Alt-azimuth Dob without a field rotator. DSLR raw files are used because the raw CR2 file provides greater dynamic range (4096 levels or more) over using JPG files which are limited to 256 levels. Astrometry tool requires the pixel size of the camera to be known. Tom Frey's Canon EOS T2i DSLR camera pixel size is 4.3 microns square.

DSLR & Bayer Conversion Settings

AIP4WIN has two settings windows that need to be configured in order to read a Canon raw CR2 file.

The first settings window is the Bayer Array -> Color window that tells AIP4WIN which of the four types of Bayer arrays is being used by the camera. The Canon raw CR2 file uses the first Bayer type called red, green, green and blue as shown below.

The second AIP4WIN settings window is the DSLR & Bayer Conversion Settings window. For science image analysis use Bi-Linear Interpolation for the De-Bayerization algorithm (private communication with Richard Berry).

DeBayer, Convert Color to Grayscale set all RGB scales to 1.0.

Opening DSLR Image in AIP4WIN

Open the Canon raw CR2 file. In Image Display Control the User Black/White values are adjusted to show the image without the background noise. Usually only the White point needs to be increased.

AIP4WIN Image Display Settings

In Image Display Control the User Black/White values are adjusted to show the image without the background noise. Usually only the White point needs to be increased.

The Image Display Control Zoom is adjusted to 25% see the complete image which will be necessary when the astrometry analysis is done.

Links

• Double Star Measurements with an Alt-azimuth Dob and DSLR
• Alt-azimuth Dob and DSLR Equipment Used in Double Star Measurements
• Double Star Separation (Rho) and Position Angle (Theta) Measurements
• Double Star Measurements with AIP4WIN
• Opening a DSLR Raw Image with AIP4WIN
• Astrometric Measurements with AIP4WIN
• Star Quality Measurements with AIP4WIN
• Double Star KUI82ABC
• Double Star KUI82AB,C Analysis with AIP4WIN
• Double Star KUI82AB,C Analysis with Astrometrica
• Alt-Azimuth Field Rotation

References

• Observing and Measuring Visual Double Stars (The Patrick Moore Practical Astronomy Series) 2nd Edition R. W. Argyle
• The Handbook of Astronomical Image Processing 2nd Edition by Richard Berry & Jim Burnell
• The Proper Motion and Parallax of Barnard's Star: Errors and Precision in Small-Telescope Astrometry by Richard Berry
• The Proper Motion and Parallax of Barnard's Star: Errors and Precision in Small-Telescope Astrometry by Richard Berry (2011SASS...30...79B)
• DSLR Photometry Tutorial by Citizen Sky
• AIP4WIN by Yahoo groups
• AIP4WIN Photometry by Yahoo groups

Thomas G. Frey Thomas G. Frey is Professor Emeritus of Chemistry at California Polytechnic State University, San Luis Obispo, CA. He has been an active member of the Central Coast Astronomical Society for over 25 years. He was a team leader at the Pine Mountain Observatory (PMO) Summer Science Research Work- shop, Bend, OR, 2009 and co-director of the PMO workshop, summer of 2011.

David Haworth David Haworth enjoys astronomy imaging and processing those images to bring out details that cannot be seen easily by visual observing with the same size optics. David Haworth started astroimaging with a Cookbook CCD camera he built in 1996 and since then has used many types of cameras to image the sky. David wrote Chapter 2: "Afocal Photography with Digital Cameras" in the second edition of "The Art and Science of CCD Astronomy" which was published in December 2005. David's images have appeared in magazine front covers, articles, books, catalogs, videos, music CD covers, T-shirts, other web sites, etc.

© 1998-2013 David Haworth