Thermal Acclimation of My Lunt50

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pedro
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Re: Thermal Acclimation of My Lunt50

Post by pedro »

Very interesting Mark, thanks for the update

Please keep us posted. I have some bad experiences with double stack etalons...


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Re: Thermal Acclimation of My Lunt50

Post by rsfoto »

Hi Mark,

Interesting and good animation.

Rainer


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Re: Thermal Acclimation of My Lunt50

Post by marktownley »

The more I experiment with this scope the more i'm convinced the etalon sits loose in the chamber it is housed in. You can definitely hear a 'moving part' in the etalon chamber and it can only be the etalon. The fact I can get the sweetspot as a band implies the etalon is tilted relative to the normal. The fact that I can alter the relative tuning by the angle the scope sits at - ie rotating it in the tube rings just screams loose etalon sitting in the chamber.

I couldn't get it uniformly on band at all this evening and was saying lots of bad words. I did try triple stacking it with another 50mm etalon with results below.

ImageHA-fd-ts-bw by Mark Townley, on Flickr

Not even.

I'm now exploring a few options here, as in it's current form this pressure tuned Lunt simply does not do it for me - too much faffing around to make it work. Firstly disassemble, reassemble and diagnose the LS50 to see what can be improved. Secondly looking at LS50 etalons with a view to double stacking with external etalons for more even larger sweetspot - 50mm etalons are pretty cheap at the moment so I think I will do Valerys trick and shop around for the best ones.


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Re: Thermal Acclimation of My Lunt50

Post by marktownley »

I got the lens spanner out last night and tightened down the cell on the ERF, so will see if that helps.


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Re: Thermal Acclimation of My Lunt50

Post by Bob Yoesle »

Looks to have great contrast when stabilized Mark. excellent imaging BTW!


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Re: Thermal Acclimation of My Lunt50

Post by marktownley »

Makes sense. This is why the etalon is flopping around...


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Re: Thermal Acclimation of My Lunt50

Post by marktownley »

Next steps with this, the etalon chamber is coming apart and i'm going to do a rebuild / re-engineer as needed.


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