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Blurry pictures can also result from shutter speeds that are too slow. To prevent this, use films that produce shutter speeds greater
than 1/250 of a second when hand-holding the lens. If the lens is mounted on a tripod, the exposure length is virtually unlimited.
Another way to reduce vibration is with the Vibration Suppression Pads (#93503). These pads rest between the ground and tripod
feet. They reduce the vibration amplitude and vibration time.
The following is a brief description of the advantages of imaging at each f-number configuration and the proper equipment needed
to use the telescope in any of its many settings
F/6.3 with Reducer/Corrector
When imaging some objects like planetary nebula (for example M57, the Ring Nebula) and small galaxies (M104, the Sombrero
Galaxy), larger image scale is needed to resolve finer detail. These objects are better shot at f/6.3 or even f/10.
Medium size to small galaxies --
f/6.3 imaging gives you finer resolution then at f/2, but the slower f-number will usually require you to guide the image while you
are taking longer exposures. Guiding can be accomplished by using an optional Radial Guider or a piggyback guide scope. The
exposure times are about 10 times longer but the results can be worth the extra effort. There are some objects that are small enough
and bright enough that they work great at f/6.3. M104 (the Sombrero Galaxy) can be imaged under dark skies with a series of short
exposures using Track and Accumulate. Ten exposures at 15 seconds each will yield a nice image and is short enough that you may
not need to guide the exposure at all. For f/6.3 imaging the optional Reducer/Corrector is needed. (See Optional Accessory section
at the end of this manual).
Lunar or small planetary nebulae--
f/10 imaging is more challenging for long exposure, deep-sky imaging. Guiding needs to be very accurate and the exposure times
need to be much longer, about 25 times longer than f/2. There are only a select few objects that work well at f/10. The moon
images fine because it is so bright, but planets are still a bit small and should be shot at f/20. The Ring nebula is a good candidate
because it is small and bright. The Ring Nebula (M57) can be imaged in about 30-50 seconds at f/10. The longer the exposure the
better.
Planetary or Lunar--
f/20 is a great way to image the planets and features on the moon. When imaging the planets, very short exposures are needed.
The exposure lengths range from .03 to .1 seconds on planetary images. Focus is critical as is good atmospheric conditions.
Generally you will take one image after another until one looks good. This is due to the atmospheric "seeing" conditions. For
every 10 exposures you might save 1. To image at f/20 you need to purchase a 2x Barlow and a T-adapter or Radial Guider.
Auto Guiding
The CPC has a designated auto guiding port for use with a CCD autoguider. The diagram below may be useful when connecting
the CCD camera cable to the CPC and calibrating the autoguider. Note that the four outputs are active-low, with internal pull-ups
and are capable of sinking 25 mA DC.
No Connect
Figure 8-7 – Pin out diagram for Autoguider
port.
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