As inspiration for ATMers out there I'm posting this new picture Of Wayne Bizzacca's new 20" F3.6 build. The scope was originally a 20" F5. He's dropped in a new F3.6 Australian made mirror, and shortened the poles and increased the diagonal size.
He reports that he can now view objects up to 75 degree elevation with feet on the ground and also fully assemble the 'scope without a ladder. The scope also has a Servo cat and Argo Navis fitted.
He's enjoying pin-sharp images with a Televue Paracor and is eagerly awaiting the arrival of his 21mm Ethos to join the 13mm and 17mm in his collection.
This was his first telescope build, and his engineering background shows in the well implemented minimalist design using all the best design principles.
That's impressive, Mark. Very handsome Alt bearings! Did you enjoy making the mirror?
Hi Erick
It was the second of that speed that I've made and definitely went a little faster than the first , though much more time consumeing than F5 mirrors. I am now in the knowledge that I can equal the image quality of the longer focus mirrors. The next fast f ratio mirror I will be making will be a 24" F3.5 ( 84" focus) .
I look forward to the release of the Parracor V2 this year that will be optimised for F3 to F4 scopes and deliver a flatter field than the V1 , whose design is about 20 years old now. Feathertouch focussers will be marketing a special version with the V2 Parracor lens screwed into the focus tube base, that will obviate the need for the 'tunable' top on the Paracor. Just put any eyepiece in and it will automatically be at the correct distance from the coma correcting lens for optimal performance.
Very nice work and looks like a beautiful wood finish too.
In my 22" F3.6, the view with the current model Paracorr is very sharp with my 28mm UWAN, 13mm and 9mm Naglers. But, I wish the new model attached to the Feathertouch focuser was available when I completed the scope, as constantly changing the setting when swapping eyepieces is a bit of a pain in the dark.
Still, it takes less time than climbing a tall ladder!
It looks fairly average. If he wants to sell it for $50 to get something back on the labour I'll buy it...
Hmm...given the lack of emoticons hard to know whether you're reply is tongue in cheek...in what way is it "average" given it's his first go at constructing a dob
Hmm...given the lack of emoticons hard to know whether you're reply is tongue in cheek...in what way is it "average" given it's his first go at constructing a dob
Apologies - a poor attempt at being tongue in cheek. I'm just hugely envious of and impressed with the scope. Well done.
Andrew
Last edited by mercedes_sl1970; 30-03-2010 at 12:41 AM.
Reason: minor revision
Mark ,how do you think the time line of my mirror to this new Feathertouch Paracorr focuser will go. Worth waiting to order one?
Mark
Quote:
Originally Posted by Satchmo
Hi Erick
It was the second of that speed that I've made and definitely went a little faster than the first , though much more time consumeing than F5 mirrors. I am now in the knowledge that I can equal the image quality of the longer focus mirrors. The next fast f ratio mirror I will be making will be a 24" F3.5 ( 84" focus) .
I look forward to the release of the Parracor V2 this year that will be optimised for F3 to F4 scopes and deliver a flatter field than the V1 , whose design is about 20 years old now. Feathertouch focussers will be marketing a special version with the V2 Parracor lens screwed into the focus tube base, that will obviate the need for the 'tunable' top on the Paracor. Just put any eyepiece in and it will automatically be at the correct distance from the coma correcting lens for optimal performance.
Mark a question for you, would these type of mirrors be any good in a astrophotography sense? and with the feather touch will it be tuned for CCD cameras?
The reason why i ask is that it will not be too long before i will start looking at this area of telescopes and i am currently trying to get my head around the decisions i need to make and the approximate costings.
The cost of mounting optics of these size photographically goes up exponentially, and probably needs to be in a permanent observatory. If you have to setup each time at an observing site then a a 10" or 12" is probably the limit. If money is no object and you have a site there is nothing intrinsically difficult about setting up a fast Newt for photography. You can get Wynne correctors in 3" and 4" diameters now like the big observatories use , that will coma correct and flatten up to 60mm diameter fields down to F3 ,which is larger CCD chip than most gear available to amateurs today.
Mark, definately an insperation for me to the point I may look at changing my order to an F3.5.
I am warming to the idea of no ladder observing.
Another site that has got my attention is http://www.loptics.com
He is regularly doing mirrors to F3 and less with great results and with the new paracorr 2 designed for even faster scopes than F4.5's around the corner coma will be eliviated.
Got any more pics with out the light shroud so we can see the working bits
Mark
Thanks for the information mark, would you be able to PM me with some approximate extimates for the 10 and 12" mirror's with these kind of specifications to work with the correctors you mentioned.?
