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metering which lets you know if your picture is under or overexposed.
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metering and changing shutter speeds
Reducing Vibration
Releasing the shutter manually can cause vibrations, producing blurred
photos. To reduce vibration when tripping the shutter, use a cable
release. A cable release keeps your hands clear of the camera and lens,
thus eliminating the possibility of introducing vibration. Mechanical
shutter releases can be used, though air-type releases are best. Blurry
pictures can also result from shutter speeds that are too slow. To prevent
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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
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telescope in any of its many settings
f/6.3 with Reducer/Corrector
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Ring Nebula) and small galaxies (M104, the Sombrero Galaxy), larger
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Medium size to small galaxies –
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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
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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
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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
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should be shot at f/20. The Ring Nebula is a good candidate because it is
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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
Ǥ Ǥ
Generally you will take one image after another until one looks good.
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exposures you might save 1. To image at f/20, you need to purchase a 2x
Barlow and a T-adapter or Radial Guider.
>>
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Fastar Option – Using your EdgeHD telescope at f/2 with optional
lens assembly.
The EdgeHD telescopes are equipped with a removable secondary
mirror that allows you to convert your f/10 telescope into an f/2 imaging
system capable of exposure times 25 times shorter than those needed
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making it the most versatile imaging system available today. With an
telescope to f/2 prime focus use in a matter of seconds. This makes the
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using the optional CCD camera for f/2 imaging.
Warning:
The secondary mirror should never be removed unless
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can easily be made by turning the screws on the top of the secondary
mirror mount without ever having to remove the secondary mirror (see
Telescope Maintenance section of this manual).
The f/# stands for the ratio between the focal length and the diameter
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tube has a focal length of 110 inches and a diameter of 11 inches. This
makes the system an f/10, (focal length divided by diameter). When
position, the system becomes f/2. This is a unique feature to some
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