Baader Afocal Digital Projection System (ADPS) - (versions I to VII)
- ADPS – Afocal Digital Projection System
- For digital imaging with cameras and/or camcorders
- Consist of base version ADPS (single parts see ADPS IV) and additional lens sided adapters on other ADPS versions
The Baader Afocal Digital Projection System (ADPS) is for eyepiece projection applications (so-called afocal projection). The system is made of a very finely stepped series of extension rings (and a T2 locking ring) to adapt it to any 1¼" eyepiece (with a body diameter of up to 38 mm), so that the eyepiece can be positioned as close as possible to the camera lens. This close distance makes a sharp image without vignetting possible.
The system is very similar to the Baader OPFA system for DSLR cameras, but the distance between the projection eyepiece and the lens of a digital camera can be set to a much shorter value.
The core part (base system) of the ADPS system, which is referred to as Version IV, consists of the following items
- focuser/eyepiece holder (T-2 part #24),
- rotation counter ring,
- 2x T-2 tube 15mm (T-2 part #25A)
- T-2 barrel (T-2 part #25C)
The central component of all ADPS systems is a sliding focuser (#2458010; marked in blue on RHS) with a T2 locking ring. A 1¼-inch projection eyepiece (not included in the ADPS) is inserted into this sliding focuser, and the sliding focus allows precise adjustment between eyepiece and camera lens.The locking ring allows the camera to be rotated continuously relative to the focuser in order to optimally position the camera for an image.
Then, three T-2 extension tubes (2x15mm and 1x7.5mm, also marked blue) are screwed onto the sliding focus, the eyepiece (with a maximum outer diameter of 38mm) is now inside of the tubes. These tubes are used to achieve the correct projection distance. In addition, you need matching DT I adapters and the DT ring to connect your camera to the ADPS.
To create the other (six) versions of ADPS, there are simply 6 telescope-side adaptors that are screwed onto the (telescope side) part of the above system. ADPS are all built like the one in the above example (from right to left). The blue marked parts correspond to the core/central part of the system - which is ADPS-IV base version with male T-2 thread on the camera side and a female T-2 thread on the telescope side. The adaptors on the telescope-side which are marked green in the figure are included in the scope of delivery of ADPS I-III and ADPS V-VII (ADPS I and ADPS II are shown in the example). The parts marked in red are not included in any ADPS!
In the table below, we present the 7 versions of the ADPS.
|ADPS Version I
|ADPS Version II
|ADPS Version III
|ADPS Version IV - BASE version
|ADPS Version V
ADPS Version VI
ADPS Version VII
|OPTICAL LENGTH (MM)||variable|
|USAGE||afocal eyepiece projection|
|CAMERA ADAPTABLE||For digital imaging with cameras and/or camcorders|
|INNER DIAMETER / CLEAR APERTURE (MM)||38|
|TYPE OF ADAPTER||Camera Adapter, Extension|