cool image Rick

i think you are right about the HII bubbles but the reason they wind up blue
is because of the QE response of your camera being skewed in favor of blue

there's goiing to be Hbeta there too and may well be some [OIII] there too,
so that may skew the color a bit considering your QE at Halpha is pretty low
with the KAI11K sensor

I added two QE plots to this posting: one is for the KAI11002 and the other
is from the KAF3200

the Full Frame KAF series have a completely different red response than the
interline KAI series


"Rick Johnson" wrote in message
...
This is a member of the M81 group. A very faint member. Even at 80
minutes this was a rather noisy image. I needed more color and had been
waiting to get it but the skies had other ideas. It is now into my
Polaris tree. At its declination I can get it only well east of the
meridian when it clears the east side of the tree. At about 3 hours
from the meridian it enters the tree and stays there the rest of the
year. So I have a short window on this one. Maybe next year. I had
figured the bright blue arcs were HII bubbles, apparently not as they
were quite weak in red light and strong in blue. Not sure what to make
of that. Must be bubbles of hot new stars rather than gas clouds. Next
time maybe some H alpha data is in order.

14" LX200R @ f/10, L=8x10' RGB=2x10' binned 3x3, STL-11000XM, Paramount ME

Rick
--
Correct domain name is arvig and it is net not com. Prefix is correct.
Third character is a zero rather than a capital "Oh".

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