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NGC 6210 (Planetary Nebula)

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: 88 x 60sec @ ISO 800

Total Exposure: 1hrs, 28min

Date: 7/14/2004, 11:30pm 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 6210 is a planetary nebula in the constellation of Hercules. 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. <g> 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.

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Saturn   [obsolete]

Image Details:

Camera: Canon Digital Rebel (300D)

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: 9525mm

Effective Focal Ratio: f/47.6

Exposure: 1 x 1.6 sec + 2 x 2.0 sec + 1 x 2.5 sec @ ISO 100

Date: 5/8/2004, 9:02pm PDT

Location: Saratoga, CA, USA

Acquisition: Manual

Focus: Manual

Dithering: None

Guiding: None

Processing:

• IRIS: registration, stacking, cropping
• Photoshop: Unsharp masking, levels, image scale (1/2 x), JPG conversion

Image Description:

Pretty horrid. Took this before I knew what the heck I was doing.

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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.

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NGC 6822 (Barnard's Galaxy)

[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: Celestron C8-N (8" f/5 Newtonian)

Configuration: Prime Focus

Additional Optics: Celestron/Baader Multi Purpose Coma Corrector (MPCC)

Filter: Hutech Hα Front Filter (HA-FF)

Effective Focal Length: 1000mm

Effective Focal Ratio: f/5

Exposure: 83 x 4min @ ISO 1600 (RGB), 22 x 8min @ ISO 1600 (Hα)

Total Exposure: 8hrs, 28min

Date: 8/23/2006 and 8/24/2006 (RGB); 8/27/2006 (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, sharpening, JPG conversion
• Neat Image: Noise reduction

Image Description:

This is NGC 6822, aka Barnard's Galaxy, an irregular (as opposed to spiral or elliptical) galaxy in the constellation of Sagittarius. NGC 6822, a member of the Local Group, is a relatively close neighbor of our own Milky Way galaxy, along with M31 (Andromeda) and others.

This image was collected over three nights: two very dewy nights worth of RGB exposures, and a third night of Hα exposures. The Hα exposures really helped to bring out the star-formation regions at the top (North) of NGC 6822. Yes, that's correct, those emission nebulae are in NGC 6822, not in our own Milky Way!

Mousing-over the image will show the Hubble designations of those regions, and will switch the displayed image to the processed Hα-only image, shown in grayscale (which, trust me, is easier on the eyes than a redscale image). One of these regions, IC 1308 (aka “[H25] X” or “Hubble X”), is rougly 11 times the size of M42 in our own Milky Way.

This image is a do-over of this this old version. (By the way, I have no idea why that old version came out so green—the color in the current version is likely to be far more accurate.) A higher-resolution image is also available. North is up.