Baader FlipMirror II star diagonal mirror (BFM II) with three ports folding mirror

Baader FlipMirror II diagonal mirror (BFM II) with three connections:
        Straight light path (S52, M48 and T-2 on both sides) for full-frame cameras, spectrographs and other instruments
        Adjustable T-2 thread on the top for eyepiece clamp, video module (up to 32mm image circle) - or even a binocular attachment
        On the bottom there is a connection for the separately available Off Axis Guider for Baader FlipMirror II (BFM-OAG) (part of the RCC-OAG #2956950) or for an optional calibration lamp for quick calibration of spectra without having to remove the spectrograph
    Precise surface-mirrored folding mirror with multi-layer Al coating, for high-resolution recordings with cameras with small pixels
    The back of the folding mirror is also Al-coated and masked to direct the light of an optional calibration lamp onto the slit of a spectrograph
    Allows the exact adjustment of all light paths
    Shortest possible length for every application – compatible with a variety of adapters from the Baader Astro T-2 system, the M48 system and the UFC system (Universal Filter Changer)
    Rotatable M48 connecting rings made of hardened, stainless steel on the front and back, adapted to the BFM housing without play. Can be fixed in the optimal position to optimally 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 capture, guiding and spectroscopy in remote operation

Baader FlipMirror II diagonal mirror
Many pages – many applications

There are a wide variety of accessories, from eyepieces to cameras to spectrographs, which can be connected to a telescope. Unfortunately, every telescope only has one connection on the eyepiece side. So it's always a matter of re-screwing and re-plugging - and usually at night in the dark. This is not good for the mechanics or the nerves. And as soon as you plan to operate remotely, the only available connection option becomes a painful reality. If you are tired of this procedure and would like to significantly improve your workflow, especially when it comes to astrophotography, then take a look at our Baader FlipMirror II star diagonal mirror (BFM II)! It is by no means a simple folding mirror, but offers much more - because it allows various accessories to be connected to more than just one side.

Make your telescope as “versatile” as your interests with the BFM II.

The FlipMirror II diagonal mirror enables a variety of permanent adaptations to your telescope 1. You can use the rotary knob 2 to switch between the rear 3 and upper 4 connection; You can also connect this button to a motor using an optional timing belt (not included). An autoguider or a calibration lamp can be connected via the AUX connection 5 at the bottom.

Basic function of the FlipMirror II diagonal mirror


The BFM II diagonal mirror makes it possible to switch between a straight beam path (position A) for a camera or measuring instruments and an angled beam path (position B), e.g. an eyepiece. The following figure shows how it works. In addition, a calibration lamp for spectrographs or an off-axis guider can be connected via the AUX connection at the bottom, which is not affected by the mirror position.
[Functions of the Baader FlipMirror II star diagonal mirror]
Scope of delivery of the Baader FlipMirror II star diagonal mirror:

    Baader FlipMirror II star diagonal mirror – with a finely 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
    Reversing ring M48a / M48a # 2958555
    Face wrench for M48 / T-2 and M4 lock nuts
    3mm screwdriver for M4 brass adjustment screws
    4x Allen keys (2.5 / 2.0 / 1.5 / 1.3 mm). The 2.0 mm wrench has a ball head so that screws can be reached with the wrench at an angle even when accessories are attached
    Bottom-side connection flange (adjustable 1mm laterally) for off-axis guider or calibration lamp for spectroscopy
    Dust protection cap for bottom connection flange
    2 x M48 dust caps
    T-2 dust cap

ITEM NUMBER (#) 2458055
OPTICAL LENGTH (MM) 55 mm with S52, 59 mm with M48/T-2 (+24 mm with optical OAG)
DIMENSIONS 63 x 77 x 69 mm
INTERNAL CONNECTION (TELESCOPIC SIDE) thread, ring clamp, S52, T-2 (M42 x 0.75), M48
WEIGHT (KG) 195 g
INTERNAL CONNECTION (EYECULAR/CAMERA SIDE) thread, ring clamp, M48, S52
EXTERNAL CONNECTION (EYECULAR/CAMERA SIDE) thread, M48
ADAPTER TYPE Variable