# Tag Info

## Hot answers tagged observation

41

Yes, I've done it myself in my backyard in suburban Houston. During a spacewalk in ISS increment 50, an MMOD shield intended for the axial port of Node 3 was lost. It's visible in this video floating below station. It ended up reentering about six months later. A few weeks after it had been lost, I noticed that it would be visible from my house, with a ...

26

Hubble can in fact observe the Moon, and has done so. Here's a picture of the Apollo 17 site (The upper right is from Apollo 17 mission itself). The x shows where the actual site is. You can also see more Hubble pictures of the Moon at this page.

13

A flag would be about five hundred micro arcseconds. (about 1 meter, at around 375 Mm) The Event Horizon Telescope has a resolution of about 20 micro arcseconds. Therefore, EHT could resolve a flag on the surface of the moon if it were a radio source. However, to view it optically would require around a 350 meter aperture. The largest 'single' telescope ...

12

The category of "observation satellites" is broad, because there are many types of observation (different wavelengths that reveal different characteristics of the observed planet). Because you're referring to 'high-resolution images' I'm going to assume you want visible-light photography. Yes, this is available for many bodies, although most planets have ...

10

I am not aware of an optical telescope capable of showing proof from earth. Part of the reason is the flags are pretty small and it's a very long distance. However, you can see the flags or what is left of them and the landing sites using images from the Lunar Reconnaissance Orbiter (LRO). The LRO was able to use it's camera to document all of the Apollo ...

10

I'll calculate the visibility of a diffuse 50% gray sphere with a 6 meter diameter. Averaging over all Sun-object-observer configurations that might be similar to a 4 x 11 meter shiny cylinder since both will scatter light over more than a hemisphere. Equations are from this answer and from sources linked therein: M_{Abs} = 5 \left(\log_{10}(1329) -\...

7

It turns out it might be very common for astronauts on the ISS (or previously the MIR) to spot satellites. This is the distribution of the number of satellites in LEO for different altitudes As you can see the ISS, with its $\sim 400 \; km$ altitude, is quite safe and alone below the huge carcass of LEO satellites moving around $800 \; km$ (it is also true ...

5

According to Heavens Above, it's the upper (2nd) stage of a Zenit-2 launcher, as you guessed. SL-16 was the identifier used by Western intelligence agencies during the cold war for the Zenit. They're cylindrical, about 4m diameter and 12m in length. Here's an artist's rendering of such a stage in orbit: It's hard to predict the orbital lifetime of objects ...

5

I believe COS (the sensitive UV instrument) could be damaged if it were pointed at the illuminated moon. (I wasn't able to find any documents online that confirm this though) The instruments don't point in the same direction. So it's possible to orient the telescope so that one is not pointed at the moon while others are. Lunar observations are difficult ...

4

I massaged some raw numbers from https://nssdc.gsfc.nasa.gov/planetary/factsheet/ For each body-Sun pair the velocity of the Sun is the velocity of the planet times the ratio of the masses since they orbit around their center of mass. Eclipse depth is just the ratio of diameters. Jupiter results in the largest velocity by far, thought the amplitude of the ...

4

In general, it is impossible to know for sure, but we can do some detective work. My two go to web sites: https://www.space-track.org -- Catalog of all space objects kept by USAF/JSPOC https://planet4589.org -- Jonathan McDowell's amazing catalog of all things space AS you point out 2010-028* is the international designator for all the objects related to ...

3

I’ve seen space debris with the naked eye, and my eyesight is far from exceptional. During a supply rocket launch to the ISS, the fairings that break off the main rocket are easily visible if the conditions are right.

2

About 6 hours after launch, the Soyuz spacecraft can be observed near the ISS. About three minutes later, Soyuz will fly after the ISS and will be visible in the same orbit. Therefore use https://www.n2yo.com/ P.S. The duration of the trip to the ISS varies. Until 2012, astronauts always spent about two days in the Soyuz spacecraft before docking to the ...

2

As seen in the photos below from https://terra.nasa.gov/about Terra is reddish, so the answer to Why is Terra reddish? is exactly what you have suspected; because it is wrapped in a thermal protection film that is reddish in color. However, the answer to a more interesting question: Why am I surprised that Terra appears reddish? would have several ...

1

The pixel size of the HST's Wide Field Camera 3 or WFC-3 is 164/2048 = 0.08 arcsec. The night side of the Moon is illuminated by Earthshine and the brightness depends on the phase angle of the moon (and the weather on Earth (clouds, wind-induced waves on the ocean) and the time (ocean versus land) but we can find some averages. Let's use +15 magnitude per ...

1

In theory, a smaller telescope can see a dim object by just looking longer than a larger one. There are issues of noise and stability that limit this, but for small factors it works. So their plan seems to be to break up a large-telescope observing plan into plans for longer observations with multiple smaller telescopes. This (somehow) saves lots of cost. ...

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