SaratogaSkies Jim Solomon's Astropics

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M20 (Trifid Nebula)   [obsolete]

Image Details:

Camera: Canon Digital Rebel (300D)
Mount: Celestron AS-GT
Scope: Celestron C8-N (8" f/5 Newtonian)
Configuration: Prime Focus
Additional Optics: n/a (Prime)
Filter: None
Effective Focal Length: 1000mm
Effective Focal Ratio: f/5
Exposure: 24 x 1min @ ISO 800
Total Exposure: 0hrs, 24min
Date: 7/11/2004, ~1:30am PDT
Location: Saratoga, CA, USA
Acquisition: DSLRfocus
Focus: DSLRFocus
Dithering: None
Guiding: None

Processing:

  • IRIS: Dark subtraction, flat frame, registration, and Kappa-Sigma stacking
  • Photoshop: Noise reduction, crop (1/2 x), image scale (1/2 x), JPG conversion

Image Description:

Another stunning object in the "summer" Milky Way. This is the Trifid Nebula, yet another gem in the constellation of Sagittarius. This is a Sigma stack of the best 24 of the 30 frames (the remaining 6 showed trailing/smearing due to tracking error). Interestingly, "dark subtraction" yielded a worse image than just stacking the un-dark-subtracted frames. I need to look into this. North is up.

 
M4 & IC 4604 (Antares / ρ Ophiuchi / M4)
SaratogaSkies Jim Solomon's Astropics

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M4 & IC 4604 (Antares / ρ Ophiuchi / M4)   [obsolete]

Image Details:

Camera: Canon Digital Rebel (300D)
Mount: Celestron AS-GT
Scope: Canon EF 200mm f/2.8L II USM lens
Configuration: Prime Focus
Additional Optics: n/a (Prime)
Filter: None
Effective Focal Length: 200mm
Effective Focal Ratio: f/2.8
Exposure: 16 x 2min @ ISO 400
Total Exposure: 0hrs, 32min
Date: 5/11/2005 1:31:15 AM PDT (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, registration, gradient removal
  • JimP: Kappa-Sigma Stacking, White balance, ASINH stretching
  • Neat Image: Noise reduction
  • Photoshop: Levels, annotation, cropping, JPG conversion

Image Description:

This is my second "test photo" with my new Canon EF 200mm f/2.8L II USM lens. This is a spectacular field at the border of the constellations of Scorpius and Ophiuchus; one that I need to revisit when it's better placed. (It was low to the horizon, in a light-polluted portion of the sky, at the time this was shot.) This image also could use much more exposure time.

Here are the highlights of this colorful region of the Milky Way:

  • Starting in the lower right-hand corner is the red-giant star Antares, the brightest star in Scorpius. The yellow reflection nebula surrounding Antares is IC 4606, and the small globular cluster within that nebula (toward the center of the frame from Antares) is NGC 6144.
  • Directly above Antares is the large, globular cluster, M4.
  • Above and to the left of M4 is another bright star, σ Scorpii. Surrounding σ Scorpii is the blue reflection nebula Ced 130 and red emission nebula Sh 2-9.
  • Continuing counter-clockwise, on the middle-left side of the frame, is the triple star ρ Ophiuchi. Surrounding ρ Ophiuchi is the blue reflection nebula IC 4604. To its right is the blue reflection nebula IC 4603.
  • Below and to the right of IC 4603 is 22 Scorpii and the blue reflection nebula IC 4605.
  • Finally, the dark regions throughout the left half of the image are various and sundry dark nebulae; i.e., clouds of dust which block our view of the stars and other objects behind them.

North is to the right in this image.

 
NGC 7009 (Saturn Nebula)
SaratogaSkies Jim Solomon's Astropics

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NGC 7009 (Saturn Nebula)

Image Details:

Camera: SBIG ST-2000XM
Mount: Takahashi NJP
Scope: Takahashi Mewlon 180
Configuration: Prime Focus
Additional Optics: n/a (Prime)
Filter: Astrodon LRGB I-Series Filters
Effective Focal Length: 2160mm
Effective Focal Ratio: f/12
Exposure: LRGB: 1 × 4min (binned 1×1)
Total Exposure: 0hrs, 16min
Date: 8/9/2007 11:48 PM PDT (Start)
Location: Saratoga, CA, USA
Acquisition: CCDSoft
Focus: CCDSoft
Dithering: None
Guiding: Self Guided

Processing:

  • IRIS: Registration, gradient removal, Richardson-Lucy deconvolution
  • JimP: Dark subtraction, Flat field, White balance, LRGB combine, ASINH stretching
  • Photoshop: cropping, JPG conversion

Image Description:

This is NGC 7009, aka the Saturn Nebula, a planetary nebula in the constellation of Aquarius. Not only does this PN resemble the planet Saturn, but is also approximately the same apparent, angular size as the ringed planet as seen from Earth (roughly 45 arc-seconds). Deep Sky photography of such tiny targets is extermely challenging, because webcam-based techniques — such as taking thousands of very short exposures to “freeze” the atmospheric turbulence — are not possible. I'm pretty happy with this result, though, since it was really more of a test shot than anything else. I used Richardson-Lucy deconvolution in IRIS to tighten up the stars and the nebula. Surprisingly, it actually worked better (more sharpening with fewer artifacts) doing the deconvolution after contrast stretching, as opposed to running the algorithm on the linear (unstretched) image. This is an LRGB composite, with both the Luminance and color data binned 1×1. I also added the color data to the luminance exposure to create a meta-luminance before doing the LRGB combine and subsequent processing. That seemed to work better than using only the RGB data or doing the straight-forward LRGB combine. The image above is a full-resolution crop. There's nothing else in the field of interest. North is up.