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Doublestack with LS50F?

Posted: Thu Aug 10, 2017 7:19 pm
by bart1805
Hi there,
At the moment I use a Bresser 127 mm pst mod.But I have also got a LS50F filter. I learned here that I need F30 (thanks Merlin and Galosimo!). So then this would be an option:
- create a F30 beam
- use a Baader 35NM H-Alpha filter in front of the telecentric system
- attach the LS50F to the telecentric system, remove the Erf.
- remove the front lens of the PST etalon and attach the etalon to the LS50F
- leave everything else as it is. So the JMI focusser is attached to the PST etalon.

Fact is that I don't own a 3x telecentric system. But I do have a Televue 2,5x Powermate (1,25 inch). Would it be wise to try if it works by using the 2,5x powermate as the telecentric system? So then I guess the only things I need are an adapter T2 to M90 and a M90 to M50 adapter.

Any advice if it is wise to pursue this? Thanks in advance!
Bart.

Re: Doublestack with LS50F?

Posted: Thu Aug 10, 2017 9:47 pm
by marktownley
Air spaced etalons really don't work well in a telecentric beam, their lower refractive index (compared to solid) etalons means they have a really wide bandpass. Been there, done it, got the t-shirt. Don't waste your time!

Sorry!

Re: Doublestack with LS50F?

Posted: Fri Aug 11, 2017 8:45 am
by bart1805
There is no need to be sorry Mark, thanks for your answer!
This is one of those adventures I think I can't resist to get the T-shirt myself...... But I saw the price of the first adapter (T2 to M90) when I calculated it on the website of precise parts. And it seems it is quite an expensive T-shirt (about 150 dollar). I have read a lot of threads about the double stacking and don't understand all of them. And it seems that some have managed to get fairly decent images with it. I will rethink this particular adventure.

Re: Doublestack with LS50F?

Posted: Wed Oct 04, 2017 10:59 am
by Anna Rose
Would it be beneficial to try if it works by using the 2,5x i think you will get better results from that thank you.

Re: Doublestack with LS50F?

Posted: Thu Oct 05, 2017 5:19 am
by marktownley
Anna Rose wrote:
Wed Oct 04, 2017 10:59 am
Would it be beneficial to try if it works by using the 2,5x i think you will get better results from that thank you.
It doesn't work in a telecentic beam.

It would work in a collimated beam.