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Re: (meteorobs) First time
In a message dated 96-08-08 16:03:07 EDT, you write:
<<
1) On the "NAMN Meteor Summary" form, the field of view column lists RA
and Dec. Now I know this is Right Ascention and Declination, but George's
example, and other sample reports show degrees instead of Hours and
Minutes in the RA. What am I missing?
2) On the same form, what does "F" (between the Teff and LM columns)
stand for?
I am also planning to photograph meteors, but for aesthetic, not
scientific purposes. I am prying my 17.5 off the equatorial platform and
am bungee-cording a tripod with an array of 4 OM-1 cameras (2 with 50mm,
2 with 28mm lenses). So far, I have four rolls of film: 1 T-Max 3200, 1
Fuji Super HG 1600, and 2 Fuji Super HG 800. At what point should I
expect sky fog to take over? Fifteen minutes? Should I get a slower,
finer grain film (I have had good luck with Fuji 400 film)? I'll be happy
to get good, untrailed constellation/Milky Way shots--and ecstatic if I
get meteor trails. Any suggestions welcome!
Thanks in advance!
--Ray-- Sidewalk Astronomers, SF:
h >>
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Ray,
1) Yes, I use degrees and I didn't mean to confuse you here...You can either
use degrees or Right Asscension and Declination. Usually it is listed in
degrees, but I put down RA and Dec with the assumption that some folks would
understand that more readily than in Degrees. It doesn't matter, but the
preference is in degrees. If for example, you have a center of view of RA
17h15m, Dec -22...In degrees it would look like this: 17hr X 15 = 255 + (15m
divided by 4m) = 255 + 3.75 = 259 deg -22.
There are 15 deg/hr and 1 deg/4minutes.
2) F stands for a value that represents your view that is being blocked...not
the percent of the sky that is blocked now...You make your initial estimate
in %...if over 20%...take a nap or just enjoy what you can see. F values can
be determined on a later date, but out in the field, you make your judgements
in Percent of view that is blocked. I will send you a separate message
explaining this in more detail.
3)As for photograping for aesthetic values...Okay, for B and W film, try
HP-5...don't use Tmax 3200 in this case. I've used both Tmax 3200 and HP-5
for at least an hour under dark skies and had no sky fog problems...make sure
you are in a very dark location though. Since, you probably won't be guiding
it manually, I'd suggest 15 or 20 minute exposures with the 28mm lens and 10
and 15 minute exposures with the 50mm to prevent any minor star
trailing...I'm assuming here that you might have a not so good polar
alignment...if your polar alignment is real good...then you can increase
these to about 5 or 10 minutes each...As for color film...Fuji 400 is good.
I hope this helps Ray...good luck.
George Z.