Astronomy Question: Visibility of Stars from The Moon?
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Patrick writes:
Dear Astronomer, Is one able to see stars or not from the lunar surface?
I was browsing the Cornell University Astronomy web site and I read in an answer to a question posed by a school teacher that one should be able to see stars from the lunar surface when looking up into the moon’s sky “day or night” as there is no atmosphere. This made sense to me.I got curious and went to see what stars the Apollo astronauts were indeed able to see as I suspected one could see stars all the better with no atmosphere. Well I must say I found myself so very surprised to hear Neil Armstrong tell Patrick Moore in a 1970 BBC interview that the only objects one can see from the moon’s surface in the lunar sky are the the planet earth and the sun. So now I am very confused.
The answer from Cornell’s Astronomy Dept. to the teacher makes sense to me.
On the other hand, the the Cornell astronomers have never been to the moon and maybe they are not as smart as they think they are. What is the correct “answer” if one could call it that?By the way, one can find the Neil Armstrong interview on You-Tube,
just search “Neil Armstrong, BBC, 1970 interview, Patrick Moore”.
It is short and the stuff about not seeing stars is the first issue addressed.
Thanks!
Very puzzling question Patrick!
Click the “read more” link below to see the video clip referred to above, and an explanation to why this is both true and false.
Here is the video Patrick is referencing where Neil Armstrong recounts his experience on The Moon.
While he mentions not being able to see any stars, he does acknowledge others had reported seeing planets, which would be significantly brighter than many stars.
Look at this recent image from the International Space Station via NASA: “Backdropped by a night time view of the Earth and the starry sky, the Space Shuttle Endeavour is photographed docked at the International Space Station on May 28, 2011.”
Image Credit: NASA
You can clearly see many stars, so yes, it’s true that you see stars outside Earth’s atmosphere. “That’s all well and good, but I asked about the Moon” you say? Right. Let’s get to that.
One thing that fuels this mystery is the sheer volume of photos from the lunar landings with no stars visible. This has more to do with exposure settings than anything else. The lunar cameras were set to short exposure settings in an effort to minimize overexposed film. The other part of the equation is due to atmospheric conditions ( or the lack of ) on the moon, as well as reflected light from the lunar surface and other objects. Remember, the lunar missions were during the “day” on the moon.
Sure, there’s no atmosphere and the sky is black, but you still have some sunlight being reflected by the surface. If you read the Apollo 11 transcripts from day 4, around 71 hours, 59 seconds on approach to the moon, Apollo 11 enters the lunar shadow and Armstrong reports being able to see many stars, again this is in space, and not on the lunar surface, but it stresses the concept that if there’s sunlight present, our eyes won’t be able to see stars.
So basically, it’s just about as difficult to see stars during the “day” on the moon as it is on Earth. If it were not possible to see stars on the moon, NASA and other agencies wouldn’t be proposing Lunar observatories.
If you have any other questions or need additional clarification, please feel free to post a comment, using the form below!
Thanks for sending in your question Patrick!
Ray Sanders is a Sci-Fi geek, astronomer and blogger. Currently researching variable stars at Arizona State University, he writes for Universe Today, The Planetary Society blog, and his own blog, Dear Astronomer
2012-12-04 08:06:09
Source: http://www.dearastronomer.com/2011/06/03/visibility-of-stars-from-the-moon/
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