Re: [APML] Tech Pan shot

[George Anderson <tillerman1@videotron.ca>]

Hi John

I haven't ruled out manual guiding. Just manual guiding with my present
EP. Once I get a better EP the eyeball torture level should be reduced
by several orders of magnitude.
I'll have a go a shooting while the moon is up if we get any clear
nights this month. The clouds have just rolled in for tonights display
of lights.
I keep tweaking the polar alignment of my mount every week or two,
usually right after developing some film and finding traces of rotation.
So I re-check the drift with a more critical eye each time.
I may just have a go at seeing how close (timewise) to the full moon I
can shoot and still get useable results.
Many thanks for the advice. Hope your weather warms up, 18c is a little
chilly for a daytime high this time of year.

George

Clear skies and good health

spampit wrote:
> 
> George,
>         If the technology fails you for guiding, there is always manual
> guiding! It builds character. :-) I didn't notice that you were using the
> Lumicon filter. That being the case, you can most certainly go longer! Under
> a moderately dark sky at f3.5 and the Lumicon filter, you can shoot for at
> least an hour with a first/last 1/4 moon up. I have always stayed 30 degrees
> away from the moon, it may well be possible to shoot closer than that. I
> never really did find the limits to this type of photography with
> telephotos. Under a dark sky and a Wratten 92 I know that I can shoot for 45
> to 60 minutes at f1.5 and still have a printable negative. (with 5 minute
> development) http://www.astrofoto.ca/john/n7822.htm Maximum exposure time
> will vary, depending on your type of light pollution, how well the film is
> hypered, humidity levels etc. Maybe start with 45 minute shots at f3.5 and
> see what happens. You are going to need a very good polar alignment for
> these long, wide field, high-rez images! I never did try shooting under full
> moon, you might as well try. Push the envelope!
> 
> John Mirtle
> Calgary, Ab. Canada
> 
> -----Original Message-----
> From: astro-photo-bounces@seds.org [mailto:astro-photo-bounces@seds.org] On
> Behalf Of George Anderson
> Sent: Monday, August 08, 2005 8:59 PM
> To: Discussion of Film Astrophotography
> Subject: Re: [APML] Tech Pan shot
> 
> Hi John, nice to hear from you again.
> I haven't done any vignetting reduction on the photo yet, too busy
> debugging other problems with my setup. I am in the process of switching
> from my 70mm f/10 guidescope with a 10mm EP containing a homemade
> non-illuminated crosshair, to my B&W quickcam on a 500mm f/8 mirror
> lens. The sensitivity is ok, just a real pain to align with the mount.
> The field of view is so small that I can't even swing polaris in a
> circle.
> That shot was done with a Lumicon HA filter under moderate light
> pollution, at 18 minutes the negative is thin to say the least. I did
> two more shots saturday night with the quickcam and laptop for visual
> guiding. Much easier on the eyes, but I hadn't aligned the camera and it
> was out by a good 5-10 degrees from the mount axis. Very nice trailing
> (three star diameters) on the two 30 minute shots...  :^(
> Just how much of a moon and at what angular separation from the target
> is safe with the HA filter? That will improve my shooting nights by 200%
> if I can shoot up to the quarter moon. Our weather always improves
> around that time.
> 
> George
> Clear skies and good health
> 
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