Equipment for the Serious Amateur Astronomer
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Hutech Astronomical Products
Equipment for the Serious Amateur Astronomer |
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For convenient switching of filters for
photographic or visual applications, we
recommend the filter holder assembly (part
number 7520) shown
in figure 1.
The filter mount accomodates a standard 52mm threaded filter (48mm with a standard camera filter step-ring). The filter mount is firmly held in place in the filter holder body with a spring-loaded retainer, but can be easily pulled out using fingers, or popped out of the filter holder body by threading a camera cable release into the ejection port. The latter technique is recommended to minimize disturbing photographic setups when filters are changed. The optional camera interface shown in figure 2 is a standard camera T-adapter thread (7522), but Borg camera interfaces are also available which allow vignette-free 35mm photography. All camera interfaces include 360-degree rotation (two retaining screws) for complete freedom in composing shots. For visual use, Borg 2" eyepiece adapters (7506, 7508, or 7509) are also available.
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Fig. 1. Basic filter holder (7520). The telescope side with standard female T-thread is shown here. The T-thread adapter may be removed and other Borg adapters may be substituted.
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Fig. 3. The two Telescope side interfaces shown are the standard female T-thread at left, and the 2" nosepiece (7425) at right. On the telescope side, the filter holder body comes with M60 (60mm dia, 0.75mm pitch) female threads and an M42 (42mm/T-thread) adapter. Optional additional adapters such as a 2" nosepiece adapter (7425) or SCT adapter (7424) make coupling to most scopes a simple matter. Note: When considering the use of filter holder 7520, be sure to take note of the focus position of your scope. The filter holder is approximately 35mm (~1.4") thick. |
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