Viewing Stars At The ISS

[SpaceKiwi]

Please excuse the extreme newbie-ness of this question but this has been bugging me for a while, and a search around Uplink has not furnished me with an answer.<br /><br />I would like to know why, when we view coverage on TV from the ISS, we don't see millions of stars twinkling out of the screen at us? Is this as simple as the cameras not being pointed up, or does the brightness of the Sun and Earth make this impossible perhaps? Or can't the TV cameras discern the stars due to technology limitations?<br /><br />What's the story please? <div class="Discussion_UserSignature"> <p><em><font size="2" color="#ff0000">Who is this superhero?  Henry, the mild-mannered janitor ... could be!</font></em></p><p><em><font size="2">-------------------------------------------------------------------------------------------</font></em></p><p><font size="5">Bring Back The Black!</font></p> </div>

 

[jurgens]

I believe its because the CCDs are not sensitive enough to detect the stars.<br /><br />Either that or because the exposure times aren't long enough to collect enough light from the stars.

 

[igorsboss]

I know this is a little off-subject... I just want to point out that stars do not appear to twinkle in space.<br /><br />The twinkle is caused by the atmosphere.

 

[SpaceKiwi]

Thanks folks, that clears that up! And igorsboss, I realised my language error after I posted the message, but was too lazy to edit it to get rid of the twinkle. <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <p><em><font size="2" color="#ff0000">Who is this superhero?  Henry, the mild-mannered janitor ... could be!</font></em></p><p><em><font size="2">-------------------------------------------------------------------------------------------</font></em></p><p><font size="5">Bring Back The Black!</font></p> </div>

 

[CalliArcale]

Normal cameras can photograph stars if they get long exposure times. This is not normally practical from the ISS, however, as the ISS is moving. You'd just get streaks, and they'd be worse than the ones you'd get on Earth. Thruster firings and attitude corrections and other vibrations would also mess with your astrophotography. It's theoretically doable, though. However, you have to be doing it on purpose. If you're taking a picture of the station, the Earth, the Moon, an astronaut, or a similarly bright object, you'll need a very short exposure, and possibly a very tight iris, in order to avoid overexposing it. You won't typically get any stars in your picture that way.<br /><br />This, incidentally, is why you don't see many stars in Apollo pictures. It's basically the same reason why it's hard to photograph stars on Earth. They're there, and your eyes can see them if there's nothing really bright screwing up your night vision, but they're just too dim to catch on a short exposure.<br /><br />Hubble takes pictures of stars, but it's a really extraordinary instrument. It's not unique; other space telescopes have this capability as well. But Hubble is remarkably well engineered and can maintain a perfect lock on a target for many minutes. (There's no point in locking on an object for hours, because its orbit will put the Earth in the way repeatedly and for long periods. To get really long exposures, they actually take dozens of pictures and stack them. Even backyard astronomers do this, actually, although it requires a lot of accuracy to do it right.) Interestinly, one of the ISS astronauts built a tracking rig to do something similar -- only he wasn't photographing stars, he was photographing the Earth at night. He took a stunning picture of London at night using his homebuilt rig to track it as the ISS moved over it, watching out the big nadir window of the Destiny lab. It's easily the best picture of city lights I've ever seen. You could do somethin <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[SpaceKiwi]

What an interesting explanation and elaboration, thanks Calli.<br /><br />I guess I was applying my flawed logic to the original problem. That is to say, if I can stand in my backyard at night and see thousands and thousands of stars when 'inhibited' by the Earth's atmosphere, then why don't I at least see some stars in the 'background' when an ISS crew are EVA. They have no atmosphere to contend with, so the view must be many orders of magnitude more impressive for them.<br /><br />Maybe they will be able to do something more official, photography-rig wise, when the Cupola gets attached to ISS? I guess that will be earthward facing also though. <div class="Discussion_UserSignature"> <p><em><font size="2" color="#ff0000">Who is this superhero?  Henry, the mild-mannered janitor ... could be!</font></em></p><p><em><font size="2">-------------------------------------------------------------------------------------------</font></em></p><p><font size="5">Bring Back The Black!</font></p> </div>

 

[glutomoto]

like Calli said, if you try you can photograph stars from ISS.<br /><br />Space Station Science Picture of the Day: Comfort Stars<br /><br />Space Station Science Picture of the Day: Star Trails<br /><br />Space Station Science Picture of the Day: 2003 archive<br /><br /><img src="/images/icons/smile.gif" /><br /> <div class="Discussion_UserSignature"> </div>

 

[SpaceKiwi]

Cheers Glutomoto, Don Petit is definitely my kind of ISS Science Officer! He was the man behind a lot of the best 'un-stuffy' science stuff that has come off ISS. <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <p><em><font size="2" color="#ff0000">Who is this superhero?  Henry, the mild-mannered janitor ... could be!</font></em></p><p><em><font size="2">-------------------------------------------------------------------------------------------</font></em></p><p><font size="5">Bring Back The Black!</font></p> </div>

 

[glutomoto]

cheers and halloo to you too spacekiwi.<br /><br />i don't know much about mr. pettit. He is the person who made the tracking device mentioned by Calli. D. Pettit poses with his Barndoor Tracker<br /><br /><br />I can't seem to find anymore space station science pictures of the day, other than the 2003 archive. I guess there hasn't been any science on ISS since. <img src="/images/icons/frown.gif" /><br /><br /><br /><img src="/images/icons/smile.gif" /><br /> <div class="Discussion_UserSignature"> </div>

 

[glutomoto]

I still didn't find anymore space station science pictures of the day, but they did provide a link to The Gateway to Astronaut Photography of Earth. Which has photos going back to the earliest days.<br /><br /><img src="/images/icons/laugh.gif" /><br /> <div class="Discussion_UserSignature"> </div>