is for the telescope and camera to
have a solid base to attach to.
The telescope:
Any telescope is suitable for the
Moon, and telescopes with longer
focal lengths are good for both the
Moon and planets. In photographic
terms I have used a William Optics
GTF-81 with a focal length of 478mm
a Celestron C90 Mak (1250mm) and
a Celestron C130 SLT (650mm) all with
good results. Planetary imaging is
better with the longer focal lengths
and the Moon is good with all of the
telescopes I have tried. The longer
the focal length, the greater the
magnification, resulting in a larger
image on the webcam sensor.
The computer:
Although planetary imaging can
be achieved on a Mac computer
the main software components are
designed to run on a PC platform.
Out of preference I use a laptop
running Windows XP, but the software
runs on all versions of Windows. The
laptop is useful to position near the
telescope to enable easy focusing
and adjustment of the equipment.
Capture software:
In order to transfer video from the
webcam to the computer some
software is required. If you have a
specialised astronomy planetary
camera or webcam then this will
have software included to control
the camera and save the output
onto the computer. If you do not
have capture software then there
are a number of free applications
available to download from the
web. Two examples are SharpCap
(http://www.sharpcap.co.uk) and
wxAstroCapture (http://arnholm.org/
astro/software/wxAstroCapture/).
Processing software:
Again a commercial planetary
camera will come with processing
software, but it will mainly be
the same freeware or shareware
software that you can download
from the Internet. The most popular
processing application is called
Registax (http://www.astronomie.
be/registax/). This analises the video,
determines which are the good
images on them, aligns them, and
A $10 Xbox webcam can take good images. The most difficult part of the Xbox webcam conversion
was opening the casing. Credit Mike Barrett (www.wired4space.com)
stacks them all into a single image.
There are then some post processing
options that can be applied to the
image to bring out the detail.
Webcam:
I deliberately left the webcam to
last as there are so many options
that you have available. These
range from buying a dedicated
‘Planetary Imaging’ or ‘Solar System
Imager’; using a telescope guide