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RE: [APML] Light pollution filters and Comet NEAT
Hi Dale
Thanks for sharing. I wonder if a polarizing filtre would do the same
job.
Regards,
Nicola
> -----Original Message-----
> From: astro-photo-bounces@seds.org
> [mailto:astro-photo-bounces@seds.org] On Behalf Of Dale Ireland
> Sent: 20 May 2004 16:09
> To: 'Discussion of Film Astrophotography'
> Subject: RE: [APML] Light pollution filters and Comet NEAT
>
>
> I took some NEAT shots with and without the IDAS filter with
> a Nikon D70, Nikon 58mm NOCT f/1.2 lens, 2-3 minutes. I got
> more and better tail structure in both the ion and dust tails
> WITH the filter which allowed longer exposures but even
> exposures of the same length looked better with the filter.
> Of course the camera has its own spectral response so I can't
> say this translates exactly to film but it worked in my
> situation. Dale
>
> -----Original Message-----
> From: astro-photo-bounces@seds.org
> [mailto:astro-photo-bounces@seds.org] On > Behalf Of steve
> banbury
>
>
> Hi Greg and Jeff:
>
> The IDAS filter response is shown at:
> http://www.sciencecenter.net/hutech/tokai/filt> plt.htm
>
> The
> only spectra I could find on the web for
> C/2001 Q4 was at: http://home.freeuk.com/m.gavin/encke.htm
>
> I didn't try to to superimpose the 2 plots, but I can see
> that some energy would be lost using the filter. It still
> seems like a coin flip as to whether the reduction of local
> light pollution would make this loss acceptable. I'm
> suprised someone hasn't already been down this path before.
>
> cheers--steve
> Greg Hartke wrote:
>
> >Hi, Jeff,
> >
> >I'm not so sure this is correct.
> >
> >The IDAS LPS filter is a very different animal than the usual light
> >pollution filters. It has relatively narrow stopbands at the
> frequency
> >of selected spectral lines which appear in prevalent public
> lighting.
> >Because the cometary spectrum really is farily broadband,
> most of the
> >light from the comet will make it through. Of course there will be
> >attenuation but it would normally be expected to be
> significantly less
> >than that of the narrowband pollution sources.
> >
> >I would expect the IDAS LPS filter to be very much worth trying for
> >this application.
> >
> >Greg Hartke
> >Sykesville, MD
> >
> >
>
>
>
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