[AZ-Observing] Re: az-observing Digest V7 #251
- From: gene lucas <geneluca@xxxxxxxxxxxxx>
- To: az-observing@xxxxxxxxxxxxx
- Date: Fri, 14 Sep 2007 12:06:13 -0700
Back in the 1980s, (the late) Ben Mayer set up a clever gadget he called
the "Problicom", which consisted of two Kodak Carousel slide projectors,
stacked one above the other, with "turnbuckle" adjustments to center up
slides projected onto a screen. The screen could be any reasonable
size, maybe 2 feet square at a short distance. There was a rotating
sector wheel placed in front of the slide projector lenses, so the
viewer saw first one, then the other image and could compare them. Same
principal as the blink comparator, more suited for 35mm photography
(remember >that<??) Mayer ran an amateur program searching for
Supernovae; the same principles as searching for asteroids or variable
stars.
Later, Mayer set up a similar gadget called the "Viblicom", using two
separate TV cameras with lenses, looking at the slides, and alternately
switched so one of the two images appeared on a TV monitor. Both of
these devices made it much easier on the viewer. These were fully
described in the magazines and conference papers of the time (1980s).
Now, of course, there are computer programs which will overlay and
"blink" sets of digital images, including re-centering and rotation to
match the images. In the case of asteroid searches, the software also
will "pattern match" and identify all of the known stars in the
field(s), and also the known asteroids, using star catalogs (such as
HIPparcos/Tycho) and the asteroid database maintained (and updated
daily) by the IAU Minor Planets Center.
We have several amateurs here in Arizona who are leading discoverers of
asteroids, including Dr. Charles Juels right here in Fountain Hills, who
has found over 200 "rocks" (and named one for me....) He has also
discovered two comets, using his CCD cameras on his telescopes in his
backyard.
Gene Lucas
(17250)
Dan Heim wrote:
>Keith Parizek had his comparator set up so that, during alignment,
>superimposed images of both plates were seen. Not sure how he did that
>except for that it involved a prism (or prisms) he scavenged from an old set
>of binocs. He just had to get a few bright stars at opposite corners to
>line up, and he was ready to blink. When he demonstrated it to me, he was
>using prints instead of plates, and it was already aligned. I'm guessing it
>only took him 10-15 minutes to load and align.
>
[earlier notes snipped - GL]
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