*
The 10" diameter dewshield from the original straight tube model has been fitted over the permanent, stumpy shield. The shield is difficult to see against the typical, Danish overcast. Fortunately there have been several clear evenings lately. Though each time with later cloud bringing a sudden end to observations. The higher the object the better the view.
The objective lens [with stumpy dewshield attached] is easily removable thanks to a very simple bayonet plate system. Two wheeled screws safely lock the plates together in use.
A polythene bag covers the 4" 2nd mirror while a protective, plastic pot covers the 5" second.
The plywood battens are a temporary clamping fix of the OTA framework onto the MkIII's 12" cast cradle.
The MkIII mounting is proving rather flexible and jerky with the heavy OTA mounted on it. Not really helped by the plywood clamping battens. Which I do not recommend. They get in the way during fixing to the mounting.
With the objective and dewshields removed the OTA is stored upright on its front plate.
The 2" Vixen refractor-style focuser rotates on the backplate with a turned birch plywood ring providing retention and adjustable, slop-free friction.
More general view of the lower OTA. The Porsa tubing I chose has a small flange running along one edge. Which provides a sunken surface for attaching covering plates. I decided that almost every kind of flat material would add unwanted weight. So I have a piece of black cloth suitable for a shroud but have not needed it so far.
I intend to transfer the OTA to the much heavier MkIV mounting once I decide how to support it.
The MkIV's massive, wheeled pier is not ideal. Being both too tall and rather difficult to move about on soft ground to find clear sky.
Click on any image for an enlargement.
*
1 comment:
Hi Chris,
A stunning entry in the category of "angular astronomy"! Do get on to Porsa and submit yourself for a design award in return for letting them take some publicity shots. What does your good lady wife think of this new addition to the family?
And - apart from modifying the MkIV stand better to accommodate the beast, what on earth are you going to do next to keep us all agog and educationally entertained? Not actually observe the heavens I trust! ;)
Best,
Andrew
Post a Comment