I’m at the 2009 Pacific Astronomy and Telescope Show (PATS) that runs Saturday and Sunday.
Early
Friday, I ducked into several sessions of the Riverside Astroimaging
Workshop (RAW). Organizers of RAW this year found speakers to present
sessions on “affordable” and “advanced” imaging. Don Goldman from
Astrodon Filters gave more seasoned astrophotographers a 2-hour talk on
narrowband imaging. Don contributes fabulous deep-sky images to
Astronomy, and his talk had lots of details astroimagers could try.
The
sessions I saw were hands-on. Participants brought laptop computers,
and they followed along as the speakers unveiled new processing
techniques. About 50 people attended this daylong workshop.
Later, as I was walking to the then-empty convention hall where PATS would occur, I saw Al Nagler, founder of Tele Vue Optics.
Nagler
has been a fixture in the telescope scene since the early 1980s when he
introduced the first Nagler eyepiece, the 13mm, that revolutionized
observing. People who know Nagler call him “Uncle Al.”
We
chatted for more than an hour, and Al showed me lots of pictures he’d
taken during the past 2 weeks. He’d been to several star parties and
also had stopped by Lowell Observatory in Flagstaff, Arizona. On
Saturday morning, he presented the first talk at PATS, “Choosing
Eyepieces.”
Al shared with me details of a new product Tele Vue
is developing — a ParaCorr, which stands for “parabolic corrector. The
ParaCorr corrects an optical defect called coma. This defect causes
stars far from the center of the eyepiece’s field of view to appear to
have tails (like comets — hence the name). Coma is present in all
Newtonian reflectors, but it’s especially noticeable in those that have
a fast focal ratio.
Some telescope manufacturers install mirrors
with ultra-short focal lengths (below f/4) in their telescopes so they
can shorten the scopes. This benefits observers who don’t want to climb
a ladder all night to observe faint objects. For example, consider a
20-inch telescope with a focal ratio of f/3.3. The eyepiece of such a
scope would be only 5.5 feet off the ground when the scope is pointed
at the zenith (the overhead point).
Such a short focal ratio
introduces lots of coma. That’s where Tele Vue’s new product comes in,
Nagler told me. The ParaCorr model will deal with coma in scopes with
focal ratios in the low-2s. That’s incredible. And it’s just one of the
cool new things I’ve learned since I arrived at this year’s PATS.
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