Questions tagged [artificial-satellite]

Questions about man-made objects orbiting astronomical objects.

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40 votes
2 answers
6k views

How do we distinguish old craters from new ones on the Moon?

The following image is the observation made by the Dual Frequency Synthetic Aperture Radar (DF-SAR) onboard the Chandrayaan-2 Orbiter: Due to image size restriction, a lower resolution image is used ...
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27 votes
1 answer
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Why do satellites arcs end abruptly when observed from Earth

I recently got an app that let me track the ISS. I noticed that during the time it's visible, it disappears before reaching the horizon, and sometimes reappears soon after for a bit. Can somebody ...
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23 votes
1 answer
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Why can't observatories just stop capturing for a few seconds when Starlink satellites pass though their field of view?

Given that the positions and trajectories of the Starlink satellites are public, why can't the telescopes just ignore the photons they receive when the satellites pass through the field of view? It ...
18 votes
1 answer
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How did New Horizons take such well-lit pictures of Pluto?

The photos of Pluto from New Horizons are truly beautiful. But considering that Pluto is so far away from its nearest start - our Sun - how is it so well lit up? Did the New Horizons have a massive ...
18 votes
2 answers
710 views

Did nobody in the Astronomy community think 12,000 new satellites in LEO might be a problem?

This answer to Can / should the Starlink satellites be blackened? mentions Space News' SpaceX working on fix for Starlink satellites so they don’t disrupt astronomy where SpaceX chief operating ...
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16 votes
2 answers
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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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15 votes
1 answer
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How can the Sun block an X-ray telescope from observing a QPO galaxy "for several years"?

Phys.org's Black hole's heart still beating says: X-ray satellite observations spotted the repeated beat after its signal had been blocked by our Sun for a number of years. and links to the Open ...
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15 votes
1 answer
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Where is Voyager 1 (or 2) going? In which direction?

Knowing it has exited the solar system, is it traveling in the direction of the center of the galaxy, away from it, orbiting it, or maybe even going perpendicular from the disk-shaped galaxy?
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14 votes
4 answers
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Can a satellite stay in one place but not above equator? [closed]

I know that there are geostationary satellites that are always seen in one place in the sky and that they all are located in the equatorial area. I wonder if it's possible for a satellite to "...
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13 votes
2 answers
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What could be an explanation for a satellite-like moving light in the night sky that dims over time

Last night I saw a bright light moving across the sky. It was probably as bright (or even brighter) than some of the brightest visible stars like Vega and moving quite slowly (so no shooting star) at ...
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13 votes
1 answer
291 views

How do radio astronomers avoid having their receivers burned out by ground-imaging radar from satellites?

After about 34:00 in the 9th press conference of AAS 235, radio astronomer and NRAO's spectrum manager Harvey Liszt talks about Radio Astronomy in a New Era of ...
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11 votes
2 answers
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Will Starlink deface the night sky?

There is some discussion (and there are some questions on this site) about the impact of Starlink on observational astronomy. I am not an astronomer, but I am amazed by the beauty an immensity of the ...
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9 votes
1 answer
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Can New Horizons be used to measure the distance to Betelgeuse (despite its fickle photocenter)?

The New Horizons spacecraft is almost 50 AU from Earth and near-simultaneous images taken by its telescope and one on Earth have demonstrated parallax without relying on the movement of Earth in it's ...
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9 votes
2 answers
2k views

Calculating the apparent magnitude of a satellite

I'm writing a program that involves calculating the apparent magnitude of satellites from a ground location. I currently have the intrinsic magnitude of the satellites and the solar phase angle in ...
7 votes
2 answers
1k views

What is k2, how does it relate to Io's volcanism and how can Juno constrain its value?

This answer to Does Juno's UVS have any chance to spot Europa plumes? links to Juno OPAG REPORT by Scott Bolton, OPAG, September 2020. The slides detail past and future Juno flybys of Jupiter and some ...
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7 votes
5 answers
408 views

Are multiple geostationary satellites required to handle arbitrary locations?

Do geostationary satellites need to have the equator as the plane of rotation, and the earth's centre to be the centre of rotation? Can it rotate over, say, the Tropic of Cancer, focusing on a single ...
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7 votes
1 answer
272 views

What is the LSST's plan to address frequent satellite trails in data?

update: From Nature.com News article: SpaceX launch highlights threat to astronomy from ‘megaconstellations’: But an upcoming, cutting-edge telescope could be in bigger trouble. The US Large Synoptic ...
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6 votes
3 answers
306 views

Is there any man-made satellite orbiting our moon?

I am just wondering whether any man-made satellites are currently orbiting our Moon. If there is one, would I be able to see it using my telescope?
6 votes
0 answers
109 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 ...
5 votes
1 answer
183 views

Is it possible to create a traditional clock solar system?

Is it possible to create the following system of satellites?: Place a satellite that orbits the some object X, once per day. Call it D. Place a satellite that orbits D, once per hour. Call it H Place ...
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5 votes
1 answer
367 views

How can satellites be safe in the atmosphere when there are so many asteroids coming in?

How can artificial satellites be safe in the atmosphere when there are hundreds of tons of dust and asteroids coming into earth's atmosphere everyday? What is an orbit of an artificial satellite? At ...
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5 votes
2 answers
161 views

App that shows what's passing in sky?

I'm not an astronomer but I enjoy looking up at the sky. So tonight I saw something moving in the sky. It looked like a star, and it was definitely not a plane (I checked in flightradar). Is there ...
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5 votes
1 answer
299 views

How do observational astronomers manage streaks and other artifacts from objects in Earth Orbit?

There are thousands of satellites and spent rocket parts in low earth orbit (LEO). Mostly near the lines of dawn and dusk they can be in sunlight while observatories below are still viewing the night ...
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5 votes
2 answers
166 views

Can the transit of satellite in front of Sun be visible in 10-inch telescope?

I have 10 inch Sky-Watcher telescope and I would like to know if a satellite passing in front of Sun can be visible. Suppose that satellite's angular diameter is 1˝. Yes, I know the formula $\theta=\...
5 votes
1 answer
125 views

What's the brightest magnitude that the ISS can appear from Earth's surface?

Heavens-above indicates that this evening, it will fly almost over my head (79°) with a sizzling magnitude of -3.9. What is the maximum brightness it can have? Is there a formula to calculate its ...
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5 votes
1 answer
496 views

Planetary phase angle of Hohmann transfer

This is Question 23 from USAAAO First Round 2015. The answer is D. Can someone show how to get the answer? Calculate the planetary phase angle (counterclockwise from Earth, a = 1.0 AU) that a probe ...
5 votes
1 answer
330 views

Did I see a meteor or a re-entry?

Last night (January 21, 2015, possibly 5:30 UTC), from my house in northern California, I saw a moving point of light in the sky, going west to east, crossing about 120 degrees of sky in 5 seconds or ...
4 votes
1 answer
72 views

How can the Advanced Composition Explorer (ACE) warn of incoming solar storms?

How can the Advanced Composition Explorer (ACE) warn of incoming solar storms when is is invested with radiation? Discovery.com article Solar Storm Warning Satellite on Last Legs states that: ...
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4 votes
1 answer
526 views

What produces gravitational waves with "periods between about 100 - 8000 seconds"?

The Ulysses mission has a compelling story. It was sent to Jupiter to perform a gravitational assist shooting it out of the plane of the ecliptic in order to fly over the Sun's north and south poles ...
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4 votes
1 answer
195 views

What were the 2 satellites I saw this morning?

This morning at 6:03am Israel time (3:03 UTC) I saw, simultaneously, what appeared to be 2 satellites streaking across the sky directly overhead. If I remember correctly, they were both coming from NW ...
4 votes
1 answer
622 views

Help identify a bright and round object photographed through a telescope

It was a brightest object in the sky. Attached is the picture taken on 25th January around 6pm in Riga / Latvia, towards the south direction: Apologies for a quality of the picture, the telescope was ...
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4 votes
1 answer
66 views

How can I replicate AstroImageJ's pixel to RA/Dec algorithm in my own code?

EDIT: solved, thanks to Eric Jensen's suggestion (in a comment on his answer) that I include the correction to my right ascension value as a function of my declination. All other comments were helpful ...
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4 votes
0 answers
97 views

Comparing Observing Techniques to Quantify the Effects of Starlink Satellites on Astronomical Observations

To take pictures of satellites I think I could use these methods listed below (are there more?) Method 1 The satellites are tracked and their positions predicted. By utilising software tools and code ...
3 votes
3 answers
255 views

Problem about orbiting of a satelite

Problem: There is an satellite that orbits the Earth. Its orbit is circular and its orbital plane is perpendicular to Earth's Equatorial Plane. It orbits is such that a person who is on equator see ...
3 votes
2 answers
103 views

Where will the planned Deep Space Atomic Clock orbit "after" Earth? [closed]

I've seen multiple sources repeat the information that the Deep Space Atomic Clock will 'at first' orbit Earth, before moving on out of Earth orbit. The Deep Space Atomic Clock (DSAC) is a ...
3 votes
1 answer
121 views

Will the lunar gateway be visible for ground based (amateur) telescopes?

Due to its low apparent magnitude and large apparent diameter, astrophotographers have managed to capture the ISS not only during solar and moon transits, but even come so far as to image individual ...
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3 votes
1 answer
629 views

Easy interactive visualization of orbital elements

To get a grip on orbital elements, I'd like to play with a ready interactive visualization like in Universe Sandbox. E.g. drag the inclination slider and see immediately what happens to the satellite ...
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3 votes
1 answer
2k views

How do we know that a natural satellite cannot be a hollow object?

In their 1966 book, Intelligent Life in the Universe, Carl Sagan and Iosif Shklovsky state that "a natural satellite cannot be a hollow object." How do we know this is absolutely true?
3 votes
2 answers
318 views

stellarium software: selective artificial satellite display

The Stellarium satellite plugin by default shows all the artificial satellites' orbits around Earth. I’d like to be able to view only certain satellites so that the view is not cluttered with every ...
3 votes
1 answer
143 views

Visible satellites real time position API

I'm trying to obtain the azimuth and elevation of all (or at least the majority) visible artificial satellites from a given latitude and longitude. Is there a quite stable API that does that for free? ...
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3 votes
1 answer
112 views

Apparent magnitude of a spherical body with specular, rather than diffuse reflectivity? How bright were Sputnik 1 and Vanguard 2?

How bright are geostationary satellites due to reflected sunlight? and Did Sputnik 1 tell us more than “beep”? What science was improved by information gained from its orbiting the Earth? now have me ...
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3 votes
1 answer
92 views

What is the accuracy of an artificial satellite at a certain magnitude?

When we say that 'accuracy of gaia satellite is 10 $\mu$as at $V = 10$ magnitude in position and annual proper motion'. What does this mean? Does it change over time?
user avatar
3 votes
0 answers
83 views

how do I read grades for knowing where I have to look for watching the ISS?

I want to watch the ISS with naked eye using this tool NASA gives https://spotthestation.nasa.gov/sightings/view.cfm?country=Argentina&region=None&city=Santa_Fe#.WCRzKS3hC1s but I dont know ...
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3 votes
1 answer
57 views

Calculating Postition of ISS / Hubble in space [closed]

How do I calculate the positions of above satellite in space ?
2 votes
1 answer
268 views

Exposure details for this now (in)famous image from Lowell Observatory?

IAU's announcement 19035 IAU Statement on Satellite Constellations, 03 June 2019 links to 19035a Trails made by Starlink satellites which contains the image shown below. Question: Is it possible to ...
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2 votes
2 answers
241 views

Events I cannot explain

In the last few days I experienced two events I cannot explain. I watch the sky since I was a child so I'm aware of most events like satellites, ISS, Iridium flares, etc... First event It was about 22:...
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2 votes
2 answers
602 views

How bright are geostationary satellites due to reflected sunlight?

We are all familiar with seeing low-Earth orbit satellites scooting across the sky in a couple of minutes. Many of them are bright and readily identifiable with the naked eye. Geostationary satellites ...
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2 votes
1 answer
122 views

Bright star or flare near orion?

This morning at 6:12 am looking south from Georgetown, Texas, there was a brief very bright stationary object what appeared to be a star that once I saw it within the next few seconds quickly vanished....
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2 votes
1 answer
201 views

Musk's Roadster is now Russell's Teapot?

Space Exploration Stack Exchange were not very fond of this question and closed it, so I think it might fit better here. Summary: Assuming no foreknowledge of its existence, can Elon Musk's Tesla ...
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2 votes
1 answer
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Mars satellite data similar to Sentinel-2?

For Earth, there is lot of free satellite data easily available. For example, I can download the Sentinel-2 optical images freely from https://scihub.copernicus.eu/. What would be the closest thing ...