Questions tagged [observation]

Questions regarding observation of spacecraft or phenomenon in space

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43
votes
7answers
45k views

Can I see the ISS from the surface with the naked eye?

Can I see the International Space Station (ISS) from the surface with the naked eye? If yes, how can I determine that it really is the ISS?
15
votes
6answers
3k views

Why do satellites appear to move faster when overhead and slower closer to the horizon?

I've been watching man-made satellites with the naked eye using the "Heavens Above" mobile app. They seem to move incredibly slowly near the horizon, but when they go overhead, they look like they ...
19
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3answers
3k views

Were the Apollo lunar activities observed from Earth?

I understand that all manned landings on the Moon were on the near side, so technically they could be visible from Earth. Was it possible to observe landings and/or extravehicular activities (EVAs) ...
18
votes
3answers
2k views

Does the ISS have zenith-facing windows?

I was looking at the NASA image of the day today, and it made me wonder about the windows on the ISS. I often see pictures of Earth taken from the ISS, but I was wondering if they had any windows that ...
22
votes
3answers
23k views

Why does the International Space Station have a downward facing light?

I really enjoy watching the International Space Station fly over head. I subscribe to alerts so I know when it is in my area during the night time. I wouldn't be able to see it if it weren't for the ...
16
votes
2answers
5k views

Are any geosynchronous satellites visible with the naked eye?

It is very easy to spot LEO satellites during dusk or dawn. I am wondering if satellites further out in a geosynchronous orbit are also visible. Of course, if even possible, these would appear more ...
16
votes
3answers
3k views

Can you make out the shape of the ISS with the unaided eye as it passes overhead?

Someone claimed to me that they could see the actual shape of the ISS as it passed overhead without use of any optical device. I would think this isn't possible since it is only about 100 meters wide ...
15
votes
4answers
2k views

When was the last time that Starman/Roadster was seen?

Starman/Roadster (2018-017A, 43205) is a Falcon 9 2nd stage with a red sports car attached, in a heliocentric orbit in deep space. It was tracked by telescopes for several weeks at least after launch ...
10
votes
3answers
2k views

What is a “Double Iridium Flare” and how close can the two satellites be?

I just saw the term "Double Iridium Flare" and I'm wondering how close two Iridium satellites might actually be (in distance (km) and angle). I found this video as an example. ...
6
votes
2answers
362 views

Atmospheric influences on earth to satellite visibility and vice versa (e.g. atmospheric seeing)

Are there qualitative differences between observing satellite from earth surface vs. observing earth from the same satellite. Given the same optics on both places. Does it matter which way we look ...
4
votes
1answer
363 views

Has anyone seen an actual spectrum of a satellite made by an amateur photographer?

If you use a shallow wedge prism or very low dispersion diffraction grating (e.g. circa 100 lines/mm) front of a camera, you can photograph the spectra of stars with a modern DSLR camera with a fast, ...
4
votes
1answer
266 views

How did Skylab's electrographic camera work?

This answer links to history.nasa.gov's SP-404 Skylab's Astronomy and Space Sciences. In what looks like chapter 2, page 14 there is mention of Skylab's electrographic camera, shown below. In the ...
4
votes
2answers
4k views

Earth angular size looking from the ISS

Imagine you're, well, actually on the ISS so you're 395 km up. We've all seen many photos roughly like this... however this can be deceptive; They might be all fisheye lenses. A great many of these ...
5
votes
1answer
196 views

Has an astronaut ever seen another object in LEO pass by that wasn't mission-related?

The (currently unanswered) question ISS - Tiangong 2 minimum safe distance suggests that the two space stations passed within about 12 kilometers of each other. @peterh comments that astronauts in one ...
5
votes
4answers
2k views

What is the fastest can we or have ever traveled in space?

What is the fastest vehicle currently in space? At what speed with our technology currently does physics restrict our speed limits in space?
5
votes
3answers
217 views

How far away can spacecraft be seen with an optical telescope?

note: For the purposes of this question "optical" means near-UV through thermal IR, let's say 0.1 to 30 microns. In the question At what time in the Apollo 14 mission did the maneuver shown in this ...
6
votes
1answer
441 views

Has an astronaut ever seen pixies, ELVEs, sprites or blue jets (without a camera)?

The NASA Science video ScienceCasts: A Display of Lights Above the Storm shows several examples of Transient Luminous Events (TLEs) (Upper Atmospheric Lightning) being filmed by high-sensitivity ...
3
votes
0answers
118 views

What's the rationale behind the false colours in solar observation photographs? [closed]

Images from SOHO, SDO and other sun observatories are often coloured differently for different wavelengths or temperatures: http://www.nasa.gov/mission_pages/sunearth/science/Sun-Wavelength-Chart....
0
votes
2answers
139 views

What could the fast moving item I just saw on July 27, 2018 have been?

I saw a fast-moving item overhead Frankfurt, DE (slightly to the east of Frankfurt) at approx. 20:35 UTC on July 27th, 2018 with a track of something between 010° and 040°. There were no blinking ...
38
votes
2answers
4k views

Is it possible to observe space debris with Binoculars?

Recently I've started to observe satellites with my 20x80 Binoculars. I'm amazed by the fact I can clearly track satellites and rocket bodies at 2000 km altitude (I've reached 8 mag with some objects) ...
42
votes
5answers
10k views

Why are so many space telescopes placed in LEO instead of at Lagrange Points? And why do we hear about Hubble more than any Langrange-orbit telescope?

Here is the list of every space telescope launched by different space agencies - List of space telescopes. Most of the listed telescopes are placed in Lower Earth Orbit (about 95% of them). It's ...
28
votes
2answers
4k views

Is this really an image of the sun, or an “artist's conception”?

I just saw this image in this article in Phys.org, which is generally a great source of physics news. Normally I would expect them to post real images, or if they use artist's conceptions, they would ...
14
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3answers
4k views

How do we measure height on celestial bodies with no significant atmospheric pressure, no seas, or no surface to speak of?

On the Earth, measuring elevation above sea level is relatively easy. Throughout the years of evolving these measurements to not rely on different reference points of the Mean Sea Level (MSL) of ...
14
votes
1answer
2k views

How to tell a satellite is tumbling and out of control?

I've just read North Korea’s “successful” satellite in orbit, but tumbling and useless. How can we tell a satellite is tumbling or not? It's so far away!
14
votes
3answers
1k views

If an unknown ship entered Earth orbit, would it be detected?

I was watching an old Stargate episode with big alien ships in orbit, and I thought 'in real life that would be spotted pretty quickly... um, wouldn't it?' I'm not saying I'm on the search for alien ...
5
votes
3answers
1k views

How does New Horizons control its attitude?

I used NASA's eyes tool to see what's going at the time of New Horizon's closest approach to Pluto. I realized that in the programmed sequence, New Horizons is rotated on its axis by more than 90° ...
4
votes
1answer
257 views

Why do all satellites seems to have the same color from earth?

When you look up right after dusk or before dawn, you are very likely to see passing satellites passing overhead, still illuminated by the sun and reflecting daylight towards you. All theses appear ...
18
votes
3answers
3k views

Could Hubble observe the night side of the Moon?

IIUC the Hubble space telescope cannot observe the Sun lit side of the Moon. And Hubble is never pointed closer than 90 degrees towards the Sun. But this still allows for observing the night side of ...
1
vote
2answers
159 views

What can Halosat do that can't be done already?

The GIF included in the BGR article Watch the International Space Station poop out a tiny satellite that will search for (missing) matter which shows a 3U 6U cubesat ejected from the ISS. The article ...
5
votes
1answer
357 views

Has the Humanity Star been spotted yet?

With all the hullabaloo that the Roadster/Spaceman duo has been getting, is there any indication that the Humanity Star has been seen visually yet? Any reports of it's sparkly mirrorball-like ...
5
votes
0answers
118 views

Astrophotographer Thierry Legault is not convinced that DarkSat is darker than the others. Have photometric measurements been reported?

In the video below Passage of 7 Starlink satellites including (supposed) "darksat" world renowned astrophotographer Thierry Legault is not impressed by DarkSat's darkness: SpaceX said they have ...
3
votes
2answers
180 views

Have astronauts seen asteroids or comets?

Have astronauts ever seen asteroids or comets from space, either by eye, through a camera, or a telescope?
3
votes
1answer
590 views

What size and shape is an SL-16 R/B and for how long will they orbit Earth?

This night I've seen two SL-16 R/B on the sky with my binoculars. These where part of some Zenit rockets that launched satellites in the 90s. They travel at altitudes that double the ISS, uncontrolled....
2
votes
0answers
51 views

Predicting non-Iridium flares and Why NOSS satellites flare?

I just saw two point-like sources flaring in the sky in perfect sync. It was spectacular and a big surprise to me. The full event lasted at most 4 seconds. My position is in the Usera district in the ...
1
vote
1answer
64 views

How will the “fleet of small asteroid hunters” proposed by the B612 Foundation & York Space Systems work?

The June 2018 news item in Science To find small asteroids that could hit Earth, private foundation embraces small satellites says: On 10 May, B612 announced a partnership with York Space Systems, ...