Comments on: Irreplaceable Astronomy http://blogs.discovermagazine.com/badastronomy/2007/07/12/irreplaceable-astronomy/ I am an astronomer, writer, and skeptic. I likes reality the way it is, and I aims to keep it that way. My real name is Phil Plait, and I run the Bad Astronomy blog. Sat, 10 Jan 2009 03:35:06 +0000 http://wordpress.org/?v=2.3.1 By: VJB http://blogs.discovermagazine.com/badastronomy/2007/07/12/irreplaceable-astronomy/#comment-41743 VJB Wed, 18 Jul 2007 21:07:27 +0000 http://blogs.discovermagazine.com/badastronomy/2007/07/12/irreplaceable-astronomy/#comment-41743 Oh, and while I on the trip down memory lane, NASA's Goddard Institute for Space Studies, which I refer to, still had a 7094 vacuum tube computer when it was still located in the Interchurch Center when I started there. When we moved to 2880 Bway (over the now-famous Tom's Restaurant) we got an almost super-computer, an IBM 360/195. It had I recall 4 megawords of semiconductor memory (4 9-bit bytes including parity). It needed water cooling. It was to come online for general use after Labor Day 1966 (I think that's the year), but over the holiday weekend, the cooling sprung a leak. Trouble ensued, and it never quite was up to snuff. This machine had the old 'washing machine' winchester hard disk drives with the removable platter stacks. The best thing, though were the IBM 2250 graphical display consoles (rental to IBM was $5K or $15K a month). I did all my plate calibrations with these, as I had to pick the iron lines for spectrum wavelength calibration, etc. I got into interactive programming much earlier than most people as a consequence, as there seemed to be no reasonable way to recognize line patterns. At least with in the limitations on my gigantic FORTRAN program (3600 cards--almost two whole boxes--WOW!) Now I sneer. The main applications program for the instrumentation my little company builds is now up to half a million lines. Oh, and while I on the trip down memory lane, NASA’s Goddard Institute for Space Studies, which I refer to, still had a 7094 vacuum tube computer when it was still located in the Interchurch Center when I started there. When we moved to 2880 Bway (over the now-famous Tom’s Restaurant) we got an almost super-computer, an IBM 360/195. It had I recall 4 megawords of semiconductor memory (4 9-bit bytes including parity). It needed water cooling. It was to come online for general use after Labor Day 1966 (I think that’s the year), but over the holiday weekend, the cooling sprung a leak. Trouble ensued, and it never quite was up to snuff. This machine had the old ‘washing machine’ winchester hard disk drives with the removable platter stacks. The best thing, though were the IBM 2250 graphical display consoles (rental to IBM was $5K or $15K a month). I did all my plate calibrations with these, as I had to pick the iron lines for spectrum wavelength calibration, etc. I got into interactive programming much earlier than most people as a consequence, as there seemed to be no reasonable way to recognize line patterns. At least with in the limitations on my gigantic FORTRAN program (3600 cards–almost two whole boxes–WOW!) Now I sneer. The main applications program for the instrumentation my little company builds is now up to half a million lines.

]]> By: VJB http://blogs.discovermagazine.com/badastronomy/2007/07/12/irreplaceable-astronomy/#comment-41742 VJB Wed, 18 Jul 2007 20:49:24 +0000 http://blogs.discovermagazine.com/badastronomy/2007/07/12/irreplaceable-astronomy/#comment-41742 Buzz Parsec--you are undoubtedly right about the rings. At our NASA facility at Columbia (where Jim Hanson came on as a post-doc with hair while I was there) only the High Priests of IT ever actually even got to touch tapes (except for the 7-track ones we used on the scanning microdensitometer built for my project and probably never used since). Incidentally, the company who built the digital interface for the recording system for this instrument was a little firm out on Long Island called Computer Associates (yes, THAT one) in its early days. All the logic was DTL in the Fairchild epoxy-sealed TO-5 like packages that were the predecessor to DIPs. All hand wired; no wirewrap. Buzz Parsec–you are undoubtedly right about the rings. At our NASA facility at Columbia (where Jim Hanson came on as a post-doc with hair while I was there) only the High Priests of IT ever actually even got to touch tapes (except for the 7-track ones we used on the scanning microdensitometer built for my project and probably never used since). Incidentally, the company who built the digital interface for the recording system for this instrument was a little firm out on Long Island called Computer Associates (yes, THAT one) in its early days. All the logic was DTL in the Fairchild epoxy-sealed TO-5 like packages that were the predecessor to DIPs. All hand wired; no wirewrap.

]]> By: Buzz Parsec http://blogs.discovermagazine.com/badastronomy/2007/07/12/irreplaceable-astronomy/#comment-41741 Buzz Parsec Tue, 17 Jul 2007 09:50:19 +0000 http://blogs.discovermagazine.com/badastronomy/2007/07/12/irreplaceable-astronomy/#comment-41741 VJB - the ring on open reel 1/2 tape is a write enable ring, not a write protect ring, so someone must have forgotten to remove it. (Or put one back in.) Used to have hundreds of them, but a few years ago I went looking for one for a friend who wanted one to use to construct a geeky christmas tree ornament and it took hours to find one! They are also a good test of antique computer knowledge. Most people seem to recognize an IBM punch card (though they might not recognize the term "Hollerith code"), but write rings are more obscure. I wonder if the 029 key punches are still in the room down the hall, up the stairs, and around the corner from the plate stacks? VJB - the ring on open reel 1/2 tape is a write enable ring, not a write protect ring, so someone must have forgotten to remove it. (Or put one back in.) Used to have hundreds of them, but a few years ago I went looking for one for a friend who wanted one to use to construct a geeky christmas tree ornament and it took hours to find one! They are also a good test of antique computer knowledge. Most people seem to recognize an IBM punch card (though they might not recognize the term “Hollerith code”), but write rings are more obscure. I wonder if the 029 key punches are still in the room down the hall, up the stairs, and around the corner from the plate stacks?

]]> By: George Martin http://blogs.discovermagazine.com/badastronomy/2007/07/12/irreplaceable-astronomy/#comment-41740 George Martin Tue, 17 Jul 2007 02:19:07 +0000 http://blogs.discovermagazine.com/badastronomy/2007/07/12/irreplaceable-astronomy/#comment-41740 Scott said: "I meant on the side of the plate" Sorry I missed that interpretation. But the plates I used were not very thick. Let's see, it is 4:00 AM some January morning and I need to load the plate holder. I take off my gloves and run my finger along a thin edge looking for an indentation in the shape of a arrow. Why don't I just moisten my finger tip and tocuh a corner on one side? I'll indentify the emulsion, get the plate loaded and my gloves back on, before I could find your arrow I bet. The real point is though, as a couple of others sort of mentioned, it was really very easy to determine the emulsion side of the plate, if you did it more than two or three times, not just once or twice for a class as some sort of "Rite of Passage". The real point is why complicate the manufacturing process of the plates to make it slightly easier, at best, to do something which was already easy? George Scott said:

“I meant on the side of the plate”

Sorry I missed that interpretation. But the plates I used were not very thick. Let’s see, it is 4:00 AM some January morning and I need to load the plate holder. I take off my gloves
and run my finger along a thin edge looking for an indentation in the shape of a arrow. Why
don’t I just moisten my finger tip and tocuh a corner on one side? I’ll indentify the emulsion, get the plate loaded and my gloves back on, before I could find your arrow I bet.

The real point is though, as a couple of others sort of mentioned, it was really very easy to determine the emulsion side of the plate, if you did it more than two or three times, not
just once or twice for a class as some sort of “Rite of Passage”. The real point is why complicate the manufacturing process of the plates to make it slightly easier, at best, to do something which was already easy?

George

]]> By: VJB http://blogs.discovermagazine.com/badastronomy/2007/07/12/irreplaceable-astronomy/#comment-41739 VJB Sun, 15 Jul 2007 08:09:14 +0000 http://blogs.discovermagazine.com/badastronomy/2007/07/12/irreplaceable-astronomy/#comment-41739 Oh, and the kicker in my work, talking about perishibility of digital stuff, is that somebody forgot to put in the write-protect ring on the tape of the final syntheses of the spectra. This was the ultimate result of more than a year's effort on my part using the huge FORTRAN program I wrote to crunch the numbers, converting densities to intensity and calibrating wavelength from the iron spectrum recorded on the plate, then correcting for proper motion and adding. The tape got written over a couple of years later and only the hardcopy graphical printouts were left. The plates were sent back to the Lick archive. Maybe I'll visit them someday. Another by-the-way. A lot of raw data tapes were erased in a NASA archive just before my time. Turned out the motor from a big floor buffer had a big enough AC magnetic field to ruin almost every tape on the bottom shelf. Oh, and the kicker in my work, talking about perishibility of digital stuff, is that somebody forgot to put in the write-protect ring on the tape of the final syntheses of the spectra. This was the ultimate result of more than a year’s effort on my part using the huge FORTRAN program I wrote to crunch the numbers, converting densities to intensity and calibrating wavelength from the iron spectrum recorded on the plate, then correcting for proper motion and adding.

The tape got written over a couple of years later and only the hardcopy graphical printouts were left. The plates were sent back to the Lick archive. Maybe I’ll visit them someday.

Another by-the-way. A lot of raw data tapes were erased in a NASA archive just before my time. Turned out the motor from a big floor buffer had a big enough AC magnetic field to ruin almost every tape on the bottom shelf.

]]> By: VJB http://blogs.discovermagazine.com/badastronomy/2007/07/12/irreplaceable-astronomy/#comment-41738 VJB Sun, 15 Jul 2007 07:50:56 +0000 http://blogs.discovermagazine.com/badastronomy/2007/07/12/irreplaceable-astronomy/#comment-41738 Back in my grad school days, my advisor was visiting faculty at Berkeley, so we got weeks of time at the 120-inch at Lick. We used the Coude focus spectrometer's 150-inch (as I recall) camera for stellar spectroscopy of bright OB stars in the blue to near UV. You wouldn't believe the resolution, 0.13nm/mm (we looked at absorption of interstellar diatomic molecules against these nearly featureless stellar spectra and got rotational temperatures and upper limits to show that the 2.7K cosmic background emission discovered by Penzias and Wilson peaked in the right place to be black body. Had to digitize and add together over 30 plates from zeta Oph to get the final results. Did some other dimmer stars so not so many plates for them, but could show reasonable isotropy at least for CN). The plates we used (2 2x10 inchers--cut from 8x10s-- end to end in the plateholder--which was curved for the whole length to be in the focal plane--had to be careful not break the glass) were sensitized IIa-O. My recollection is that only one person could sensitize properly, the oldest night asst, with the beard. I think it involved exposure to IR, then an extended bake-out. Relied on him to have the plates face up in the boxes. So all I had to do was load the plates into the holder, go through the light-lock doors, use my well-developed kinesthesis to negotiate the catwalk down to the camera focus, slide in the light safe slide and exchange holders. All of course in absolute darkness. BTW, in the plate loading room somebody had posted a sign 'The East is Red', the name of a popular song of the Cultural Revolution (this was in 1967-68). They posted it because it was literally true there. Also James Lick is buried in the pier of the 36-inch Alvin Clarke refractor he paid for. Was still being used at that time for sky survey work, just like the Harvard plates. Another bit or two of Lick-lore: the 36-inch objective lens was being transported by mule up the mountain, slipped from its restraints, and rolled down hill and broke. Took two years to replace. The mirror blank for the 120-inch reflector was a test blank for the 200-inch at Palomar (donated by Corning Glass). The whole telescope, including spectrograph and dome cost about $2.5M by the time it was completed in the beginning of the 50's. Th blank was thin-ish, hence the long-ish focal length of the telescope--about f/5 or f/6. One night we had Werner von Braun with us to get an idea of telescopes at the time they first were conceiving of what became the Hubble. Which cost a wee bit more than the 120-inch, as I recall. We were fogged in all night and couldn't even open the dome. The nice ladies in the kitchen were afraid NASA was going to shoot their telescope into orbit. He was very polite and assured them it was not so. There was a packrat, but organized, chief astronomer there some decades before my visits who had a wall of drawers for oddments. Supposedly there was one drawer marked ,'String too short to use'. A suggestion, if you haven't already done it, might be to have an occasional post on telescope history and personal reminiscences from student days and early careers--the olden times of glass plates and such. This comment might provide a start of one such post. Back in my grad school days, my advisor was visiting faculty at Berkeley, so we got weeks of time at the 120-inch at Lick. We used the Coude focus spectrometer’s 150-inch (as I recall) camera for stellar spectroscopy of bright OB stars in the blue to near UV. You wouldn’t believe the resolution, 0.13nm/mm (we looked at absorption of interstellar diatomic molecules against these nearly featureless stellar spectra and got rotational temperatures and upper limits to show that the 2.7K cosmic background emission discovered by Penzias and Wilson peaked in the right place to be black body. Had to digitize and add together over 30 plates from zeta Oph to get the final results. Did some other dimmer stars so not so many plates for them, but could show reasonable isotropy at least for CN). The plates we used (2 2×10 inchers–cut from 8×10s– end to end in the plateholder–which was curved for the whole length to be in the focal plane–had to be careful not break the glass) were sensitized IIa-O. My recollection is that only one person could sensitize properly, the oldest night asst, with the beard. I think it involved exposure to IR, then an extended bake-out. Relied on him to have the plates face up in the boxes. So all I had to do was load the plates into the holder, go through the light-lock doors, use my well-developed kinesthesis to negotiate the catwalk down to the camera focus, slide in the light safe slide and exchange holders. All of course in absolute darkness. BTW, in the plate loading room somebody had posted a sign ‘The East is Red’, the name of a popular song of the Cultural Revolution (this was in 1967-68). They posted it because it was literally true there.

Also James Lick is buried in the pier of the 36-inch Alvin Clarke refractor he paid for. Was still being used at that time for sky survey work, just like the Harvard plates. Another bit or two of Lick-lore: the 36-inch objective lens was being transported by mule up the mountain, slipped from its restraints, and rolled down hill and broke. Took two years to replace.

The mirror blank for the 120-inch reflector was a test blank for the 200-inch at Palomar (donated by Corning Glass). The whole telescope, including spectrograph and dome cost about $2.5M by the time it was completed in the beginning of the 50’s. Th blank was thin-ish, hence the long-ish focal length of the telescope–about f/5 or f/6. One night we had Werner von Braun with us to get an idea of telescopes at the time they first were conceiving of what became the Hubble. Which cost a wee bit more than the 120-inch, as I recall. We were fogged in all night and couldn’t even open the dome. The nice ladies in the kitchen were afraid NASA was going to shoot their telescope into orbit. He was very polite and assured them it was not so.

There was a packrat, but organized, chief astronomer there some decades before my visits who had a wall of drawers for oddments. Supposedly there was one drawer marked ,’String too short to use’.

A suggestion, if you haven’t already done it, might be to have an occasional post on telescope history and personal reminiscences from student days and early careers–the olden times of glass plates and such. This comment might provide a start of one such post.

]]> By: Scott de B. http://blogs.discovermagazine.com/badastronomy/2007/07/12/irreplaceable-astronomy/#comment-41737 Scott de B. Sun, 15 Jul 2007 04:58:41 +0000 http://blogs.discovermagazine.com/badastronomy/2007/07/12/irreplaceable-astronomy/#comment-41737 I meant on the side of the plate, not the front or the back. If a bump would cause problems, make it an indentation instead. I meant on the side of the plate, not the front or the back. If a bump would cause problems, make it an indentation instead.

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