# Tag Info

22

It is not that it is blocked by the Sun, but that the duration of time for which it can be continuously observed was too small to be useful for the investigations performed in the paper. The object was observed by XMM-Newton, which has a highly eccentric ($e \sim 0.8$), 48-hour orbit arond the Earth. This is designed so that the satellite can stare for ...

16

Satellites, even in geostationary orbits, move with respect to the background stars and make "trails" on telescopic images that are tracked at the sidereal rate. Removal of these can be as straightforward as taking the median of a set of exposures. What I mean by this, is that in a sequence of exposures, the satellite trail will pollute different ...

8

In principle yes, in practice no. The telescope is good enough, but the CCD camera will saturate, preventing a good positional measurement. Salient facts. The parallax to Betelgeuse as seen between Earth and New Horizons will be about 250 mas. The current distance uncertainty is ~20%, so to better that, the position of Betelegeuse measured by New Horizons ...

6

What caught SpaceX and the astronomy community off-guard wasn't that the satellites might affect astronomy, it was just how bright the Starlink satellites were. "We all knew the satellites were coming, but we never imagined they were going to be so bright," James Lowenthal, an astronomer at Smith College, Source

4

Satellites already cause problems for telescopes, but not by obstructing their view. Actually the light reflected from satellites is a bigger problem, and for observations of radio waves, their communications are the really big problem. In terms of reflected light, you might remember the controversy around the "Humanity Star" being too bright. The ...

4

If all you need is a quick and free tool to visualize orbits around earth, websites such as the following might be enough: First, the very simple orbitalmechanics.info, where you can just ignore the "add launch" option: And then, the more artsy Harmony-of-the-Spheres, which can also visualize some other systems. Maybe that already helps.

3

You are right! Apogee is higher than Perigee, except when the orbit is perfectly circular when they're equal. Semi-major axis will be half-way between the two. 572 km doesn't make sense. As pointed out in comments, expressed like this they are the distances from Earth's center minus a fixed equatorial radius of the earth, in this case about 6378.137 ...

3

Have a look at Is it possible to capture geostationary satellites with DSLR? See the excellent advice in this answer to Are any geosynchronous satellites visible with the naked eye? No, but they are easily seen with a small telescope on a sturdy mount. March and September are the best times. Use an app to help you. My favorite way is to keep M11, the Wild ...

3

I'm not a spectroscopist, but, I know a fair bit about spacecraft data reduction. CRISM is a spectrometer that's very sensitive, but it needs more light than it can get by just riding along with the spacecraft, so it slews in the reverse direction of motion (that's why CRISM images have that hourglass shape). Despite that, it STILL has some light issues ...

3

Both of these sound like satellites reflecting the Sun, even the first one which didn't fade. There are so many satellites now with unusual orbits that being close to midnight in time doesn't mean you won't see them anymore like it used to. Years ago, if the local time was midnight you could almost be assured no satellites would be visible but that's not ...

3

Does not sound astronomical. But in order to test for astronomical phenomenon you need to state date time (time zone) and location, and direction (roughly). Of course if it was cloudy. The free software Stellarium (stars planets, satellites + ...), in conjunction with Heavens Above (up to date satellite info) can answer most of these types of questions.

2

I can personally attest that the Starlink satellites are visible with the naked eye even after they have spread out, however they are quite dim - with apparent magnitudes near 5.5. Here is a brightness comparison drawn from a widefield capture where two Starlink satellites are can be seen (albeit barely) juxtaposed with another satellite with apparent ...

2

Partial answer only. 120 degrees of sky in 5 seconds or so. 120 degrees in 5 seconds is about 0.42 radians per second. At a distance of 70 km (roughly the distance where an overhead meteor would start to glow visibly) that would be roughly 29 km/sec. That's a nice number for a meteor. But it's quite a challenging number for an originally earth-launched ...

2

Satellites are provided by a plug-in (that is enabled by default) Configuration (the spanner-and-star button) -> plug-ins -> Satellites -> configure. You can configure which satellites to display from here. It might be worth noting that meteosat-8, a geostationary satellite has a magnitude of about 19, and so is not a naked eye object, and is in ...

1

It doesn’t seem possible to have a general view of selected satellites, however the bookmark plugin seems the best workaround to keep a custom list without having to search satellite plugin configuration panel each time.

1

Geostationary satellites are often seen with telescopes and occasionally result in a "Something Moved! Did I see a UFO?" sort of message. If you have a tracking telescope aimed at a star in the same field if view of a geostationary satellite the satellite will appear to move against the background. It you turn off telescope tracking the satellite ...

Only top voted, non community-wiki answers of a minimum length are eligible