Try increasing gamma if dark sections aren't distinguished

Try increasing gamma if dark sections aren't distinguished

Sunday, March 19, 2017

Abell 30, the born again nebula

March has been a difficult month for me in recent years, 
a number of events have prevented me from completing this project, but finally,
here is my image of Abell 30, a rare "born again" planetary nebula who's central star re-ignited after turning into a white dwarf,
creating a new system of complex knots of oxygen (blue-green)
inside a mature spherical shell of hydrogen (red) and oxygen:
Abell 30 in Hydrogen (red) and Oxygen (blue-green)

Here's a blink first in Helium showing no nebulosity, only stars, then hydrogen with spherical shell, then oxygen with complex inner knots:
Abell 30 He II, Ha, OIII

The O III signal was faint, Ha signal extremely faint, and He II nonexistent.  
I remain baffled by sources stating that the knots have strong He II emissions, e.g., 
Osterbrock's Astrophysics of Gaseous Nebulae and Active Galactic Nuclei p. 264.
My He II filter is spec'd at 468.6 nm with a 4 nm band width, but detects no signal, might have to confirm it with a spectroscope.  

A few findings regarding exposure variation and binning:
for OIII 3 nm 
40 min binned 2x not much deeper than 20 min binned 2x, if at all.
but 
20 min binned 4x (4 subs) much deeper than 40 min binned 2x (2 subs)
though it was difficult to be sure conditions were identical.  

filter band width:
for 40 min binned 2x 3 nm OIII deeper than 5 nm or 8.5 nm; not much difference between latter two
older unbinned subs with my SX H9 (0.6"/px) were far worse than either, threw all subs out


8" LX200R, SX Trius 694 binned x2 to 0.8"/px, binned x4 to 1.6"/px, (final image at .8"/px)
astrodon 5nm Ha, 5nm, 3nm OIII, chroma 4 nm He; custom scientifics 8.5 nm OIII
ASA DDM60
OIII 10x 20 min bx4, 28x 40 min bx2, 44x 20 min bx2
Ha 2x 20 min bx2, 15x 40 min bx2, 60 x 20 min bx4
HeII 13x20 min bx4
2/16/13-3/6/17
eastbluff, CA

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