Stars from the ISS / Earth / Moon / Mars

The cosmos at our fingertips.
ShaileshS

Stars from the ISS / Earth / Moon / Mars

Post by ShaileshS » Mon May 16, 2016 5:18 am

Hello,

Sorry for the question unrelated to today's APOD, hope you all won't mind.
I came across this photo at -
http://earthobservatory.nasa.gov/IOTD/view.php?id=88026

I was wondering, if astronauts on ISS can see the stars and milky way band then the cameras that captured earth and surrounding night sky from all the lunar missions should have also seen tons of stars and milky way band in some shape or form. No ? Most photos of earth from moon show only dark surrounding sky, no stars, nothing else .. What am I missing ? And, would rovers on Mars be able to capture something similar ?

Thanks in advance.

User avatar
geckzilla
Ocular Digitator
Posts: 9146
Joined: Wed Sep 12, 2007 12:42 pm
Location: Modesto, CA

Re: Stars from the ISS / Earth / Moon / Mars

Post by geckzilla » Mon May 16, 2016 5:35 am

That photo is from Earth's *dark* side. In other words, the Sun isn't up. It's night. The astronauts on the ISS have a hard time seeing the stars when the Sun is up unless they can get in the shadow of the station and not have any illuminated objects in the scene.

Astronauts visited the Moon during day, so the stars were difficult to see.

Mars rovers could see stars at night with the right kind of camera. There current cameras produce rather grainy images of the night sky, unfortunately.
http://mars.nasa.gov/msl/news/whatsnew/ ... ewsID=1627

Here's one of Earth at dusk:
http://www.nasa.gov/jpl/msl/earth-view- ... -pia17936/
Just call me "geck" because "zilla" is like a last name.

User avatar
Nitpicker
Inverse Square
Posts: 2692
Joined: Fri Sep 20, 2013 2:39 am
Location: S27 E153

Re: Stars from the ISS / Earth / Moon / Mars

Post by Nitpicker » Mon May 16, 2016 5:56 am

Also, what the astronauts can see and what their cameras can capture, are two different things. The human eye has a greater dynamic range than most cameras, but is not as sensitive to low light.

The night time photo you linked to was taken from the ISS with what appears to be a 1.3 second exposure time and with a high ISO setting of 12800. If such a camera, with these settings, were to take a photo of the sunlit Earth from a sunlit Moon, the Earth and Moon would be completely overexposed, but you'd probably be able to see some stars. To expose the Earth and Moon properly would require less exposure, such that the stars are not exposed.