pn/DJ.OUTPUT/

spots.april21.1998  ****************************************

Hi Nigel

Here are the spot files that go with the fax. Same nomenclature:

"PNS11TA.SPT"
"PNS11WA.SPT"
"PNS11W.SPT"
"PNS10W.SPT"
"PNS10T.SPT"

There is a bit more pupil distortion in "PNS11WA" which will cause some
overlap out in the corners - is there a limit on this (in mm)?

All the best

spots.april23.1998  *****************************************

Nigel

Sorry about all this. It does get pretty complicated.

>PNS11TA  is  dedicated TNG collimator  traced at TNG - right?

right

>(does dedicated mean that "fixed group" is also optimised?)

yes, this group is optimised for the TNG telescope or "feed" (but see below)

>PNS11WA  is same set up (ie same "fixed group") but
>       with WHT "adaptor group" -- but at which telescope?

WHT (feed)

>PNS11W  is  dedicated TNG collimator  traced at WHT

Yes

>PNS10T  is  dedicated WHT collimator traced at TNG

Yes Yes

>... but wouldn't it be more reasonable to show us the
>spots for the optimum compromise? If it lies between
>PNS10W and PNS10T it is probably OK, although I appreciate
>that the aberrations of the camera have yet to be
>accounted for. Also, unless we misunderstand
>"dedicated", we have not seen your proposed solution
>traced, i.e. optimum compromise "fixed group" with
>2 "adaptors", although PNS11WA is relevant to this.
>

I didn't think the optimum compromise was good enough actually, but I'll
send it.

The "fixed group" has little to do with the effects (mainly in the field)
seen with the different feeds because its main contribution is the
correction of colour residual and spherical aberration which are more or
less the same for both feeds + either adaptor. But it's optimised for the
TNG feed anyway. A compromise solution is little different - the big changes
occur in the adaptor group.

PNS12 is the compromise collimator.

The spotfiles are:

"PNS12T.SPT" : PNS12 + TNG feed
"PNS12W.SPT" : PNS12 + WHT feed

Hope this is OK

Cheers

spots.april27.1998  ************************************


Nigel

The combined collimator/camera spot files:

"PNS14T.SPT" : TNG + compromise collimator + camera
"PNS14W.SPT" : WHT + compromise collimator + camera

"PNS15T.SPT" : TNG + TNGadaptor + fixed group + camera
"PNS15W.SPT" : TNG + WHTadaptor + fixed group + camera

The TNG systems suffer from field curvature effects because of the smaller
scale of the telescope (which makes the telescope image surface more curved)
and the larger sky field (which pushes image points further out, relatively,
onto this curve).

I'll try and organise some fax pictures tonight too.

A ZEMAX file would be best but there is a bug. Gabe is helping me fix it.
With any luck they'll come through too, and then I won't need to fax.

John Hart is working on the compromise system, with the rider that things
may change. In any case the camera will now remain unchanged. I've wrung
about as much performance as I can out of that beast!

All the best



Damien's fax 18 May 1998


11 series: collimators with adaptors. superseded by 15.
12 series: compromise collimator. superseded by 14.
13 series: ------------------
14 series: system with compromise collimator.
15 series: systems with adaptors in collimators.
16 series: system with compromise collimator and compromise camera.


note: he also shows a "window" in front of the detector in version 16.