Hi there,
tried to double-stack two PST Etalons with a custom made adapter, works nearly perfect after i eliminated several problems:
- first i had to remove the inner lenses of both etalons (the outer lenses were not removed)
- then i had lots of ghost-images / reflections, expanding the distance between the two etalons moved the ghost images out of the FOV, solved
- next problem was banding, its not so easy to tune the two etalons to each other - i did not really solve this problem, but with artificial flats generated in pixinsight i managed to flatten the image
the adapter to connect the two etalons is simply a M50x1 outer with a m50x1 inner tube with a stop-ring, so it's basicly a m50 extension tube with variable length
here are some pics
PST with two etalons (one with rubber-band, other without rubber band) and the adapter between them:
and here the final test, today ad 5pm, 10% out of 2000 frames, processed in PI, ZWO ASI 178mm on this PST-Mod,
i'm not sure, how to judge the resulting bandwith - is it comparable to a real DSL with front-etalon? more tuning of the etalons needed?
Jonas
Another PST-Etalon-Double-Stacking-Mod
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Re: Another PST-Etalon-Double-Stacking-Mod
Nice work and excellent result. It would still need a larger objective diameter and you will have an excellent solar telescope.
I do not look at the sky with the eyes of an astronomer, but of a person looking for the beauty of nature.
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Re: Another PST-Etalon-Double-Stacking-Mod
Good result and mod! Welcome to the forum!
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!
Re: Another PST-Etalon-Double-Stacking-Mod
Finally adopted the Dual-PST-Etalon-Stack to my Skylux 70/700 Refractor, it works
from left to right:
- Skylux (LidlScope) 70/700 Refractor
- reducer to 2"
- 2" Baader Red-Filter (not visible, inside)
- 2" beloptik UV/IR-Cut KG3 Filter (not visible, inside)
- 2" to M50 PST adapter
- Etalon 1 (inner Lens removed)
- M50 to M50 adapter
- M46 Hoya IPC Polarizing filter (not visible, inside, tilted)
- Etalon 2 (inner Lens removed)
- M50 to T2 Adapter
- T2 helical focuser
- some T2 extensions to reach focus
- Coronado BF10 without ITF (not needed)
look ok i think
Jonas
from left to right:
- Skylux (LidlScope) 70/700 Refractor
- reducer to 2"
- 2" Baader Red-Filter (not visible, inside)
- 2" beloptik UV/IR-Cut KG3 Filter (not visible, inside)
- 2" to M50 PST adapter
- Etalon 1 (inner Lens removed)
- M50 to M50 adapter
- M46 Hoya IPC Polarizing filter (not visible, inside, tilted)
- Etalon 2 (inner Lens removed)
- M50 to T2 Adapter
- T2 helical focuser
- some T2 extensions to reach focus
- Coronado BF10 without ITF (not needed)
look ok i think
Jonas
- marktownley
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Re: Another PST-Etalon-Double-Stacking-Mod
Nice result!
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!
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Re: Another PST-Etalon-Double-Stacking-Mod
Nice setup Jonas !
If you go to normal display (i.e. BW and non inverted), then you will have a better look at the current limitation of the images, and possibly find some way of improvement.
If you take the FD image, there is a clear reduction in resolution at the bottom of the image.I can't see no clear explanation to this. Maybe something is not square somewhere ? Nor sure whether seeing condition could explain that ?
This is a bit the same for the last image, with increased resolution to the center of the image.
Maybe you can try to rotate the etalons to see if there is any change ?
If you go to normal display (i.e. BW and non inverted), then you will have a better look at the current limitation of the images, and possibly find some way of improvement.
If you take the FD image, there is a clear reduction in resolution at the bottom of the image.I can't see no clear explanation to this. Maybe something is not square somewhere ? Nor sure whether seeing condition could explain that ?
This is a bit the same for the last image, with increased resolution to the center of the image.
Maybe you can try to rotate the etalons to see if there is any change ?
Christian Viladrich
Co-author of "Planetary Astronomy"
http://planetary-astronomy.com/
Editor of "Solar Astronomy"
http://www.astronomiesolaire.com/
Co-author of "Planetary Astronomy"
http://planetary-astronomy.com/
Editor of "Solar Astronomy"
http://www.astronomiesolaire.com/