[LargeFormat] Leonid Meteor Shower

[Michael Briggs]

On 17-Nov-01 Clive Warren wrote:
> As for technique - yep and thanks for the advice. I am hoping to use 
> a 7" aero Ektar on 4x5. This has an aperture of f2.5 and is corrected 
> for infinity - probably performs very well wide open. This is one of 
> those times that not having a shutter is an advantage in the dark - 
> just take the lens cap off :-)

This should work.  I wonder whether a f2.5 Aero Ektar delivers more light than
a modern f5.6 lens.  The Aero Ektars must be uncoated and the rear glass has
turned brown from self-induced radation damage.  I am doing a historical and
labortory study of the Aero Ektars.  Two of the rear elements contain Thorium.

> 
> As for film - B&W 400ASA pushed one stop. As you seem to know a bit 
> about astro photography, what do you think my chances are?  I 
> understand that the meteors will probably be as bright as the the 
> brightest stars but will be very fast moving.

You approach sounds good.  You can develop one sheet and adjust the time. 
Since it is not a pictorial scence, the criteria for developing are different. 
I have used high-constrast developers like D-19.  I don't know what the best
choice would be, perhaps Microphen or XTOL.

One thing, base your exposure time on the sky brightness from light pollution. 
If you are near a city you will have to keep the exposures shorter, of the
order of a minute or two, I can't say exactly.   With truly dark skys, much
longer exposures will work.   You can stop the exposure when you think you have
a bright meteorite, or you keep going for longer star trails and possible
additional ones.

Good luck with the weather.

--Michael