SH2-157 & LBN537 in Cassiopeia

[pietervdv]

Greetings all,

I'd like to share my latest h-alpha image. Sh2-157 in Cassiopeia with the bright nebula LBN537 embedded inside it.

It's a 2 pane mosaic, the data was captured over 4 nights the last 3 weeks.

The data capturing (autofocusing, mosaicing, platesolving, mount flip) was fully automated with SGP.

The last night was also the first outing with the newly supported Platesolve 2 routine in SGP.

The latest version of SGP supports this PlaneWave platesoving feature.

After struggling with slow / faulty Astrometry.net platesolves one night, I find Platesolve 2 lighting fast and a joy to use!

Some further technical details:

CCD: sbig st8300 using a 5nm astrodon h-alpha narrowband filter

Exposure: 20h 40min in total (2 panel mosaic), 20 minute subframes

Scope: 10" f/3.8 Newtonian astrograph

Mount: Mesu200 Sitech

Larger sizes:

Med size: http://www.astronomie.be/pieter.vandevelde/deepsky/Sh2_157_20h40min_small.jpg

Large size: http://www.astronomie.be/pieter.vandevelde/deepsky/Sh2_157_20h40min_med.jpg

Thanks for taking the time to look,

Regards, Pieter

[Knight of Clear Skies]

10 hours per pane at f3.8... quite deep then!

There is a small planetary nebula there too at lower left, above and to the left of the bright star.

[pietervdv]

Interesting...

I assume you are referring to this object?

I checked some catalogues and found this paper:

http://astrogea.org/ibvs/ibvs5009/ibvs5009.htm

It says it was previously mistaken as a planetary nebula (We 1-12) but observations from 1998 show it to be an isolated H-II region around an eclipsing binary star?

To quote it:

"V807 Cas was discovered as a variable star by the Hipparcos mission (ESA, 1997). It was classified as a periodic variable with a 0^d.97463 period, a mean V magnitude of 10^m.79, and an average B-V=0^m.340 without specifying variability type. V807 Cas is in the center of PK110-0.1, which was initially classified as the planetary nebula We 1-12. Recent spectroscopic data by Kimeswenger (1998) indicate that V807 Cas has a B1V spectral type, and that We 1-12 is not a planetary nebula but an isolated H II region, as was also suggested by earlier works (e.g. Zijlstra et al. 1990; Kaler and Feibelman 1985). Kimeswenger also claims that V807 Cas is the only source of excitation of the H II cloud."

Regards,

Pieter

[michael.h.f.wilkinson]

Lovely image, and interesting find of that "pseudo-planetary"

[laudropb]

Nice photos and very interesting post.

[Knight of Clear Skies]

That's interesting. I've seen it referred to as PLN 110-0.1, I see that's an alternative designation for We 1-12.

[swag72]

A great mono image that stands up well on it;s own ........ who needs colour?