[AZ-Observing] Re: Flaming star region etc
- From: Brian Skiff <bas@xxxxxxxxxx>
- To: az-observing@xxxxxxxxxxxxx
- Date: Sat, 13 Jan 2018 12:01:42 -0700
On Sat, 2018-01-13 at 11:36 -0700, Albert Barr wrote:
Brian do you think that would improve this image? Actually unless I misread
you I am more interested in all the gas than the stars.
No, I am not suggesting an improvement in the image,
which is excellent, but is a pictorial/graphics-arts thing.
I am more interested in the science that could be got
from having a big uniform set of images along the Milky Way
irrespective of whether there's anything of pictorial
interest or not in any specific field.
A survey was done in the past decade called IPHAS,
where narrow-band H-alpha and broad-band red and far-red
images were taken along the entire northern Milky Way
to look at emission-line stars of various sorts. This was
done with the 2.4-m Isaac Newton Telescope in the Canary
Islands. This is very useful, but the _bright_ limit of
the survey was around mag 12 or 13:
http://cdsarc.u-strasbg.fr/viz-bin/Cat?II/321
So nearly all the 'classical' emission-line stars (and
planetaries and compact HII regions and other strange stuff)
are saturated in the resulting data-catalogues. There remains
a problem of actually identifying these stars (the early work
50 to 70 years ago wasn't always done very well), so one would
like to have the red and H-alpha data to try to identify
the stars. (Having a spectral survey on-line would be best,
but nobody seems to want to do that.)
The southern sky has already been done like this,
and you can access the images here:
http://www-wfau.roe.ac.uk/sss/halpha/index.html
(digitized photographic films, mind you)
So I'm just suggesting a long-term project to do this at
the bright end from the north with the wonderful hardware
you have at hand.
Try taking some shots around NGC 663 in Cassiopeia,
which has about three dozen emission-line stars in it.
Can you adjust the red and H-alpha exposures so that
most stars in the general field are very nearly the same
brightness, but the H-alpha stars are noticeably brighter?
\Brian
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