Jupter's out, IR test and a new scope

the bright star in the east after dark (which is pretty late these days)

is in fact Jupiter. 

seeing has been lousy this season, but i finally gave it a try on a night of mediocre seeing and got this:

Jupiter 4/11/2017

ran a few tests with an infrared (IR) pass filter to see if it would yield a sharper image.  In theory the redder the light (longer wavelength), the less it is distorted by atmospheric seeing, so images should be sharper, but...
the optical resolution limit of a telescope is defined by the wavelength of the light: longer wavelength reduces the theoretical limit of the telescope.  furthermore, the IR pass filter typically allows less light than a standard red filter.  therefore, exposures may need to be longer (leading to more atmospheric motion) and/or higher noise.  
so in practice is the IR image sharper than the others?
here's a blink comparing red to infrared (no contest comparing to blue and green):

red vs infrared

clearly sharper, but perhaps a bit more noise.  

However, for the combined image, it was difficult to appreciate any difference:

here's RGB vs IRGB (substituting IR for red):

RGB vs IRGB

the difference is very subtle, with perhaps a bit more detail in the short blue stripe just above the middle white band.  

lastly, i used IR as the luminance channel which changed the colors dramatically, but probably a bit too far from the RGB:

RGB vs IR-IRGB

this, i think, is my first successful image with a new (used) larger scope
which i picked up on astromart almost a year ago
in order to catch saturn's hexagon,
explaining a year of poor seeing.
the new scope is pretty friggin' big and a PITA to haul around in the dark at 2 AM so i hope it works out

new scope specs

Meade LX850 12" f/8 ACF OTA + Feathertouch focuser

2438mm

0.38"

41 lb. tube weight

UHTC coating

primary 12" (305 mm)

secondary 4.72" (120 mm) / 41%

image details:

ZWO ASI120MC/ASI120MM-S

ZWO RGB filters, Baader IR pass "685" nm

2x90 second captures for each filter R G B IR

captures with firecapture @ ~140 fps

stacked in autostakkert, combined in WinJupos, sharpened in registax 6

Southern California

4/11/17

starburst nebula NGC 1569, narrow band

Here's starburst nebula NGC 1569 in hydrogen (Ha) and oxygen (OIII)

this sat on my hard drive for a year as i was initially disappointed for 2 reasons:
1 there was little difference between the OIII and Ha at this resolution besides signal strength
2 the narrow band and LRGB (below) were so discordant, i couldn't imagine the combine working well.  the Ha didn't enhance the image, it overwhelmed it.

here it is in LRGB:

when i finally combined the narrow and broad band images i was pleasantly surprised to see the sum adding up to more than the parts, even though some details of each were lost in the combination.
the combined image gives the classic appearance of stars clearing out and illuminating the surrounding hydrogen:

in this case the two bright "stars" appearing to illuminate the surrounding nebula are unresolved globular clusters containing thousands of stars (anyone fooled?), making this dwarf galaxy the largest "nebula" i've ever imaged

here's an interesting slow motion blink of the two images
some structures disappear, others appear, and others seem to move (lower left) as if being illuminated by a nearby source:

lastly here's an annotated mosaic:

more details on dwarf galaxy ngc 1569 at this site including observations of the "elephant's trunk" to the right
hubble image resolving the star clusters and more details at wikipedia
interestingly, the galaxy is blue-shifted, which means it's moving towards us, rather than moving away with the expansion of the universe.  

thanks to rick johnson for pointing out this galaxy with it's extreme narrow band emissions.

image details:

8" LX200R, SX Trius 694 binned x2 to 0.8"/px,
astrodon 5nm Ha, 3nm OIII, LRGB E SERIES GEN-II
ASA DDM60
L 472x1 minute, 24x3 minutes, R 64x3 minutes, G 59x3 minutes, B 55x3 minutes (RGB included in luminance)
Ha 25x20 minutes, OIII 11x20 minutes.
1/29/16-2/8/16, bortle white skies
eastbluff, CA

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)

The O III signal was faint, Ha signal extremely faint, and He II almost nonexistent.  

I was 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 detects almost no signal in the outer shell, but did detect signal in the small knots closest to the central star.  My best guess is that "helium rich" refers to the relative ratio of He II to Ha in specific areas of the nebula.  Here's a mosaic of images with the various filters displayed using the linear stretch that best displayed the central knots.  The continuum filter removes the narrowband emissions of the nebula, showing only stars in this case:

Abell 30

Edited the section above (a filter wheel error on my initial attempt substituted a continuum filter for the Helium II filter).

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, 540x50 nm filter (greenish continuum) ; 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 36x 1200s bx4 2x2400s bx2!

continuum filter 13x2400s bx2 (in error, black point 30K ADU!)

2/16/13-3/6/17

eastbluff, CA