Search
Latest news
December: Test shots with new scopes/mounts
Dec 21: TMB 80/480 Arrives!
Dec 3: AP1200 Arrives!
Nov 30: TMB 152/1200 Arrives!
Links:
Fire (Henry Coe State Park)
| |
| 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: None
- 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: 410 x 6sec @ ISO 200
- Total Exposure: 0hrs, 41min
-
- Date: 9/4/2007 10:30pm PDT
- Location: Saratoga, CA, USA
- Acquisition: DSLRfocus
- Focus: DSLRFocus
- Dithering: None
- Guiding: None
Processing:
- IRIS: Dark subtraction, PIC to BMP Conversion
- JimP: Flat field, White Balance, ASINH stretch
- BMP2PNG: BMP to PNG conversion
- Mencoder: PNG to AVI movie encoding
- Photoshop: Image scale, JPG conversion
Image Description:
This is a photo and animation (5 MB) of what threatens to become one of the largest wildfires in Santa Clara County history, according to the San Jose Mercury News. The images were captured from my house in Saratoga, roughly 35miles west of Henry Coe State Park, where the fire is centered.
While not really an astrophoto per se, the acquisition and subsequent processing of these images use the exact same process I've been using for DSLR imaging of the universe, including calibration (dark subtraction, flat fielding) and subsequent processing in IRIS and home-brewed software tools. Note, for example, the complete absence of checkerboard “pattern noise” in the background, as well as a complete lack of vignetting. In addition, Coe is one of the sites frequented by Bay Area astronomers seeking dark skies.
The animation (5 MB) is a time lapse, consisting of 410 stills taken with the DSLR, each a 6 second exposure with 5 seconds between them for mirror lockup (to avoid vibration) and for time to save the image to compact flash. Total time span is about 1 hour and 15 minutes.
A higher resolution image is also available. The camera is looking almost due East in this picture, with San Jose between the camera and the fire, but off-camera to the left (North).