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(meteorobs) Re: photo strategies for Leonids '00?

First of all Bob I would avoid the temptation of extramarital relations
with the radiant as one contributor suggested. It can lead to nothing
but heartache :)

Seriously, the last quarter moon is not nearly as bad as one would
think. I cannot recall the exact figure but it is roughly 25 percent as
bright as the full moon. If the sky is transparent I can easily achieve
a limiting magnitude of +6.0 with a last quarter moon in the sky. Of
course I would need to be at looking at least 60 degrees away from the
moon to achieve these results.

If your sky is transparent I would aim low and catch some lunar lit
landscape in your photos. This worked well for me in Spain last year
producing nice photographs with a the local hills and a brilliant sky
full of faint Leonid meteors.

If your conditions are hazy then I would suggest aiming higher making
sure the moon is still out of your field of view.

I would bet you could go 5 minutes with 800 film with transparent skies.
Any landscape shots may limit that to 2-3 minutes.

The idea of catching earth grazers is interesting. These long-lasting
meteors would leave a nice image. I don't believe I have seen a picture
of an earth grazer other than the famous Teton/Yellowstone daylight
fireball.

I would forget the big aperture scope. Unless a storm appears the odds
of capturing one through a scope are minimal.

As for fireballs I would not hold your breath. I would expect a
brightness display much like last years with lots of Leonids in the +3
to +5 magnitude range and only an occasional meteor in the negative
range.

I hope this helps!

Bob Lunsford



B Yen wrote:
>  I would like your input (& from anyone else) on *strategies* for photographing
> the Leonids, with the last-quarter moon near the radiant.
> 
>  At 1st, I figured meteor photography was an impossibilitiy, given the moon
> interference.  So, I decided not to do anything for 2000 Leonids.
> 
> On 2nd thought, maybe no.  There actually, may be some "clever" tactics to use:
> 
> 1) use short exposures (i.e., prevent the moonlight from saturating the sky
> back-ground density on film).  Say 2 min exposures on 800 asa film (just a
> guess).  But, that would eat up a roll of 36 exposure film in 1 hr 12m.  Do that
> all night (5-6 hours), that means 4 rolls/camera.  Since I use a bank of cameras
> (3 on 1 mount, 3 on a 2nd mount, 3 on a 3rd mount), that could get expensive.
> Over 2 nights, Nov 16-17 & Nov 17-18.  (Last year I spent over $300 on film &
> developing costs, for 2 nights of meteor patrol photography!!  see
> http://www.comet-track.com/meteor/leonids99/leonids99.html).
> 
>  I guess I could back-off, & use less cameras.  But, that compromises my blanket
> approach ("covering the sky")
> 
> 2) go for earth grazers, near midnight (when Leo rises at my 34 deg N latitude).
> (The half-moon is near the horizon, so the sky isn't that light-polluted).  Then,
> I can get meteor shots with semi-darksky conditions (shows the Milky Way,
> deep-sky objects.)
> 
> 3) use big aperture scope (to get meteors, since point-source exposures are
> function of aperture), with slow f-ratio (to "knock down"  sky-background fog).
> But, this means very long focal-length lenses.  This minimizes chances of getting
> meteors.  Contradiction.  Paradox.  No solution?
> 
> For 1), has anyone come up with a formula (ASA, f-ratio, lens diameter, exposure
> time), that is sky-background limited for half-moonlit conditions?  I can figure
> this out, by just going out & testing (long trip, hassle, $$, etc.)
> 
> (example)
> The Geminids '98, had a crescent moon come up in the east, ~4am.
> 
> http://www.comet-track.com/meteor/geminids98/16mm/16mm_36.jpg
> 
>  I backed off my exposures to 5 min (instead of 15 min, moonless sky), 1000 ASA,
> f2.8.  But this year, there will be a half-moon, so I would have to go less
> exposure.  2 min?  3 min?
> 
> Given the predictions, what are the chances of "fireballs" for 2000?  ('98 was
> noted for the quantity of fireballs.  see
> http://www.comet-track.com/meteor/leonids98/leonids98.html).  '99 was
> disappointing..I spent all that $$, the photos paled in comparison to '98.
> 
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