Sunday, March 9, 2008
M13, second tryout
Gropped area from M13. The extended exposuretime reveals more and more dim stars around
the core.
After I was shooting Sh2-240, I moved to M13.
This is a second tryout at this season.
Weather was ok to shoot with 200mm lens, but with2000mm situation was different.
Very bad seeing and since I shoot from very center of the city, there was lots of heat current from buildings.
M13 altitude was between 30 and 45degrees. Moust of the frames are shooted trough not so thin clouds.
This time I composed image so, that I was able to placea litle galaxy, NGC 6207, at the same field of view.
There is 5 x 10min and 11 x 5min, unfiltered subs used in the image.I allso add lights from previous tryout, 7 x 15min, IDA filter. Total exp. time is three and half hours.Camera: QHY8, telescope: LX200 GPS 12", Guiding: SXV-AO+LodeStar.
Image is scaled down
Ps.
The "Shadows and Highlights" tool under Photoshop is great for targets like this!
I can pull out dimmer stars as much as I like without blowing up the core.
Saturday, March 8, 2008
Sh2-240, four more hours.
This is a false color image of the Sh2-240.
Image of the object with no stars was added as lighten mode to the Red channel,
under PS.
h-alpha image.
Inverted version
This is a version with no stars (image processing trick)
to bring out the structure better. This image was used to make a false color image.
This is really difficult target!
I can see effects of light pollution here, even with 7nm H-a
filter. Bad gradients etc...
This time I shooted 4 X 3600s = One hour subs!
My record so far. Longer subs are needed to bring out very
faint structure of this object.
So far there is about 7h exposures, I thin an other 10 hous is needed here.
I'll shoot more when weather allows.
Inverted version Thursday, March 6, 2008
Sh2-240 (Simeis 147)
this is a start of the long project.
my goal is to capture enough photons from this dim object to
be able to reveal its beauty.
This is a supernova remant in Taurus & Auriga.
The angular diameter of the object is huge, about 200'x180'!
Thats about 8 full Moon diameters. Doe the large size
the surfage brightness is very low, I think, I'll need least
20 hours of exposures to capture this well.
Last night I had problems with frost and I was not able to see
it before image processing. All the frames are practically useless.
You can see big bloated stars, even in small image.
How ever, I put small image here just for example.
There is both normal H-alpha image and inverted one.
exposures ( with frost in optics)
4 x 2700 s
3 x 900 s
FD 200mm f2.8 lens, QHY8, guiding QHY5 and LX200 GPS 12"
(This large object and the 200mm lens are very good match.)
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