NGC 6946 (Caldwell 12, Arp 29, Fireworks Galaxy)

Telescope: Planewave 24" CDK reflector, 3962mm FL
Camera: FLI PL09000, 3056 x 3056 pixels
Exposure: Lum: 8x3 minutes. Seeing 2.2" FWHM. Processed with PixInsight and Photoshop.
Location: Sierra Remote Observatory, California (Elevation 4610')
Image Center (J2000): RA 20h 34m 52s, Dec 60° 09' 12"
Image Size: 19' x 18'

Face-on, low surface brightness spiral galaxy. Only 11 degrees from the Milky Way plane, dimmed 1.1 mags by obscuring galactic dust. For this reason background galaxies are absent. 540 HII regions were identified in 1984. 231 Star clusters were identified in 1999 and 2004. The galaxy has a bright knot at the end of one its arms, a cluster of star clusters, C1 in the annotations. Limiting mag about 21. Stars across the galaxy's face are foreground Milky Way stars. In this image galaxy core intensity was reduced only slightly, contrast was also increased slightly.


NGC 6946 (Caldwell 12, Arp 29, Fireworks Galaxy), Face-on, low surface brightness spiral galaxy. Only 11 degrees from the Milky Way plane, dimmed 1.1 mags by obscuring galactic dust. For this reason background galaxies are absent. 540 HII regions were identified in 1984. 231 Star clusters were identified in 1999 and 2004. The galaxy has a bright knot at the end of one its arms, a cluster of star clusters, C1 in the annotations. Limiting mag about 21. Stars across the galaxy's face are foreground Milky Way stars. In this image galaxy core intensity was reduced only slightly, contrast was also increased slightly.
, acquired with a remote telescope at Sierra Remote Observatory, California (Elevation 4610')

Object Label Identifier Notes
Star Cluster C1 [L2004] n6946-1447 Cluster of Stars, mV=15.7. Many other clusters in the immediate region.
Star Cluster C10 [L2004] n6946-4587 Cluster of Stars, mV=18.26
Star Cluster C2 [L99] n6946-4207 Cluster of Stars, mV=17.11. Other clusters in the immediate region.
Star Cluster C3 [L2004] n6946-1090 Cluster of Stars, mV=18.29. Other clusters in the immediate region.
Star Cluster C4 [L99] n6946-4614 Cluster of Stars, mV=17.52
Star Cluster C5 [L2004] n6946-3959 Cluster of Stars, mV=15.14. Brightest cluster in NGC 6946.
Star Cluster C6 [L2004] n6946-3764 Cluster of Stars, mV=15.66
Star Cluster C7 [L2004] n6946-3660 Cluster of Stars, mV=15.70
Star Cluster C8 [L99] n6946-760 Cluster of Stars, mV=17.52
Star Cluster C9 [L99] n6946-281 Cluster of Stars, mV=18.56

Click on the image to display the plate solved image with annotations. 4' across NGC 6946 is about 26,000 light years. Star clusters in NGC 6949 were cataloged in 1999 and 2004 of which 192 are brighter than mag 19.5.


FITS files to create this image:

Luminance:

NGC 6946 Luminance

Image shown is Luminance 001.fits. Each file is 180 seconds, Planewave 24" reflector, 3056x3056 pixels, unbinned with Darks, Bias and Flats applied. Data acquired July 7 and 8, 2016.


Luminance 001.fits
Luminance 002.fits
Luminance 003.fits
Luminance 004.fits
Luminance 005.fits
Luminance 006.fits
Luminance 007.fits
Luminance 008.fits


Files can be loaded into PixInsight directly from the PixInsight console. For example, in the PixInsight console enter:
    open "http://www.remote-astrophotography.com/NGC6946/NGC 6946-Luminance-BIN1-008.fits"