© Baader Planetarium GmbH | 2023
23
• Modern smartphone cameras are amazingly powerful and can already deliver
impressive images when you place them on the eyecup of the eyepiece. For best
results, use a smartphone mount such as the Celestron NeXYZ Universal 3-Axis
Smartphone Adapter
# 825821
.
You can find more about this technique in our info brochure
"Digiscopy – Camera Adaptations for Afocal Photography and
Eyepiece Projection" (available as PDF download on
www .baader-planetarium .com
).
Projection photography
This technique is used whenever granulation or sunspots need
to be photographed in high resolution and detail. For this, a focal
length-extending system must be used. And here – despite the
Herschel prism and 4.6% light transmission – the exposure times
increase rapidly.
The camera is used without its own lens in order to keep the number of lenses low.
Instead of individual images, short films of a maximum of 15-30 seconds are recor-
ded – since the sun is very dynamic despite its size, details would already be washed
out in longer sequences. These films are then further processed with software such as
Autostackert! or Registax.
The necessary extension of the focal length is achieved either by
• eyepiece projection (with OPFA System
# 2458142
) or
• preferably by barlow lenses or even the FFC, see page 14.
Today's cameras with their small pixels do not need the very high magnifications
achieved with eyepiece projection. A Barlow lens is therefore to be preferred; for
extension factors above 3x, the FFC is the first choice and achieves – compared to
normal eyepiece projection – an unrivalled high quality of imaging.
For first test shots with a DSLR camera, a simple Barlow lens can be used, which
approximately doubles the telescope focal length. For best results, use an astronomi-
cal camera, preferably in a monochrome version. The magnification factor depends on
the distance of the Barlow lens to the camera sensor.
Please note:
Any focal length extension – whether by Barlow lens, eyepiece projection, teleconver-
ter or FFC – must be introduced into the optical path after the Herschel prism (i.e. on
the camera side, between the camera and the Herschel prism).
Left: A compact camera with a MicroStage II; Center: Compact camera, attachted to a Morpheus eyepiece using
the filter thread ofthe camera lens; Right: Smartphone with Celestron NeXYZ Adapter.
DIGISKOPIE
Ein Überblick über die gängigen Kameraadaptionen und benötigten Adapter
für afokale Fotografie und Okularprojektion mit Spektiven und Teleskopen
Beispiel
AfokAle fotogrAfie
Beispiel
okulArprojektion
