Simcoe Skies Astronomy

M51 - The Whirlpool Galaxy

For more information on M51 from Wikipedia, click here.

Object type: Galaxy (top-down view)
Location: Canes Venatici
Magnitude: 9.0
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M51 Date: Sept 12/09
Camera: Meade DSI-2C
Exposures: 58
Exposure length: 60 seconds
Gain: 63
Offset: 0
Filters: None
Processing: Aquired, stacked in K3CCDtools, post-processing in Photoshop.

Notes:More detail than an equivalent shot below.

Date: Aug 31/08
Camera: Meade DSI-C
Exposures: 50
Exposure length: 60 seconds
Gain: 45
Offset: 0
Processing: Aquired, stacked, and histogram adjusted in K3CCDtools, post-processing in Photoshop.

Notes:The Meade DSI-C made nice work of this shot.

Date: July 21/05
Camera: ToUcam SC1.5 (prior to direct bias injection modification)
Exposures: 51 best of 80, autoguided in RA only w/70mm refractor
Exposure length: 20 seconds
Amp on setting: OFF
Brightness: 100
Gain: 40
Gamma: 52

Notes:Early experiments in guiding. I suspect that the guidescope cam was not rotated correctly, but still a decent shot. Fighting the rising moon at 85% waning, thus a longer exposure wasn't possible. Previously noted amp glow problem was solved by taking the dark frame with the cam IN the eyepiece adapter.

BONUS! Supernova SN2005CS

Date: July 21/05
Same data as previous.

Notes:I saw among some online postings that there was a new supernova reported in M51, discovered on June 28, 2005. Naturally, I checked my image from last year vs. my image from this July, and sure enough, there it was! So here's an animation from my two previous shots, to show where it's located. Amazingly bright!

M51 Date: Sept 19/04
Camera: ToUcam SC 1.5 (prior to direct bias injection modification) Exposures: 19 best of 40
Exposure length: 45 seconds
Amp on setting: OFF
Brightness: 100
Gain: 20

Notes: First try at M51. Amp glow really killed it. This was with Amp off, so I figure (in retrospect) it was a dark frame subtraction issue, where my background level wasn't high enough (all pixels should have a value >0). I expected to get some amp glow in a 45 second shot, but after dark subtraction, it should have disappeared.

M51 with amp glow removed in Photoshop

Trying to get rid of amp glow

Same image, amp glow removed in Photoshop.

Details: see previous

Notes: I doctored up my first shot with Photoshop to try to eliminate some of the amp glow. It worked, to some extent. Future images should have gain increased to 40 or so and provide a minimum level on all pixels for proper dark subtraction.

M51 different processing


Same AVI, another kick at the processing can...

Details: see previous

Notes: Processed differently, just for the heck of it. In some ways, it looks better! Shows the density of the galaxy better, as well as the interaction with its companion galaxy.

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