Santa Barbara Instrument Group ST-8300C, Руководство по эксплуатации

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SBIG ST-8300 Manual
4. At the Telescope
Connect the camera to the computer and start CCDOps . Establish a link to
the camera and run the Camera Setup command. Enable the cooling to ~30
degrees below ambient and then watch the Link Status field to see the
temperature come down. Once the temperature reaches the Setpoint it will
jump back and forth by about 0.5 degrees. This is normal. The ST-8300
regulates the CCD temperature by dithering back and forth across the
Setpoint and while the readout of the temperature has a half-degree
resolution, the actual temperature is regulated to 0.1 degree. At this point
we’re ready to hook up to the telescope.
Focusing a CCD camera at the telescope can be a tedious operation, so
a few hints should be followed. Before using the software to focus the
camera the first time you should place a diffuser (such as scotch tape or
ground glass) at the approximate location of the CCD's sensitive surface
behind the eyepiece tube and focus the telescope on the moon, a bright
planet or a distant street lamp. This preliminary step will save you much
time in initially finding focus. The distance behind the eyepiece tube for
the ST-8300 is approximately
0.7 inches ( backfocus ).
To achieve fine focus, first center a bright star then insert the CCD head
into the eyepiece tube, taking care to seat it, and then enter the CCDOps
Focus Mode . Do not initially try to focus on the moon or planet – they are
harder. As we learned in the tutorial, the Focus Mode automatically
displays successive images on the screen as well as the peak brightness
value of the brightest object in the field of view. Using the telescope
controls, center the star image in the CCD, and adjust the focus until the star
image is a small as can be discerned. Next, shift the telescope to fainter
stars so the CCD is not saturated. Further adjust the focus to maximize the
displayed star brightness in counts and minimize the star diameter. This can
be tedious. It helps considerably if a pointer or marker is affixed to the
focus knob so you can rapidly return to the best focus once you've gone
through it.
An exposure of 1 to 3 seconds is recommended to smooth out some of
the atmospheric effects. While you can use the Full frame mode to focus,
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