Re: [APML]: exposure time with 500mm lens

[Jim Fedina <jfedina@sbsusa.com>]

Mike,

Thanks for the info, unfortunately I'm finding out that the 500mm lens is
not an option right now because I do not have any tracking capability. I
will be building a barndoor tracker in the future, but even then I'm hearing
that the 500mm will not be good with it.

Thanks,
Jim


Richmann, Michael wrote:

>
> Hmmmm...  I got good density on the negative using a hypered
> Fuji Super G800 emulsion at f/6.3 and 30 minutes so a ballpark
> number might be about 50 minutes at f/8 assuming no further
> reciprocity failure.  As for the Pleiades (M45), if you're simply
> trying to image the stars, 10-20 minutes would do it.  If you're
> after the nebulosity around them, I'd use a least an hour if
> not more.
>
> Mike
>
> > -----Original Message-----
> > From: Jim Fedina [SMTP:jfedina@sbsusa.com]
> > Sent: Wednesday, February 25, 1998 9:10 AM
> > To:   astro-photo@nightsky.com
> > Subject:      [APML]: exposure time with 500mm lens
> >
> >
> > I know I'm being a pain about these exposure times, but I just want to
> > get experience in astrophotography. The question today is:
> >  I have a fixed 500mm lens which is fully opened at F8. Does anyone
> > know
> > what the exposure time would be for M42 with this lens? Also the same
> > for the Pleiades. Since they are at diiferent celestial locations, I
> > would assume that the exposure times would be different.
> >
> > Any help would be greatly appreciated.
> >
> > Thanks,
> > Jim Fedina