This astrograph utilizes the new Borg 4-element ED super reducer, which is optimized for Astrophotographer, yet covers a full 35mm-sized frame. it also includes built-in filter holders as well as a camera rotator for flexible image composition. Borg helical focuser is standard,However motorize Feather Touch focusers are an option.
Focal reducers are optimized for specific distances between the optical components and the image plane. For the F4 focal reducer, these are achieved through the use of spacers for specific focal lengths. Two 63mm diameter spacers are provided for the front (between focuser and front reducer lens assembly), as well as two 58mm diameter spacers for the rear (between the rear reducer lens assembly and the camera adapter).
There is a provision for the attachment of filters via a 55mm diameter filter thread on the front reducer lens assembly (for semi-permanent filter installation) and via an easily removed filter holders which accommodate 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.
The following items are included in the system;
- BORG 77EDII OTA
- 0.65x reducer
- Total of 6 elements
- 330mm focal length
- 35mm full-frame coverage