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****** SUPASLIM 48 FILTER WHEEL*****
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We are pleased to announce The SupaSlim 48 filter wheel, which at only 21mm thick is a full 6mm (over 20%) slimmer than the Narrow version of the Custom-Wheel series, and takes standard 48mm/2" screw-in filters (screw thread M48 x 0.75). There are two versions available, one at lower cost, with onboard electronics, requiring only a 12v dc power source, and a RJ cable for serial control (the pictures above show this version),
and one with no onboard electronics, but connected to the standard Hand-Unit of the Custom-Wheel (see main Custom-Wheel page). The SS48 has a different housing to the other SupaSlim wheels, so cannot accept the other internal wheels, and vice-versa. However, control is identical for both types of SupaSlim Wheel.
A. Filter side of SS48 wheel, showing IR emitters at front, and electronic interface box lower right. On other versions of the Custom-Wheel series, this side would normally be the CCD side, but it is recommended that for the SS48, this side should be towards the telescope, provided that this is possible (see B)
B. Motor side of SS48 wheel, showing the motor, and the electronic interface box lower left. It is recommended that for the SS48, this side should be towards the CCD camera, provided that the camera is not so large diameter that it fouls the motor. Note that the clearance from the centre-line of the filters to the top of the motor is 48.5mm, so a CCD camera of 95mm diameter (3.75") can be accommodated without touching the motor.
C. Filter side of 5-way disk, showing standard screw-in 48mm filters. A 4d wheel (4 x filter position + dark position) is also available
D. Non-filter side of the 5-way disk, showing the nylon drive gear. On other versions of the Custom-Wheel the filters would screw into the disk on the same side as the nylon gear, but the SupaSlim wheels have the nylon gear attached close to the disk, and the only way to accommodate screw-in 48mm filters is to screw them into the disk from the other side.
E. Top view of the SS48, with the wheel open, showing filters at left. The clearance between the left inner wall of the wheel housing and the disk is 8.5mm, so filter rings of this thickness, plus 3mm thread (the thickness of the disk itself) can be accommodated.
SS48 with Starlight Xpress SXV-H9
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F. Side view. The SS48 and SXV-H9 are connected using a one-piece SCT-T-LR adapter, which has a lock-ring to fix the SXV at the required angle, and an internal thread to take a standard 1.25" filter (eg IR-Blocker). The adapter on the front of the SS48 is a 2PFM-SCTM and this is plugged into a standard 2" focus tube.
The distance from the back of the 2" focuser to the front face of the SXV in the above configuration, is just under 32mm (1.25")
G. View through SS48, with a 48mm filter in place (clear aperture of True Tech 48mm filters is 45mm), showing the SXV-H9 CCD sensor in the centre
H. Vignetting considerations. There would appear to be none, even with a 1.25" IR-Blocker screwed in behind the main 48mm filter,as shown above. A light ray from the diagonal edge of the chip passes clear of the small filter edge, is well inside the edge of the 48mm filter, and where it clears the edge of the 2" adapter would then strike the edge of the main focus tube, which would be the limiting factor in determining vignetting.
SS48 with S-BIG ST10-XME
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I. The ST10 is connected to the SS48 using a short version of the SCT-T-LR adapter (actually skimmed to length) without the locking-ring, as the ST10 faceplate incorporates a 'T-Ring' to permit the angle of the camera to be adjusted. The flange on the SCT-T short adapter is only 2mm, so in this configuration the distance from the 2" focuser to the front faceplate of the ST10, including the adapters, is 25.5mm (1"). Note that the SS48, in common with all True Tech filter wheels, has a SCT female thread on the faceplate. This means that, provided a SCT-LR (SCT-thread lock-ring) is used, the wheel can be screwed directly onto the back of a (eg) f/6.3 focal reducer or similar, if this is required instead of the 2" push-fit arrangement shown in these pictures
J. View through the SS48, with a 48mm filter in place, showing the ST10 CCD sensor
K. Vignetting considerations. A light ray from the corner of the chip which passes just inside the edge of the optical window of the camera itself, passes clear of the edge of the 2" adapter on the front of the wheel. Thus vignetting will be determined by the 2" tube of the telescope's focuser. Note that if a True Technology 'type 2' filter set is used (with integral IR-Blocker) then the field of view will be as shown in this image. If a type 1 filter set is used, with an external IR-Blocking filter, then if it is a 48mm IR-Blocker, this can be directly screwed into the front of the 2" push-fit adapter, so no vignetting will occur.
L Vignetting considerations (cont). Some of you may already have a 'FSET48-Rb' where the IR-Blocking filter is 1.25". In this case the field of view would be less as shown in this image, where a 1.25" IR-Blocker
has been screwed in the adapter infront of the CCD camera. To be certain of no vignetting we recommend that either a type 2 filter set is used, or a type 1 with 48mm IR-Blocker screwed infront, as per image K
Canon EOS film and digital cameras
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M. We have an adapter (SCTM-M54F) which screws onto the SS48, to enable 'Wide' T-Ring to be used. These are special T2 mounts which use a 54mm external thread, rather than the 42mm internal T-thread. By this means much wider light cones can be accommodated without vignetting occurring. Thus a Wide T-Ring with the EOS bayonet fitting connects directly to the EOS camera, and the whole assembly screws onto the SCTM-M54F adapter. Note that all 'T-Rings' by definition, permit angular adjustment so that the camera can be set at the required angle
N. View through showing the outline of the SLR mirror. The EOS in the picture is a normal 35mm film camera, with an image frame of 24 x 36mm. ON the diagonal this measures 43mm, so only very high focal ratio systems will have zero vignetting on a film camera, even where 2" focusers and 48mm filters are used. The good news is that the EOS 10D digital camera, with 6 million pixels, has a chip measuring 22.7mm x 15.1mm, and this has a diagonal of 27.26mm, which is way smaller than the 43mm of the 35mm film camera.
O. Vignetting considerations. As you can see, one does not have to move far off the optical axis before vignetting occurs with a 35mm film camera.
Takahashi adapter (TAK72-SCTM)
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P. The TAK72-SCTM adapter is designed to screw directly onto the standard 2.7" focus tubes of Takahashi refractors (eg FS-102, FSQ106, FS-128, FS-152). It converts directly to a male SCT thread to accommodate any of the following (or other items with the same thread):
True Technology filter wheel
JMI NGF-S focuser
Meade focal reducer (f/6.3 or f/3.3)
Large format CCD camera with SCT-threaded faceplate
The flange thickness is 5mm only, and the male SCT thread is 9mm long
Q. Face view of adapter. The clear aperture is 46mm, as large as possible, to accommodate large chip CCDs and/or fast focal ratio systems. There is a fine internal thread to act as light baffle so that no stray light is deflected off the internal side walls
R. The apapter screwed on the front of a SS48 wheel, using a LR-SCT adapter which acts as spacer and permits angular adjustment of the wheel.
S. Face view of the arrangement of (R). A Starlight Xpress SXV-H9 is mounted on the wheel, and this view shows plenty of clear aperture around the CCD chip
Not a 'feldstein'
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T. We have simulated another product which has a T-thread in the centre, to accommodate T-thread accessories. The downside of this is that the internal clear aperture cannot be more than 38mm
U. Oblique view of simulated adapter with T-thread restriction, showing that a lot of the rear adapter is covered at the onset of vignetting
V. 'Normal' view without the T-ring, showing that vignetting only commences after virtually the whole of the rear adapter is in view. Note that if you want to mount T-thread accessories use the standard Tak back-plate plus M43-M42 male-male adapter, or indeed use a Tak Extender Q (M43) directly, plus T-extension tubes as required.
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The pricing of the SS48 is identical to the pricing for other SupaSlim and Narrow wheels.
For pricing details click HERE
For details of Narrow and Wide versions, plus the LARGE range of adapters available, click HERE