Quote:
Originally Posted by jeelan
hey Atmos,
I wouldnt hand hold the scope, but wouldnt be purchasing a astronomy tripod either.
My intention (at this stage) would be to use a standard spotting scope tripod with fluid filled head that has X and Y axis movement.
The only other thing is I'd need an erect image diagonal. I know this is done using a prism - does this compromise image quality at all for astro visual?
cheers
Jeelan
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Hi Jeelan
A Skywatcher/Orion ED80 tube weighs 3.5kg. It will sit on a midsize tripod like a manfrotto 090 with 041 head ok for terrestrial. This is the tripod at the small end of the professional range. For astro use, a taller stronger tripod is much better. On a small tripod, pointing up puts the eyepiece very low and awkward and balance and clearance of the tripod can become an issue when looking up. Using a large tripod - eg a Manfrotto 475 is much more comfortable. IF you put a Vixen dovetail clamp on top of the tripod and attach the tube with rings and a dovetail bar, you can re-balance in one axis and the mounting will be more secure. This arrangement will make balance around the elevation axis more of a problem.
A 70mm f6.2 refractor such as, william optic M71, stellar vue etc with 400mm focal length, will sit much better on a small to mid-size tripod for terrestrial and astro viewing.
Eyepieces, diagonals are interchangeable so you can get an erect image prism and a star diagonal for Terrestrial/astro viewing.
Alternatively, you can just use a star diagonal. If you stand behind the refractor facing the thing you are looking at and look down into the star diagonal, you will get an erect but mirror reversed left to right image. This is usually not an issue for wildlife viewing.
Joe