Simcoe Skies Astronomy

M57 - The Ring Nebula

	First attempt with Meade DSI-2C camera This shot was taken using a guidescope, and under a 93% full moon. Date: August 31/09 Camera: Meade DSI-2C Exposures: 120 Exposure length: 20 seconds Gain: 63; Offset: 0 Filters: built-in IR filter Magnification: No barlow, no resizing Processing: post-processing in Photoshop Notes: Very satisfied with this shot. Despite the moon's light, good contrast. Nice, crisp result. The increased size of the imaging chip is very evident (M57 looks smaller).
	New shot with the proper zener diode in the camera amp-off circuit See previous shot - this one has the correct amp-off voltage on the CCD. Date: July 12/08 Exposures: 105 of 150 Exposure length: 12 seconds Amp on setting: OFF; RAW mode Brightness: 100% Gain: 70% Gamma: 52% Color Balance: R34B16 Processing: Acquired, stacked, histogram adjusted in K3CCDtools, adjustments in Photoshop. Notes: A pleasing shot... longer, guided images would probably improve contrast and detail.
	1st try with direct bias injection modification to camera This is my first image after performing Tom How's direct bias modification to the ToUcam. I subsequently discovered that part of the circuit (the zener diode) was of an incorrect value. I changed it afterwards, and will try this shot again. Date: June 12/07 Exposures: 50 of 80 Exposure length: 10 seconds Amp on setting: ON Brightness: 51% Gain: 81% Gamma: 52% Color Balance: R34B16 Processing: Acquired, stacked, histogram adjusted in K3CCDtools, adjustments in Photoshop. Notes: The combination of RAW mode and less histogram stretching led to better star images. Definitly worth a revisit after changing the zener diode to the correct voltage.
	Demonstration of dark frame mismatch... I revisited the Ring Nebula on Sept. 26/04 with amp off (to reduce glow), and reduced gain (sharper image), and reduced time (less drift) to see if I could get a better image. Date: Sept 26/04 Exposures: ? of 91 (not recorded) Exposure length: 12 seconds Amp on setting: OFF Brightness: 100% Gain: 25% Processing: Acquired, stacked, and histogram adjusted in K3CCDtools, noise reduction subsequently done (Aug 2005) in NeatImage. Notes: Although I captured more subtle nuances of the Nebula, amp glow showed up, particularly in the upper left. I later found this was because I was REMOVING the camera from the eyepiece adapter to take dark frames, thus introducing a mismatch due to a change in temperature.
	Negative image - determining limiting magnitude of modified ToUcam I inverted this image to try to determine what the limiting magnitude of the camera was at these settings, through my scope. I compared the image to Cartes du Ceil's USNO-A (online resource) catalog and the ESO skycat DSS1 image. The results were around M18.0-18.3 or so with this length of exposure and gain settings. Date: Sept 26/04 Exposures: ? of 91 (inverted previous image) Exposure length: 12 seconds Amp on setting: OFF Brightness: 100% Gain: 25% Notes: Not bad for a 12 second exposure. In future, I'll have to do this with a longer exposure and see what the absolute limitations of my equipment are (in guided long exposure).
	Same data as the image below, different processing Date: Aug 30/04 Exposures: 21 of 77 hand picked Exposure length: 20 seconds Amp on setting: ON Brightness: 50% Gain: 55% Notes: more selective with frames, and increased contrast to eliminate background glow More Below...
	M57 - 2nd try 2nd attempt. I fixed my "blue overkill" on the white balance, and recorded all settings for future reference. Date: Aug 30/04 Exposures: 32 of 77 hand picked Exposure length: 20 seconds Amp on setting: ON (forgot to change this) Brightness: 50% Gain: 55% Notes: much improved from first attempt, some background "glow" More Below...
	The Ring Nebula - first image with my modified ToUcam 840K This was my first experience with a DSO, before I understood much about post-processing. It gave me more to shoot for, but I was pleased to have something to show for my first time out. I decided that for the next time out, I'd record settings in the filename so I'd have them for future reference! Date: Aug 26/04 Exposures: not recorded Exposure length: not recorded Amp on setting: ON Brightness: not recorded Gain: not recorded Notes: white balance off (toward blue) More Below...