Santa Barbara Instrument Group STL-1001E Operating Manual page 66

Focal Reducer - A Focal Reducer reduces the effective focal length of an optical system. It
consists of a lens mounted in a cell and is usually placed in front of an eyepiece or
camera. With the relatively small size of CCDs compared to film, focal reducers are
often used in CCD imaging.
Frame Transfer CCDs - Frame Transfer CCDs are CCDs that have a metal mask over some
portion (usually half) of the pixel array. The unmasked portion is used to collect the
image. After the exposure is complete, the CCD can very quickly shift the image from
the unmasked portion of the CCD to the masked portion, thus protecting the image
from light which may still be impinging on the CCD. This acts as an electronic shutter.
Full Well Capacity - Full Well Capacity refers to the maximum number of electrons a CCD
pixel can hold. This number is usually directly proportional to the area of the pixel.
Histogram - The Histogram is a table of the number of pixels having a given intensity for each
of the possible pixel locations of the image file. Remember that, in the end, the image file
is nothing more than a list of pixel values, one for each CCD pixel. These value numbers
can be displayed in two formats; as a table or plotted as a graph.
Light Frame - The Light Frame is the image of an object before a Dark Frame has been
subtracted.
Photometry - Photometry is the study of stellar magnitudes at a given wavelength or bandpass.
Pixel Size - The smallest resolution element of a CCD camera is the CCD pixel. The pixel sizes
for each of the SBIG cameras are as follows:
Camera
TC-237 Tracking CCD
STL-4020M
STL-1301E
STL-1001E
STL-11000M
STL-6303E
Planet Mode - Planet Mode is the most useful way to achieve focus. When you select Planet
mode, a full frame is exposed, downloaded, and displayed on the computer monitor. A
small window can be placed anywhere in the image area and the size of the window
can be changed. Subsequent downloads will be of the area inside the box resulting in a
much faster update rate.
Quantum Efficiency - Quantum Efficiency refers to the fractional number of electrons formed
in the CCD pixel for a given number of photons. Quantum Efficiency is usually plotted
as a function of wavelength.
Readout Noise - Readout noise is associated with errors generated by the actual interrogation
and readout of each of the CCD pixels at the end of an exposure. This is the result of
fixed pattern noise in the CCD, residual charge in the readout capacitors and to a small
extent the noise from the A/D converter and preamplifier.
Resolution Mode - The resolution of a CCD camera is determined by pixel size. Pixel size can
be increased by combining or binning more than one pixel and displaying it as one
pixel. Doing so decreases the effective resolution but speeds up the download time of
Section 8 – Glossary
Pixel Size (microns)
7.4 x 7.4
7.4 x 7.4
16 x 16
24 x 24
9 x 9
9 x 9
Page 64