SaratogaSkies Jim Solomon's Astropics

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Jupiter and Moons   [obsolete]

Image Details:

Camera: Canon Digital Rebel (300D)
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: 2844mm
Effective Focal Ratio: f/54.2
Exposure: 9 x 1/2 second @ ISO 800
Date: 6/22/2004, 9:28pm PDT
Location: Saratoga, CA, USA
Acquisition: Manual
Focus: Manual
Dithering: None
Guiding: None

Processing:

  • IRIS: Dark subtraction, flat field, registration, stacking
  • Photoshop: Compositing of IRIS moons and Jupiter images, sharpening, saturation, scale, JPG conversion

Image Description:

An interesting shot of Jupiter and the four Galilean moons. The f/ratio is so high because I put the aperture mask on the end of the telescope, effectively turning the 200mm obstructed Newtonian into a 52.5mm unobstructed offset-Newtonian. For those familiar with telescope optics, the Newtonian design has a secondary mirror in the path of the light that hits the primary mirror, and this so-called "obstruction" can cause a loss of contrast, especially on objects like planets that have low contrast to begin with. By putting the aperture mask on, the secondary is out of the path of the light hitting the primary (now effectively only 52.5mm instead of 200mm), preserving all of the contrast. However, the lower effective aperture could conceivably cause a loss of resolution, but since this is a relatively low effective focal length (2844mm), that loss of resolution isn't evident, and is overwhelmed by the seeing conditions in any case. [In retrospect — what was I thinking!?!? <grin>]

 
NGC 6820 & NGC 6823 (Emission Nebula & Open Cluster)
SaratogaSkies Jim Solomon's Astropics

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NGC 6820 & NGC 6823 (Emission Nebula & Open Cluster)

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: Celestron C8-N (8" f/5 Newtonian)
Configuration: Prime Focus
Additional Optics: Celestron/Baader Multi Purpose Coma Corrector (MPCC)
Filter: None
Effective Focal Length: 1000mm
Effective Focal Ratio: f/5
Exposure: 40 x 4min @ ISO 800
Total Exposure: 2hrs, 40min
Date: 8/30/2005 9:41:31 PM 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
  • JimP: Flat field, Kappa-Sigma Stacking, White balance, ASINH stretching
  • Neat Image: Noise reduction
  • Photoshop: Levels, cropping, JPG conversion

Image Description:

This is a "do over" of NGC 6820, an Emission Nebula in the constellation of Vulpecula. In my previous attempt with an unmodified camera, I was unable to capture the faint Hα emission nebula, and was only able to capture the open cluster NGC 6823. The modified camera excels in shots like this. A high-resolution image is also availble. North is up.

 
NGC 6826 (Blinking Planetary)
SaratogaSkies Jim Solomon's Astropics

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NGC 6826 (Blinking Planetary)

Image Details:

Camera: Canon Digital Rebel (300D)
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: 2844mm
Effective Focal Ratio: f/14.2
Exposure: 51 x 30sec @ ISO 800
Total Exposure: 0hrs, 25min
Date: 7/15/2004, ~2am PDT
Location: Saratoga, CA, USA
Acquisition: DSLRfocus
Focus: DSLRFocus
Dithering: None
Guiding: None

Processing:

  • IRIS: Dark subtraction, flat field, registration, Kappa-Sigma stacking, Wavelet processing
  • Photoshop: Compositing, cropping, JPG conversion

Image Description:

NGC 6826, the Blinking Planetary, is a planetary nebula in the constellation of Cygnus. It is so named because when you stare directly at the central star through the eyepiece of a telescope, the surrounding nebulosity all but vanishes. But when you avert your vision (i.e., look slightly off too one side), the nebula blinks into view. Why does this happen? Well, the human eye "sees better" off of center; i.e., you can see dimmer things not when looking directly at them, but by looking (slightly) away from them. So, when you're looking straight at the central star, the eye has trouble seeing the faint nebula that surrounds it. But when you look slightly away, your peripheral vision is sensitive enough to detect the nebula. It's very cool to try this in a decent telescope. It's a pretty amazing effect.

I used IRIS's Wavelet Processing capabilities to bring out details in the nebula. However, that made the surrounding stars and the sky background look icky, a technical term. So I used Photoshop to composite the wavelet-processed nebula with a non-wavelet-processed background using layer masks. There, I feel much better for coming clean. Also, I was very careful at every step of the aquisition and processing chain not to clip any of the nebula or its central star, in order to preserve the color and appearance of the nebula. This is a crop of the full-size image. North is up.

 
SH 2-27 (Emission Nebula East)
SaratogaSkies Jim Solomon's Astropics

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SH 2-27 (Emission Nebula East)

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

Image Details:

Camera: Mofidied Canon Digital Rebel (300D): Hutech (no filter)
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: 33 x 4min @ ISO 200
Total Exposure: 2hrs, 12min
Date: Date: 7/2/2005 9:44:35 PM 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: Flat field, Kappa-Sigma Stacking, White balance, ASINH stretching
  • Photoshop: Levels, image scale, cropping, clone tool, JPG conversion

Image Description:

This is the Eastern portion of SH 2-27, a very large but very faint emission nebula in the constellation of Ophiuchus. Thanks much to Rich S. for letting me borrow his Modified 300D, without which I would not have been able to capture any of the red Hα nebulosity. Unfortunately, only after the fact, did I discover that there was a pretty obnoxious globber on the camera's sensor that moved (!) between the time I captured the Lights and Flats, so I had to do some unholy clone-tool operations in Photoshop to clean it up. There, I feel much better for coming clean on this. <grin>

Move your mouse over the image above to see annotations of the various dark-nebula regions, or click on the image for a higher-resolution version. The image above is the full frame, shrunk for display on the web. North is right.

 
Mars
SaratogaSkies Jim Solomon's Astropics

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Mars

Image Details:

Camera: Mofidied Philips ToUcam Pro II (840k): Color RAW Hack
Mount: Celestron AS-GT
Scope: Celestron C8-N (8" f/5 Newtonian)
Configuration: Eyepiece Projection
Additional Optics: University Optics 7mm HD Ortho
Filter: None
Effective Focal Length: 6000mm
Effective Focal Ratio: f/30
Exposure: 256 @ 1/25s, 5fps, gain=0%
Date: 10/30/05, 1:05 AM PDT
Location: Saratoga, CA, USA
Acquisition: QCFocus
Focus: Manual
Dithering: None
Guiding: None

Processing:

  • IRIS: AVI conversion, CFA conversion, Registration, Best-frame selection, Stacking, Wavelet processing
  • Photoshop: Levels
  • ImageReady: Animated GIF conversion

Image Description:

This is a passable webcam image of Mars on a night of lousy seeing. This webcam image blows away this old one taken with a Digital Rebel.

The above image isn't an image at all — it's actually an animation. Each frame of the animation is the result of stacking the best 256 of 1000 frames from an AVI (with wavelet and levels processing, of course). Then each such frame is assembled into an animation using ImageReady. The individual frames of the animation are sperated in time by about 11min. Yes, Mars rotates about its axis very quickly. Mars's North is up and to the right in this animation. (I think. <grin>)