Baader Planetarium SUNDANCER II User manual

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 the Baader SunDancer II H-alpha lter! It is a high quality
product for solar observation. When observing the sun, always exercise due caution and
follow the safety instructions.
For best results, we recommend that you spend a few minutes reading this manual before
using the SunDancer II.
– EN ver. 09/2021 –

2© Baader Planetarium GmbH | 2021 3
Manual: SunDancer II
Baader SunDancer II H-Alpha-Filter
Congratulations on your purchase of the SunDancer II from Baader Planetarium.
It is a compact H-alpha lter that integrates a 3x telecentric system, a blocking lter
and a heated H-alpha etalon from SolarSpectrum in two separable housings. It has
been designed with safety and ease of use in mind, combined with an extremely age-
resistant construction and a high-quality lter. The most important features are:
• H-alpha lter with a half-width (FWHM) of 0.6±0.1Å at an effective focal ratio of f/30;
shows prominences and solar surface details.
• Integrated 3x telecentric system with 2nm Half-Bandwidth (FWHM) blocking lter.
The TZ3-system is suitable up to 35 mm eld of view without vignetting. Optimal for
telescopes with f/10, recommended up to about f/8 and usable up to about f/6.5.
On optics faster than f/10, the FWHM (Full Width at Half Maximum) increases
• Easy change of the transmission line by turning the micrometer screw to observe
fast solar events in the blue wing of the H-alpha line (Doppler shift)
• Resistant to ageing: The dielectric coating of the blocking lter (instead of the usual
silver coating) and the airtight storage of the Etalon lter in oil prevent the ageing
processes of simpler lter designs. With proper treatment, the lter will retain its
performance for many years
• 25 mm Etalon from SolarSpectrum – with 23 mm aperture behind 19 mm aperture bafe
• Removable focusable 1¼" eyepiece clamp and T-2 thread for connecting cameras
• On telescopes with up to 80 mm aperture and a focal ratio of f/8 or slower, it can be
operated without an additional D-ERF energy protection lter in front of the objecti-
ve – tested for 10 hours on the Baader-Apo 95 at f/6.1
• Electrical temperature control: the lter automatically heats up to its optimum ope-
rating temperature as soon as it is connected to the power supply
• Low power consumption: Via the supplied main adapter or, in mobile use, via an
optional rechargeable battery pack
• Wide operating temperature range: -10 to +40° C; storage temperature not below
0° C
Table of Content
SunDancer II H-Alpha-Filter ............................................ 3
All in one! ........................................................... 4
Scope of Delivery .................................................... 5
Preparations......................................................... 6
Choosing a Dielectric Energy Rejection Filter .............................. 6
Usage without an Energy Rejection Filter ........................................7
The Telecentric System and Thoughts about the Telescope ................... 7
Eyepieces.......................................................... 9
Choosing a Star Diagonal ............................................ 10
Power Supply...................................................... 10
Observing with the SunDancer II ....................................... 11
The parts of the SunDancer II ......................................... 11
Connecting to the telescope .......................................... 11
The Functions of the Temperature Control Box............................ 12
Changing the Operation Temperature ..........................................13
Using a Neutral Density Filter ......................................... 13
Using a Telecompressor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Using a Bino-Viewer ................................................ 15
Calibrating the Filter and Settings of the Temperature Control Box .......... 16
Setting the Temperature.............................................. 16
Calibrating the Filter................................................. 17
Tilting the Filter ...........................................................17
Troubleshooting ...........................................................17
Photography ....................................................... 18
1¼" Video Modules/Planetary Cameras ................................. 18
DSLR and CCD Cameras............................................. 19
Telecompressor .................................................... 20
Afocal Photography ................................................. 20
Storage and Maintenance ............................................ 21
Safety information ................................................... 21
Technical Data ...................................................... 21
Don't miss anything – The Baader-Planetarium Newsletter .................. 22

4© Baader Planetarium GmbH | 2021 5
Manual: SunDancer II
1
23
4
5
Scope of Delivery
of the SunDancer II
1. SunDancer II H-alpha-lter unit comprising the blocking lter, 3x telecentric system
and focusing eyepiece holder # 2458125
2. Temperature control box (hand control)
3. Power supply (with international adapters)
4. Carrying case
5. Baader Utility Bag # 2954201
All in one!
An H-alpha lter system consists of several elements:
• The etalon filter is the actual H-alpha lter. As an interference lter, it cancels out all
wavelengths except the H-alpha line. Its lter effect depends on the lter thickness
and is automatically controlled by the temperature control.
• The telecentric system provides the parallel beam of light path which is necessary
for the etalon to function properly. A Barlow lens or even a telescope with f/30 pro-
vides the necessary focal ratio, but not the necessary parallel beam of light.
• The blocking filter reects the
incident sunlight just in front of
the etalon and the telecentric. This
protects the etalon from excessive
heat. In addition, an etalon also
transmits wavelengths that are
many times the desired transmissi-
on line; these are also blocked by
the blocking lter.
• The D-ERF energy rejection filter
is mounted in front of the telescope
and protects the lter system from
unnecessary solar energy by al-
lowing only red light to pass.
With the SunDancer II, the etalon,
telecentric system and blocking lter form one unit; on telescopes with a maximum
aperture of up to 80 mm, the energy protection lter can be omitted if necessary (see
chapter "Choosing a Dielectric Energie Rejection Filter"). The result: easier handling
and lower entry costs!
Front Lens
Mirror Star
Diagonal
2nm H-alpha
Blocking Filter
(Ø12mm)
Achromatic 3x
Telecentric System
Etalon (Ø25mm)
tiltable, heated
Bae (Ø19mm)
Micrometer Screw
Research Grade
H-alpha 0.4x
Telecompressor 2"
Focusing
Eyepiece Holder
(# 2458125)
Eyepiece
Eyecup with
Folding Wing
D-ERF
(for apertures > 80mm)
Aperture Bae
or Diaphragm
Schematic Structure of A H-alpha-Telescope with
SunDancer II Filter
A D-ERF filter is only necessary on telescopes with
more than 80 mm aperture. With an optional aperture
baffle or iris diaphragm, the telescope can be stopped
down to the ideal focal ratio of f/10.
Red: Components of the SunDancer II.
Yellow: Optional accessories.
SunDancer II at a telescope with mirror star diagonal.
Hand control and power supply are stored in the yellow bag.

6© Baader Planetarium GmbH | 2021 7
Manual: SunDancer II
Usage without an Energy Rejection Filter
With telescopes with an aperture of
80mm or less and a focal ratio of f/8 or
slower, the SunDancer II can be used
without an energy protection lter (ERF)
in front of the telescope objective. This
makes it a particularly inexpensive and
safe system for H-alpha solar observation,
as you only need one accessory and do
not run the risk of forgetting the D-ERF
front lter.
However, only the observer behind the
eyepiece is safe. When using the telescope
without D-ERF, the tightly bundled light beam is rst reected inside the tube at the
front block lter before the telecentrics and is then deected out of the telescope
towards the front again. Therefor when using the telescope without a D-ERF, make
sure that no one can look into the telescope from the front. The risk is highest with
low-mounted, short-focal length telescopes pointed at a low-elevation sun. The photo
shows the glistening bright reected light beam in front of an 80 mm objective.
You can also use D-ERF lters on smaller telescopes, as they protect the inside of the
tube from the heat of the sun. This has no inuence on the function of the SunDancer II,
but it may affect the tube entrance and thus the possible maximum magnication.
The Telecentric System and Thoughts about the Telescope
The SunDancer II has a built-in 3x telecentric system with an integrated blocking lter.
Similar to a Barlow lens, the telecentric system triples the focal length and effective
focal ratio of the telescope, but unlike a Barlow, it also ensures a parallel beam path.
There is no way that a parallel light beam would result without a telecentric even in a
native f/30-telescope or in a telescope would be brought to this focal ratio with a Bar-
low! A slightly conical beam path with f/30 would give a weaker contrast with an etalon
with 0.5 Å FWHM – comparabable to a lter 0.7 Å FWHM or less. Only a telecentric
system delivers this perfectly parallel beam path, which is essential for the unrestricted
function of an etalon.
The SunDancer II is optimized for an effective focal ratio of f/30, i.e. for telescopes
working natively with f/10. It can be operated on telescopes up to about f/8 (giving an
effective focal ratio of f/24) without too much increase in half-width.
The lter can also be used on faster telescopes with the restrictions mentioned abo-
ve. However, with an effective focal ratio of f/20 or faster (i.e. on f/6.6 telescopes), it is
mandatory to mount a Baader D-ERF lter in front of the lens. In addition, the target
Preparations
Choosing a Dielectric Energy Rejection Filter
A Dielectric Energy Reection Filter
(D-ERF) is used to protect the actual
H-alpha lter from the intense solar
energy. In principle, it is a plano-op-
tically polished lter that only allows
red light in the vicinity of the H-alpha
line to pass and thus ensures that
the actual H-alpha lter does not
become too hot. It does not have to
be as narrow-banded as the actual
H-alpha lter; however, the same
demands are made on its surface
accuracy as on the telescope
objective. A white-light solar lter
(e.g. made of AstroSolar lm) cannot be used for this purpose because it also darkens
the H-alpha line, which is weaker than the rest of the solar radiation.
On all telescopes with more than 80 mm aperture as well as on telescopes with
secondary mirrors (e.g. Newtons or Schmidt-Cassegrains), a D-ERF protective
filter (not included in the scope of delivery) is absolutely necessary for long-term
observations (more than five minutes). A selection of suitable lters can be found
at baader-planetarium.com/derf; a suitable 3D-printed lens mount can be created by
yourself or by various service providers.
These D-ERF lters also serve as UV and IR blocking lters and reect the incident
sunlight instead of absorbing it. If you want to use a smaller D-ERF lter diameter on
an obstructed telescope to simultaneously stop it down to a more favourable focal
ratio, choose the diameter of the D-ERF in such a way that it sits off-centre next to the
secondary mirror in the optical path. Otherwise you will lose aperture if the secondary
mirror sits behind the D-ERF. Do not try to put several smaller D-ERFs next to each
other in order to use more aperture despite having a secondary mirror – this also does
not give satisfactory results.
A suitable mount specically for your telescope can be made by us only if you
purchase a complete system consisting of D-ERF and H-alpha lter. However, this is
relatively expensive due to the design and production time. For a quotation we need
the diameter of the mount with an accuracy of 1/10 mm. Instructions on how to const-
ruct your own mount can be found at baader-planetarium.com/derf.
The lter should be mounted as close as possible to the front of the lens so that no
warm layers of air can accumulate between the lens and the lter and impair the image
quality. Always make sure that the lter is rmly seated to avoid it dropping from the
telescope!
Energy protection filters up to 180 mm aperture can
individually made for your telescope, if necessary also with adjus-
table iris diaphragm or fixed aperture diaphragm.
The concentrated, reflected solar radiation in front of an
80 mm telescope without D-ERF in front of the objective.
Without a D-ERF, never look
into the telescope from the front!
Baader Telezentrische Linsensysteme (TZS) für die
Sonnenbeobachtung mit schmalbandigen H- Filtern
Zur erfolgreichen Sonnenbeobachtung mit schmalbandigen Linienfiltern (Halbwertbreiten unter 1
Angström) der Marken "Solar Spectrum" und "Day Star" ist ein Teleskop mit einem Öffnungsverhältnis
von mindestens f/30 die Voraussetzung. Dieses Öffnungsverhältnis lässt sich entweder durch Abblen-
den der Objektivöffnung –oder vorzugsweise durch Brennweitenverlängerung mit einem "Telezentri-
schen System" (TZS) –erzielen. Telezentrische Systeme sind nicht mit Barlowlinsen gleichzu-
setzen (siehe Grafiken)! Nur mit einem TZS entsteht ein paralleles Strahlenbündel, nur damit ist eine
gleichmäßige Darstellung der chromosphärischen Strukturen über das gesamte Bildfeld des Tele-
skops gewährleistet.
Generell sind nur Refraktoren und katadioptrische Teleskopsysteme mit Hauptspiegelfokussierung
(z.B. Schmidt-Cassegrain Teleskope) zur H-alpha Sonnenbeobachtung geeignet, bei den meisten an-
deren Teleskopsystemen (Newton) steht bauartbedingt der erforderliche Fokussierweg zum Anschluss
des Zubehörs zur H- Beobachtung nicht zur Verfügung.
Einsatz der Telezentrischen Linsensysteme
Es gibt drei verschiedene Telezentrische Linsensysteme. Je nach gegebenem Öffnungsverhältnis des
Fernrohrs kann entweder ein 2-faches, 3-faches oder ein 4-faches TZS in Kombination mit Abblen-
dung der Optik eingesetzt werden, um f/30 zu erhalten. Die Beobachtungsmöglichkeiten und die Fle-
xibilität eines Sonnenteleskops werden jedoch durch den abwechselnden Einsatz der TZS enorm er-
weitert.
Zum Beispiel empfiehlt es sich für Detailbeobachtungen z.B. von Strukturen rund um Sonnenflecken
mit möglichst großer Öffnung (= hohe Auflösung) zu arbeiten während für die Fotografie und Beobach-
tung von Protuberanzen, die durchaus Höhen von mehreren 100.000 km erreichen können, ein gro-
ßes Gesichtsfeld von Vorteil ist.
Das TZ-3 unterscheidet sich von beiden anderen TZ-Systemen dadurch, dass das Linsensystem für
ein H-Etalon mit 46 mm Maximalgröße ausgelegt wurde, um auch die großen Research-Grade-Filter
von SolarSpectrum vollkommen auszuleuchten. Aus diesem Grund ist das Gehäuse auch beidseitig
mit 2" (50.8 mm) Gewinden ausgestattet, und es sind alle Adapter im Lieferumfang enthalten um das
TZ-3 beidseitig an 2" oder an T-2 (M42x0.75 mm) Gewinden anschließen zu können. Alle Solar
Spectrum Filter werden ebenfalls beidseitig mit 2" und mit T-2 Gewinden ausgeliefert.
Strahlengang eines 6"/f6 Refraktors der mit einer 5-fach
Barlowlinse auf f/30 verlängert wurde
Strahlengang eines 6"f/30 Refraktors. Diesen Zustand
stellt das Telezentrische System her!
Telezentrische Systeme TZ-2, TZ-3 und TZ-4
Baader Telezentrische Linsensysteme (TZS) für die
Sonnenbeobachtung mit schmalbandigen H- Filtern
Zur erfolgreichen Sonnenbeobachtung mit schmalbandigen Linienfiltern (Halbwertbreiten unter 1
Angström) der Marken "Solar Spectrum" und "Day Star" ist ein Teleskop mit einem Öffnungsverhältnis
von mindestens f/30 die Voraussetzung. Dieses Öffnungsverhältnis lässt sich entweder durch Abblen-
den der Objektivöffnung –oder vorzugsweise durch Brennweitenverlängerung mit einem "Telezentri-
schen System" (TZS) –erzielen. Telezentrische Systeme sind nicht mit Barlowlinsen gleichzu-
setzen (siehe Grafiken)! Nur mit einem TZS entsteht ein paralleles Strahlenbündel, nur damit ist eine
gleichmäßige Darstellung der chromosphärischen Strukturen über das gesamte Bildfeld des Tele-
skops gewährleistet.
Generell sind nur Refraktoren und katadioptrische Teleskopsysteme mit Hauptspiegelfokussierung
(z.B. Schmidt-Cassegrain Teleskope) zur H-alpha Sonnenbeobachtung geeignet, bei den meisten an-
deren Teleskopsystemen (Newton) steht bauartbedingt der erforderliche Fokussierweg zum Anschluss
des Zubehörs zur H- Beobachtung nicht zur Verfügung.
Einsatz der Telezentrischen Linsensysteme
Es gibt drei verschiedene Telezentrische Linsensysteme. Je nach gegebenem Öffnungsverhältnis des
Fernrohrs kann entweder ein 2-faches, 3-faches oder ein 4-faches TZS in Kombination mit Abblen-
dung der Optik eingesetzt werden, um f/30 zu erhalten. Die Beobachtungsmöglichkeiten und die Fle-
xibilität eines Sonnenteleskops werden jedoch durch den abwechselnden Einsatz der TZS enorm er-
weitert.
Zum Beispiel empfiehlt es sich für Detailbeobachtungen z.B. von Strukturen rund um Sonnenflecken
mit möglichst großer Öffnung (= hohe Auflösung) zu arbeiten während für die Fotografie und Beobach-
tung von Protuberanzen, die durchaus Höhen von mehreren 100.000 km erreichen können, ein gro-
ßes Gesichtsfeld von Vorteil ist.
Das TZ-3 unterscheidet sich von beiden anderen TZ-Systemen dadurch, dass das Linsensystem für
ein H-Etalon mit 46 mm Maximalgröße ausgelegt wurde, um auch die großen Research-Grade-Filter
von SolarSpectrum vollkommen auszuleuchten. Aus diesem Grund ist das Gehäuse auch beidseitig
mit 2" (50.8 mm) Gewinden ausgestattet, und es sind alle Adapter im Lieferumfang enthalten um das
TZ-3 beidseitig an 2" oder an T-2 (M42x0.75 mm) Gewinden anschließen zu können. Alle Solar
Spectrum Filter werden ebenfalls beidseitig mit 2" und mit T-2 Gewinden ausgeliefert.
Strahlengang eines 6"/f6 Refraktors der mit einer 5-fach
Barlowlinse auf f/30 verlängert wurde
Strahlengang eines 6"f/30 Refraktors. Diesen Zustand
stellt das Telezentrische System her!
Telezentrische Systeme TZ-2, TZ-3 und TZ-4
Light beam of a 6"lens telescope, which was
extended to f/30 with a barlow lens
Light beam of a 6"lens telescope, which was
extended to f/30 with a telecentric system

8© Baader Planetarium GmbH | 2021 9
Manual: SunDancer II
temperature of the lter must be increased (see section
"Calibrating the Filter"), and the half-width increases
to more than 1 Å instead of the usual 0.6±0.1Å, as
already mentioned. This will cause many details on the
solar surface to disappear. For best results, it is better
to stop down the telescope in front of the lens to f/8
or slower than to use the lter with articially enlarged
half-width. For this purpose we offer the stepless ad-
justable iris diaphragm 13-113 mm (# 2459300). It has
elaborately white-painted blades so that no unnecessa-
ry heat is generated close to the lens. A simple, white-
painted bafe can easily be made yourself and attached
with Velcro in front of the D-ERF, for example, as in the
picture on the right.
Telescopes with a slower focal ratio can also be used,
but due to the longer focal length they quickly reach minimum magnications that can
rarely be used during the day (due to air turbulence or exit pupil).
The telecentric of the SunDancer II also contains a blocking lter. It shimmers golden
when you look into the SunDancer from the telescope side. This block lter is absolu-
tely necessary to protect the actual H-alpha lter from solar radiation.
Although the telecentric system can be seperated from the etalon, the SunDancer II
must only be used in combination with the included telecentric system!
The modular design of the SunDancer II allows it to be used with other telecentrics
(and an additional blocking lter!).
Attention: Using it with a telecentric without
this additional block lter would destroy the
etalon just as much as using it without D-ERF
on larger telescopes than 80 mm.
The 3x telecentric (# 1363070) is also
available without blocking lter, e.g. for use on
other H-alpha lters. The blocking lter is not
available separately.
A 4x telecentric with integrated blocking
lter is planned in the long term, the existing
blocking lter of the TZ-3 must then be moun-
ted in the TZ-4.
A D-ERF can be stopped down with a
simple baffle
The 3x telecentric system
(# 1363070) without blo-
cking filter is also available
separately.
The 3x telecentric system
with integrated blocking
filter is only available com-
bined with the SunDancer II.
Eyepieces
In principle, you can use any eyepiece that provides a
sharp, high-contrast image. Special H-alpha eyepieces are
mainly corrected for the red part of the spectrum and may
not provide a similarly sharp image as in H-alpha when ob-
serving white light. Long focal length eyepieces still provide
a bright image even at the ideal focal ratio of f/30 for an
H-alpha lter and avoid to high magnications. Exceeding
the highest useful magnication would cause a sensitive
loss of sharpness.
Note: Because of the telecentric, the system is very tole-
rant concerning working distances. Even a bino-viewer can
be used without an additional glass path corrector.
1You can use any 1¼" eyepiece via the focusable 1¼"
eyepiece clamp (# 2458125) included in the scope of delive-
ry. We recommend eyecups with a foldable side light shade.
An observation cloth that is white on the outside and black
on the inside also helps to suppress stray light and increase
contrast.
The telecentric allows you to reach high magnications
very quickly and end up in over-magnication very quickly
with common eyepieces. The blocking lter in front of of the
telecentric has a diameter of 12 mm. The etalon itself has
a diameter of 23 mm with a 19 mm bafe on the eyepiece-
side.
Long focal length 1¼" eyepieces have eld stop diame-
ters up to about 28 mm. This eld stop diameter covers the
available image circle of the SunDancer II.
The use of 2" eyepieces is nevertheless protable, as it
allows lower magnications and thus a brighter image, plus
often a more comfortable viewing behaviour and an even
slightly larger eld of view. You have two options for using 2"
eyepieces:
2Replace the 1¼" eyepiece clamp (# 2458125) included
in the scope of delivery with the optional Baader 2" Click-
Lock T-2 (M42i × 0.75) clamp (# 2956242). For 1¼" eyepie-
ces, you will then need an adapter such as the Baader 2" to
1¼" ClickLock reducer (# 2956214).
3Screw the optional Expanding Ring T-2f / M48m
(# 2458110) into the 2" lter thread of the nosepiece of your
eyepiece. This way you have a "theft-proof" connection,
which is especially useful for public use when the eyepiece
is rarely changed.
1
2
3
The SunDancer II consists of two parts (plus the 1¼" eyepiece clamp). On the left is the actual H-alpha filter, i.e. the
etalon with the heating element and the micrometer screw. To the right, in the 3x telecentric system, the integrated
block filter can be seen in the entrance opening.

10 © Baader Planetarium GmbH | 2021 11
Manual: SunDancer II
Choosing a Star Diagonal
In principle, the SunDancer II can be
used on any telescope that is suitable
for solar projection. When using a D-
ERF energy protection lter, catadi-
optric systems can also be used, as
well as Newtonian telescopes stopped
down to a suitable focal ratio. Make
sure that the secondary mirror does
not cause any additional obstruction
and mount the D-ERF off-centre.
The focus position when using the 2"
sleeve corresponds approximately to
that with a normal eyepiece.
On most telescopes, a star diagonal
is necessary for comfortable viewing. Mirrors are preferable to prisms, as the sunlight
does not then pass through the glass of the prism heating it up. For best quality, we
recommend Baader BBHS® star diagonals with astro-sitall mirror material (glass cera-
mic with zero expansion coefcient) and 1/10 l surface nish.
You can use both 1¼" and 2" star diagonals but it is mandatory to mount the mirror
in front of the SunDancer (i.e. between the SunDancer and the telescope's focuser).
Power Supply
If operating the SunDancer II from the mains, it is
recommended that the power is supplied via the
included Baader OTP II 19W: Outdoor Telescope Po-
wer Supply 19W with right-angle plug (# 2457615). It
supplies 12.8V at 1.5A.
If no power outlet is available, the SunDancer II can
be operated with an optional battery pack for mobile
use. The Celestron PowerTank Lithium LT 12V DC/
USB 5V/ 73,3Wh (# 821038) has proven itself. Please
note the correct polarity: The positive pole is on the
inside (tip positive).
Tip for experienced DIY builders: A sufciently
strong 12V power source can, if necessary, supply
both the mount and the SunDancer II via an optional Y-cable, which makes for a very
tidy setup.
Caution: Do not reverse the polarity of the power supply. If possible, use the
supplied power supply or cables with reverse polarity protection. Damage
caused by reverse polarity is not covered by the warranty.
The hand control can be used inside of the
yellow utility bag, where it is protected from
direct sunlight.
The SunDancer II at a 8" Triband SC
where the D-ERF is part of the Schmidt corrector plate.
Observing with the SunDancer II
The parts of the SunDancer II
1. SunDancer II
2. Micrometer screw for quick netuning of the Etalon
3. Three locking screws for the eyepiece
4. Locking screw for ne focuser
5. Connection cable to hand control
6. Hand control (temperature control box)
7. Connection cable to SunDancer II
8. Connection port for 12V power cable (on the back;
power supply is not shown)
1
2
3
4
5
6
7
8
Connecting to the telescope
1. Do not point the telescope at the sun yet. First put a light-proof cover in front of all
optics that are not used (nder, guide scopes etc).
2. If necessary, install the D-ERF energy protection lter in front of the telescope.
3. Remove the dust cap from the 1¼" socket of the SunDancer II.
Caution: If you use a 2" eyepiece clamp and point the SunDancer II at the sun with
the 1¼" dust cap still on, the plastic will evaporate and may deposit on the optics
of the telescope or on the blocking lter and destroy them!
4. Place the SunDancer II in the eyepiece clamp or the star diagonal (1¼" or 2") of
the telescope and secure it.
5. Connect the temperature control box to the SunDancer II via the 8-pin plug con-
nection.
6. Connect the temperature control box to the 12V power supply or an optional bat-
tery pack. Note the correct polarity: the positive pole is on the inside (tip positive).
The supplied power cable and that of the Celestron LiFePO4PowerTanks are
correctly polarised and not interchangeable.
7. Pay attention to the cable management: make sure that nobody can get caught
on the cables and that the cables are not be under tension when the telescope
moves. You can store the power supply unit and control box in the supplied yellow
utility bag shown on page 10. Attach the bag to the mount in such a way that the
cables cannot interfere or come under tension. The optional Celestron PowerTank
can be connected to the tripod legs so that it does not interfere. The control box
should not be in direct sunlight.

12 © Baader Planetarium GmbH | 2021 13
Manual: SunDancer II
8. As soon as the control box is powered, it automatically heats the lter up to the
necessary operating temperature. The display shows the temperature difference
to the set point; when the value 0 is shown, the lter is ready for operation. After
about ve minutes, the temperature control has stabilized and you can ne-tune it
if necessary (see the following chapter "Filter calibration").
9. While the lter heats up, you can can insert an eyepiece, point the telescope at the
sun and observe. Due to the longer focal length caused by the telecentric, the sun
must be positioned exactly so that it can be seen in the eyepiece.
10. The micrometer screw tilts the etalon a maximum
of 3° from the optical axis. This has two functions:
(1) You can check the setting of the H-alpha line
without changing the temperature of the lter. To
do this, turn the micrometer screw sensitively and
without using force clockwise all the way in, as far
as it will go, and the H-alpha structures on the sun
should be clearly visible. The scale itself is only for
orientation, the stop does not have to correspond
to the 0 position.
(2) The micrometer screw is used for fast Doppler-event observations: For example,
if a prominence is moving quickly towards you, this may be enough for the H-alpha
line of that structure to shift so far into the blue part of the spectrum that you need
to readjust – this can be done quickly and easily with the micrometer screw or by
decreasing the temperature, which takes a little bit more time, but keeps the lter
in the ideal tilting angle.
Note: After about three to ve minutes the lter is in temperature equilibrium, before
that slight changes in the image are possible due to readjustment.
Note: Observe the operating temperature of 0 to +40° C. At lower temperatures, the
lter must be thermally insulated so as not to overload the heating.
The Functions of the Temperature Control Box
Once the lter has been correctly calibrated to your
system (see chapter Calibrating the Filter on page 16),
you only need to connect the temperature control box
to the SunDancer II and then to a 12V power source.
The electronics will then bring the lter up to operating
temperature and automatically switch it off if it becomes
too warm.
The display of the control box shows the difference
from the factory set temperature. If your particular setup
requires a different operating temperature, please refer
to the chapter "Filter calibration" for instructions.
As soon as the display shows a stable "0", the lter is
ready for operation. When the telescope is pointed at the
sun, it takes about three to ve minutes for the lter to
reach temperature equilibrium.
The micrometer screw can tilt the filter
to easily observe the blue wing of the
H-alpha-line
The display shows the temperature
difference to the ideal operating
temperature. Above shortly after po-
wering up, below once the operating
temperature is reached
The lter has a temperature sensor that switches off the heating if the lter becomes
too hot. In this case, the heating element is automatically switched off and will not
be reactivated until the lter has cooled down to 25 °C and the control box has been
disconnected from the mains.
To switch off, simply disconnect the temperature control box from the power source.
Changing the Operation Temperature
You can easily change the temperature of the lter and thus the position of its transmis-
sion window. Increasing the temperature shifts the maximum to the longer-wavelength
red wing of the H-alpha line; decreasing it shifts it to the blue wing in the shorter-
wavelength spectral range. A change of 10.0 units shifts the transmission maximum by
about 1 angstrom, which is also the maximum possible change.
Press the up arrow to increase the temperature or the down arrow to decrease it.
After a few seconds, the display changes to the current value and the lter is tempered
to the new setpoint (displayed as a deviation from the factory-set temperature value).
The new setpoint remains stored. So the next time you use it, the control box will
always show the last set value.
Note: For quick observations in the blue wing of the H-alpha line, you can also use the
micrometer screw.
Using a Neutral Density Filter
The difference in brightness between the prominences and the solar disk is very large,
and it can be helpful, especially when observing with a large exit pupil, to screw a neu-
tral density lter into the eyepiece. This makes the structures on the solar disk more
visible to the eye, while the prominences become less
visible. You can achieve the same effect with a single
polarising lter that you screw into the eyepiece.
Then, as when used with a Herschel prism, the image
brightness can be adjusted by rotating the eyepiece
in its eyepiece clamp.
How strong the effect is depends on the respective
system as well as on your own eyes. In principle, the
image brightness can also be adjusted simply by
increasing the magnication; however, this presuppo-
ses that the air turbulence permits higher magnica-
tions at all.
We recommend the following lters:
• Polarising lters: 1¼" # 2408343; 2" # 2408342
• Neutral density lters (grey lters) ND 0.6 (T=25%): 1¼" # 2458343; 2": # 2458321
• Neutral density lters (grey lters) ND 0.9 (T=12.5%): 1¼": # 2458344; 2": # 2458322
Polarizing and Neutral Density Filters dim
the brightness, which may lead to better
visibility of details in the eyepiece

14 © Baader Planetarium GmbH | 2021 15
Manual: SunDancer II
Using a Telecompressor
Especially on long focal length telescopes, very high mini-
mum magnications are achieved through the 3x telecentric.
With a telecompressor, the focal length can be signicantly
reduced again. The SolarSpectrum Research Grade H-alpha
0.4x Telecompressor 2" (# 2459260) has proven itself. It has
SC threads on both sides and can be used both photogra-
phically and visually. Its ideal working distance is 74 mm
with a corrected eld of view of 16 mm diameter.
To screw it onto the T-2 connection thread of the SunDan-
cer II, you need:
1) Reducing-Ring 2"i / T-2a, with 1.5mm optical length
# 2958244.
2) SolarSpectrum Research Grade H-alpha 0.4x telecom-
pressor 2" # 2459260
3) Reducing-Ring 2"i / T-2a, with 1.5mm optical length
# 2958244
4) T-2 Conversion Ring # 2958110
You will need additional adapters to place an eyepiece or a camera in the desired di-
stance. The included focusable 1¼" eyepiece clamp (# 2458125) has an optical length
of 29-35.5 mm. For the ideal working distance of 74 mm you still need a
5) T-2 / 40 mm Extension Tube # 1508153
On the other hand, for a camera, the necessary adapters depend on the backfocus
of the camera.
The ideal distance will give you a reducing factor of 0.4x. However, the telecompres-
sor can also be used with a shorter distance, in which case the compression factor
changes. Instead of the 1¼" eyepiece clamp, the Baader 2" ClickLock T-2 (M42i x
0.75) clamp (# 2956242) with 36.6 mm optical length can also be used.
Note: On obstructed systems, the "secondary mirror shadow" becomes visible when
the exit pupil of the telescope becomes larger than the aperture of your own eye pupil.
This is more noticeable during the day than at night, as the pupil then opens less wide.
Using a dark observation hood during daytime observations helps your pupil to open
wider.
Using a Bino-Viewer
The sun is particularly impressive in a bino-viewer; the relaxed binocular vision allows
details to be seen even better.
Compared to the standard 1¼" eyepiece clamp, a bino-viewer only needs about one
centimetre more back focus thanks to the use of a telecentric system, and a glass
path corrector is superuous. To use a bino-viewer with T-2 connection, simply screw
the T-2 coupling nut onto the T-2 thread of the SunDancer II instead of the 1¼" eyepi-
ece socket. If you are using the binocular attachment with Zeiss micro bayonet, screw
the Baader TQC Heavy Duty T-2 Quick Coupler (# 2456313A) or the T-2 Standard
Quick Coupler with Zeiss Micro Bayonet (# 2456313) onto the SunDancer II.
In this conguration, only the glass path correctors for Zeiss
ring dovetail can be used, which are screwed directly
into the binocular (# 2456314Z and # 2456316Z).
Due to the parallel beam path of the telecentric,
however, their effect changes so that the 1.25x
glass path corrector only saves about 3 mm
back focus; the 1.7x saves about 5 mm.
The change in magnication is corre-
spondingly small – in practice, the
glass path corrector behind the
telecentric should be omitted.
Please note that the combi-
nation of the SunDancer II
with telecompressor and
glass path corrector
in front of a binocular
attachment does not
work – and would be
useless as you reduce
the focal length only
to increase it right
away again.
The T-2 thread also allows
bino-viewers to be used with the
SunDancer II, here the MaxBright
II with a pair of 36 mm Hyperion
Aspheric eyepieces in 1.25"
configuration.
SunDancer II with
Telecompressor
23
1 2 3 4
4
Above are the necessary parts to connect the telecompressor to the SunDan-
cer II, on the right they are fully assembled.
1
Note: The maximum eld of view is limited by the 19 mm aperture behind the etalon;
the telecompressor can only reduce this image circle. As a rule of thumb for the size of
the solar disk, it appears about 10 mm in diameter per metre of telescope focal length.
Therefore with the built-in 3x telecentric, the whole sun disc (with prominences) can be
viewed in telescopes with a native focal length of up to about 600 mm.

16 © Baader Planetarium GmbH | 2021 17
Manual: SunDancer II
Calibrating the Filter and
Settings of the Temperature Control Box
Setting the Temperature
The target temperature of the lter and thus the position of the central wave length of
the transmission window can be adjusted via the temperature control box. This serves
on the one hand to calibrate the lter to your individual system (see the following
chapter "Filter calibration"), and on the other hand for netuning to observe the red
or the blue wing of the H-alpha line. For observations in the blue wing, you can also
simply use the micrometer screw so that the lter is set exactly to the H-alpha line.
To change the target temperature, proceed as follows:
1. Wait until the lter has reached its stable operating temperature and displays the
numerical value "0".
2. Press UP or DOWN once to enter the programming mode. The display "0.0" a-
shes. Now press UP to increase the temperature or DOWN to decrease it. If no key
is pressed for a few seconds, the new setpoint is accepted.
3. The value can be changed by a maximum of 10.0 degrees. A change of 10.0 de-
grees shifts the central wavelength by about 1 angstrom (1Å, equals 0.1 nm).
4. An increase in the setpoint value corresponds to a shift of the central wavelength
into the longer focal length, i.e. the red region of the spectrum. A decrease shifts it
accordingly to the shorter wavelengths, or the blue range of the spectrum. In the
blue wing of the H-alpha band, they can observe the rapid, high-energy changes on
the solar disk.
The new value is stored even if you disconnect the power supply. The display always
refers to the factory preset target temperature.
Note: The lter temperature is inuenced by the incident solar heat. If the lter is not
pointed at the sun for some time, the transmission line shifts into the blue range of the
spectrum. As soon as the telescope is pointed at the sun again, the heating compen-
sates for the additional solar energy, and after 30 to 60 seconds it is back to its original
wavelength.
Note: For best imaging and to avoid reections, the lter should not be tilted. The
micrometer screw is used for quick observations of Doppler effects; the H-alpha line
should be adjusted via the temperature.
Calibrating the Filter
The SunDancer II has been calibrated at the factory and should give the best image
when the micrometer screw has been turned clockwise as far as it will go without
applying force and the heater has reached the preset target temperature, so that the
temperature difference display is also at "0". After about three to ve minutes of solar
observation, the lter has reached temperature equilibrium and you can assess its
performance.
For optimal performance on your particular system, you should calibrate the lter
to compensate for differences in aperture ratio, energy rejection lter and more. This
should require only small corrections to the factory setting, which was set at an effecti-
ve focal ratio of f/30. To do this:
1. Turn the micrometer screw clockwise as far as it will go (without applying force).
2. Set the temperature control box to a value of -5.0 as described above in the chap-
ter "Setting the temperature". Give the lter 3 to 5 minutes to stabilise and observe
the sun exactly in the centre of the image of the lter. You should now see it in the
blue wing of the H-alpha line.
3. Increase the target temperature by 1.0 degree (corresponding to 0.1 Å) and give the
lter a couple of minutes to stabilise again.
4. Increase the target temperature until you see the sun with the best contrast. The
solar disk is then darkest and you have centred the lter exactly on the H-alpha line.
Increasing the target temperature moves the lter to the red wing, decreasing it
moves it to the blue wing. A change of more than ±10 degrees is not advisable.
Increasing the temperature too much can destroy the filter.
Tilting the Filter
With the micrometer screw, you can tilt the lter up to 3° off the optical axis to quickly
shift the central wavelength into the blue wing. If the image improves when you tilt the
lter, this may have two causes:
1. The lter line is in the red wing of the H-alpha line at target temperature.
2. The micrometer allows the lter to be tilted past the neutral position.
The set point of the target temperature should be adjusted to give the best image
when the micrometer screw is turned gently clockwise to the stop. Then you can tilt
the lter towards shorter waves, into the blue wing of the H-alpha band, by turning the
micrometer screw back. In the blue wing, y
ou can better observe rapid, high-energy
changes on the sun.
Troubleshooting
If the lter does not deliver the expected contrast, it is usually because it is not aligned
exactly to the optical axis. Even with a tilt of 0.5°, the lter can no longer work as desi-
red. A tilt can be compensated for to a small extent by increasing the target tempera-
ture, but this also increases its half-value width.
In case of tilting, rst check whether your focuser tube is correctly adjusted or whe-
ther it has play and gives way under load. Simple clamping screws on the focuser or
zenith mirror can also cause tilting.

18 © Baader Planetarium GmbH | 2021 19
Manual: SunDancer II
glass and the sensor during H-alpha photogra-
phy. This is a problem of the camera and not
of the lter; the fringe patterns rotate with you
when you turn the camera. In this case, it can
help to tilt the camera or make a at, but this is
not trivial with such a narrow band lter. Ano-
ther possibility might be to tilt the lter. Within
certain limits, the lter tilt can be compensated
again by the temperature control, so that the H-
alpha line is hit again even with a tilted lter.
You can use a tilting unit like our Baader M68-Tilter # 2458170 to tilt the camera very
precisely behind the lter and remove the interference pattern.
However, this problem does not occur with all cameras, so there is no patent remedy
for it. We have had good experience with the monochrome cameras made by QHY.
DSLR and CCD Cameras
If you unscrew the focusable
eyepiece clamp, you can connect
astronomical cameras with T-2
threads as well as DSLR and mir-
rorless system cameras via the T-2
thread (M42 × 0.75); you can nd
suitable T-adapters for the respec-
tive camera bayonet at baader-
planetarium.com.
Via the Expanding Ring T-2f /
M48m (# 2458110), you can also
use M48 camera adapters and
Baader Planetarium's Wide-T rings
to avoid mechanical vignetting on
full-frame cameras.
Here, too, you should observe the ideal working distance of 65 mm. An SLR camera
with a standard T-ring has a ange focal distance of 55 mm; with the T-2 internal th-
read ring 10 mm (# 2958110) and the T-2 reversing ring adapter T-2 to T-2 (# 1508025),
you will achieve the ideal distance of 65 mm; you will also achieve good results with
the T-2 quick-change system (# 2456322) with 15 mm construction length. Mirrorless
system cameras and astronomical cameras have a shorter ange focal length and
require different extension tubes, depending on the model.
Tip: In principle, black-and-white cameras are better suited for H-alpha solar photo-
graphy, because the Bayer matrix of a colour camera means that three quarters of the
pixels cannot perceive red light at all.
Tip: The surface of the sun and the prominences have very different brightnesses and
normally cannot both be exposed correctly in one shot - the solar disk is much brigh-
ter. If the green channel of your colour camera is also slightly sensitive to red light, you
can try to expose on the prominences and use only the weaker green channel for the
solar disk.
A DSLR with a standard T-ring still needs a 10mm T-2 extension.
A standard T-ring has an overall length of 55 mm - here using the
example of a mirrorless Micro Fourthirds camera with the Micro
Fourthirds T-ring # 2408330 (with 19 mm extension).
# 2408330
# 2958110 + # 1508025
Photography
In total, you have three options for connecting a camera to the SunDancer II. For the
best imaging quality, you should pay attention to the working distance of 65 mm, alt-
hough the system also works well at other distances. A deviation from the ideal working
distance will affect the magnication and image quality, although the system has pro-
ven to be quite docile. The working distance is also long enough for use with a DSLR.
1¼" Video Modules/Planetary Cameras
A modern imaging camera like the ones used for pla-
netary photography is the rst choice for obtaining
high-resolution images of details on the solar surface
or in the photosphere. To maintain the optimal wor-
king distance, you can place T-2 extension sleeves
between the eyepiece clamp of the SunDancer II and
the actual lter unit. Simply unscrew the eyepiece
clamp to expose the T-2 thread.
The focusable eyepiece clamp has an overall length
of 29 - 35.5 mm. Which extension sleeves you need
depends on the sensor position of the camera – on
some models the sensor is in the 1¼" socket, on
others behind it. On baader-planetarium.com you
will nd various extension sleeves, including among
others:
• T-2 extension tube 40 mm # 1508153
• T-2 extension tube 15 mm # 1508154
• T-2 extension tube 7,5 mm # 1508155
• VariLock 29, lockable T-2 ExtensionTube
20-29 mm with spanner tool # 2956929
If possible, use a stop ring to reproduce the positi-
on of the camera over and over again. If no stop ring
is included with your camera, you can use the 1¼"
stop ring (# 1905131) for this purpose. It can also be
used to make the camera parfocal with an eyepiece, if necessary in conjunction with
the 1¼" extension tube with 1¼" lter thread
on both sides (# 1905130).
Monochrome cameras are more suitable
because they are more sensitive to light and
allow shorter exposure times. In addition, all
pixels are used in this way; in colour cameras
with an RGGB matrix, only a quarter of the
pixels are sensitive at all to the deep red H-
alpha light.
With some monochrome cameras, interfe-
rence patterns occur between the protective
SunDancer II with Baader M68-Tilter and adapters
# 1508153
A planetary camera with 1¼" plug-in slee-
ve. A 40 mm T-2 extension sleeve provides
the ideal working distance of 65 mm.
Interference pattern of a monochrome camera.

20 © Baader Planetarium GmbH | 2021 21
Manual: SunDancer II
Storage and Maintenance
As long as you handle the lter with care like any other precision optical instrument
and use the dust caps when not in use, it requires no special care.
Caution: The lter must not be stored permanently below +4° C,
otherwise the lter stack will freeze out and be irreparably damaged.
Store it dry and dust-free at room temperature.
The lter should be used at an ambient temperature of 0 to +40° C;
at lower temperatures it must be additionally thermally insulated so
as not to overload the heating.
Safety information
Finally, we would like to urge you once again to observe all safety precautions when
observing the sun. This includes:
• Never leave the telescope unattended
• Always cover all viewnders and other optics that are not in use.
• Ensure that the energy protection lter is held securely in place.
• Set the tracking of the mount to the speed of the sun instead of the star.
• Remember sunscreen for yourself when observing for long periods.
Technical Data
• Operating temperature: 0 to +40° (below 0° only with insulation).
• Storage temperature: +4 to +50°C, ideally at room temperature. Protect from frost!
• FWHM: 0.6±0.1 Ångström, shows chromosphere and prominences
• 3x telecentric with built-in block lter, optimal for refractors up to f/10, recommen-
ded up to f/8 and usable up to f/6.5
• Usable up to 80 mm aperture without additional D-ERF energy lter
• Blocking lter: 2nm Half-Bandwidth (FWHM) and 12 mm diameter
• Diameter of the etalon: 25 mm, with 23 mm free aperture and 19 mm eye-side bafe
• Ideal working distance for photography: 65 mm from the base of the T-2 thread
• Connection on telescope side: 2" and 1¼" plug-in sleeve
• Connection on eyepiece side: 1¼" with ne focusing; T-2
• With telescopes up to approx. 600 mm focal length, the entire solar disk is visible
Telecompressor
The already mentioned 0.4x telecom-
pressor 2" (# 2459260) can also be used
photographically. If the telecompressor
is adapted to T-2 as described before,
its ideal working distance is still 73.5
mm. A DSLR or system camera with
a standard T-ring has a ange focal
distance of 55 mm. The remaining 18.5
mm can be bridged with T-2 extensions,
e.g. as in the picture on the right with
• TQC/TCR Heavy duty T-2 Quick
Changing System # 2456322 – 15 mm,
optionally additionally
• 3x T-2 ne-adjustment ring (1 mm – gold) made of aluminium # 2457913 or
• T-2 adjustment/spacer-rings (set of 15) # 2458102
The distance does not have to be kept exactly, but the compression factor changes
with the distance.
Afocal Photography
Finally, the possibility of photo-
graphing with the camera through
the eyepiece should be mentioned
– even if this option combines the
worst of both worlds: a large lens
stack and a colour camera. This
makes it more of a feasibility study,
but it may offer the chance to
photograph the entire sun even with
a smaller camera sensor without
having to buy a telecompressor. If
you see the entire sun in the eye-
piece, you can capture the image
with a camera – ideally even with
your smartphone. Better is a camera whose xed focal length lens has a lter thread
that can be connected to the M43 thread of our Hyperion and Morpheus eyepieces
via our Hyperion-DT rings. For this you need a lens that you bring as close as possi-
ble to the objective without the lenses touching each other. The objective focal length
depends on the size of the solar image in the eyepiece.
In practice, the method has some disadvantages and is only useful with xed focal
length lenses; however, if you already have a sufciently short focal length lens, it can
temporarily be an alternative to buying a full-frame camera or a telecompressor.
The telecompressor delivers much better results and is much easier to use, at a com-
parable price to a xed focal length lens.
A DSLR with 0,4x telecompressor and T-2 quick-changer
Even this possible in principle: an MFT camera with a 12mm lens
overlooks almost the entire field of view of a Hyperion 36mm
eyepiece.

22 Manual: SunDancer II
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