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Borg 45EDII F4.7 (Mini Borg) Astrograph System |
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Borg 45EDII F4.7 (Mini Borg) Astrograph System
One of the fundamental cornerstones of Borg''''s'' scope designs has been excellence in performance as astrographs - high-performance objective.
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One of the fundamental cornerstones of Borg's scope designs has been excellence in performance as astrographs - high-performance objectives combined with uniquely high-performance flattener/reducer elements, specially designed for imaging.
The Mini Borg astrographs incorporate the 0.66x Triplet Super Reducer, optimized for APS-sized sensors.
Focal reducers are optimized for specific distances between the optical components and the image plane. For the F4 focal reducer, these are accomplished through the use of calibrated spacers for specific focal lengths. Two 63mm diameter spacers are provided for the front (between focuser and front reducer lens assembly), and two 58mm diameter spacers for the rear (between the rear reducer lens assembly and the camera adapter):
Filter Attachment Provision for the attachment of filters is via a a 55mm diameter filter thread on the front reducer lens assembly (for semi-permanent filter installation) and via an easily removed filter holders which accomodate 52mm or 48mm filters. A camera shutter cable can be attached to the focal reducer assembly to make removal of the filter holder a simple operation which does not disturb the optical train. Additional filter holders are available for quick changes between filters.
Physical Data:
| 45ED F4.7 |
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| | F.L. (mm) | 210 |
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| | Weight (kg) | 0.6 |
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| | Length (mm) | 230 |
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