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Post by Jason Thompson on Jun 27, 2006 17:38:33 GMT -4
So if they landed on the moon in the early moon morning than would this have been viewed as a crescent, quarter, or Gibbous phase of the moon from Earth?Well, there isn't one universal lunar morning any more than there is one universal morning here on Earth. It was just past sunrise at each landing site when the LM touched down. Here is a simple map illustrating the landing sites: www.boulder.swri.edu/~durda/Apollo/landing_sites.htmlFrom this map you can see that Apollo 11 and 17 landed when the Moon was a waxing crescent, Apollo 16 when it was nearly at first quarter, Apollo 15 virtually at first quarter, and Apollo 12 and 14 during the waxing gibbous phase.
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Post by nomuse on Jun 27, 2006 18:04:37 GMT -4
And besides that, it allows you to say "waxing gibbous."
I've always felt that more conversations should include the phrase "waxing gibbous."
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Jason
Pluto
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Post by Jason on Jun 27, 2006 18:47:41 GMT -4
Or "penguinaut."
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Post by freon on Jun 27, 2006 22:30:48 GMT -4
Thanks for the input. Here's what I found. The Apollo landings were during these phases. Sound right? Apollo 11 - 1.2 days before first quarter Apollo 12 - 3.6 days after first quarter Apollo 14 - 3.7 days after first quarter Apollo 15 - .8 days after first quarter Apollo 16 - 1.8 days after first quarter Apollo 17 - 1.5 days before first quarter
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Bob B.
Bob the Excel Guru?
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Post by Bob B. on Jun 28, 2006 0:03:41 GMT -4
Thanks for the input. Here's what I found. The Apollo landings were during these phases. Sound right? Apollo 11 - 1.2 days before first quarter Apollo 12 - 3.6 days after first quarter Apollo 14 - 3.7 days after first quarter Apollo 15 - .8 days after first quarter Apollo 16 - 1.8 days after first quarter Apollo 17 - 1.5 days before first quarter Yep, that sounds about right (except Apollo 16 - see note below). Here is the longitudes of the Apollo landing sites: Apollo 11 - 23.47 E Apollo 12 - 23.42 W Apollo 14 - 17.47 W Apollo 15 - 3.63 E Apollo 16 - 15.50 E Apollo 17 - 30.77 E Since the terminator advances across the face of the Moon at 12.3 degrees/day, we can calculate the longitude of the terminator based on the number of days before or after first quarter. I get approximately, Apollo 11 - 14.7 E Apollo 12 - 44.2 W Apollo 14 - 45.5 W Apollo 15 - 9.8 W Apollo 16 - 22.1 W Apollo 17 - 18.4 E Of course these calculations ignore libration, that is, I've assumed the first quarter terminator crosses 0-degrees longitude. This can actually vary by as much as +/- 7.9 degrees due to east-west libration. Realizing there is error in these numbers due to libration, we can still see that all the landing sites lie a relatively short distance east of the terminator -- between about 8.7 and 37.6 degrees. This means it was morning at each location at the time of the landing. NOTE: The Apollo 16 data looks out of place to me. Even if there is a large libration error, these numbers show the site being at least 29.7 degrees from the terminator. I have a hard time believing the landing occurred that far past sunrise. Are you sure about the phase data, freon?
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Post by Count Zero on Jun 28, 2006 0:21:33 GMT -4
For a visual representation, go to this Earth and Moon Viewer. On the pages for viewing the Earth from the Moon or the Moon from the Earth, scroll down and enter the following UTC coordinates (cut & paste) and click on "Update". Apollo 11 - 1969-07-20 20:17:39 Apollo 12 - 1969-11-19 06:54:36 Apollo 14 - 1971-02-05 09:18:13 Apollo 15 - 1971-07-30 22:16:29 Apollo 16 - 1972-04-21 02:23:35 Apollo 17 - 1972-12-11 19:54:58 Compare the phases with this map of the landing sites. [edited to add map. Landing times are from this site]
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Post by Jason Thompson on Jun 28, 2006 4:40:58 GMT -4
According to the Moon Viewer site, Apollo 16 landed about 14 hours after first quarter, which would put the terminator about 7 degrees west, which is still 22 degrees from the landing site. Had it landed on time it would have been only 18 degrees past the landing site, as Apollo 16 was some sic hours late due to the problem in the CSM.
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Bob B.
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Post by Bob B. on Jun 28, 2006 8:45:07 GMT -4
According to the Moon Viewer site, Apollo 16 landed about 14 hours after first quarter, which would put the terminator about 7 degrees west, which is still 22 degrees from the landing site. Had it landed on time it would have been only 18 degrees past the landing site, as Apollo 16 was some sic hours late due to the problem in the CSM. Yes, I just checked that too. It looks like the phase was only 0.57 days past first quarter rather than 1.8 days. If the libration (would it be east or west?) happened to be near its maximum at that time, the landing could have been as little as 14 degrees from the terminator (or 10 degrees at the planned time). These numbers looks better and are in line with the Apollo 15 and 17 data.
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Post by freon on Jul 6, 2006 16:50:14 GMT -4
On Apollo 15, the sun would have heated the surface of the moon for about 4 earth days when they did the hammer and feather experiment. Even though it was lunar morning, what would be the approximate temperature of the lunar surface at the time of the experiment.
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Post by Jason Thompson on Jul 6, 2006 18:15:50 GMT -4
The temperature would have probably been quite high, but don't forget it was right next to the LM. I'm not sure whether the surface had received uninterrupted sunlight or the LM had cast shadows, or what.
Why do you want to know?
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Post by JayUtah on Jul 6, 2006 19:42:57 GMT -4
Rough estimate: about 130 F, based on changes in form factor.
Keep in mind that "heating for 4 days" can be misinterpreted. The surface will come close to equilibrium before the sun angle changes markedly, and it is the sun elevation that really governs the problem. It's not as if it just keeps getting hotter and hotter forever the longer the sun shines on it at any particular angle.
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Post by Apollo Gnomon on Jul 6, 2006 20:37:31 GMT -4
For the same reason solar panels (both thermal and photovoltaic) are pointed at the sun as straight-on as possible. The insolation is non-linear. An hour of sun at 8am isn't the same as an hour of sun between 10am and 2pm.
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Post by sts60 on Jul 6, 2006 21:39:09 GMT -4
Rough estimate: about 130 F, based on changes in form factor.
I have about 140 to 170 F. But I'm just glancing at a surface temperature graph we used for a recent design study; I didn't do the calculation myself.
Anyway, it's not the heat, it's the humidity.
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Post by freon on Jul 10, 2006 22:14:41 GMT -4
After roughly 100 hours of continuous sun exposure, the moon's surface temperature during this feather experiment was only about 130 F? That's about the same temperature as a hot day in Death Valley California and it only has sunlight for 12 hours a day.
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Post by PhantomWolf on Jul 10, 2006 22:17:16 GMT -4
Well Apollo 16's EVA was at 185°F so...
Stil this is only 85°C, so the feather still wouldn't have been adversely affected, especially since rock is a rather poor conductor of heat.
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