Re: *fast* film/Hale Bopp

[P3D Brian Reynolds <reynolds@xxxxxxxxx>]

Bob Wier wrote:
> 
> 
> I'm attempting to do some pictures of my little town here with
> Hale-Bopp visible just over the western mountains. Tonight this
> was about 8PM local with a nearly full moon (not good - washes out
> the dimmer background stars). What I'm doing is a time exposure (via
> "bulb") moving the tripod a bit and doing a second time exposure
> (this is a variation of the shifted foot technique...). The eventual
> target if anthing works is holmes type views and/or images for the
> photo-3d site.
> 

I would think that some sort of slide bar arrangement would work
better.  It is pretty difficult to keep the camera pointing at the
same spot when moving the tripod.  You should probably try using a
focusing screen with a cross hair so that you can try and point
consistently.

> Now, the question is, does anyone have suggestions for exposure
> lengths? I'm bracketing from about 30 seconds up to 5 minutes or so.
> On the 30 second end I'm expecting the sky to be too dim. On the 5
> minute end, the town lights will probably be very exaggerated, and
> I *may* have star/comet trails. This is hard to judge, though since
> in order to get both the comet and the town, I'm running about 40mm
> on my Pentax SLR which results in a pretty small image on the comet
> (unless I'm picking up tail that I can't see naked eye wise).
> 

A 40mm lens would probably give you a good image of the comet, but
light pollution from the town will very likely wipe out the tail.

> I may have one more chance at this tomorrow night (although the forecast
> is for clouds to start coming back in). Does anyone have any hints
> to offer? I've not used that fast a print film much (incidentally
> max aptr on my Pentax is 3.5 on the zoom I'm using). Seeing is pretty
> good since I'm at around 8,000' elevation with no air pollution, little
> light pollution, and reasonably steady (but cold) atmosphere.
> 

You might want to check out Sky & Telescope's web page
<URL:http://www.skypub.com/>, Astronomy magazine's web page
<URL:http://www.kalmbach.com/astro/astronomy.html>, and Popular
Science's web page <URL:http://www.popsci.com>.  Astronomy magazine
(and I think Sky&TEk also) ran a how to article on hale-bopp
photography in a recent issue.  Popular Science is running a Hale-Bopp
photography contest and has some hints and links to other places.  By
the way, in spite of the hint at the Popular Science home page you
don't really need extremely fast film for comet photography,
especially if you are going to include a twon in the foreground.

-- 
Brian Reynolds                  | "Humans explore the Universe with five
reynolds@xxxxxxxxx              |   senses and call the adventure science."
http://www.panix.com/~reynolds/ | - Edwin P. Hubble


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