Questions tagged [artificial-satellite]

Questions about man-made objects orbiting astronomical objects.

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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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13 votes
2 answers
3k views

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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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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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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2 votes
0 answers
46 views

Slow moving pulsing light

I was looking at the stars as it was clear tonight. I saw a slow moving and slow pulsing star like object. It moved across the sky turning on and off a ‘light’ only being visible when lit and it was ...
1 vote
1 answer
117 views

How to calculate the minimum number of satellites needed to maintain constant link between themselves? [closed]

Suppose we want to build a number of space stations, all orbiting Earth at the same altitude, equally distanced from one another, and with the same inclination. How many of those stations are needed ...
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1 vote
2 answers
95 views

Did I see a satellite (or space station)? [duplicate]

In the UK (south east) - when outside this evening at about 19:10 UTC (22nd Feb 2022), looking due south, with Orion directly above me. There are two bright stars vertical to each other, just to the ...
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-2 votes
1 answer
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I believe I saw a UFO, what else could it be? [closed]

When looking at the night sky some time ago I noticed a white dot. The amount of light coming from or being bounced on that object made it the same size of a average star. But differently from a star, ...
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1 vote
1 answer
47 views

Calculation of time delay in NASA's STEREO project

I'm trying to solve this task: Astronomers recently managed to get an image of the entire surface of the Sun for the first time. This became possible thanks to the STEREO project. In 2006, two ...
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2 votes
1 answer
35 views

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 ...
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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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 ...
14 votes
4 answers
1k views

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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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 ...
1 vote
0 answers
40 views

How exactly will Trailblazer (the precursor to SatHub) help Astronomers plan their optical observations? Will it be open to the public?

Space News' Astronomers back technical efforts to reduce impacts of satellite megaconstellations while seeking regulatory solutions says: At the conclusion of the weeklong SATCON2 workshop July 16, ...
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5 votes
2 answers
167 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=\...
1 vote
0 answers
115 views

Would a future Dyson sphere or swarm around our Sun actually be beneficial to people on Earth? [closed]

A Dyson sphere or swarm's function is to harvests most of a star's energy, correct? However, a future Dyson sphere around our Sun would also block the Sun's rays from reaching Earth. Wouldn't it ...
11 votes
2 answers
2k views

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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3 votes
2 answers
320 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 ...
1 vote
0 answers
64 views

Calculate Global (ECEF) coordinates of Observer

I have the local coordinates of satellite and global coordinates of satellites. I want to calculate the observer position in global (ECEF) system. How can I do this? I also explain this question with ...
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9 votes
1 answer
318 views

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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3 votes
1 answer
638 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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2 votes
1 answer
179 views

Why is the height of a satellite greater than the apogee of its orbit?

I read in the German Wikipedia for the Indian Technology Experiment Satellite, that the apogee (Apogäumshöhe) is 567 km, while the height of the orbit (Bahnhöhe) is 572 km. I had always thought that ...
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6 votes
0 answers
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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 ...
3 votes
1 answer
117 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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2 votes
2 answers
606 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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16 votes
2 answers
2k views

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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1 vote
1 answer
96 views

What object did I see in the sky? [duplicate]

Tonight, while looking at the night sky, I saw a moving object which I cannot assign to any cosmic or man-made object known to me. The object looked like a star, and hadn't it been moving, it would ...
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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
1 answer
80 views

Can any satellite train still be seen?

I "missed the train" on the Starlink satellites last year, and now it looks like they've separated, and the conservative voices convinced Space X to darken new ones with visors or paint. Is ...
15 votes
1 answer
1k views

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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1 vote
0 answers
19 views

Lights moving fast and in a straight line coming from the northwest headed southeast tonight at 9:15CST [duplicate]

What is going on tonight? Bright lights in the same high orbit moving very fast across the night sky from Northwest heading southeast...then 10 minutes later same line but far fewer almost in ...
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1 vote
1 answer
42 views

Any active solar X-ray imager in orbit?

NOAA GOES-14 & 15 went very recently in storage mode. With those also went the solar X-ray imagers (SXI), as GOES-16 & 17 do not have such instruments on board. Hence, my question: Are there ...
5 votes
1 answer
497 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 ...
3 votes
1 answer
144 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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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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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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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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1 vote
0 answers
45 views

Line of satellite like moving objects [duplicate]

Earlier this morning when I went outside to get a drink around 04:00 Tasmanian time (GMT +11), I saw a line of moving lights in the night sky. They were all moving at the same speed similar distances ...
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18 votes
2 answers
711 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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2 votes
1 answer
100 views

Force exerted by space debris on satellites [closed]

Hypothetically, if space debris were to collide with the currently orbiting satellites, how much force would they exert, and how much damage would they make? Will the satellites be able to withstand ...
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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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1 vote
0 answers
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Reason for Orbital Reflector [closed]

We know that last year, space X rocket took orbital reflector with it into the space. But what might be the reason behind launching this weird object into the space? Does it do any work there?
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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2 votes
2 answers
970 views

How to calculate phase angle of a satellite?

I'm making a program for predicting satellite passes. I'm trying to find out if the satellite is illuminated by the Sun and not in Earth's shadow. I need to know its phase angle: the angle between the ...
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1 vote
1 answer
164 views

Strange object crossing the sky

Was stargazing last night and spotted an object traversing the sky from roughly East to West. It had a bright light that was intermittently flashing but with three different intensities. The "third" ...
0 votes
3 answers
23k views

Slow moving star like objects in the night sky [duplicate]

So yesterday at about 2am I was watching the sky when I saw a small star like object moving very slowly across the sky. My initial thought was that it was a satellite due to the fact it was moving so ...
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1 vote
1 answer
369 views

How much delta-v does a typical geostationary satellite carry? [closed]

I'm wondering - how much delta-v do typical geostationary satellites carry with them once they get into the orbit for things like orbital adjustment or movement to the graveyard orbit?
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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 ...
1 vote
0 answers
55 views

Four Lights (star like) Moving in a Line Together [duplicate]

About 20 minutes ago, we saw four lights lined up and moving relatively quickly across the sky. These lights looked exactly like the stars around them - not red or blue or flashing or anything, just ...
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