Baader-FlipMirror II Star Diagonal (BFM II) with three ports:
- Straight-through (S52, M48 and T-2 on both sides) for full-frame camera, spectrograph, or other instruments
- Adjustable T-2 thread on top for eyepiece clamps, video modules (up to 32 mm image circle) or even a binoviewer
- Bottom flange for the optional Off Axis Guider for Baader FlipMirror II (BFM-OAG) or for an optional calibration lamp for quick calibration of spectra without removing the spectrograph
Precise surface-mirrored flip mirror with multi-layer Al coating, for high-resolution images with cameras with small pixels
The back of the flip mirror is also Al coated and masked to direct the light of an optional calibration lamp onto the slit of a spectrograph
Enables precise adjustment of all light paths
Shortest possible overall length for any application – compatible with a large number of adapters from the Baader Astro T-2 system, the M48 system and the UFC system (Universal Filter Changer)
Rotatable M48 connection rings made of hardened, stainless steel on front and rear, backlash-free adapted to the BFM housing. Can be fixed in the optimum position to rotate any accessory around the optical axis.
Prepared for an optional toothed belt for motorization (e.g. by Steeldrive II motor focuser with Controller) – basic requirement for image acquisition, guiding and spectroscopy in remote observatories

Various ports – variable work

Telescope auxiliary instruments cover a wide range of interests, from a sole eyepiece, via camera use, to high end spectroscopy. Unfortunately every telescope just features one exit port. This causes relentless manual exchange of parts in the dark, causing huge time loss, wear on the parts - and "nerves". And whenever you start controlling your telescope remotely - the single port becomes a painful reality.

Improving workflow, especially during astrophotography is the goal set out for the BFM II. This is not just a simple flip mirror but much more, as there are three ports to be put into action.

BFM II makes your single telescope port variable - to suit your various interests.

The FlipMirror II Star Diagonal allows a variety of permanent adaptations to your telescope 1 . Use the rotary knob 2 to switch between the rear port 3 and the top port 4; you can use an optional toothed belt to operate it with a motor (not included). An autoguider or a calibration lamp can be connected to the bottom port 5.

General Function of the FlipMirror II Star Diagonal

The BFM II lets you switch between a straight light path (Position A) for a camera or other measuring instruments and an angled light path (Position B), e.g.
for an eyepiece. The following figure shows how it works. In addition, a calibration lamp for spectrographs or an Off-Axis-Guider pick-off prism (that is not affected by the mirror position) can be connected at the AUX-port on the bottom

What's in the Box

Baader FlipMirror II Star Diagonal – with fine-optically polished, movable mirror
Laterally adjustable T-2a top ring
2x M48i / S52 Dovetail ring made of hardened stainless steel # 2958552
Reducing ring M48a / T-2i # 2958553
Reducing ring M48a / T-2a # 2958554
Inverter ring M48a / M48a # 2958555
Pin type face wrench for M48 / T-2 and M4 counter nuts
3 mm screwdriver for M 4 brass adjustment screws
4x hex keys (2.5 / 2.0 / 1.5 / 1.3 mm). The 2.0 mm wrench has a ball head to reach screws even when accessories are mounted by holding the wrench at an angle.
Bottom flange (laterally adjustable 1mm) for off-axis guide or calibration lamp for spectroscopy
Dust cap for bottom flange
2 x M48 dust caps
T-2 dust cap

Specifications

Manufacturer	Baader Planetarium
SKU (#)	2458055
Optical length (mm)	55 mm with S52, 59 mm with M48/T-2
Dimensions	63 x 77 x 69 mm
Inner Connection (lens sided)	Thread, Dovetail ring clamp, S52, T-2 (M42 x 0,75), M48
Weight (kg)	195 g
Inner Connection (eyepiece/-camera-sided)	Thread, Dovetail ring clamp, M48, S52
Outer Connection (eyepiece/-camera-sided)	Thread, M48
Type of Adapter	Variable