Specifications

2 AUTOSTAR CCD PHOTOMETRY
3. Practicing Photometry – Once you have mastered the imaging
steps, you are ready to practice photometry. Pick some stars that
are high in the sky when they cross the meridian. The closer to the
zenith, the better. The further from the meridian the poorer quality
the images will be and thus poorer photometry. Try to plan your
observing so that the star is to the East of the meridian and will
cross during the observing session.
4. Take multiple sets of images of a star field with a Program
and a Comparison star. Be sure to save the images as FITS. If you
save the images as a JPG or GIF or other than a FITS format, you
cannot do photometry on the image.
5. Practice getting data from a single image until you get
consistent magnitude values. The values should repeat exactly for
the same image. This may require investigation into the profile of
the star image and adjusting the Aperture and Annulus settings.
(These settings are discussed in later sections.)
6. Practice getting data from several images of the same star
field taken near the same time and with the same filter. The
magnitude data on the individual stars should be the same between
images. Most likely, the data will not be the same at first. Work to
find out why and how to minimize the differences.
7. Once you have repeatable data and are confident in knowing
what you are doing, start some serious photometry.
The following chapters describe suggested procedures for using a
Meade
®
Deep Sky Imager (DSI)™ Pro or DSI Pro-II monochrome
CCD camera with the AutoStar Suite™ and Envisage software.
Note: Aside from the specific steps involved in taking images with
the DSI camera, once images have been acquired with most any
CCD camera and stored as standard FITS files, the AutoStar Suite
Image Processing software can be used, and the rest of the
instructions for photometry also apply.