NGC 4631: The Whale Galaxy and NGC 4656: The Hockey Stick
Date: June 15, 2020
Cosgrove’s Cosmos Catalog ➤#0032
The Whale (NGC 46310 and the Hockey Stick (NGC 4656) as captured by the William Optics 132mm Platform (click to enlarge)
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About the Target
NGC 4631(The Whale) and NGC 4656 ((The Hockey Stick) are fascinating pair of galaxies. Both galaxies fit in the same frame, and this creates an interesting composition. These galaxies are found in the constellation Canes Venatici.
NGC 4631 is the larger and brighter of the two. Located about 30 Million light-years from Earth, this galaxy has a wedge-shaped form that resembles a whale, thus - its name. In addition, NGC 4631 has a nearby dwarf elliptical galaxy, NGC 4627, as a companion. This is a rare example of a double galaxy and, as such, is listed in the Atlas of Peculiar Galaxies.
NGC 4656, the Hockey Stick - also known as the Crowbar Galaxy, is a highly warped barred-spiral galaxy. Its distinctive shape is due to a *recent* gravitational interaction with NGC 4631. The "hook" of the galaxy is also listed as its own object, NGC 4657. Beyond the hook is a fuzzy patch that may be a dwarf elliptical galaxy merging with NGC 4656.
The Annotated Image
Annotated version of The Whale and the Hockey Stick - created with Pixinsight ImageSolve and AnnotateImage scripts.
The Location in the Sky
IAU/Sky & Telescope Constellation Map for Sagittarius - Messier 17 is indicated with the yellow arrow.
About the Project
Wow - we have been having an extended stretch of great weather, and I have been taking advantage of it!
This image resulted from 50 x 180 captures.
Comment on 7-29-21 as this entry was added to the Website
The evening must have been very good. The quality of this image is surprisingly good - especially when one considers the fairly short integration times. The noise is reasonably handled and the details on the galaxies themselves are quite good. They hold up well- even when compared to a more recent attempt.
More Information
Wikipedia Entry: NGC 4631 (The Whale)
Scie.News: Astronomers Spot Huge Magnetic Structures in ‘Whale Galaxy’
Wikimedia Commons: Hubble Mosaic Image of NGC 4631
The Sky Live: NGC 4631
Wikipedia Entry: NGC 4656 (THe Hockey Stick)
The Sky Live: NGC 4656
NASA: NGC 4656
Capture Details
Lights Frames
50 x 120 seconds, bin 1x1 @ -15C, Gain UNity
Total of 1.6 hours
Cal Frames
Not recorded
Capture Hardware
Scope: Astrophysics 130mm Starfire F/8.35 APO refractor
Guide Scope: Televue 76mm Doublet
Camera: ZWO AS2600mm-pro with ZWO 7x36 Filter wheel with ZWO LRGB filter set,
and Astronomiks 6nm Narrowband filter set
Guide Camera: ZWO ASI290Mini
Focus Motor: Pegasus Astro Focus Cube 2
Mount: Ioptron CEM60
Polar Alignment: Polemaster camera
Software
Capture Software: PHD2 Guider, Sequence Generator Pro controller
Image Processing: Deepsky Stacker, Pixinsight, Photoshop, Topz AI Denoise - assisted by Coffee, extensive processing indecision and second-guessing, editor regret, and much swearing…..
During August and September I was out shooting every clear night. I had learned a lot of things but I was also noticing several issues that were causing me problems as I did more imaging. I decided to do something to address those issues….