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Manual: Cool-Ceramic Safety Herschel Prism Mark II
Photography
In solar photography, a general distinction is made between focal photography and
photography with Barlow lenses or using eyepiece projection for focal length extensi-
on. The recording medium is a camera sensor. The phenomena that are documented
are the same as described for visual observation.
Focal photography (= direct connection of a camera body)
Focal photography is always used when the complete solar disk is to be imaged. For
this purpose, the camera (without lens) is connected directly to the Safety Herschel
prism via a T-2 adapter, as shown in the picture on the right using a DSLR as an ex-
ample.
As a rule of thumb for the size of the solar image, the following applies:
1 m telescopic focal length results in an approx. 1 cm large
solar disc on the recording chip
At a telescope focal length of two metres, the sun
would be about two centimetres in size and would not
fit completely on an APS-C sensor with a sensor size
of 22.5 mm × 15.0 mm. This rule of thumb is only a gui-
deline, also the size of the sun's image changes in the
course of the year due to the elliptical orbit of the earth.
First, leave the ND 3.0 and the Solar Continuum Filter
installed and switch your camera to RAW mode. Exposu-
re times should be around 1/1000 of a second (at low ISO
values of around 125). This ensures that the seeing (air
turbulence) is really "frozen". If 1/1000 sec. is not feasible (depending on the focal ratio of
the taking lens), change the ND 3.0 for the ND 1.8 filter to shorten the exposure time.
If you cannot get into focus, you can replace the eyepiece clamp with one of the S58
adapters with a ring dovetail and thus save about 30 mm of construction length.
Afocal photography (using a digital camera with a fixed lens)
Afocal photography is mostly used when there is no DSLR camera available, but the
recording camera is equipped with a fixed lens (point-and-shoot camera). Afocal pho-
tography is a special version of projection photography. It is suitable both for overview
photography (whole solar image) and for detailed photography. The change in the so-
called equivalent focal length required for this is made by changing the focal length of
the zoom lens of the recording camera or the eyepiece.
This shooting technique with selected digital viewfinder cameras can also be realised
with BAADER accessories. You have three options for this:
• You can position lightweight compact cameras behind the eyepiece with the
Microstage II Digiscoping Adapter
# 2450330
.
• Cameras with a filter thread can be screwed to the eyepiece with the Hyperion
DT rings. Our Hyperion and Morpheus eyepieces offer corresponding connection
threads; slim eyepieces such as the Classic Ortho/Plössl up to 38 mm diameter
can be used with the Afocal Digital Projection System ADPS II with 2" nose piece
# 2458072
.