Instructions
Protective T-Ring CANON EOS

Protective T-Ring for CANON EOS#2958550 (basic version: T-Ring without filter)(scope of delivery e.g. version 2958550C – with built-in clear protective filter
with Phantom GroupTM multi-coating

Instructions for use:
as of 11/11

The Protective T-ring for the Canon EOS allows Baader filters to be used with a T-ring,
providing the largest possible free aperture of 47.3mm (M48 thread), and protecting the camera
body from dust and humidity. To allow optimal use of the Protective T-ring, several versions ofit are now available with a built-in 50.8mmx3mm or 50.4mmx 3mm Baader filter.
The Protective T-ring not only offers exposures free from vignetting with extremely short focal
length telescopes, it can also be universally connected. Four different types of telescope
connection are included. The adapters of our Astro T-2 system can be used for many othertypes of mounting onto a large range of telescopes.
After carefully examining the CANON bayonet fitting we have optimized the fit and tolerances
between the camera bayonet and T-ring. The result is the Protective T-ring, which is wobblefree and has no lateral play thus always guaranteeing a stable image platform, even for longexposures or when the telescope slews.
The Protective T-ring replaces other built-in camera filters which are installed directly into thecamera body. All unmounted 50.8mm or 50.4mm Baader filters, and Baader 2" filters mounted
in low-profile filter cells (LPFC) may be used with the Protective T-ring. (LPFC describes allBaader filter mountings where the effective overall height of the filter cell is not more than 6mm).

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Instructions
Protective T-Ring CANON EOS
The glass thickness (3mm) of the built-in 50.8x3mm filter is taken into account in themechanical construction. The resulting effective overall optical length for each CANON EOS
camera thus amounts to 55mm - precisely the overall optical length of standard T-rings.
If, instead of a 3mm thick filter, a normal Baader 2" Filter with a low profile filter cell is used, theeffective overall height of 55mm deviates from the standard by just +0.3mm. This deviation isnegligible.
Included in delivery:
1. Protective T-Ring for CANON EOS body
2. Optional: Baader clear protective filter, 50.8mm x 3mm (protective T-rings are available witha range of pre-assembled filters – see price list or the label on the product packaging)
3. Temperature compensation ring (to prevent filter damage at high temperatures)
4. S52/M48 adapter ring (M48 corresponds to the international 2" Astro filter thread)
5. M48/T-2 insert ring
6. S52/2" connector socket (with additional 2" M48 filter thread on the front side)
7. 1.5mm Allen key

Fig. 1: Included in delivery and assembly sequence:(The unmounted filter is only shown here to illustrate the assembly sequence!)

When supplied with filter, a Baader clear protective 50.8mm filter is built
in to the Protective T-ring for the CANON EOS for example. TheS52/M48 adapter, as well as the M48/T-2 insert ring, are similarly preassembled – however, the M48/T-2 insert ring is only loosely screwed in.
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Instructions
Protective T-Ring CANON EOS

Fig. 3: Illustration:
Protective T-Ring for
Canon EOS with 2"
socket (S52/2")

Changing the filter:
To change the filter, loosen the 6 grub screws on the side of the unit by means of the 1.5mm
Allen key supplied. Then tilt the body of the Protective T-ring carefully forward and take out thebuilt-in 50.8mm filter and the Delrin temperature compensation ring. Now insert another 50.8mm
or 50.4mm filter and place the temperature compensation ring on top of it. Now put either theS52/M48 ring or the S52/2" connector socket into the body and fasten the unit together bymeans of the 6 Allen screws. Here, S52 is a description of the diameter of the retaining cone
which is clamped in place by means of the 6 screws.
Alternatively, you can install a Baader 2" low profile filter. This is screwed in from the inside into
the M48 thread in the main body of the T-ring. After this - as previously described - either theS52/M48 ring and the M48/T-2 or the S52/2" connector socket can be inserted and tightened up
by means of the 6 Allen screws.
The FILTER SHOULD ‘RATTLE’! This is not a defect. The slight looseness of the filter in themounting is very small and serves to protect the filter against stress. This minimal play will notaffect the image position.

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Instructions
Protective T-Ring CANON EOS
Applications:Fig. 4:
Protective T-Ring for CANON EOS, with 50.8mm clear protection filter,
Delrin temperature compensation ring, S52/M48 adapter and M48/T-2 insert ring

Fig. 5:
Protective T-Ring for CANON EOS with 50.8mm clear protection filter,Delrin temperature compensation ring and S52/2" connector socket

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Instructions
Protective T-Ring CANON EOS
Fig. 6:
Protective T-Ring for CANON EOS, shown with Baader 2" clear protection filter
in low profile filter mounting, S52/M48 adapter and M48/T-2 insert ring

Fig. 7:
Protective T-Ring for CANON EOS, shown Baader 2" clear protection filter
in low profile filter mounting and S52/M48 adapter ring

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Protective T-Ring CANON EOS
Fig. 8:The Protective T-ring is supplied withinserted S52/M48 ring and with theM48/T-2 reducing ring screwed in. Theconnector socket S52/2" is separate.
To employ the M48 thread instead of
the T-2 thread to attach the Protective
T-ring to your setup, simply undo theloosely attached M48/T-2 insert ring byusing two fingers in the slots providedandunscrew
theinsert
ring
anticlockwise.
If the M48/T-2 insert ring is screwed in
too firmly after previous use, we
recommend using a spanner with 2mm
pins for disassembly (see Fig.8A). This spanner is available from tool shops.

Fig. 8A: Optional, adjustable 2mm face spanner (#2450062)
Fig. 9:To use the 2" connector socket, loosen the 6
grub screws on the side that retain theS52/M48 ring with the 1.5mm Allen key
supplied and remove it from the body.

Caution: When the 6 grub screws areloosened and the S52/M48 ring removed, the50.8mm filter is no longer secure and can fallout of the front of the body of the Protective
T-ring. To avoid this, do not tilt the baseforward.

Removing the 2" connector socket:Loosen the 6
grub screws on
the side by meansof 1.5mm Allen key
supplied

Now insert the 2" connector socket andtighten the 6 Allen screws carefully and evenly. Sufficient tightness is achieved by using the longside of the Allen key.

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