| This piggyback system is precision-machined of aluminum and anodized black for long life. It can be used to support a camera and lens for taking a long exposure photo, or a CCD camera being used to guide a long exposure photo being taken through the main optics. While the factory description of the DCM2 claims that it offers three-axis camera orientation, this is not strictly accurate if you consider the three axes to be the normal roll, pitch, and yaw. The DCM2 has a 360° camera rotation (yaw) and a +/- 45° camera tilt (pitch), but does not have a true roll capability (to quickly swing the camera 90° from a landscape to a portrait orientation, for example). What the DCM2 has instead is (in addition to two-axis rotation and tilt) a complete piggyback unit rotation. With a simple two-axis adapter, rotating the camera to aim at a subject away from the scope’s optical axis and tilting it up or down to frame the object will cause the camera image to rotate in relation to the horizon (producing the unintended optical equivalent of roll). This may not correctly frame the object you’re trying to photograph. The DCM2’s ability to rotate both the piggyback assembly and the camera on the piggyback, as well as tilt the camera, allows you to cancel out much of the optical roll. The procedure is easier done than described. It is not a perfect solution to the lack of a true roll ability, but it allows the camera platform to be supported on two sides by 3/8” thick aluminum. These assure that even the heaviest camera/lens load will be held firmly, with no image-blurring flexure during the exposure.
In addition, the DCM2 has the ability to move the entire piggyback assembly laterally out 4” from the centerline of the dovetail. Simply rotating a camera with a long lens on a conventional one- or two-axis piggyback will put the weight of the lens off to one side of the optical tube, throwing the scope out of balance and possibly causing unintended tracking errors. By using the DCM2 to shift the camera body laterally, and pointing the lens across the optical tube, you keep the combined weight of the camera/lens assembly over the centerline of the scope and avoid any possible balance problems. The DCM2 has a slot that fits the 75mm wide dovetail of any Losmandy D-plate accessory dovetail plate. A quick release knob lets you position it at any point along the length of the D-plate and lock it securely in place, with no tools needed. Two knobs lock in the up/down tilt of the camera support for extra security when using a camera with a long telephoto lens. The DCM2 weighs 3 lbs. The height from the top of the dovetail plate to the top of the camera mount is 3.6” when the camera mount is parallel to the surface of the telescope optical tube. The range of lateral motion is 4”. |
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