Re: [APML] Widefield H-a pic of milky way

["Brian Larmay" <brileau@earthlink.net>]

When using an H-a filter with wide lenses you must go through a tedious
calibration process to focus on the right spectrum of light.
This is done bye.....o heck...heres John mirtles page dedicated to the how
to's of H-a photography<g>

http://members.shaw.ca/jmirtle/ha.htm?

The reason i used f/4 instead of 1.8 was at that stop it would be sufficient
enough to achieve close to accurate focus with the filter.

I used a 52mm lumicon H-a filter for around 30-40 bucks I think which also
came with a step ring.

Thanks for the comment,
Brian





----- Original Message -----
From: "lkt" <tan@cox.net>
To: <astro-photo@seds.org>
Sent: Thursday, March 07, 2002 1:58 AM
Subject: Re: [APML] Widefield H-a pic of milky way


> Brian,
>
> Nice shot. Was there a reason you did not use the lens wide open at
> f/1.8? I am thinking maybe the limitations in the lens will not be
> apparent in a narrow band filter. Also, which h-alpha filter did you
> use? Thanks.
>
> Loke
>
>
>
> > Brian Larmay wrote:
> >
> > Heres a shot I took while experimenting with widefield lenses, an H-a
> > filter, and hypered tech pan the summer before last.
> > After scanning the neg, I think I might try this again soon...possibly
> > a
> > mosaic of the entire north american half of the milky way as a project
> > for
> > this summer.
> >
> > The lens used was a 50mm Nikon f/1.8 @ f/4 for 35 mins
> >
> > A bit of uneven illumination but still looks pretty...i get lost in it
> > and
> > thats all that matters to me :)
> >
> > Heres the pic:
> > http://home.earthlink.net/~brileau/_wsn/page4.html
> >
> > Good fortune,
> > Brian
> >
>
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