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Re: (meteorobs) meteors & lenses
Tom,
To be honest I've not actually optimised my photography. The criterea I
used were really cost and sky coverage. My five 28mm lenses (and a 24mm
overhead) cover the sky above 15 deg elevation. If you look at the IMO
photography pages, I'm sure you will find notes or references on how to
optimise a system. One of the most important factors is the magnitude
index. A low magnitude index will favour wide angle lenses (as for
sporadics or last years Leonids) and a high index (as for this years
Leonids) will favour longer focal lengths. My 50mm lens gave much the
same results as the 28mm lenses, BUT I grossly overexposed (5 mins at ISO
1600 at f/1.2) no doubt with the resulting loss of the faintest meteors.
The other factor is what your intent is. For triangulation, a longer
focal length will give better spatial and temporal resolution but at the
expence of reduced sky overlap, whereas for rates alone, choose the focal
length that gives the most meteors.
Cheers, Rob
Robert H. McNaught
rmn@aaocbn.aaodot gov.au
On Sat, 18 Dec 1999, Tom Fleming wrote:
> Rob,
>
> I have photographed meteors over the years ( sporadically :-) ) with 50mm , 28mm and this year 35mm lenses on my venerated Canon FT Ql. It appears you have opted for the 28mm as the most desirable. I would be interested in your experiences and criteria which led to the decision to go mainly with the 28mm lens. I haven't really settled on any particular lens yet but the review of photos (for esthetic purposes) in Sky & Tel from the Leonid shower of 1998 prompted me to try a 35mm this year. (I didnt bag any due to weather). For myself and the audience in general could you run down the pluses and minuses of these lenses from your experience.
>
> Thanks, Tom
>
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