Philipp
Salzgeber
Wolfurt / Austria
|
My Astronomical
Equipment
The observatory
 Probably
the most important piece of equipment right now is our roof-top
terrace. While the place where I live has some strong light
pollution, and is sometimes plagued with fog. The ability
to quickly step outside the house and have access to the whole
sky is a big bonus to the hobby. I have put my telescope,
mount and accessories in an aluminum box, which up to now
has stood up agains the elements. Now I can start observing
pretty quickly and even had some success in astrophotography
from home. |
The
evolution of my self-built 6" f/5 Newtonian Telescope:
|
| Travel-Dob |
|  After
seeing a very light weight travel-dobson telescope at the
Internationales Teleskoptreffen
in Carinthia, I decided to build a similar telescope. After
lot´s of trial and error I was quite content with
my work. You can find the whole story with some pictures
of the finished scope, the building process and images from
the optical shop (Interferometry, Ronchi, Foucault,...)
here: building a 6"
dob. While I liked the liitle weight and uncomplicated
setup, the fact that I was not able to use it for photography
bothered me, to resolve this issue I decided to put it into
a tube...
|
| Tube |
 A
20cm diameter drainage tube and a Vixen 2" focuser were
the start for my project. The tube was cut off squarely and
I built a curved spider similar to the one used for the dob.
The mount of the main mirror stayed the same, I just made
a new baseplate for it. Adhesive black velour was applied
to the inner tube, while the outside was lined with blue dc-fix
foil. The dc-fix foil is easier to apply than paint and less
messy too! After some searching I found the tube rings at
a plumbing equipment shop, they are quite heavy - but stable.
While the scope looks quite finished I have to fine-tune the
secondary holder. While doing a star-test on Vega I noticed
astigmatism, maybe the secondary is the culprit, after some
research I may have to replace it...
Some first images done with this setup are: M13,
M27, M57
and M71. |
 
 
|
| Truss-Tube |
| It turned out, that
the pvc tube was too heavy for my Super-Polaris mount, especially
when adding a guide-scope to the setup. I decided to rebuild
the tube using an open three-truss design. And yes, the secondary
was the cause of the Astigmatism, it has been replaced. Using
simple tools and materials this is the result:
|
Eschenbach Novalux 60/415
Refractor
 I
used this scope as a "grab-and-go" scope for quite
some time. But after viewing the lunar eclipse in November
2003 with a Orion ST80 (from Florida!) I decided to buy
a 80mm GSO f/6 refractor, which is described above....
The Novalux has
bad chromatic aberration and quite some astigmatism and
spheric aberration, furthermore the tube was too short and
demanded lots of extension tubes behind the wiggly focuser.
I replaced the original tube with a plumbing pvc tube, and
added an adapter to use 1 1/4" eyepieces. While the
scope is very bad visually, it tuns out that it is quite
usable photographically
and I am also able to use it as a guidescope with the QHY5
autoguider. |
Vixen
R-130S Telescope on Super Polaris Mount
 Telescope:
Vixen 130S, Newtonian Telescope with 130mm (5,1") aperture
and 720mm focal length (f/5,5). A drawback of this telescope
is the 1,25" focuser, which does not allow unvignetted
35mm photography. The mirror is slightly overcorrected,
delivering less than perfect planetary images.
Mount: Vixen Super Polaris german equatorial mount
with dual axis drive. While it is too light for this kind
of setup, the polar alignment with the built in polar scope
is very accurate. Corrections in declination are only needed
a few times during an exposure. The yellow/orange surveyor
tripod I use is much more stable than the original aluminium
tripod.
Guidescope:
Optus 70/700 Achromatic refractor. I bought this refractor
with a quite reasonable equatorial mount at an outlet of
the Lidl supermarket chain. It´s low price makes it
quite popular with amateurs in Austria and Germany. I found
mine to perform quite well as a Guidescope. It is very light
regarding it´s size, which is a bonus for me and my
overloaded Super Polaris! I use the Baader Microguide as
Guiding eyepiece. |
Nikon
FM2
 The
FM2 is a fully mechanical 35mm camera, it does not need
a battery for its full range of shutter speeds from 1/4000s
to B. When the self-timer is activated the camera swings
up the mirror at the push of the button, so when the exposure
starts some seconds later, the vibrations have dampened
out. For widefield shots I use lenses from 20 to 105mm,
with the AF 85/1.8 and the AF 105/2.8 Micro Nikkor being
my favorites. Focusing is difficult, but the 2x focusing
magnifier helps a little. So far I this method proved to
be sufficient for my purposes.
|
Pentax
6x7 [sold]
 With
lenses from 55 to 400mm this should be a powerful camera
for widefield shots. I have not used it very much for astrophotography
yet. The combo Pentax 6x7
and 400/4.0 is quite impressive! In the picture it is shown
alongside with the FM2. The biggest problem with this camera
is the current lack of good astro-films in 120 format. The
camera is quite old, and I had to replace the shutter (700
€ - ouch!) but it works fine and it delivers nice slides.
|
Nikon Coolpix 4500
[broken]
 Much
more advanced than the 950 this camera is sensitive enough
for basic deep-sky astrophotography. You find some deep-sky
and planetary images here. I
have used exposures of up to two minutes quite successfully.
When not using my self build cable release bracket I use
my laptop running Snappix
and a serial cable.
-
Nikon
Coolpix 950: This digital camera is usable for shots
of the moon, planets
and the sun.The images are taken
afocally, i.e. The camera looks through the eyepiece
like an observer. I use a Vixen Digital Camera adaptor
to couple the Coolpix to the eyepiece. For use with
a cable-release I made a bracket of surplus pci-card
slot covers from my computer. I also tried some deep-sky
shots with this camera, but the results were not very
encouraging.
|
GSO
80mm f/6 Achromatic Refractor [sold]
 Quick
Look scope: I bought this GSO 80mm f/6 (480mm focal
length) refractor used over the internet. The GSO is nicely
built. It is much bigger than other 80mm f/5 scopes I have
held in hand. The dew-shield is quite large and the tube
is also a little wider than absolutely necessary.
The focuser is a very nice rack-and-pinion type. It is very
smooth, better than the Vixen 2" focuser on my self-built
scope. The optical quality is quite good, I made a direct
comparison to a Japanese 80mm f/5, and the GSO had better
limiting magnitude, resolution and contrast. The Cassini
division was clearly seen, while in the other scope it was
quite difficult. Chromatic aberration was a lot less in
the GSO.
During the Venus transit,
I was able to spot the atmosphere of Venus outside the Sun
before second contact.
 The
star test looked quite funny, so I made some inquiries and
at last the telescope was optically tested. The asymmetrical
star test stems from a irregulary polished surface of the
cemented doublet. Misalignment of the lenses was not the
cause, as some people speculated. While optical quality
is not perfect, it is better than in the comparison scope.
For a quick look at the sun or the moon this scope is exactly
what I needed, It will come with us to the camping-holiday
to!!
|
Webcam
I found this Philips Vesta 675K for only about 22€
at the local Media Markt. It is well suited for planetary
imaging. On my planet page you
can find images of Mars, Jupiter and Saturn.
The more expensive
ToUCam Pro could give you up to 30frames per second in VGA
(640x480) resolution, but because of the compression taking
place, it is recommended to use 5fps in any case, so this
camera with its limit to 5 fps works just as well.
To increase the
meager 720 mm focal length of my R-130S I use a Vixen 3-element
Barlow and a Diagonal Prism between the barlow and the camera,
which results in a 2.7 increase in f.l. |
|
Astrophotography by Philipp Salzgeber
