Recent comments in /f/space

astro_pettit OP t1_j3enwpx wrote

Reply to My 1st ever star trail from space. More details in comments. by astro_pettit

My first orbital star trail; taken during Expedition 6 in early 2003. I took this before we had low noise, nighttime-sensitive digital cameras. This photo was taken with a Nikon F5, 58mm noct-Nikkor f1.2 lens with Fujichrome ISO 800 film and a 65 second exposure. All the detail seen in my later digital star trails can be seen; atmospheric airglow appearing as a green key lime pie layer, the fainter upper atmospheric red f-region, cities streaking by from orbital motion, lightning storms flashing as a function of time, and star trails. The blips in the star trail arcs were caused by the ISS attitude shifting around due to a down mode failure of our control moment gyros. For high speed film, it would become fogged by cosmic rays after about a month and was typically flown only on short two week Space Shuttle missions.

I got special permission to fly this film, launching with us on STS 113 in November 2002 and was supposed to return on STS 114 in February. Due to the STS 107 Columbia disaster, STS 114 was delayed for 2½ years. I returned about 70 rolls of film on our Soyuz TMA-1 in May 2003. Working with the photochemistry engineers at NASA JSC, we developed one roll at a time to find the best development process that minimized the effects of cosmic ray damage. This photo is the result from that effort.

More star trails from space can be found on my Instagram and Twitter accounts.

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That-Soup3492 t1_j3ekary wrote

Reply to comment by Riegel_Haribo in A moon you haven't seen 1000x: I composed Saturn's moon Dione crossing in front of Titan, seen from Cassini spacecraft - a red-green-blue sequence of images for color showing it's movement over three minutes by Riegel_Haribo

It's cool to me that the giant gas planets have moons that would be dwarf planets if they were on their own, but the only rocky planet with a moon like that... is us.

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Riegel_Haribo OP t1_j3ejawt wrote

Reply to comment by That-Soup3492 in A moon you haven't seen 1000x: I composed Saturn's moon Dione crossing in front of Titan, seen from Cassini spacecraft - a red-green-blue sequence of images for color showing it's movement over three minutes by Riegel_Haribo

Correct! Dione is the half-cratered small moon in the foreground (it has distinct geography in each hemisphere), while the large moon Titan with it's dense near-uniform atmosphere is moving in the background. You can also see the haze of Titan's high level atmosphere on the left. The visual color of Titan (when it is not evading capture) is like the orange-yellow at the dark edge of Dione.

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Riegel_Haribo OP t1_j3eib0v wrote

Reply to A moon you haven't seen 1000x: I composed Saturn's moon Dione crossing in front of Titan, seen from Cassini spacecraft - a red-green-blue sequence of images for color showing it's movement over three minutes by Riegel_Haribo

Here instead, an animation of the monochrome source frames, where we see the alternating color filters instead changing the yellow atmosphere of Titan in to different levels of brightness in each exposure.

https://i.redd.it/glxpxisnopaa1.gif

As you can see from the gif's jitter, although Cassini was tracking Dione, I had to tweak each frame to line up Dione for this composite image (and moons are also rotating).

(yes, I know its/it's)...

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poiqwe2 t1_j3ecram wrote

Reply to comment by onlycodeposts in give me some of your favorite space facts by ChocolatePizza2121

Yeah that's interesting. I'm really curious about a binary system with a wide separation, which might allow for multiple planets around both stars (though from basic googling this seems exceptionally rare). The mechanics of that system would be fascinating. Also imagine if there was life on some of those planets... what kind of cultural artifacts would come up surrounding the interactions between all those planets.

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