Celestron NexStar 5SE telescope. If you want to see my client code it can be found here on github. My ...
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1answer
36 views

Limiting magnitudes for different telescopes

I live in an extremely light polluted place. On a new moon night, magnitude 3.5 stars are at the limit of naked eye visiblity on clear nights, and the Orion nebula is visible as a smudge through my ...
31
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4answers
3k views

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 ...
5
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3answers
1k views

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 ...
5
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2answers
122 views

What is the gain of a telescope?

What is the gain of a telescope? How would I go about calculating the gain from a flatfield image?
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0answers
16 views

Spectrograph Arrangement, Noise, and Fourier Domain [closed]

If the transform of a line profile extends out to the Nyquist frequency such that we cannot see the noise level, what could we change in our spectrograph arrangement that would allow us to see the ...
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0answers
78 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
37 views

Celestron Inspire 80az

I am new to stargazing, so I am unsure of what I am doing. I have an Inspire 80az telescope and 20mm and 10mm lens. I can view the moon really well but would like to view more planets, so I want to ...
3
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1answer
59 views

Maritime telescopes: Stabilisation requirements for optical vs. radio telescopes?

SOFIA stands for Stratospheric Observatory for Infrared Astronomy. She says: My telescope stays stable with a spherical bearing, shock absorbers, and gyroscopes. I suppose a similar system would ...
6
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2answers
192 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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0answers
38 views

Please Help Me With Choosing my 1st Telescope

I'm going to buy my 1st telescope. With the budget, I've shortlisted some. Tried with the YT videos, reviews and guide. Few things still bugging me. Hope somebody can give me any advice on this. There ...
2
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1answer
68 views

Telescope showing high chromatic aberration

Hi i have made a telescope with 1100 mm focal length objective lense and 21mm plano convex as eyepiece. Both these lenses are not achromatic. But when is looked through it , the images were completely ...
8
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3answers
668 views

When did “resilvering” large telescope mirrors actually refer to aluminization, and why was it necessary?

This answer nicely summarizes the general picture of historical use of silver for mid to large size telescope mirrors, and the shift to aluminum once good quality vacuum pumps and chambers suitable ...
8
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1answer
164 views

Why telescope mirror glass shipped as randomly broken chunks of a constant size in cardboard boxes?

The video MIRROR LAB: Preparing for Casting GMT's Mirror 6 shows the unpacking several hundred boxes full of broken glass from OHARA, packed in styrofoam. The glass chunks are a fairly uniform size of ...
3
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1answer
60 views

Diameter of the moon from the diameter seen in the telescope

I'm reading a chapter on convex lenses and it has this diagram: The chapter explains that triangles ABC and ADE are similar. Thus, ratio of CB to DE is equal to the ratio of BA to AD. Does this mean ...
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0answers
35 views

Can you attach an old Vixen model to a celestron tripod?

I would like to know if I can put an old Vixen VMC model (15 years old) onto a celestron 4se tripod. I am aware that some adaptations must be made, but I want to know if it's even possible or if it ...
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7answers
922 views

Could mirrors be replaced with CCDs?

Why do telescopes use mirrors that simply reflect photons, when they instead could be covered with large sensors to register them? Reflection is all good and well, all thanks to silver and beryllium ...
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1answer
7k views

Has THC been detected in space?

I was wondering if and how astronomers have/had detected the molecule Tetrahydrocannabinol (THC), commonly known for it's effects in marijuana, in space. I had previously seen a hoax regarding the ...
2
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0answers
63 views

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 ...
3
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1answer
101 views

Does the summit of a small mountain offer better seeing?

I have a small amateur telescope, and would like to defeat the atmospheric seeing conditions as much as is possible. Fortuitously, I happen to live fairly close to this lovely patch of bare elevated ...
3
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1answer
155 views

What is tilt anisoplanatism for Laser-guide-star usage in adaptive optic systems?

How does tip-tilt mirrors correct such issue? What is the physical origin of the error?
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1answer
157 views

Looking at ourselves with a powerful telescope?

Could a small curved mirror and/or lens in Earth's orbit be aimed at a different hemisphere from where you are be be viewed with a powerful telescope to see the ground through the mirror? Would a more ...
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2answers
335 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 ...
3
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1answer
59 views

How to plot curvilinear coordinates in the frame of a Cartesian telescope field of view

I am wondering what projection is used to produce plots like this: (Image taken from here, author: NASA/Ames/JPL-Caltech, Image credit: Software Bisque) More generally, I am trying to figure out the ...
3
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2answers
866 views

DIY tracking motor - gear mating

I have a Skywatcher 130/900 and I found that if I do an accurate polar alignment I'll need only one motor to track a celestial body, so I decided to build my motor. Right now I'm facing a problem with ...
2
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1answer
81 views

Can angular information be known more precisely than the diffraction limit?

The diffraction limit deals with the ability to determine if two things are separate. I am interested in the ability to find the the centroid of a single object. Imagine a star with no near ...
3
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2answers
55 views

Understanding energy loss in a telescope aperture due to atmospheric dispersion

I'm trying to understand energy losses due to atmospheric dispersion, given the plot below from the Keck telescope. For a typical seeing I'm told that there's 80% encircled energy in 1". The ...
0
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1answer
48 views

What eyepiece to use for moon?

I'm using a 95mm f/8.4 telescope. What's the best eyepiece that I can buy for a very close look at the moon or even planets? I'm a beginner in this field so please help me. Thank you.
2
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1answer
142 views

Can I see Jupiter, Saturn, Mars and Venus with the Spectra Optics Telescope 600x50? [duplicate]

Is it possible to see Jupiter, Saturn, Mars and Venus with the Spectra Optics Telescope 600x50? And even the moon? This is the description of the telescope: User-friendly and easy to install with ...
1
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2answers
101 views

Can I see Jupiter, Mars and Saturn through the National Geographic 76/350 Dobsonian Telescope?

Is it possible to see Mars, Jupiter and Saturn through the National Geographic 76/350 Dobsonian Telescope? It's the most affordable telescope I can get at the moment. Also, what about the moon? Will ...
6
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1answer
303 views

If we had the right technology could we see a distant star in detail?

If, for instance, Hubble's camera was a $10^{300}$ times better, could it see a distant star in details, or is there a limit to the amount of light that reaches the Earth's orbit or perhaps does the ...
5
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3answers
717 views

How would a Fast Fourier Transform Telescope work without a mirror, dish or lenses?

I recently came across a short article mentioning the idea for a telescope built without mirrors or lenses that instead uses an array of antennas and massive computing power to resolve an image. Such ...
9
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4answers
628 views

Why are telescope mirrors made of glass?

Optical telescope mirrors are typically made from endlessly polished glass surfaces that have been aluminised to provide a very smooth surface of reflective aluminium. But why the need for glass at ...
29
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5answers
8k views

Is it possible to mount a telescope on a plane? Is it beneficial?

I was wondering if any planes had mounted telescopes with the intent to observe the stars. I understand that the atmosphere itself can warp and hinder incoming light and even completely obscure views ...
7
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1answer
88 views

Occultations of Triton

I've been listening to an episode of the "NASA in Silicon Valley" podcast about the SOFIA mission. One of the techniques they use at SOFIA is stellar occultations to study different objects. My ...
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0answers
28 views

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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0answers
43 views

Benefits to adding a 32mm Pössl to my Celestron AstroMaster 130EQ's eyepieces?

I am getting a Celestron AstroMaster 130EQ soon. I have heard that its eyepieces aren't the best, so I am considering a 32mm Pössl. For such a choice, what would be the arguments for and against? How ...
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0answers
160 views

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 ...
2
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0answers
36 views

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 ...
3
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1answer
29 views

Is sky-glow affected by height?

I'm an architecture student and my graduation project will consist of building a research center for outer space, my question is whether or not height would affect sky-glow or not ? Thanks in advance, ...

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