260719 - LDN 43 "Cosmic Bat" nebula
ASTRO:
type=dark nebula
const=Ophiuchus
mag=(not published - very faint)
dist=1400 ly
size=12 ly
IMAGE:
location=Utah Desert Remote Observatories (SW Utah)
BrtlCls=1
moon=33% WxCr
exposure=CMOS Mono: 60x300s (8.6h) < Luminance only
EQUIPMENT:
optics=16" Dream Astrograph newtonian, FL=1500mm, f/3.75
camera=ZWO ASI6200MM-Pro
filters=Chroma L, R, G & B
mount=Software Bisque Paramount ME
guiding=(none)
SOFTWARE:
acquisition (UDRO)=Voyager
processing (CNPAstro)=PixInsight (RCAstro), Photoshop (Web Sharp Pro), LrC
click image to enlarge
What is the most spooky nebula in the galaxy? One contender is LDN 43, which bears an astonishing resemblance to a vast Cosmic Bat flying amongst the stars on a dark Halloween night. Located about 1400 light years away in the southern part of the constellation Ophiuchus, this molecular cloud is dense enough to block light not only from background stars, but from wisps of gas lit up by the nearby reflection nebula LBN 7. This 12 light-year long filament of gas and dust is actually a stellar nursery. Glowing with the eerie light of several Herbig-Haro objects, the "bat" is lit up from inside by those dense gaseous knots that are just now forming new, young stars.
This object is the 43rd entry in the Lynds Dark Nebulae (LDN) Catalog, published by US astronomer Dr. Beverly Turner Lynds in 1962. Dr. Lynds used the 48 inch telescope at the Palomar Observatory to develop two (2) extensive catalogs concentrating almost exclusively on nebulae, of which the LDN list was the first. (The other was her Lynds Bright Nebulae (LBN) Catalog list.) Her LDN list includes 1,802 dark nebulae down to the -33° declination limit of the Palomar telescope.
LDN 43 is obscuring a larger bright nebula behind it, LBN 7. LBN 7 is the illuminated dust surrounding the dark nebula. In addition, two cometary nebulae are seen at the center of LDN 43. The first, GN 16.31.7 is the bright yellow object at center, lit up by the hidden young star RNO 91. Slightly below and left is the 2nd cometary nebula, GN 16.31.3 lit up by RNO 90.
The small galaxy seen below LDN 43, immediately adjacent to a bright orange star, is LEDA 3868080. This galaxy is located 400 million light years away. At about 180,000 light years in diameter, it is comparable in size to our home Milky Way. This background galaxy is appx 285,000 times further away than the foreground nebula, with the large difference in distance reflected in the galaxy's apparent small size.
IMAGER'S COMMENTS: After 3 full nights of imaging on this object, the results were disappointing at best. In order to achieve adequate framing, we attempted to use the Baader Hyperion 24mm eyepiece in afocal projection mode to "bring" the object in close enough to adequately span our FOV. The afocal configuration normally works well for brighter galaxies and star clusters. But to our dismay, the Cosmic Bat's EXTREME FAINTNESS proved to be a complete mis-match for the f/ratio-killing afocal format.
So, to address the shortcomings of our equipment, we turned once again for help to Craig Stocks of Utah Desert Remote Observatories (UDRO) located under Bortle class 1 skies in SW Utah. Craig is the lead operator of that facility; and this makes the 3rd project he has assisted us with. Craig regularly rents-out his own personal equipment for purposes such as the Cosmic Bat. His telescope is a 16" FL=1500mm f/3.75 research-quality Newtonian astrograph manufactured by Dream Aerospace Systems, Ltd. It has an ASI6200MM-Pro full-frame mono camera mounted on it with Chroma L, R, G, & B broad-band filters; and, it is mounted on a Paramount ME mount with no guiding assist at all. It's an amazing rig, ...and FAST too! Once the raw data was acquired, subexposures with accompanying calibration frames were delivered via online electronic means, and processing was completed using CNP Astronomy's in-house resources. Thank-You's and "Kudos" to Craig and his Team for their help!
IMAGER'S COMMENTS: After 3 full nights of imaging on this object, the results were disappointing at best. In order to achieve adequate framing, we attempted to use the Baader Hyperion 24mm eyepiece in afocal projection mode to "bring" the object in close enough to adequately span our FOV. The afocal configuration normally works well for brighter galaxies and star clusters. But to our dismay, the Cosmic Bat's EXTREME FAINTNESS proved to be a complete mis-match for the f/ratio-killing afocal format.
So, to address the shortcomings of our equipment, we turned once again for help to Craig Stocks of Utah Desert Remote Observatories (UDRO) located under Bortle class 1 skies in SW Utah. Craig is the lead operator of that facility; and this makes the 3rd project he has assisted us with. Craig regularly rents-out his own personal equipment for purposes such as the Cosmic Bat. His telescope is a 16" FL=1500mm f/3.75 research-quality Newtonian astrograph manufactured by Dream Aerospace Systems, Ltd. It has an ASI6200MM-Pro full-frame mono camera mounted on it with Chroma L, R, G, & B broad-band filters; and, it is mounted on a Paramount ME mount with no guiding assist at all. It's an amazing rig, ...and FAST too! Once the raw data was acquired, subexposures with accompanying calibration frames were delivered via online electronic means, and processing was completed using CNP Astronomy's in-house resources. Thank-You's and "Kudos" to Craig and his Team for their help!