I'm new to the world of astronomy and while studying the different forms of electromagnetic radiation (light) I've had a question in my mind that I know is a stupid question but I can't help but ask.... Why is radio astronomy associated with listening? Or is it? All I have ever learned about science comes from the movies and I remember watching "Contact" with Jodi Foster's character sitting with her eyes closed "listening to the stars". I suppose radio telescopes can pick up radio waves and convert them to sounds but is that really what they are used for. I would assume radio telescopes are mostly used to pick up radio waves and convert them to images, like the ones seen on the world wide telescope. Am I right in this assumtion? Daren Campbell Tri-Co Realty & Investment Co. Ph. 801-571-8833 Fax 801-571-9888 -----Original Message----- From: utah-astronomy-bounces@mailman.xmission.com [mailto:utah-astronomy-bounces@mailman.xmission.com] On Behalf Of utah-astronomy-request@mailman.xmission.com Sent: Wednesday, June 11, 2008 10:13 AM To: utah-astronomy@mailman.xmission.com Subject: Utah-Astronomy Digest, Vol 64, Issue 18 Send Utah-Astronomy mailing list submissions to utah-astronomy@mailman.xmission.com To subscribe or unsubscribe via the World Wide Web, visit http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy or, via email, send a message with subject or body 'help' to utah-astronomy-request@mailman.xmission.com You can reach the person managing the list at utah-astronomy-owner@mailman.xmission.com When replying, please edit your Subject line so it is more specific than "Re: Contents of Utah-Astronomy digest..." Today's Topics: 1. Re: Saturday night at the Gravel Quarry (Joe Bauman) 2. Re: holograms (Richard Tenney) 3. Re: holograms (ROBERT MARILYN GRANT) 4. STS-ISS by Moon shortly (nothing political, Chuck <g>) (Canopus56) 5. Re: holograms (Joe Bauman) ---------------------------------------------------------------------- Message: 1 Date: Tue, 10 Jun 2008 19:21:44 -0700 (PDT) From: Joe Bauman <josephmbauman@yahoo.com> Subject: Re: [Utah-astronomy] Saturday night at the Gravel Quarry To: Utah Astronomy <utah-astronomy@mailman.xmission.com> Message-ID: <402454.80204.qm@web38908.mail.mud.yahoo.com> Content-Type: text/plain; charset=iso-8859-1 Oh, c'mon. As long as we keep it friendly, a little rough-housing over politics now and again is a good thing. -- jb Overall a worthwhile event for SLAS, great viewing if you hung around and a pretty good night for observing and NO POLITICS. (HINT!) Bob Taylor _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://gallery.utahastronomy.com Visit the Wiki: http://www.utahastronomy.com ------------------------------ Message: 2 Date: Tue, 10 Jun 2008 19:42:27 -0700 (PDT) From: Richard Tenney <retenney@yahoo.com> Subject: Re: [Utah-astronomy] holograms To: Utah Astronomy <utah-astronomy@mailman.xmission.com> Message-ID: <495102.34496.qm@web53211.mail.re2.yahoo.com> Content-Type: text/plain; charset=iso-8859-1 I'm probably the least qualified to comment here (never had college physics, but I did dabble a little in holography in H.S.); I doubt you could create a hologram with filters, but I know you can see holograms using filters, FWIW. --- Joe Bauman <josephmbauman@yahoo.com> wrote:
I've been thinking about Chuck's question, basically what I meant by non-laser-produced holograms, and I admit it's hard to describe my idea. That's probably because it's a b.s. idea. But here goes: There are filters, I assume grid-like, that can eliminate most wavelengths of light. If you could put together one that eliminated all but one wavelength, would that one wavelength work like a laser for the purpose of creating a hologram? I think holograms are possible because the laser illuminating the target emits just one frequency of light. When that light hits the target and bounces back to the film, the waveforms from interfering light bouncing back from various objects are preserved on the film. When a laser shines on the developed film, those overlapping waveforms are reconstituted and you see the object that was photographed in 3D. The fact that the laser is an extremely powerful pulse of light has nothing to do with this process; it's the single-wavelength property that is important. My idea is, what if you were to place a piece of photographic film in a shallow box, with the filter in front of the film, in ordinary daylight. Would you get the same effect because only waveform was penetrating the filter? Of course, to actually see the hologram (assuming you really could make one that way), I assume you'd need to illuminate the film with a laser. Thanks, Joe
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------------------------------ Message: 3 Date: Tue, 10 Jun 2008 22:31:56 -0600 From: "ROBERT MARILYN GRANT" <cincoymaya@msn.com> Subject: Re: [Utah-astronomy] holograms To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Message-ID: <BAY106-DAV142A37CF682ECB9140EC4C0B20@phx.gbl> Content-Type: text/plain; charset="iso-8859-1" Joe- I claim no expertise about holograms, but I remember watching my college roommate (Physics Major) making some. As I recall, the two light waves must have both the same frequency AND the same wave phase (called "coherence") in order to cause an interference pattern than can be recorded on film. I don't know how you can get coherent light except from a laser, but maybe someone else can chime in. Due to the difficulty of getting two lasers into coherence, a single laser was used, with the light going thru a splitter to direct the light at the object in two different paths. When the two light paths recombined, the differences in path lengths caused localized out of phase interference, the pattern of which was recorded on film. This is my layman's perspective. Bob Grant ----- Original Message ----- From: Joe Bauman<mailto:josephmbauman@yahoo.com> To: Utah Astronomy<mailto:utah-astronomy@mailman.xmission.com> Sent: Tuesday, June 10, 2008 11:06 AM Subject: [Utah-astronomy] holograms I've been thinking about Chuck's question, basically what I meant by non-laser-produced holograms, and I admit it's hard to describe my idea. That's probably because it's a b.s. idea. But here goes: There are filters, I assume grid-like, that can eliminate most wavelengths of light. If you could put together one that eliminated all but one wavelength, would that one wavelength work like a laser for the purpose of creating a hologram? I think holograms are possible because the laser illuminating the target emits just one frequency of light. When that light hits the target and bounces back to the film, the waveforms from interfering light bouncing back from various objects are preserved on the film. When a laser shines on the developed film, those overlapping waveforms are reconstituted and you see the object that was photographed in 3D. The fact that the laser is an extremely powerful pulse of light has nothing to do with this process; it's the single-wavelength property that is important. My idea is, what if you were to place a piece of photographic film in a shallow box, with the filter in front of the film, in ordinary daylight. Would you get the same effect because only waveform was penetrating the filter? Of course, to actually see the hologram (assuming you really could make one that way), I assume you'd need to illuminate the film with a laser. Thanks, Joe _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com<mailto:Utah-Astronomy@mailman.xmission.c om> http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy<http://m ailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy> Visit the Photo Gallery: http://gallery.utahastronomy.com<http://gallery.utahastronomy.com/> Visit the Wiki: http://www.utahastronomy.com<http://www.utahastronomy.com/> ------------------------------ Message: 4 Date: Tue, 10 Jun 2008 22:25:45 -0700 (PDT) From: Canopus56 <canopus56@yahoo.com> Subject: [Utah-astronomy] STS-ISS by Moon shortly (nothing political, Chuck <g>) To: Utah Astronomy List Serv <utah-astronomy@mailman.xmission.com> Message-ID: <440909.44347.qm@web32603.mail.mud.yahoo.com> Content-Type: text/plain; charset=us-ascii Poor quality digicam capture of part of the overflight. Gives some sense of the relative angle movement of the ISS during overflight. About 6 feet of the roof line of the adjacent house gives some sense of scale. http://members.csolutions.net/fisherka/astronote/photos/20080609ISSOverpass. avi 5megs I misjudged the TFOV of the orbit path relative to the Moon. The ISS went underneath the camera frame. Then repositioned. Peace - Kurt ------------------------------ Message: 5 Date: Wed, 11 Jun 2008 09:12:38 -0700 (PDT) From: Joe Bauman <josephmbauman@yahoo.com> Subject: Re: [Utah-astronomy] holograms To: Utah Astronomy <utah-astronomy@mailman.xmission.com> Message-ID: <563098.37399.qm@web38903.mail.mud.yahoo.com> Content-Type: text/plain; charset=iso-8859-1 That's what I love about this newsgroup -- there's always somebody who knows enough about a subject to help me learn! Also I appreciate that I can venture a probably-dumb idea without somebody making fun of me. Thanks all, Joe ROBERT MARILYN GRANT <cincoymaya@msn.com> wrote: Joe- I claim no expertise about holograms, but I remember watching my college roommate (Physics Major) making some. As I recall, the two light waves must have both the same frequency AND the same wave phase (called "coherence") in order to cause an interference pattern than can be recorded on film. I don't know how you can get coherent light except from a laser, but maybe someone else can chime in. Due to the difficulty of getting two lasers into coherence, a single laser was used, with the light going thru a splitter to direct the light at the object in two different paths. When the two light paths recombined, the differences in path lengths caused localized out of phase interference, the pattern of which was recorded on film. This is my layman's perspective. Bob Grant ----- Original Message ----- From: Joe Bauman To: Utah Astronomy Sent: Tuesday, June 10, 2008 11:06 AM Subject: [Utah-astronomy] holograms I've been thinking about Chuck's question, basically what I meant by non-laser-produced holograms, and I admit it's hard to describe my idea. That's probably because it's a b.s. idea. But here goes: There are filters, I assume grid-like, that can eliminate most wavelengths of light. If you could put together one that eliminated all but one wavelength, would that one wavelength work like a laser for the purpose of creating a hologram? I think holograms are possible because the laser illuminating the target emits just one frequency of light. When that light hits the target and bounces back to the film, the waveforms from interfering light bouncing back from various objects are preserved on the film. When a laser shines on the developed film, those overlapping waveforms are reconstituted and you see the object that was photographed in 3D. The fact that the laser is an extremely powerful pulse of light has nothing to do with this process; it's the single-wavelength property that is important. My idea is, what if you were to place a piece of photographic film in a shallow box, with the filter in front of the film, in ordinary daylight. Would you get the same effect because only waveform was penetrating the filter? Of course, to actually see the hologram (assuming you really could make one that way), I assume you'd need to illuminate the film with a laser. Thanks, Joe _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://gallery.utahastronomy.com Visit the Wiki: http://www.utahastronomy.com _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://gallery.utahastronomy.com Visit the Wiki: http://www.utahastronomy.com ------------------------------ _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.utahastronomy.com End of Utah-Astronomy Digest, Vol 64, Issue 18 **********************************************