What can you do with an SM 40?

[poita]

There is an external SM40 with tuner up for sale, designed for double stacking the PST.
As I am already down the 80mm mod path, is this of any use, or can it be used as the base for another solar mod?
Cheers

-Peter

[colinsk]

A 40 mm etalon would be great for an 80mm objective bout you have to collimate or make a telecentric. The threads are easy.

[poita]

http://www.opto-engineering.com/telecen ... orial.html

I had to do some reading

I would need to get the light beam parallel before it enters the etalon yes?

Is there a lens available to purchase to do this?

I would be using a 80mm F11 scope.

[poita]

My first search turned up this:
http://www.ebay.com/itm/1998-OGP-14-TOP ... 5d33b50b59

I laughed out loud, but it looked so cool I thought I would share it.

[Merlin66]

Check out some of the early mod threads...
Marcon uses a matched achromat to achieve the collimated beam, gives a very long light path but excellent results.

[solarchat]

while it may still work, the SM40 was designed to doublestack an external etalon SM40 scope and the PSM40 was designed to doublestack the internal etalon PST.

[Merlin66]

Stephen,
I'm 100% sure it's OK to use - in a parallel beam.
I used one on the ED80 before upgrading to the SM60 .....

[solarchat]

like I said, it will probably work but the actual doublestacker for the internal etalon version is the PSM40.
You guys in th mod section make all kinds of things into magic though so I am sure it will be fine. I get real nervous when buying anything used in this hobby. (see Gabor's posts on the PT probolems)

Anyway, speaking of mods...I have a ton of etalons, focusers and various scopes laying around, I really should get out my hacksaw and duct tape and start making a Franken-scope.. how hard can it be? Rusty does it! (just kidding Apollo)

[Merlin66]

Stephen,
from memory the only physical difference between the SM40 and the PSM40 was the mount attachment....
I'll send you a copy of the PST mod write up - you can see how easy it is - and 110% safe.

[swisswalter]

Hi Apollo

whowly cow , what a beast

[scorpio]

Peter,

I'm planning a 120mm solar telescope, based on a SM40. As other also said before, you have to build your own telecentric system for the SM40. I plan to do this via a concave and convex Edmund lenses with the etalon placed in the middle.

Depending on the focal lengths of the lenses, you can move the etalon position in the light beam, so that you should not get too much vignetting.

The telescope has arrived, the concept is progressing and the ERF will be ordered soon :-)

Best regards,
Martin

[swisswalter]

Hi Martin

great. Wish you all the luck and skill needed.Looking forward to pics