Baader Planetarium TRIBAND-SCT User manual

– EN ver. 05/2023 –
BAADER PLANETARIUM
Zur Sternwarte 4 •D-82291 Mammendorf •Tel. [phone] / 8089-0 •Fax [phone]
www.baader-planetarium.com •[e-mail] •www.celestron.de
G
M
B
H
Manual
and Application Tipps
Thank you for your purchase of a Baader Planetarium TriBand Schmidt-Cassegrain. These
telescopes are made for professional observations of the Sun with large apertures (espe-
cially in combination with H-alpha-lters) and for narrowband astrophotography.
There are some special things to take in account when observing the Sun with such a
large aperture. For best results, we recommend that you spend a few minutes reading this
manual before using your new TriBand-SCT telescope.

2Manual: Baader Planetarium TriBand-SCT
Table of Contents
Scope of Delivery .................................................... 3
Installing the TriBand ................................................. 4
Attaching accessories ................................................ 4
Focussing.......................................................... 4
Observing the Sun.................................................... 5
Installing the Heat Shields ............................................. 5
Using a Herschel prism (whitelight and CaK) .............................. 5
Using a H-alpha-Filter ................................................ 6
Example Configuration for SolarSpectrum H-alpha-Filter – visual use, M48-System ..........7
Example Configuration for SolarSpectrum H-alpha-Filter – visual use, T-2-System ...........8
Example Configuration for SolarSpectrum H-alpha-Filter – Bino-Viewer ...................9
Example Configuration for SolarSpectrum H-alpha-Filter – for Photography without Reducer .10
Example Configuration for SolarSpectrum H-alpha-Filter – for Photography with a Reducer ..11
Example Configuration for SunDancer TZ3-S, TZ4-S and SunDancer II H-alpha-filter .......12
Example Configuration for Baader FlipMirror II ......................................12
About Magnication and Back Focus of Telecentric Systems ................ 13
Tips for Observing the Sun ........................................... 13
Observing Moon and Planets .......................................... 15
Accessories for Observing the Planets .........................................15
Observing Deep-Sky-Objects. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Technical Data ...................................................... 16
Transmission of the Schmidt Corrector Plate ....................................16
Das Schmidt-Cassegrain-System ...................................... 17
Attaching Accessories ......................................................18
Recommended Accessories ........................................... 19
Collimation ......................................................... 20
Cleaning & Care..................................................... 22
Cleaning Eyepieces ........................................................22
Please note ..............................................................23
Dew ....................................................................23

© 2023 Baader Planetarium GmbH 3
Scope of Delivery
The Baader Planetarium TriBand-SCT telescopes are based on Celestron's proven
Schmidt-Cassegrains. The original Schmidt plate has been replaced by a corrector
plate coated with a TriBand lter, so that the telescope can be used for solar observati-
on (especially with Baader Planetarium and SolarSpectrum H-alpha lters or a Baader
Herschel prism) as well as for narrow-band photography, similar to using a UHC lter.
It consists of:
1
23
4
4
1TriBand-SCT
(SCT = Schmidt-Cassegrain Telescope)
2Celestron 1¼" Visual Back
eyepiece-clamp
3Dovetail
(3" CGE-standard)
4Heat shields for the telescopes front
ring and the secondary mirror
The heat shields 4of the 8" TriBand are
made of two pieces, those of the larger mo-
dels are made of four pieces.

4Manual: Baader Planetarium TriBand-SCT
1
Installing the TriBand
The telescope is connected to the mount like any other telescope via the 3"/CGE
dovetail bar. Please note that the 3" Celestron CGE bar is not identical to the 3" Los-
mandy standard, but is compatible with the 3" clamp of most mounts. If your mount
can only accept dovetail bars with the Losmandy standard, you can use one of the
following dovetail bars:
• Baader Planetarium Dovetail Bar 3", 470 mm for Celestron # 1501615
• Baader Planetarium Dovetail Bar 3", 530 mm for Celestron # 1501620
Both bars t for TriBand C8, C9¼and C11. The longer bars protrude slightly at the
back of the C8 to help balance the telescope when attaching accessories such as
heavy cameras or a long H-alpha lter with a telecentric system. You may need to
remove the telescope's carrying handle for installing the bar.
For the Triband C8, you can also use
• Baader V-Dovetail Celestron-orange anodized, 345 mm für 8" SC/HD # 2451734
to use the telescope on mounts with Vixen-style clamps
Longer rails with matching holes are possible as custom-made products.
Attaching accessories
The telescope has got a 2" adapter thread (SC-thread). The Celestron Standard Visual
Back for connecting 1.25" accessories is screwed onto it. The TriBand 11" also has a
3.3" adapter thread.
The 2" SC thread allows you to connect heavy accessories tightly and tilt-proof. For
the adaptation of accessories with T-2 thread please use
• Baader SC / HD Ultra Short T-Adaptor, 9 mm optical length # 2958500B
For accessories with the standard 2" nose piece, you can install the 2"-SC-Clicklock
eyepiece clamp # 2956220 at the telescope. This eyepiece clamp ts to all three
telescopes. For the 11" model, you can alternatively use the SCL clicklock # 295623,
which ts the 3.3" thread and allows maximum light transmission.
Focussing
To focus the telescope, simply turn the focusing knob 1
at the back of the telescope. Counterclockwise rotation
focuses on more distant objects, clockwise rotation on
closer ones.
As with all telescopes with main mirror focusing, slight
mirror tilting may occur when you change the focusing
direction (see also page 17/18). Get into the habit of always
focusing anti-clockwise last, then the mirror will be clam-
ped sliding on its guide tube and the collimation will also be
maintained.
Tip: Especially for photography, use a motor focuser such as the Celestron Focusing
Motor # 821160 to focus vibration-free from your PC or via a Celestron mount with
Nexstar hand controller.

© 2023 Baader Planetarium GmbH 5
Observing the Sun
Caution: The TriBand coating only replaces the Energy Rejection Filter. For
solar observation, you absolutely need another lter – either a Herschel
prism for white light observation or an H-alpha lter!
Installing the Heat Shields
The outer heat shields are made of two or four segments, which are clicked together
into a ring by strong neodym-magnets.
Remove the telescope's dust cover. To do this, loosen the bayonet lock by turning
the dust cover a little bit counterclockwise. Now you can pull it off, put on the heat
shield and secure it by turning it clockwise. Place the small, round heat shield on the
secondary mirror holder by placing the magnets on the collimation screws. The cover
of the collimation screws of the larger models must be opened for this (see p.20).
The TriBand-telescopes with their heat shields
Avoid setting up the telescope for a long time in such a way that sunlight enters the
tube without the telescope pointing directly at the sun. The integrated ERF will keep
harm from the telescope, but the walls of the tube will heat up unnecessarily.
TriBand C8 with 2"-Clicklock # 2956220
and Baader Cool Ceramic Herschel prism
1
2
Using a Herschel prism
(whitelight and CaK)
We recommend using a 2" ClickLock®clamp
# 2956220 1and the Baader Cool-Ceramic Safety
Herschel prism 2" Mark II Photo # 2956510P 2for
observing in white light. The Solar Continuum Filter
included with our Herschel prism can not be used,
because the energy reecting lter blocks the wave-
lengths around 540 nm. For the necessary further
light attenuation, please use either anadditional neu-
tral density lter or a single variable polarizing lter
(e.g. Baader Single Polarizing Filter 2", # 2408342).
For the sharpest possible images, we recommend
using a monochrome camera combined with a red

6Manual: Baader Planetarium TriBand-SCT
lter such as the Baader RGB R lter 2" # 2961603R or the H-alpha bandpass lter 20
nm 2" # 2961853. This way you observe in the part of the spectrum that is least dis-
turbed by air turbulence. The 7.5 nm Solar Continuum Filter # 2961581, which comes
with our Herschel prism, was designed for 540 nm, as most refractors are optimised
for this wavelength – with a catadioptric telescope, this restriction is removed and you
can use the red part of the spectrum, where there are less air turbulences. The O-III 2"
Super-G lter (9 nm) # 2961551 with passband at 502 nm also delivers similarly good
results as the Solar Continuum lter.
At the other end of the spectrum, in the near UV, the Baader Calcium GEN-II 1¼"
# 2961590 can be combined with the Herschel wedge to observe the sun in the region
of the calcium K-lines. This lter may only be used photographically and absolutely
requires a Herschel prism or one of the following Baader Digital Solar Filters as a pre-
lter:
• TriBand 8": Baader Digital Solar Filter (BDSF) OD 3.8 – 200 mm # 2459376
• TriBand 9¼": Baader Digital Solar Filter (BDSF) OD 3.8 – 240 mm # 2459377
• TriBand 11": Baader Digital Solar Filter (BDSF) OD 3.8 – 280 mm # 2459378
Using a H-alpha-Filter
Depending on the model, an H-alpha lter can either be screwed directly to the
telescope's 2"-thread, or it is connected via the 2" ClickLock clamp # 2956220 if it
is equipped with a 2" nose piece. Especially with the large SolarSpectrum lters, we
recommend the sturdy screw connection to avoid tilting.
On the TriBand telescopes, you do not need an additional energy rejecting lter;
otherwise, the operating instructions for your H-alpha lter apply without restriction.
Both the SolarSpectrum lters and the Baader SunDancer II ideally require a focal
ratio of f/30 to provide the best H-alpha contrast. Therefore, they need a 3x telecentric
system, which increases the focal length of the telescope to 6096 mm (TriBand C8),
7050 mm (TriBand C9¼) or 8400 mm (TriBand C11). Even with a 40 mm eyepiece, you
can thus achieve a very high minimum magnication of 150x to 210x with an exit pupil
of 1.3 mm in each case and are close to the range of maximum magnication that can
be used during the day. By using a SolarSpectrum telecompressor, you can reduce
the magnication again behind the H-alpha lter. This is especially useful when using
modern CMOS cameras, whose small pixels harmonise better with faster focal ratios.
The following telecompressors are available for photography:
• SolarSpectrum Research Grade H-alpha 0.4x Telecompressor 2" # 2459260
• SolarSpectrum 0.7x Telecompressor 2" # 2459259
Resulting focal length with 3x telecentric system and telecompressor:
Telecompressor TriBand 8" TriBand 9¼" TriBand 11"
0,4x Research Grade 2438 mm 2820 mm 3360 mm
0,7x 4267 mm 4935 mm 5880 mm
Please note that the eld of view is limited by the diameter of the H-alpha lter which
is located in front of the reducer.

© 2023 Baader Planetarium GmbH 7
Example Configuration for SolarSpectrum H-alpha-Filter – visual use, M48-System
For very large H-alpha lters, it is worth using the M48 system and 2" eyepieces to
make use of the entire eld of view without vignetting caused by 1¼" eyepieces or T-2
adapters. Smaller H-alpha lters can also be used with 2" accessories, but here the
lter diameter limits the visible eld of view.
The 2" Research Grade TZ-3 # 2459257 has a back focus of 250 mm, although there
is some exibility due to the parallel beam of light. We recommend the following setup
for 2" eyepieces:
1TriBand Schmidt-Cassegrain with SC-thread
2# 2958243 Baader Ultrashort 2"/ 2" Thread-Inverter-Ring, included with the TZ-3
3# 2459257 2" Research Grade TZ-3 Telecentric System (3-times extension of the
focal length),
4# 2958244 Baader Reducing-Ring 2"i / T-2a, with 1.5 mm optical length, included
with the TZ-3 – to attach SolarSpectrum-Filters with T-2-thread. Not needed for
SolarSpectrum-lters with female SC-thread.
5
SolarSpectrum-Filter with female SC-thread on both sides. Filters which only have
T-threads on the eyepiece side need in addition the reducing piece M48a / T-2i
# 2958553, cf. 6
6# 2454834 2"a / M48i Zero-length reducing piece (zero optical length) and
# 2958555 Conversion Ring M48a/M48a. If your lter has got a xed male T-2-th-
read, you need Reducing piece M48a / T-2i # 2958553 instead.
7# 2958593 Baader Heavy Duty M48 Quick Changing System, length 15 mm *
82 pieces # 2958610 Baader M48 extension tube 10 mm
9# 2956248 Baader 2" ClickLock M48i Eyepiece Clamp, length 36,5 mm *
10 Prism diagonal, e.g. # 2456117 Baader 2" BBHS®Prism Star Diagonal
11 Eyepiece, z.B. # 2454636 36 mm Hyperion Aspheric 2" Eyepiece
*) When using the eyepiece clamp 9, the quick changer 7can be replaced with M48
extensions, or vice versa. Instead of using 9, the nosepieces of our 2" star diagonals
can also be screwed directly onto a M48 extension tube.
1 2 10
11
5
7
6
8
9
43

8Manual: Baader Planetarium TriBand-SCT
Example Configuration for SolarSpectrum H-alpha-Filter –
visual use, T-2-System
For smaller H-alpha-lters with a diameter of 42 mm or less, an adaptation with the T-
2-System and a 1¼" or 2" eyepiece clamp can be used.
1TriBand Schmidt-Cassegrain with SC-thread
2# 2958243 Baader Ultrashort 2"/ 2" Thread-Inverter-Ring, included with the TZ-3
3# 2459257 2" Research Grade TZ-3 Telecentric System (3-times extension of the
focal length),
4# 2958244 Baader Reducing-Ring 2"i / T-2a, with 1.5 mm optical length, included
with the TZ-3 – to attach SolarSpectrum-Filters with T-2-thread. Not needed for
SolarSpectrum-lters with female SC-thread.
5
SolarSpectrum-Filter with female SC-thread on both sides.
5SolarSpectrum-Filter with T-2-threads. Filter with SC-thread can be attached
directly to the telecentric system, without 4
6# 1508035 Baader Adapter 2" (male) / T-2 (male) – only for SolarSpectrum-lters
with female SC-thread, included with the SolarSpectrum-lters
7Recommended: 3x # 1508153 Baader T-2 / 40 mm Extension Tube
8# 2456322 Baader TQC/TCR Heavy duty T-2 Quick Changing System
9T-2 prism diagonal, e.g. # 2456095 Baader T-2 Star Diagonal (Zeiss) Prism with
BBHS®coating
10 T-2 eyepiece clamp, e.g. Baader Focusing Eyepiece Holder 1¼" / T-2 # 2458125,
Baader 2" to 1¼" ClickLock Reducer (T-2 part #15B) # 2956214
or Baader 2" ClickLock T-2 (M42i x 0.75) clamp # 2956242
11 Eyepiece, e.g. # 2454636 36 mm Hyperion Aspheric 2" eyepiece – can be used as
2"-eyepiece as well as 1¼"-eyepiece
Please note: The perfect working distance of the TZ-3 is 250±10 mm, but in practice
the system is very good-natured, so that one or more the three 40 mm extensions
# 1508153 may also be omitted if desired.
In principle, smaller magnications (but not a larger eld of view!) are possible with a
reducer, so that the telescope can also be used with highly visible air turbulence. How-
ever, if the exit pupil becomes larger than the pupil of your eye (which is only about
1 2
10
11
5
7
68
9
4
3

© 2023 Baader Planetarium GmbH 9
1.5 mm in daytime), you may see the shadow of the secondary mirror as a dark spot,
and the distance of the eyepiece to the reducer must be maintained for it to work as
desired. Therefore, a long focal length eyepiece is easier to handle for visual use than
a reducer.
Typical long focal length eyepieces give you:
Classic Ortho 32mm
1¼" – #2954132
Hyperion 36mm
1¼" (2") – #2454636
Celestron Omni 40mm
1¼" – #810246
Celestron Omni 56mm
2"– #810248
Mag. | EP | FoV Mag. | EP | FoV Mag. | EP | FoV Mag. | EP | FoV
TriBand C8 190x | 1 mm | 0.26° 166x | 1,2 mm | 0.3° (0.43°) 152x | 1,3 mm | 0.28° 109x | 1,9 mm | 0.43°
TriBand C9¼ 220x | 1 mm | 0.22 195x | 1,2 mm | 0.25° (0.37°) 176x | 1,3 mm | 0.25° 126x | 1,9 mm | 0.37°
TriBand C11 262x | 1 mm | 0.2° 233x | 1,2 mm | 0.21° (0.31°) 210x | 1,3 mm | 0.21° 150x | 1,9 mm | 0.31°
EP = Exit pupil | FoV = Field of View
The eld stop of the Hyperion 36 in 1¼" conguration is 32 mm, providing the largest
eld of view achievable with 1¼". The eld stop of a typical long focal length 1¼" eye-
piece is a maximum of about 26 mm, that of a 2" eyepiece about 45 mm.
The achievable eld of view is determined both by the diameter of the eld stop of
the eyepiece and that of the H-alpha lter; a longer eyepiece focal length or a 2" nose-
piece therefore do not necessarily also provide more eld of view.
Example Configuration for SolarSpectrum H-alpha-Filter – Bino-Viewer
1TriBand Schmidt-Cassegrain with SC-thread
2# 2958243 Baader Ultrashort 2"/ 2" Thread-Inverter-Ring, included with the TZ-3
3# 2459257 2" Research Grade TZ-3 Telecentric System (3-times extension of the
focal length),
4# 2958244 Baader Reducing-Ring 2"i / T-2a, with 1.5 mm optical length, included
with the TZ-3 – to attach SolarSpectrum-Filters with T-2-thread. Not needed for
SolarSpectrum-lters with female SC-thread.
5SolarSpectrum-Filter with T-2-threads. Filter with SC-thread can
be attached directly to the telecentric system, without 4
6# 1508035 Baader Adapter 2" (male) / T-2 (male) – only for
SolarSpectrum-lters with female SC-thread, included with the
SolarSpectrum-lters
7#2456322 Baader TQC/TCR Heavy duty T-2 Quick Changing System
12
10
5
7
6
8
9
4
3

10 Manual: Baader Planetarium TriBand-SCT
8T-2 prism diagonal, e.g. # 2456095 Baader T-2 Star Diagonal (Zeiss) Prism with
BBHS®coating
9# 2456313A Baader Heavy Duty T-2 QuickChanger (T-2 part #06A) for bino-viewers
with Zeiss dovetail. Not necessary for binoviewers with T-2 knurled slip ring
10 Bino-viewer, e.g. # 2454636 MaxBright II or # 2456410 Mark V Großfeld (Giant)-
Binocular, to be used without glasspath corrector
In this conguration, the generous working distance of the TZ-3 shines, and you can
observe the sun with both eyes.
Example Configuration for SolarSpectrum H-alpha-Filter – for Photography without
Reducer
1TriBand Schmidt-Cassegrain with SC-thread
2# 2958243 Baader Ultrashort 2"/ 2" Thread-Inverter-Ring, included with the TZ-3
3# 2459257 2" Research Grade TZ-3 Telecentric System (3-times extension of the
focal length),
4# 2958244 Baader Reducing-Ring 2"i / T-2a, with 1.5mm optical length, included
with the TZ-3 – to attach SolarSpectrum-Filters with T-2-thread. Not needed for
SolarSpectrum-lters with female SC-thread.
5SolarSpectrum-Filter with T-2-threads. Filter with SC-thread can be attached di-
rectly to the telecentric system, without 4
6# 1508035 Baader Adapter 2" (male) / T-2 (male) – only for SolarSpectrum-lters
with female SC-thread, included with the SolarSpectrum-lters
7T-2-extensions to set up the camera's working distance. The back focus of the
TZ-3 is 250 mm ±10mm. E.g. for a camera with 17 mm back focus and a circa 60
mm long H-alpha-Filter as shown above, you can use 4x # 1508153 Baader T-2 /
40 mm Extension Tube.
8Monochrome Camera
Please note: You can also integrate a camera tilter or an ADC into the stack of T-
2-extensions 7to avoid Newtonian rings in your images. Cameras with M48-thread
can be adapted with a T-2-adapter or using the M48-system as described on page 7.
1 2
5
6
7 8
4
3

© 2023 Baader Planetarium GmbH 11
Example Configuration for SolarSpectrum H-alpha-Filter – for Photography
with a Reducer
1TriBand Schmidt-Cassegrain with SC-thread
2# 2958243 Baader Ultrashort 2"/ 2" Thread-Inverter-Ring, included with the TZ-3
3# 2459257 2" Research Grade TZ-3 Telecentric System (3-times extension of the
focal length),
4# 2958244 Baader Reducing-Ring 2"i / T-2a, with 1.5 mm optical length, included
with the TZ-3 – to attach SolarSpectrum-Filters with T-2-thread. Not needed for
SolarSpectrum-lters with female SC-thread.
5SolarSpectrum-Filter with T-2-threads. Filter with SC-thread can be attached
directly to the telecentric system, without 4
6In addition only for SolarSpectrum-Filters which only have a T-2-thread: # 2958110
Baader T-2 Conversion Ring and # 2958244 Baader Reducing-Ring 2"i / T-2a, with
1.5 mm optical length. Not necessary for SolarSpectrum-lters with SC-thread
7# 2459259 SolarSpectrum 0.7x Telecompressor 2" with 110 mm back focus
or
# 2459260 SolarSpectrum Research Grade H-alpha 0.4x Telecompressor 2" with
74mm back focus
Please note the adjacent
diagram for the correct orien-
tation of the reducer.
8# 2958244 Baader Reducing
Ring 2"i / T-2a, with 1.5 mm
optical length
9T-2-extension(s) to set the
working distance for your
camera
10 Monochrome camera
1 2
5
7
6
8
9 10
4
3

12 Manual: Baader Planetarium TriBand-SCT
Example Configuration for SunDancer TZ3-S, TZ4-S and SunDancer II H-alpha-filter
The Baader SunDancer TZ3-S # 1363070 with 115 mm backfocus and TZ-4S
# 1363080 with 120 mm backfocus have a combined 2"/1¼" nosepiece. For
photographic use, a # 2956220 SC / HD
2" clicklock can be connected directly to
the telescope. For visual use, an additional
star diagonal in front of the telecentric is
recommended.
The SunDancer II H-alpha lter # 2456117
uses a modied version of the TZ-3, with
the block lter built into the TZ3-S. To
use the SunDancer II with the TZ4-S, this
block lter must be moved from the TZ3-S
to the TZ4-S. The connection of eyepieces,
cameras or reducers is done according to
the manual of the SunDancer II.
SolarSpectrum lters do not require an additional block lter when using the TZ3-S
or TZ4-S.
Example Configuration for Baader
FlipMirror II
If you use the telescope both
photographically and visually, wor-
king with a ip mirror such as the
Baader FlipMirrorII star diagonal
# 2458055 becomes particularly
convenient. With a ick of the wrist,
you can switch between eyepie-
ce and camera. The ip mirror is
mounted behind the H-alpha lter
via the T-2 thread. An eyepiece can
be brought into the same focus
position as the camera sensor with
the Baader Focusing Eyepiece Hol-
Baader SunDancer II with 2" BBHS
star diagonal # 2456117 for connection
to the 2" SC-Clicklock # 2956220
The Flip Mirror II behind a Baader SunDancer II (above)
and a SolarSpectrum Filter (below, without the additional 40 mm T-2-extensions).

© 2023 Baader Planetarium GmbH 13
Tips for Observing the Sun
A solar telescope of this size makes special demands on observation conditions. Ple-
ase take note of the following tips:
• Let the telescope cool down well, and always use the heat shields. With (Schmidt)
Cassegrain optics, the light passes through the tube three times, so air turbulences
inside the tube are more noticeable than with a refractor. Therefore, avoid that the
sun moves out of the centre of the image and illuminates and heats the inner walls
of the tube. Do not turn the telescope out of the sun during observation breaks, as
then only one side of the telescope will heat up unevenly. It is better to cover it. If
you are observing from an observatory, simply close the roof or dome slit so that
the telescope is completely in the shade.
der 1¼" / T-2 # 2458125, so that it is not necessary to refocus when looking through
the eyepiece. The working distance for the camera sensor at the straight port and for
the eld diaphragm of the eyepiece at the top port is identical in each case.
With the T-2 quick-release system # 2456322, the ip mirror or camera can be rotated
into a convenient position, even when the H-alpha lter is screwed tightly onto the
telescope.
The SunDancer II with integrated TZ-3S has an ideal working distance of 65 mm,
the folding mirror can be screwed directly onto the SunDancer unit. The 2" Research
Grade TZ-3 # 2459257 has a working distance of 250 mm, here we recommend additi-
onally two pieces # 1508153 Baader T-2 / 40 mm Extension Tube.
About Magnification and Back Focus of Telecentric Systems
In contrast to a barlow lens, behind which the beam of light widens, a telecentric
system provides a parallel beam of light. This is necessary for the proper functio-
ning of an H-alpha lter (which requires both at least f/30 and a parallel beam for
best results). The second advantage of this design is that the distance between ca-
mera/eyepiece and telecentric system can also be signicantly shortened without
noticeably affecting the image.
In practice, you can therefore often also work with fewer extension tubes and a
shorter distance. The 2" Research Grade TZ-3 # 2459257 is calculated for a wor-
king distance of 250 mm, so that it also works perfectly with a binoviewer. But even
with a distance of only 180 mm, you will hardly notice any degradation
of the image – while the shorter lever means that there is less strain on
your mount.
Unlike a Barlow lens, you cannot change the image
scale by changing the working distance. For higher
magnication (if feasible with your camera's pixel size),
instead of a Barlow lens, we recommend our Telecentric
System TZ-4 # 2459256 (230 mm working distance) or
the SunDancer TZ-4S # 1363080 (120 mm working dis-
tance). Unlike standard barlow lenses, these telecentrics
are also optimised for H-alpha observation. SunDancer TZ-4S # 1363080 (left) and
TZ-4 # 2459256 (right)

14 Manual: Baader Planetarium TriBand-SCT
• Wait for moments of good seeing. The large aperture leads to a high minimum mag-
nication, so that disturbing inuences of bad seeing become visible, which are not
noticeable in smaller instruments. Observe the local conditions at your observation
site during the course of the day; the air is usually calmest in the morning.
• Keep your distance. Especially for photography, you can set up the control PC at a
greater distance behind the telescope. Even sitting next to the telescope can have a
negative effect on local seeing.
• Use a good glare shield. Both good eyecups and an observation cloth which is
white on the outside and black on the inside and which is pulled over your head are
very effective in blocking stray light and increasing the perception of detail.
• Avoid exit pupils that are too large. If the exit pupil is larger than the pupil of your
eye (approx. 1.5 mm during the day), you will see the "shadow" of the telescope's
secondary mirror oating in the image as a black spot.
• Avoid too small exit pupils when observing in H-alpha. The rule of thumb that the
maximum magnication is twice the telescope aperture in millimetres (i.e. an exit
pupil of 0.5 mm) does not apply to H-alpha observation because of the longer
wavelength. If the exit pupil is much smaller than about 0.8-0.7 mm, the image
contrast will eventually break down.
• Use a double polarising lter or a single circular polarising lter to suppress reec-
tions. Some light attenuation can also make it easier to perceive faint structures.
• Some monochrome cameras show conspicuous Newtonian rings on H-alpha lters,
which cannot be eliminated even by ats. They are caused by interference in the
camera. Sometimes they only appear when observing with (or without) a reducer.
There are two ways to eliminate them:
1. A tilter can tilt the camera so far that no
more interference occurs. However, it
may be necessary to tilt the camera so
much that, with large sensors, even at
f/30, parts of the sensor are no longer in
the focal plane.
2. An ADC (Atmospheric Dispersion Cor-
rector) can also effectively eliminate the
Newtonian rings and is better suited for
this than a tilter. Make sure that the ADC
has sufcient free aperture.
• When photographing solar structures, it can be useful to use guiding with an
autoguider even for the sun, so that the structures remain centred in the image for
a long time. You can connect a guiding camera via the VarioFinder with a suitab-
le solar lter (see p. 19). Software such as Sharpcap offers the option of "feature
tracking" to also track sunspots.
• Take ats to compensate for dirt on the sensor or on the telescope.
Newtonian rings are the result of interferences in
monochrome cameras (here a ZWO ASI120MM).

© 2023 Baader Planetarium GmbH 15
Observing Moon and Planets
The slightly different transmission widths of the individual transmission windows
result in slightly different exposure times for RGB images for the same brightness. The
Baader LRGB lter set needs approximately the following exposure times for same
brightness, normalised to the luminance channel:
Luminance: 1x Red: 2x Green: 5,3x Blue: 5,3x
Depending on the camera sensitivity, these values may vary, but they give a good
start and should be taken into account for colour weighting.
When taking black-and-white photographs (especially of the moon), it is advisable to
use a red lter (e.g. LRGB red lter # 2961603R or 20-nm H-alpha # 2961853) or the OIII
Super-G 9 nm green lter # 2961551, as these reduce the inuence of air turbulence
compared to photography without a lter.
With a colour camera, it must be taken into account that the blue channel in particular
is very close to the edge of the visible spectrum. The white balance must be adjusted
accordingly. For an automatic white balance, the moon is a good reference.
Accessories for Observing the Planets
Since the TriBand telescopes are based on classic Schmidt-Cassegrains, you can use
any conventional Barlow lens or telecentric system for focal length adjustment, and
also the Baader FFC for particularly high magnications. You will nd a selection at
Baader-planetarium.com.
The heat shields are not necessary for night-time observing, instead you should use
a dew cap. The Celestron heat rings (# 825912, # 825913, # 825914) are not compatible
with the TriBand, as you will then not be able to insert the heat shields.
Observing Deep-Sky-Objects
Deep sky observation is possible with the TriBand as usual, but the image is darker
because you are already observing with a built-in lter, similar to a UHC lter. For ob-
serving objects with a continuous spectrum such as galaxies or star clusters, a normal
telescope is therefore better suited.
The TriBand coating is designed for use with narrowband nebula lters and allows
the important H-beta, O-III, H-alpha and S-II lines to pass. For RGB images, a little
more effort may be required in colour calibration or adjustment of the exposure time of
the individual RGB channels.
Using the SC thread or the T-adapter # 2958500B, you can connect lter wheels or
the Baader UFC lter slider to the telescope in the usual tilt-proof manner. For optimal
image quality, please note the specication of the back focus in the technical data.
The Baader Planetarium TriBand telescopes are based on the Celestron Schmidt-
Cassegrains and can be used like these with the common reducers.

16 Manual: Baader Planetarium TriBand-SCT
Technical Data
TriBand 8" TriBand 9¼" TriBand 11"
SKU # 2301002 # 2301003 # 2301004
Aperture 203 mm (8") 235 mm (9¼") 279 mm (11")
Focal Length 2032 mm 2350 mm 2800 mm
f/ratio f/10 f/10 f/10
Optical Design Schmidt-Cassegrain Schmidt-Cassegrain Schmidt-Cassegrain
Transmission Range 380 to 400 nm, 480 to 515 nm, 630 to 680 nm
Accessory Adaptation 2" SC-thread,
1¼" Visual Back
2" SC-thread,
1¼" Visual Back
3,3" + 2" SC-thread,
1¼" Visual Back
Ideal Back Focus 127 mm primary mirror
baffle tube lock ring
139 mm from primary
mirror baffle tube lock ring
139 mm from 3 in-2 in
Reducer Plate / 152 mm
from 3 in Primary Mirror
Baffle Tube Lock Ring
Secondary Mirror
Obstruction
6,9 cm 8,5 cm 9,5 cm
Secondary Mirror Ob-
struction by Diameter
33,8 % 36,2 % 34 %
Secondary Mirror
Obstruction by Area
11,4 % 13,0 % 11,6 %
Resolution (Rayleigh) 0,69" 0,59" 0,5"
Resolution (Dawes): 0,57" 0,49" 0,42"
Optical Tube Material Aluminium Aluminium Aluminium
Optical Tube Length 43 cm 56 cm 61 cm
Dovetail Bar 3" CGE 3" CGE 3" CGE
Weight 6,25 kg 10 kg 13,1 kg
Transmission of the Schmidt Corrector Plate
The transmission of the TriBand coating and the position of important emission lines
The corrector is blocked in the IR up to 1400 nm to prevent the tube from heating up.

© 2023 Baader Planetarium GmbH 17
The Schmidt-Cassegrain-System
The optical design of the Schmidt-
Cassegrain telescope can be seen in
the illustration to the right.
The (parallel) beam of light from an
observation object enters the tube
from the right, passes the Schmidt
corrector plate and is reected by the
main mirror onto the secondary mirror.
This reects the beam of light and
simultaneously focuses it at the focal
point (image plane) of the telescope.
The two sky bafes are bafes that
also enable low-stray light observations in daylight with a Schmidt-Cassegrain tele-
scope. The tube at the rear end (left in the illustration) also serves as a guide for the
main mirror for focusing. The adjustment of the image sharpness (focusing) of diffe-
rent distances of an observation object is achieved with this design by changing the
distance between the main mirror and the secondary mirror. The secondary mirror is
xed and the primary mirror is moved back and forth on the sky bafe via a threaded
spindle.
The primary mirror has a spherical surface shape, the secondary mirror is also sphe-
rically curved, extending the primary focal length of the primary mirror by a factor of 5.
The combination of these mirror shapes makes it possible to build relatively long focal
length telescopes in mechanically short tube lengths.
Classical, so-called Seidel aberrations (such as coma), which are caused by the com-
bination of a spherical primary mirror with a spherical secondary mirror, are corrected
by the Schmidt plate that closes the front tube opening. The image eld plane in the
focus of the SC system is slightly curved. If the image eld is to be at (planar), an
additional optical corrector must be installed in the beam path.
The illustration on the right shows
the inner workings of a Schmidt-
Cassegrain telescope. It is focused
by moving the main mirror (this
changes the distance between the
main mirror and the secondary mir-
ror changes and thus also the focus
position behind the tube end plate).
The main mirror is mounted on an
aluminium plate, which in turn is
connected to a sleeve. This sleeve
slides (lubricated with grease) over
the tube of the rear sky bafe (gui-
de). The aluminium plate and thus
the main mirror with guide sleeve
are connected to the focus screw.
A left turn of the focus screw (when
Main Mirror
Image Plane Secondary Mirror
Sky Baffle Schmidt Corrector
Accessory Thread
("Visual Back")
Focus Mechanism
Back of Tube
Back of Tube
Main Mirror housing
Guide Sleeve
Sky Baffle
Main Mirror
Focusing
Right Left
(clockwise) (counter-
clockwise)
Main Mirror

18 Manual: Baader Planetarium TriBand-SCT
looking in the direction of the Schmidt plate) pushes the main mirror towards the
Schmidt plate, a right turn pulls the mirror towards the tube back plate.
Now there must inevitably be some space between the outer diameter of the sky
bafe and the inner diameter of the sleeve; otherwise you could not move the sleeve.
This minimal difference in diameter (which is sometimes greater and sometimes smal-
ler due to temperature differences) is responsible for the so-called mirror shift. If you
turn the focus screw back and forth (left and right), the main mirror tilts minimally (due
to the play in the diameters of the guide sleeve and sky bafe) in its position relative to
the optical axis. During visual observation, this tilting is noticeable by a slight change
in the position of the object of observation in the eld of view and is not too tragic.
The situation is different in photography: If the position of the telescope tube chan-
ges slowly in the course of the exposure time,
it can happen that the main mirror suddenly
changes its position and tilts slightly. This
results in a change of position of the object of
observation in the eld of view.
The slight tilting of the main mirror can
easily be avoided if you "focus correctly". The
picture on the right is intended to illustrate
this. "Wrong focus" is when the focus position
is adjusted by turning the focus screw to the
right. The mirror is pulled back and the play
between the sky bafe and the guide sleeve
is at the bottom left. If the tube now slowly
moves to a more vertical position due to the
tracking, the mirror can suddenly slide back a
little under its own weight.
In the case of "correct focusing", tilting of
the mirror is impossible. If you turn the focus
screw to the left (counterclockwise), it pushes
the main mirror forward. The play between the sleeve and the sky bafe is now at the
bottom right. The mirror mount is practically clamped onto the Sky Bafe with the
guide sleeve. This prevents the mirror from tilting.
Attaching Accessories
Caution: For mounting accessories, only the three pairs of pan head screws 1
, 2and 3in the illustration on page 19 may be loosened on the rear tube cell, but
not the other countersunk screws. For mounting accessories, you may need slightly
longer screws (8/32 UNC, 1/2 inch). Do not use screws that are too long, as they may
damage the main mirror. There are one or two screws 4on the front tube cell which
are used to attach an accessory bar (together with the pair of screws 2). We offer
matching screws under order number #889001 if no matching screws are included
with your accessories.
Play
Play
Push
Pull
Focusing
clockwise
Focusing
counter-
clockwise
Mirror can
move
Mirror is
locked

© 2023 Baader Planetarium GmbH 19
Recommended Accessories
We recommend the following accessories to expand the scope of delivery:
• Baader Standard Base for all Vixen-style finderscope mount bases # 2457000
• Baader Multi-Purpose Vario Finder 10x60 with MQR IV finder holder # 2957465
plus 65 mm AstroSolar Spotting Scope Filter (ASSF) # 2459336
This combination already includes a standard base for mounting the nder on the
telescope and serves with the ASSF solar lter as a solar nder. With a T-2 Extensi-
on Tube 40 mm # 1508153, a camera can also be attached, either for guiding or ob-
serving the sun in white light. With the Baader FlipMirror II star diagonal # 2458055,
it is possible to switch between an eyepiece and a camera.
• 2"-Eyepiece Clamp for 2"-accessories:
• For TriBand 8", 9¼"and 11": 2" ClickLock SC / HD (2") Clamp # 2956220
• Alternatively only for TriBand 11": 2" ClickLock SCL (3.3") Clamp # 295623
• Dovetail bars for Mount or Accessories (Custom lengths on request)
• 3" Dovetail Bar, 470 mm for Celestron # 1501615
• 3" Dovetail Bar, 530 mm for Celestron # 1501620
These dovetail bars are compatible with the 3" Losmandy standard and can also
be installed on top of the telescope to attach additional accessories
• V-Dovetail Bar, 345 mm for 8" SC/HD # 2451734 – short dovetail bar to use the
TriBand C8 on Vixen-stlye mounts
• V-Dovetail Bar, 470 mm for SC # 2451101 – extra long dovetail bar to use the
TriBand C8 on Vixen-style mounts, and to better balance them. Please note
that this bar can only be installed on the upper side of the TriBand C8 – this is
nor problem for using the telescope, but then it is upside down, and installing a
nder is not practical.
• Leveling Counterweights to balance the telescope, are
mounted on the dovetail bar:
• 1 kg leveling counterweight and 3" riderclamp
# 2451576
• 1 kg leveling counterweight and V-dovetail clamp,
# 2451531
• Celestron Focus Motor # 821160
• Solar Shade with drilled hole T-2 # 2959279
• Dew Shield (only for observations at night, without the
heat shields)
• Celestron Dew Shield DX for C6 & C8 # 821128
• Celestron Dew Shield DX for C9¼ & C11 # 821129
1
2
4
3
The screws for attaching further
accesories

20 Manual: Baader Planetarium TriBand-SCT
Collimation
The collimation of the optical system is necessary so that the telescope can deliver its
best possible imaging performance. The centring of the optical axes of the telescope
is guaranteed at the factory by the installation of the primary mirror, Schmidt plate and
secondary mirror. The primary mirror in the Celestron SC telescopes is also centred via
the guide tube on the Sky Bafe and is not designed to be adjustable. For collimation,
therefore, only the secondary mirror must be adjusted via three small screws to the
primary mirror. Especially for mobile use, you should check the collimation occasio-
nally, as the setting screws can be slightly misaligned due to shocks or temperature
changes.
The two illustrations above show the position of the respective adjustment screws of
the secondary mirror in the centre of the Schmidt plate. The screws of the 8" TriBand
SCT are exposed, those of the larger models are hidden behind a cover. They can be
accessed by turning the cover.
Collimating a SC telescope is not complicated, but it does require concentration.
Before moving these screws, be sure that the system really needs to be collimated
and any unsatisfactory view is not caused by seeing effects. The following images
show a brighter star through a decollimated SC telescope, at various focus positions.
To check, let the telescope cool down (in case of strong temperature differences,
e.g. in winter, up to 45 minutes). Then point the telescope at a sufciently bright star
at least 20° above the horizon and use a high-magnication eyepiece (focal length
10mm or shorter). Turn the focusing knob half a turn to the right or one turn to the left.
The image series shows the image of a star (from left to right) strongly out of focus (extrafocal), in the middle exactly
in focus and on the right strongly in focus (intrafocal). The black eccentric circle is the shadow of the secondary
mirror. The decollimation can be recognised by the eccentricity of the shadow.
If the image of a star in your telescope is similar, collimation is necessary. It is best
to work in pairs, one person looking through the eyepiece, the second turning the
adjustment screws.
The collimation screws in the secondary mirror mount. On the Triband C8 they are exposed, on the TriBand C9¼
and C11 they are under a cover flap (left), which you have to turn to expose the screws (right).