PESO: Hot Air

[Christine Aguila]

Glen:  Truth be told, I don't really have a clear understanding of all the 
mechanics you explain here (not really knowing anything about telescopes or 
guns), but the details don't matter:  what's impressive is your 
inventiveness--good luck with whatever it is you're trying to build, but 
your point about the police seems to be a wise one--don't forget it!!! 
Cheers, Christine


----- Original Message ----- 
From: "D. Glenn Arthur Jr." <dglenn at panix.com>
To: <pdml at pdml.net>
Sent: Monday, July 21, 2008 1:30 PM
Subject: Re: PESO: Hot Air


> Rick Womer <rwomer1004 at yahoo.com> asked:
>> Neat!  Where were you, and how far away was the chopper?
>
> Short answer:  I was at home and the helicopter was a mile away.
>
> The chopper was over downtown Baltimore, MD, US, preparing to
> land atop the University of Maryland Medical Center. I was
> about a mile to the west of that (1.1 miles according to my
> car's odometer; I haven't double-checked that with Google Maps
> yet), using the telescope I borrowed from my brother (which
> he describes as "a cheap, Wal-Mart scope" -- f=700mm, d=60mm,
> poor correction (if any) for chromatic aberration and spherical
> aberration (I got colour fringing when I tried to shoot Jupiter
> and didn't have it centered), a similarly cheap "Barlow lens"
> (2x teleconverter, more or less, as far as I can tell), and
> using a cymbal stand with a boom instead of a tripod, because
> the tripod that came with the scope doesn't work so well for
> leaning out a window and looking sideways.
>
> Just to complete the picture of the kludginess involved:  the
> telescope/microscop->Kmount adaptor I'm using (given to me
> by a bandmate a few years ago) is sized for a _real_ telescope
> ... and this scope uses eyepieces that various amateur astronomy
> websites describe as "occasionally found on cheaper, department
> store telescopes", so instead of fitting into the receiver
> tube it slides _over_ the tube and I'm holding it on with
> gaffer's tape.  (I'll eventually either get a cheap eyepiece
> adaptor that'll fit the camera adaptor, or drill and tap holes
> for set-screws in the camera adaptor.)
>
> So, near as I can figure, that was 1400mm and f/22, on a wobbly
> support.
>
>
> My brother also gave me the wooden stock from a busted rifle;
> I'm going to try to turn it into a grip for the scope+camera
> combination to make it a little easier to use handheld than it
> currently is.  I plan to put two shutter switches on it:  one
> roughly where the rifle's trigger had been, and one up under
> the telescope, so I can use whichever hand isn't fussing with
> the focus knob to trip the shutter.  I'm hoping that having
> a big, fat, white thing on top instead of a slender, dark rifle
> barrel will keep the police from mistaking the rig for a weapon
> once it's completed.
>
> In the meantime, I should get up on the roof at some point and
> use the proper telescope tripod.  But I haven't gotten around
> to that yet.
>
> -- Glenn
>
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