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Post by Jason Thompson on Nov 29, 2006 12:56:22 GMT -4
Checking Wikipedia seems to suggest we are both right, Bob. I had the right alteration applied to the wrong specific instance.
On Apollo 11 and 12 the CSM/LM stack was in an orbit with a 69 miles perilune, at which point they separated and the LM performed a burn to drop its perilune to 50,000 feet, at which point powered descent was initiated. From Apollo 14 onwards the CSM did the burn that dropped the perilune to 50,000 feet, allowing the LM to concerve fuel so it could land with more equipment and consumables.
In the case of Apollo 15 onwards this saving was combined with the shorter rendezvous technique to allow still more equipment to be included, such as the special rake.
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Post by lionking on Nov 29, 2006 15:45:16 GMT -4
not if you use the UV equipment.
you were saying the UV light blurrs the star image, if I correctly undrstood, so they will blurr the surface of the moon. Taking the UV equipment, like they did with Apollo 16 ? ,would give them good images of the moon. as for the time, I don't see how taking similar images added to the research. Anyhow, that's not a major issue.
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Post by sts60 on Nov 29, 2006 16:00:45 GMT -4
not if you use the UV equipment.
No. A UV telescope will not magically resolve a stellar disk. It takes lots of aperture, clear and stable viewing, and sufficient observing time.
you were saying the UV light blurrs the star image, if I correctly undrstood, so they will blurr the surface of the moon. Taking the UV equipment, like they did with Apollo 16 ? ,would give them good images of the moon. as for the time, I don't see how taking similar images added to the research.
UV light doesn't "blur" anything. In fact, the shorter (than visible) wavelengths can theoretically afford somewhat better resolution. But that doesn't help resolve a stellar disk when all you have is a small telescope like that which could be carried on Apollo.
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Post by AtomicDog on Nov 29, 2006 16:05:25 GMT -4
lionking, you misunderstand.
Quote DataCable:
"No, a blurry, smeared shot of stars is not worth it. Stars CAN NOT be photographed with a hand-held camera."
The stars would not have been blurry because they were shot in UV. They would have been blurry because the exposure would have been several minutes with a hand held camera.
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Post by lionking on Nov 29, 2006 16:40:39 GMT -4
O.K, now I get it
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Bob B.
Bob the Excel Guru?
Posts: 3,072
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Post by Bob B. on Nov 29, 2006 16:53:06 GMT -4
The basic rule of thumb is that the fastest shutter speed a person can use without blurring the image is 1 over the focal length of the lens. In other words, if you are using a camera with a 60mm lens, then the fastest recommended shutter speed is 1/60 second. A particularly steady person may do better (I usually can), but it is simply not possible to take a photograph of several seconds duration while hand holding the camera without producing significant blurring.
The Hassalblad cameras used by the Apollo astronauts were hand held, and recording star images would have taken exposures of at least several seconds. It was therefore impossible for the astronauts to obtain unblurred photographs of stars. What good is a badly blurred photograph? Why waste the time to take unusable photos?
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Post by echnaton on Nov 29, 2006 17:36:38 GMT -4
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Post by nomuse on Nov 29, 2006 17:56:38 GMT -4
If I had to guess, I would say the UV camera would be a large-format camera on a tracking mount, hosting film with a greater sensitivity to the UV range and possibly using optics that blocked less UV than is normal. I believe that in modern astronomical use this would be coupled with one or more specific narrow-pass filters that restricted what the camera saw to one or more narrow ranges of UV light.
None of this is adaptable or applicable to the Lunar Hassleblads. Especially as I suspect the "UV Camera" flown also had a bit of a telescopic lens on it. The wide-angle view of the sky one of the Hassie's would provide would not, I think, be that informative.
And this still....for astronomical purposes, you could send a larger camera and apparatus into orbit without going through all the hassle and fuel of lifting it to the Moon.
For "gosh, wow" purposes it would be meaningless. It isn't like you are going to get Al Bean in front of the UV picture of a star formation waving and going "Here I am, Mom!"
And for authentication? I tend to think the pictures taken by Earth-bound astronomers of the Apollo craft in transit towards the Moon work a little better for that. No HB would be even slightly swayed by finding a picture or two of stars, however taken and however framed. No-one with any sense (that certainly leaves us in this forum out!) would make any effort to take pictures towards satisfying them.
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Post by 3onthetree on Nov 29, 2006 18:17:39 GMT -4
The Apollo craft bristled with camera's. A 12 even had the luxury of one that was broken. Astronomical purposes, isn't that what this was all about, visiting a body in space and not bothering to image other bodies from a new perspective is crazy when you consider the OSO missions were trying to do just that. Is there any Televised images of the Earth from the Lunar surface? How about images of the Stars, not distant stars I mean the one that was dictating the life and death situation for the Astronauts. Were any coronagraph images taken over the course of the Apollo missions?
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Post by AtomicDog on Nov 29, 2006 18:30:46 GMT -4
You can find the answers to all of these questions on the web. Look it up.
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Post by echnaton on Nov 29, 2006 18:32:57 GMT -4
Ya, I can see it now.
HB: The moon missions were faked. Look at all the faked pictures, this one shows crosses behind objects, this one shows a haze that could only be from air, this one shows no stars, they are all perfectly framed.
AB: Here is a photo of the little dipper, see how the reticules are in front of the stars, look how clear the stars are. Unfortunately you cant see Polaris because they didn’t have a view finder, but it is nice anyway.
HB: Oh, that's quite different...Nevermind!
not bothering to image other bodies from a new perspective is crazy
In your opinion. Bedsides it is not another perspective. The positions of the stars would look identical to a view from earth. I’ll ask this question again. Have you ever photographed stars? It really does take special equipment and artistic skills to get anything more than a meaningless blur for aesthetic purposes. It has already been shown that the scientific value of what the astronauts could do, beyond what they did, was negligible.
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Post by PhantomWolf on Nov 29, 2006 18:39:09 GMT -4
something interesting from the Apollo 12 ALSJ [Al is about to do some star sighting with the Alignment Optical Telescope ( AOT). It is basically just a sighting scope, with no magnification and a 60 degree field-of-view. The AOT is ceiling-mounted above the forward instrument panels. In training photo KSC-69P-814, Al has his right hand on the AOT guard. There are six fixed viewing directions (the "detents"). To do the start sightings, Al will look through the AOT and, using two sets of marks called the spiral and cursor, will measure star locations so that the computer can determine LM orientation. On Apollo 11, the locations of the Earth and Sun were such that Buzz could only use two of the detents and, in those, there weren't any bright stars near the center.]
[Apollo 14 and 17 Training Coordinator Tex Ward writes, "There was a small observatory on the roof of building 16A (at the Manned Spacecraft Center, Houston). It contained the Apollo Optical Telescope (AOT) that the engineering people used and the crews used it some, also, for training."]
[Conrad, from the 1969 Technical Debrief - "Al took a quick look around through the AOT and, except for the detents that had the Sun in them, we had lots of stars and no big problem night-adapting to see stars in the AOT."]
[Bean, from the 1969 Technical Debrief - "Star (and) Earth visibility was interesting. We could always see stars at the upper rendezvous window. We could see Dick (Gordon) go by us, also. (With regard to the AOT), I guess Apollo 11 had a different set of circumstances between the Sun and the Earth clobbering up most of their AOT detents. The Earth was above us and behind. The Sun was low and behind, so our front three detents were in excellent shape."]
[As per Sur-4, they have probably removed their helmets and gloves. The line "Window Shades - Up", on Sur-4 means that they are covering the windows so that they can let their eyes adapt to a darkened cabin and start the platform alignment (P57) on Sur-5.]
[Al's comment that they could see stars in the in the upper rendezvous windown raises the question of whether or not stellar images could have been captured in any of the lunar surface photography. All of the photos taken out on the surface were taken at an exposure of 1/250th of a second at f/8 or f/11. The two film types were SO 368 Ektachrome MS color-reversal film ASA 64 and 2485 black and white film, ASA 6000. Sky and Telescope Senior Editor Dennis di Cicco states, "Sirius and a few other bright stars might actually be bright enough to have recorded on the exposures, but the images would be impossibly small and hard to find on the original negatives. Furthermore, when such a negative was printed to show the foreground properly, it certainly would not have shown the star(s)" di Cicco notes that it would be easy to preform such an experiment on Earth. "Go out at night with a similar setup used for the lunar photos and take a similar exposure of bright stars. Develop the film and see if you can find any star images. Then, have the negative printed with an exposure that would be proper for a normally exposed daylight negative. I am confident that you'll never, ever see a star on the print!"]Apollo 16 did a lot of UV photography, including using a special Hasselblad UV lens to photograph the moon from Orbit. UV images are either black and white (for B&W film) or blue for coloured. The colourful UV's you see with Apollo 16's UV camera are false colour ones. Here are the Hasselblad UV images.
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Bob B.
Bob the Excel Guru?
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Post by Bob B. on Nov 29, 2006 19:12:07 GMT -4
Were any coronagraph images taken over the course of the Apollo missions? I'm not sure about the Moon missions, but a coronagraph equipped telescope was flown on Skylab in 1973. You have to consider that the planning for and construction of Skylab was well underway while the Moon landings were taking place. Much of what you people are insisting should have been done while on the Moon was part of the plan for Skylab. These missions were to be long duration with plenty of time for astronomical observations at considerably less cost. It makes no sense to squeeze these observations into the Apollo mission plans when the upcoming Skylab program was designed for just such a purpose.
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Post by nomuse on Nov 29, 2006 19:14:35 GMT -4
Interesting. Makes sense that as they were photographing the Moon from orbit anyhow, to get a look in different wavelengths. Still, not going to get the completeness of, say, Ranger -- or any other craft designed to spend months in orbit passing over as much surface as possible.
3onthetree, perhaps you could be more specific about which bodies you would wish to image from the Moon's surface, and why that work can't be duplicated either from Earth's surface or Earth orbit?
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Post by PhantomWolf on Nov 29, 2006 20:16:47 GMT -4
Ranger
I think you mean Lunar Orbiter, Ranger just sort of smacked into the moon taking images on the way down.
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