Bob B.
Bob the Excel Guru?
Posts: 3,072
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Post by Bob B. on Jul 18, 2011 9:00:48 GMT -4
I'm not going to put much faith in any of these numbers quoted my fattydash without studying the original documents for myself. I don't trust fattydash's ability to quote the numbers back to us in the proper context. I'm not convinced the numbers mean what he says they mean.
One thing I can confirm, however, is that one second of arc does equal a distance of 27.6 feet. Though 6,783 miles is the circumference of the moon, not its diameter.
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Post by Jason Thompson on Jul 18, 2011 9:28:15 GMT -4
One thing I can confirm, however, is that one second of arc does equal a distance of 27.6 feet. Something I pointed out to him several pages ago but which was ignored until it suited his purpose to start using those numbers...
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Post by drewid on Jul 18, 2011 12:21:46 GMT -4
I'm not going to put much faith in any of these numbers quoted my fattydash without studying the original documents for myself. I don't trust fattydash's ability to quote the numbers back to us in the proper context. I'm not convinced the numbers mean what he says they mean. One thing I can confirm, however, is that one second of arc does equal a distance of 27.6 feet. Though 6,783 miles is the circumference of the moon, not its diameter. Is that longitude or latitude though? I think he missed that distance per second of arc latitude changes with the longitude.
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Post by capricorn1 on Jul 18, 2011 12:29:01 GMT -4
I'm not going to put much faith in any of these numbers quoted my fattydash without studying the original documents for myself. I don't trust fattydash's ability to quote the numbers back to us in the proper context. I'm not convinced the numbers mean what he says they mean. One thing I can confirm, however, is that one second of arc does equal a distance of 27.6 feet. Though 6,783 miles is the circumference of the moon, not its diameter. Is that longitude or latitude though? I think he missed that distance per second of arc latitude changes with the longitude. That's a good point. Does the discrepancy lie in latitude or longitude..........and what is the variance according to the longitude accordingly. The LICK team indicated they had a 500m variance, ie. they said the figures they expected lay within that tolerance.
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Post by Data Cable on Jul 18, 2011 12:34:40 GMT -4
I think he missed that distance per second of arc latitude changes with the longitude. Isn't that backward?
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Post by Jason Thompson on Jul 18, 2011 12:51:59 GMT -4
Is that longitude or latitude though? I think he missed that distance per second of arc latitude changes with the longitude. That's the other way around, I think. The distance per degree longitude changes with your latitude. At a latitude of 90 degrees north, for example... For the Apollo 11 landing site the distance from the equator is small enough that you can pretty well disregard it, I think.
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Post by drewid on Jul 18, 2011 13:33:44 GMT -4
Oh yeah, got that Wackbards.
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Post by Glom on Jul 18, 2011 13:35:44 GMT -4
Ok, now I'm lost. fattydash was trying to say NASA knew the location of the LRRR to a very high degree of precision. That proves fakery how?
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Post by drewid on Jul 18, 2011 13:42:11 GMT -4
I think the gist is that the "known" position of the LRRR, and the "known" position of the LM don't match the distance between them shown in the photos.
That's part of it anyhow.
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Bob B.
Bob the Excel Guru?
Posts: 3,072
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Post by Bob B. on Jul 18, 2011 14:28:20 GMT -4
One thing I can confirm, however, is that one second of arc does equal a distance of 27.6 feet. Though 6,783 miles is the circumference of the moon, not its diameter. Is that longitude or latitude though? I think he missed that distance per second of arc latitude changes with the longitude. That's a good question. At the equator they are both the same, but as you move away from the equator the lines of longitude converge, so the length of an arc-second in longitude gets shorter. The distance in latitude is always 27.6 feet, but the distance is longitude is 27.6*cos(latitude). To fattydash's credit, he addressed this somewhere. He said that since Apollo 11's landing site was so close to the equator we could ignore the shortening in longitude. I actually agree with him on this point.
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Post by capricorn1 on Jul 18, 2011 14:57:58 GMT -4
I just dug this up, which makes me think this whole business is one gigantic pile of nothing...... www.spacekb.com/Uwe/Forum.aspx/space-history/2419/Lick-Observatory-and-the-Apollo-11-LRRRLooks like Jay knew about this already and as a scientist was naturally intrigued. The pdf in this quote is 0.7mb for those on dial-up...... I found this in the "The Lunar Laser Ranging Experiment" from Science, by Bender et al., 1973"The Apollo reflector panel was placed on the lunar surface by astronauts Armstrong and Aldrin on 21 July 1969. Attempts were made almost immediately to obtain range measurements, but these were hampered by the brief time available before the moon became too low in the sky on that night and by some initial uncertainty in the actual landing site. Ground instrument difficulties and weather problems caused some further delays, but on August the Lick Observatory succeeded in obtaining strong return signals from the Apollo 11 reflector and in measuring the difference between the observed and predicted ranges with an accuracy of 7 m. Soon afterwards, return signals were obtained with a high confidence level at McDonald also...."
A scan of this article can be found at physics.ucsd.edu/~tmurphy/apollo/doc/Bender.pdf
So it seems clear that returns were not detected immediately. Someone may have thought they did (excitement can do that) but the first honest returns seem like 1 August....
Lou SchefferOther source...... adsabs.harvard.edu/abs/1969Sci...166...99FAs far as I am concerned, either those scientists are "in on it" or it's much ado about nothing.
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Post by echnaton on Jul 18, 2011 15:00:37 GMT -4
To fattydash's credit, he addressed this somewhere. He said that since Apollo 11's landing site was so close to the equator we could ignore the shortening in longitude. I actually agree with him on this point. It was certainty a fair observation on his part. To bad it didn't serve to increase his understanding of what actually occurred. It seems he was capable of being rational as long as the application of rationality didn't challenge his conclusion.
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Post by drewid on Jul 18, 2011 15:40:39 GMT -4
To fattydash's credit, he addressed this somewhere. He said that since Apollo 11's landing site was so close to the equator we could ignore the shortening in longitude. I actually agree with him on this point. Y'see I've been more or less following the thread but completely missed that point. Was it buried in a wall of florid nonsense perchance?
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Bob B.
Bob the Excel Guru?
Posts: 3,072
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Post by Bob B. on Jul 18, 2011 16:26:31 GMT -4
Was it buried in a wall of florid nonsense perchance? Please don't ask me to find it again. I don't remember where or how he said it, but I recall some mention of it. My last post was me paraphrasing.
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Bob B.
Bob the Excel Guru?
Posts: 3,072
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Post by Bob B. on Jul 18, 2011 22:04:49 GMT -4
Capricorn2,
Here’s my take on the situation given what I’ve read in the transcripts. When Apollo 11 first landed, NASA estimated, based on “physics/math and trajectory,” that the LM landed 4 miles long. This produced the first estimated landing coordinates of 0.799 N and 23.46 E. These numbers were read to Collins at GET 104:20:42, or about 95 minutes after landing.
After the LM was on the ground, NASA attempted to pin down the position using geological features. Several different positions were radioed to Collins for him to check visually, but he was never able to spot the LM. These positions weren’t latitude-longitude coordinates, but rather, positions based on a series of grid lines drawn on a map of the planned landing area. I’ll explain more about this later.
At GET 112:22:37, the Capcom gave Collins new figures for latitude and longitude – “Latitude 00 decimal 691 … that would be plus 00.691. And longitude over 2 is plus 11.713.” A minute later the latitude was corrected to 00.692. The “over 2” means the longitude is divided in half, thus the actual longitude was 23.426. So we now have a revised position of 0.692 N and 23.426 E, which is very close to the final determined coordinates.
At GET 122:51:36, or about 90 minutes before liftoff, Armstrong is radioed the following: “LM Ascent Pad: TIG, 124:22:00:00; Noun 76, 55349, 00322, plus 0017; DEDA 47, plus 37104, minus 70470, plus 58604, plus 56936. Your LM weight 10837. Your T14 is 126, plus 20, plus 12.” Now I admit I don’t know what all that gibberish means without doing a bit more research, but Fattydash explains in one of his posts that, in part, it translates to a position of 0.72349 N, 23.44 E. For now, let’s take his word for it.
At GET 123:55:36, the Capcom gave Collins the latest position of Tranquility Base: “It’s just west of West Crater, Juliet 0.5, 7.7.” So what does this mean? Collins had a lunar surface map that had a series of grid lines drawn across it. The lines were laid out in one-kilometer squares. The east-west lines were labeled A through W and the north-south lines were labeled 1 through 27. Juliet stood for the J line and 0.5 meant that the position was halfway between the J and K lines. The 7. stood for the #7 line and the .7 meant the position was 7/10s of the way between the 7 and 8 lines. This position is normally written as J.5/7.7.
After completion of the mission, the final estimated position of the LM was improved to J.65/7.52 after examining mission photos and film. This position was published in the post mission report as 00 41 15 N and 23 26 00 E, or 0.6875 N and 23.4333 E.
Since the map grids were one-kilometer square, we can see that the difference between J.5/7.7 and J.65/7.52 is 150 meters in latitude and 180 meters in longitude. This means the best estimated position prior to liftoff was only 234 meters from the final determined position. Also, if we move 180 m west and 150 m north of the final position we get 0.692 N and 23.426 E. These are the coordinates radioed to Collins at GET 112:22:37.
So why were the coordinates given to Armstrong for entry into the computer different? Honestly, I don’t know. It could be that Fattydash is wrong, but let’s give him the benefit of the doubt. It could also be that a different coordinate system was being used. For instance, Earth has geocentric latitude and geodetic latitude. Geodetic is what we read on maps but geocentric is used in orbital mechanics. The bottom line is that the numbers put into the computer are only that, i.e. the numbers used by the navigation system. They are not necessarily the map coordinates of the LM. We know the best estimate of the map coordinates prior to liftoff was 0.692 N and 23.426 E as detailed in the transcripts.
So now we’re left with only the discrepancy that Fattydash claims the coordinates of 00 41 15 N and 23 26 00 E were give to Lick Observatory on the night of 7/20/69. I have to believe this is a mistake. From all I’ve been able to determine, these are the final coordinates determined after completion of the mission. They are also probably those given to Lick on 8/1/69 as Fattydash originally claimed. I think somewhere along the way Fattydash just got confused or made some bad assumptions. And if there really is a source stating those coordinates were received by Lick on 7/20/69, it is probably just a case of faulty recollection. These types of conflicts are common and certainly nothing to get heartburn over.
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