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Post by showtime on Apr 20, 2007 8:39:04 GMT -4
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Post by JayUtah on Apr 20, 2007 8:48:26 GMT -4
Yawn.
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Post by BertL on Apr 20, 2007 8:51:47 GMT -4
No.
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Post by showtime on Apr 20, 2007 8:58:11 GMT -4
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Post by Count Zero on Apr 20, 2007 9:03:10 GMT -4
Seems that a bright star like Sirius would show up...
Why should it "seem" that? Have you tried photographing Sirius with ISO 160 film? How long of an exposure is needed? Don't guess, and don't suppose. Just spend some time on an actual experiment, instead of sitting at a computer making star charts.
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Post by JayUtah on Apr 20, 2007 9:21:27 GMT -4
Showtime, if you don't want to be treated like a troll, stop behaving like one.
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Bob B.
Bob the Excel Guru?
Posts: 3,072
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Post by Bob B. on Apr 20, 2007 9:27:50 GMT -4
Seems that a bright star like Sirius would show up Why? |
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Post by Data Cable on Apr 20, 2007 9:28:06 GMT -4
Seems that a bright star like Sirius would show up Compare the apparent magnitude of of Sirius at -1.5 with the minimum apparent magnitude of Venus at -3.8, and you'll see that Venus is, at least, 200 times as bright as Sirius. 10 ^ [ ( -1.5 ) - ( -3.8 ) ] = 199.52 At it's maximum apparent magnitude of -4.6, Venus is over 1250 times as bright as Sirius. 10 ^ [ ( -1.5 ) - ( -4.6 ) ] = 1258.93 In the Apollo 14 photos discussed on the other thread, Venus was somewhere between those values. (Anyone know a reference for Venus' apparent magnitude in Feb. '71?) And while there are several stray light spots in the black sky of this photo, none of them correspond with the overlapping areas of the preceding and following photos from that pan, so they can be dismissed as optical contamination after the fact. [edit: Whoops... screwed up the calculations. Corrected formulas: 10 ^ ( [ ( -1.5 ) - ( -3.8 ) ] / 2.512 ) = 8.23 10 ^ ( [ ( -1.5 ) - ( -4.6 ) ] / 2.512 ) = 17.14 So, between 8 and 17 times as bright. Still a substancial difference, considering how faint Venus was in the A14 photos. ] |
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Post by showtime on Apr 20, 2007 9:32:56 GMT -4
Does anyone know much about this image? I think I got from a fake website somewhere if I remember. It's suppose to be of Apollo 17.  |
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Post by JayUtah on Apr 20, 2007 9:34:40 GMT -4
Does anyone know much about this image?
Those aren't stars.
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Post by Count Zero on Apr 20, 2007 9:36:32 GMT -4
Not so fast. You've been asked several times why you think Sirius should show up in AS-12-47-6985. Answer those questions before you move on to another issue.
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Bob B.
Bob the Excel Guru?
Posts: 3,072
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Post by Bob B. on Apr 20, 2007 9:38:08 GMT -4
Compare the apparent magnitude of of Sirius at -1.5 with the minimum apparent magnitude of Venus at -3.8, and you'll see that Venus is, at least, 200 times as bright as Sirius. 10 ^ [ ( -1.5 ) - ( -3.8 ) ] = 199.52 At it's maximum apparent magnitude of -4.6, Venus is over 1250 times as bright as Sirius. 10 ^ [ ( -1.5 ) - ( -4.6 ) ] = 1258.93 Sorry, Data Cable; your formula is wrong. Magnitude is definied such that a change of 5 magnitudes equates to a 100 fold change in brightness. Therefore each change of one magnitude equals a 100 1/5 = 2.512 change in brightness. Your calculations should therefore be, 2.512 ^ [ ( -1.5 ) - ( -3.8 ) ] = 8.3 2.512 ^ [ ( -1.5 ) - ( -4.6 ) ] = 17.4 Nonetheless your point is still valid. There is a 3 to 4 stop difference in exposure between Venus and the brightest star Sirius. EDIT: Data Cable found his own mistake and corrected it while I was typing the above. |
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Bob B.
Bob the Excel Guru?
Posts: 3,072
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Post by Bob B. on Apr 20, 2007 9:43:14 GMT -4
Does anyone know much about this image? Yes. I think I got from a fake website somewhere if I remember. How does someone fake a website? It's suppose to be of Apollo 17. It is. |
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Post by BertL on Apr 20, 2007 9:45:34 GMT -4
The photograph is AS17-134-20508. You can find it here. And hi-res here. Now, what is your point? |
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Post by showtime on Apr 20, 2007 9:59:21 GMT -4
Oh sorry ,I thought you guys were going to ignore me....  anyhow , isnt anyone going to mention the blue dot>>> ? what is it?? & dont go looking for Arcturus , I'm saving that. |
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