My main telescope is a GSO (Guan Sheng Optical) photo Newton with 200mm mirror diameter and 800mm focal length.
With a focal ratio of f/4 this telescope is predestinated for astro photography.
In order to illuminate the full field of my Canon 40Da the original secondary mirror (63mm diameter) was replaced with a larger one
with 70mm diameter.
For increasing the constrast I've laminated the complete scope inside with black velours.
To avoid coma, I'm using the TeleVue Paracorr coma corrector.
This corrector corrects the complete field of my camera perfectly with an extension of the focal length of 15% up to 920mm.
Key Facts GSO 200/800mm:
|Focal ratio ||f/4
|Diameter secondary mirror||70mm
|Focuser||2" Crayford with 1:10 Ratio
After a MEADE LXD-55, a EQ-6 I am now a satisfied owner of a Losmandy G11 equatorial mount with the Gemini Goto control.
I've installed the mount on a steel column which is doweled on my roof-deck. The column only provides a EQ-6 connection.
Therefore I've purchased the original Losmandy MA adapter, which works fine.
Key Facts Losmandy G11:
|Weight||17,5kg (Equatorial head)
|Achsen|| 36mm stainless steel axis
|Worm gears||143mm Diameter - 360 Tooth
The Gemini Goto control replaces the original Losmandy control and offers among other things
Actually goto functionality is rather unimportant for photography, however it saves a lot of
time, especially when searching for faint objects which are nearly unvisible.
The moving speed is with up to 6° per second pretty high at very low noise what's good for my neighbourhood ;).
The Gemini Control's Object catalog provides:
|110|| Messier Objects||
|7840|| NCG Objects||
|5386|| IC Objects||
|313|| Sharpless 2 Objects||
I'm using a modified Canon 40D for imaging.
For increasing the H-α sensivity (the emission line of most nebulas) the original filter was replaced by a
from Firma Baader-Planetarium.
Thanks to the replaced filter, very low noise, 14 bit data, RAW format and Live View functionality,
which makes focussing very simple, this camera could be considered as an adequate astro camera.
Only at warm nights the missing cooling leads to increased background noise.
|Chip size||22,2 x 14,8 mm (CMOS)
|Resolution||3.888 x 2.592 Pixel (RAW)
|Pixel isze||5,7 μm
|ISO speed||100 - 3200
That's my imaging setup with the Newton. I'm using a FH refractor with 80mm diameter and 900mm focal length
as guiding scope. In order to avoid drift problems, the guiding scope has regular tube rings which
are rock-solid screwed with the tube rings of the Newton.
My guiding camera is an ALccd5 (QHY5).
For being somewhat more flexible when looking for guiding stars, I'm using a excenter
which allows to search in the complete field of view for a suitable guiding star without
changing the position of the telescope.
For autoguiding and controlling the exposures series I use the freeware software
of Matthias Garzarolli.