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© Baader Planetarium GmbH | 2019
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Manual: FlipMirror II
Use the 1,5mm Allen key to loosen the grub screws and retighten them again. They
grip into the S52 dovetail ring made of steel. Loosen these screws only so much that
you can rotate the threaded and. Once you're satisfied with the orientation, tighten
them again hand-tight.
2) Adjusting the upper T-2-thread
The adjustable T-2 top-ring can be moved sideways on
the housing, to center an eyepiece or video module onto
an object which is centered in the main instrument.
Firstly, center a star in the main unit mounted on the rear
port with the mirror up (position A). Then flip down the
mirror (position B) and view the image e.g. in the eyepi-
ece or camera on the top port. If the star is not placed
in the center, loosen the four screws with the supplied
2mm hexagon wrench, move T-2 top-ring adapter plate
with the T-thread on the housing and fix it in the desired
position by tightening the screws again.
3) Adjusting the mirror
The mirror is held in position by a spring mechanism.
When it is flipped down, it rests on two conical pins. If
necessary, the inclination of the mirror can be adjusted
by adjusting the two pins in opposite directions. The two
tools
7
and
8
are used for this purpose.
Always turn both screws by the same amount and then
check whether the mirror rests on the sharpened sur-
faces of the two brass screws. This allows the image to
be moved along the optical axis. For this adjustment our
LaserColli Mark III
# 2450343
can be used for example.
4) Adjusting the bottom port
You can adjust the bottom port similarly when an
off-axis guider is connected. To do this, check the
orientation of the prism and make sure that the vertical
surface points towards the telescope – if necessary,
loosen the small grub screws to rotate the prism unit.
Then center the reference object in the rear beam path
and check where it appears in the guiding camera.
If necessary, loosen the three fastening screws (red
arrows) with the 2mm hexagon wrench supplied.
They have a rounded head so that you can loosen
the screws even if a wider instrument is connected to the lower port. Then move the
Off-Axis-Guider as necessary to center the star (you may have to check the tilt of the
prism of the radial guider).
Focusing
The focus position at the upper and rear ports is approximately the same if the T-2 ad-
apters are used for each port. However, we recommend that you make one connector
focusable in order to be able to accommodate tolerances, deviating focus positions of
eyepieces or diopter compensation.
If you
do not use an off-axis guider
, you can simply attach the eyepiece to the top and
the camera to the rear port of the BFM II. First focus the camera with the telescope's
focuser, then fix its position if possible. Now focus the eyepiece, e.g. over a focusing
eyepiece clamp, or by pulling it slightly out. With most 1¼" eyepieces, the focus plane
is approximately at the transition from the housing to the nosepiece. Take into account
the length of the eyepiece clamp and the back focus of the camera for the setup.
If you
are using an off-axis guider
, you must also consider the
focus position of the guiding camera. If you use the Off-Axis-
Guider for Baader FlipMirror II (
# 2956951
) as well as a guiding
camera whose image plane is at the upper end of the Off-Axis-
Guider (i.e. without additional back focus), the image plane of the
camera and eyepiece is about 24mm behind the two T-2 threads
of the BFM II. A CCD camera with a short back focus, for examp-
le, can be adjusted to this distance with a VariLock 29, as can
the Polaris I crosshair eyepiece when connected directly to the
VariLock 29 via T-2. Thus, a very short adaptation is possible.
If you use a
DSLR
via a T-2 adapter, or an eyepiece clamp for
the eyepiece, you need more back focus. Then, the guiding
camera must be placed at a greater distance from the BFM II.
The easiest way to do this is to use the DT-4 nosepiece exten-
sion
# 1905130
with an overall length of 18.5mm. It has the diameter of a 1¼" eyepie-
ce and is screwed into the 1¼" filter thread of the guiding camera. With one or two of
these extensions, you can place virtually any camera over the off-axis guider so that it
is parfocal with the recording camera. Tip: With the FR-4 adjusting ring 1¼"
# 1905131
you can fix the insertion depth so that you "save" a focus position.
Adjustment of the FlipMirror II
There are many set screws to adjust the BFM II
perfectly to your imaging setup.
1) Rotating the Housing and Camera/Main
Instrument
The M48 threads on both sides (and with them
also the T-2 threads inserted into them) can be
rotated and fixed in the socket via the four M3
grub screws on the sides, so you can rotate the
FlipMirror housing into any desired position when
screwed to the telescope. An instrument firmly
connected to the straight beam path can also be
rotated into the desired position.
The orientation of the adapter threads on
both sides can be changed with the four grub
screws. This way, you can align instruments like
the DADOS spectrograph in this image to the
BFM II, or you can rotate the whole BFM, if it is
screwed directly to the telescope.
BFM II – seen from above. Use the
screws for adjusting the thread.
Setting and "saving" the focus
position of an eyepiece or
camera module with an FR-4
Focusing Ring Collar and a
DT-4 extension
The two pins on which the mirror
lays on
The screws for adjusting the bottom
port of the BFM II.
