SaratogaSkies Jim Solomon's Astropics

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M1 (Crab Nebula)

Click to see high-res version.

Image Details:

Camera: Mofidied Canon Digital Rebel (300D): Hutech (no filter)
Mount: Celestron AS-GT
Scope: Celestron C8-N (8" f/5 Newtonian)
Configuration: Negative Projection (Barlowed)
Additional Optics: TeleVue 2x Barlow
Filter: None
Effective Focal Length: 2250mm
Effective Focal Ratio: f/11.1
Exposure: 39 x 8min @ ISO 800 (total over 2 nights)
Total Exposure: 5hrs, 12min
Date: : 3/2/2005 7:57:06 PM PST (start) and 3/5/2005 7:39:22 PM PST (start)
Location: Saratoga, CA, USA
Acquisition: DSLRfocus
Focus: DSLRFocus
Dithering: Manual
Guiding: GuideDog via Philips ToUcam Pro II (840k) through Orion ST80 w/ Celestron 2x "Kit" Barlow

Processing:

  • IRIS: Dark subtraction, flat field, registration, cropping, Kappa-Sigma stacking
  • JimP: White balance, ASINH stretching
  • Photoshop: Levels, image scale, JPG conversion

Image Description:

This is M1, a Supernova Remnant in the constellation of Taurus. This was a rather ambitious project to shoot a relatively small object at a high focal length (and, unfortunately, a correspondingly slow f/ratio). This is two nights worth of imaging, a total of 5.2 hours of exposure. But due to the "square law" of focal ratios, this is equivalent to only 1 hour at f/4.9, which is the focal ratio of most of the shots I've taken.

The first night's frames (19 of the 39) were taken with my Unmodified 300D. The second night's frames (20 of the 39) were taken with fellow Saratogan Rich S.'s Modified 300D. No filters in either case, just the TeleVue 2x Barlow. The first night had better seeing, the second night had much better transparency.

Given the tracking ability of my mount (well over 1 arc-second of guiding error, RMS, in both axes), and the blurring effect of lousy seeing, I wonder if shooting at this higher focal length really increased the resolution over shooting at f/4.9. It certainly accomplished a quintupling of the required exposure time, but to what avail is the question -- and I'm too sick of shooting this object to try it again at f/4.9 for comparison. It'll have to wait til next year.

The image above is a 50% shrink of the full-size image, then cropped to 768x512 for display on the web. North is up.

 
B33 (Horsehead Nebula)
SaratogaSkies Jim Solomon's Astropics

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December: Test shots with new scopes/mounts

Dec 21: TMB 80/480 Arrives!

Dec 3: AP1200 Arrives!

Nov 30: TMB 152/1200 Arrives!

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B33 (Horsehead Nebula)

[Hα+R G B]

Mouse-over to see annotations. (Requires Javascript) Click to see high-res version.

Image Details:

Camera: Mofidied Canon Rebel XT (350D): Hutech Type I Filter Replacement
Mount: Celestron AS-GT
Scope: Orion ED80 (80mm f/7.5 APO Refractor)
Configuration: Focal Reduced
Additional Optics: William Optics 2" APO 0.8x Reducer/Field Flattener
Filter: Hutech Hα Front Filter (HA-FF)
Effective Focal Length: 480mm
Effective Focal Ratio: f/6
Exposure: 21 x 8min @ ISO 800 (RGB), 29 x 8min @ ISO 1600 (Hα)
Total Exposure: 6hrs, 40min
Date: 2/21/2006 (RGB); 12/28/2006 (Hα)
Location: Saratoga, CA, USA
Acquisition: DSLRfocus
Focus: DSLRFocus
Dithering: GADFly 1.0.5
Guiding: GuideDog via Philips ToUcam Pro II (840k) through Orion ST80 w/ Celestron 2x "Kit" Barlow

Processing:

  • IRIS: Dark subtraction, registration, gradient removal
  • JimP: Flat field, Kappa-Sigma Stacking, White balance, HαRGB combination, ASINH stretching
  • Photoshop: Levels, cropping, reflection removal, JPG conversion
  • Neat Image: Noise reduction

Image Description:

This is an update of my previous Horsehead Nebula image, with nearly 4hrs of Hα exposure added to the existing RGB data. The Hα really helps bring out many of the features in this busy field.

To create the HαRGB composite, I first added some Hα into the red channel of the original RGB data, which was then converted to Hue, Saturation, Luminance. Then I used a process similar to Photoshop's “Screen” blending mode to combine the luminance of the original RGB data with the (grayscale) Hα data. This Screen-blended Luminance, along with the Hue and Saturation of the Hα-enhanced RGB image, was then converted back to RGB. This method seemed to preserve details in the non-Hα-emitting regions, provide excellent detail in the Hα regions, and preserve the colors.

A higher-resolution image is also available. North is left.

 
Saturn
SaratogaSkies Jim Solomon's Astropics

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December: Test shots with new scopes/mounts

Dec 21: TMB 80/480 Arrives!

Dec 3: AP1200 Arrives!

Nov 30: TMB 152/1200 Arrives!

Links:

Saturn   [obsolete]

[Hα+R G B]

Image Details:

Camera: Philips ToUcam Pro II (840k)
Mount: Celestron AS-GT
Scope: Orion ED80 (80mm f/7.5 APO Refractor)
Configuration: Eyepiece Projection
Additional Optics: University Optics 7mm HD Ortho
Filter: None
Effective Focal Length: 3500mm
Effective Focal Ratio: f/44
Exposure: 256 frames @ 1/25s, 10fps, neutral brightness, gamma, saturation, and gain
Date: 12/24/2004, 11:18pm PST
Location: Saratoga, CA, USA
Acquisition: Philips VRecord
Focus: Manual
Dithering: None
Guiding: None

Processing:

  • IRIS: Registration, best-frame selection, stacking
  • Photoshop: Levels, Unsharp Msking, JPG conversion

Image Description:

This is my first decent planetary image using a webcam as the imaging platform. I was just playing around with my new toy -- the Orion ED80 -- and thought I'd try capturing a planetary image, since the moon was very bright and there was no chance of getting a decent deep sky image. I'm amazed at what that little refractor can do, and what a webcam is capable of as well. Can't wait to try this again with the 8" Newt. North is down in this image.