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Author Topic: How did Rosetta take such good photos of the comet?  (Read 1449 times)

Offline thedoc

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Keith Duggan asked the Naked Scientists:
   
How do they take the stunning pictures of the comet with the Rosetta space probe in the blackness of space. The detail is incredible. Is it because of the comet pointing towards the sun ?. There is no visible light source.
What do you think?
« Last Edit: 20/08/2014 18:30:01 by _system »


 

Offline evan_au

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Re: How did Rosetta take such good photos of the comet?
« Reply #1 on: 22/08/2014 13:07:40 »
When Rosetta caught up with the comet, they were about 500 million km from the Sun, or 3-4 times the distance from Earth to Sun.
At this distance, sunlight is 10 times dimmer than on Earth, but you can still get good pictures with a telescope, if you are prepared to take a long exposure.
I saw one photo from Rosetta that used an exposure of 5 minutes. Take several of these every hour, and you can make a video of the comet rotating. In one such video, The comet showed few areas in dark shadow, which suggests that Rosetta was approaching from the sunward side of the comet.
As Rosetta gets closer to the comet, and they both get closer to the Sun, it will become easier to take high-resolution still and moving images of the comet.
 

Offline PmbPhy

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Re: How did Rosetta take such good photos of the comet?
« Reply #2 on: 23/08/2014 05:14:48 »
Keith Duggan asked the Naked Scientists:
   
How do they take the stunning pictures of the comet with the Rosetta space probe in the blackness of space. The detail is incredible. Is it because of the comet pointing towards the sun ?. There is no visible light source.
What do you think?
If you mean http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rosetta_arrives_at_comet_destination then it's not in the blackness of space. Sunlight is shining on it and that illuminates it and cameras can take pictures with long integration times (i.e. long exposure times) thus making the light more intense. So yes, here definitely is a light source.
 

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Re: How did Rosetta take such good photos of the comet?
« Reply #2 on: 23/08/2014 05:14:48 »

 

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