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Author
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Topic: Viewing the CM in lunar orbit from Earth
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Fezman92
Member Posts: 1031
From: New Jersey, USA
Registered: Mar 2010
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posted 12-21-2010 04:05 PM
   
I have a feeling that the answer is "no, because of the size" but I'm going to ask anyway. Were there any telescopes or satellites around during the Apollo missions that could have seen the CM while it was orbiting the Moon? |
randy
Member Posts: 2231
From: West Jordan, Utah USA
Registered: Dec 1999
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posted 12-21-2010 05:09 PM
The closest thing to seeing a CM in lunar orbit that I can recall is after the O2 tank explosion on Apollo 13, some amateur astronomers in Houston could see the expanding 'sphere' of escaping oxygen around the spacecraft. |
jasonelam
Member Posts: 691
From: Monticello, KY USA
Registered: Mar 2007
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posted 12-21-2010 06:34 PM
That is correct, here is the picture in case you are interested. |
Apollo Redux
Member Posts: 346
From: Montreal, Quebec, Canada
Registered: Sep 2006
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posted 12-21-2010 11:58 PM
Thank-you for the link. Very interesting. |
micropooz
Member Posts: 1532
From: Washington, DC, USA
Registered: Apr 2003
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posted 12-22-2010 05:50 AM
I remember in the TV coverage of one of the Apollo flights, the network had gone to some observatory that had what looked like about a 24 - 36 inch reflector telescope. Before LOI they put out a lot of hype about how they would try to catch an image of the CSM in lunar orbit. Then they never said anything more about it, so I could only assume that they failed.Wish I could remember which flight it was, and which network did that, but memories fade after ~40 years...  |
SpaceAholic
Member Posts: 4494
From: Sierra Vista, Arizona
Registered: Nov 1999
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posted 12-22-2010 07:41 AM
The Dawes limit (maximum theoretical angular resolution) for a ground based telescope of 360 inches (just under 10 meters) is .01 arc seconds. Assuming the lunar orbiting CSM was oriented so that its full 32 foot length were presented to the Earth based observer, its angular size at 250K miles would be .005625 arc seconds / 1.5626e-6 Degrees (below the sensitivity threshold of telescopes at the time). |
ilbasso
Member Posts: 1522
From: Greensboro, NC USA
Registered: Feb 2006
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posted 12-22-2010 09:21 AM
A telescope certainly would not have been able to resolve the CSM. Theoretically, they could have caught a glint off of the CSM. That would require "perfect" geometry of Earth-Moon-Sun such that the Sun was reflected straight back to the observer on Earth and the CSM was as far as possible above the limb of the Moon as seen from Earth. A CSM orbiting at 60 miles would clear the limb of the Moon by less than one arc minute.At that distance from Earth, though, the relative brightness of the Moon would easily overpower the reflection from the CSM. Today's CCDs and computer processing techniques might have been able to catch a flash, but I seriously doubt anyone would have been able to see it with a telescope. |
Space Cadet Carl
Member Posts: 225
From: Lake Orion, Michigan
Registered: Feb 2006
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posted 12-22-2010 12:49 PM
I definitely recall CBS News attempting to see Apollo 8 in lunar orbit during their live coverage, either just before or just after the famous "Genesis broadcast" in December 1968. CBS's attempt using a large telescope was unsuccessful. |
micropooz
Member Posts: 1532
From: Washington, DC, USA
Registered: Apr 2003
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posted 12-22-2010 07:24 PM
Thanks for the sanity check, Space Cadet Carl! Was beginning to doubt my memory... |
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