Tal 200K

[AndyH]

With it being wall to wall cloud for as long as I can remember, I have been

trying out things with my 200K.

I took out the mirror in my 200K's diagonal to paint the inside flat black(Also

did my Tal eyepieces). I noticed that it's mirror is looking a bit worn, with

scratches and pits on the mirrors surface.

I decided to try out a good quality dielectric 1.25" diagonal, but was

frustrated by the loss of a LOT of infocus, meaning my University Optics 32mm

Konig wouldn't come anywhere near focus.

I have been using a Takahashi 1.25" prism diagonal on my 80mm finder, again to

get enough infocus, on it. I put this in the focuser of the 200K and would you

believe it, focus was achieved. In fact 7mm more infocus has been gained over

the Tal stock unit. I checked collimation through it, on the scope, with the

excellent Helix mfg grid pattern laser and all was well. So far so good.

During one of the very few clear spells between clouds, it let me test the Tak

and the Tal diagonals. Switching back and forth between the two, showed no loss

of light throughput, which was surprising and pleasing. It seems to be the

unwritten rule, that folks say prism diagonals are cr*p and mirrors are far

superior. Not so here.

I'll need to wait for another clear spell before I can check the contrast

performance on the planets, but I'm hopeful. Seems this Tak prism is of good

quality.

I have been tempted of late to move the corrector assembly forward a knotch for

more infocus, but if this Tak diagonal continues to prove it's worth, I'll not

bother. I do think however I'll try to source a new mirror for the Tal diagonal.

It really is in bad shape.

Cheers, from a seemingly never ending, cloudy Scotland.

Andy:glasses1:

[SpookyKatt]

Good report Andy, many thanks for posting it here and in the TalScopes

group. I'll be interested if planetary viewing is affected in anyway.

Its nice to know that changing the diagonal results in more infocus for

the scope as the limited focus is a bit of a pain.

Kathleen