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Sunday, September 14, 2008

New equipmets and some development work.

New focusing system for the Tokina 300mm lens.
System is based on temperature compensating TCF-s focuser and
it's very accurate.
I printed an angular scale and glued it to telescope ring.
The ring is supporting the front end of the heavy lens and same time works
as an indicator to a camera angle.


Unknown said...

Hello again,

Sorry to bug you once more. I like the set up with the TCF-S focuser. I have one too.

One question not related to the TCF-S. With this set-up how do you autoguide? Thru the SCT OTA?


J-P Metsavainio said...

I Guide with the SCT.
I have a f6.3 reducer and pretty
long extencion tube between it and the guider.
The final FL is closer to f4 with
this sytem.
Tokina 300mm system has 5"/pix,
so only semi good guiding is needed here. I'm a perfectionist
with astro imaging and like to
guide 2"/pixel with the Tokina.
(Modern guiding algorithms has
so good centerpoint calculation rutines, that this is actually meaningless)

Fast lenses has extremely narrow critical focus zone. The focusing system, with TCF-S, gives me accurate focusing + temp. comp.
It was easy to build, I recomend something similar.
If I shoot with SCT, I simply move the focuser there, takes about 60s.

Ethernal said...

Hi JP,
After you got the Canon 200/1.8 - what happens with the Tokina lens? I try to find one but cannot succeed...
If it is redundant, can you contact me to arrange something?

J-P Metsavainio said...

Hi Delyan,

I still have the Tokina lens.
I'm not going to sale it in near future.
It's a great lens and I need it to
my remote imaging project.
More about this project later.