First light PST mod : how to fine tune Etalon?

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Mathieu80
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First light PST mod : how to fine tune Etalon?

Post by Mathieu80 »

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Hi all!
This the first lights i catched last week with this new setup :

Taka FS152
ERF 160
TZ x3,7 Beloptik
Etalon from Coronado PST
Coronado BF15 + ITF Beloptik

I would like to know please how you fine tune your etalon according to what see on your PC screen when imaging?

It looks like there are Ellerman Bombs showing on part of my pictures suggesting i am à little bit out of band in the blue wing.

Another question i have please is how to tilt the ERF in its cell in the right way. I bought this second hand ERF in a tiltable cell but don’t know why ERF should be tilted? ( i tried different positions and it did not have any effect on newton rings for which i had to tilt the camera).

Thanks in advance!

Mathieu
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Re: First light PST mod : how to fine tune Etalon?

Post by arnedanielsen »

Very nice, Mathieu!

Thanks for sharing,
Arne


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Re: First light PST mod : how to fine tune Etalon?

Post by rigel123 »

I can’t answer your question about fine tuning this type of setup, it looks pretty good to me. As to seeing Ellerman Bombs it wouldn’t surprise me to see them in a single stack configuration as well as more details from the photosphere coming through.


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Re: First light PST mod : how to fine tune Etalon?

Post by Dennis »

Thats true, sometimes they are bright enough to shine through with my single stack setup.
Very nice resolution btw.


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Re: First light PST mod : how to fine tune Etalon?

Post by marktownley »

I think these images are spot on to me Mathieu, looks to be a good etalon. Welcome to the forum!


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Re: First light PST mod : how to fine tune Etalon?

Post by Mathieu80 »

Thank you all for your messages :-)


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Re: First light PST mod : how to fine tune Etalon?

Post by Mathieu80 »

marktownley wrote: Thu Jun 23, 2022 7:27 pm I think these images are spot on to me Mathieu, looks to be a good etalon. Welcome to the forum!
Thank you Mark :-) what do you suggest as a method for tuning it when imaging please ? I did it by « feeling » when looking at the captures liveview on PC screen but i imagine it could exist some more accurate methods?
Good night and thanks for the welcome :-)
Mathieu


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Re: First light PST mod : how to fine tune Etalon?

Post by marktownley »

Mathieu80 wrote: Thu Jun 23, 2022 10:44 pm
marktownley wrote: Thu Jun 23, 2022 7:27 pm I think these images are spot on to me Mathieu, looks to be a good etalon. Welcome to the forum!
Thank you Mark :-) what do you suggest as a method for tuning it when imaging please ? I did it by « feeling » when looking at the captures liveview on PC screen but i imagine it could exist some more accurate methods?
Good night and thanks for the welcome :-)
Mathieu
What you're doing works, go for the darkest most even field simply.


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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: First light PST mod : how to fine tune Etalon?

Post by MAURITS »

Looks really nice Mathieu.


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Re: First light PST mod : how to fine tune Etalon?

Post by robert »

Tilting the ERF gets rid of internal relections that may cause ghost images of the sun. Tilting the camera can get rid of Newton rings.

Great images

Robert


images and animations http://tinyurl.com/h5bgoso
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2023 images https://www.flickr.com/photos/69734017@ ... 0304905278
2022 images https://www.flickr.com/photos/69734017@ ... 0295810277
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Re: First light PST mod : how to fine tune Etalon?

Post by Mathieu80 »

marktownley wrote: Fri Jun 24, 2022 5:22 am
Mathieu80 wrote: Thu Jun 23, 2022 10:44 pm
marktownley wrote: Thu Jun 23, 2022 7:27 pm I think these images are spot on to me Mathieu, looks to be a good etalon. Welcome to the forum!
Thank you Mark :-) what do you suggest as a method for tuning it when imaging please ? I did it by « feeling » when looking at the captures liveview on PC screen but i imagine it could exist some more accurate methods?
Good night and thanks for the welcome :-)
Mathieu
What you're doing works, go for the darkest most even field simply.


Ok! Thank you Mark


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Re: First light PST mod : how to fine tune Etalon?

Post by Mathieu80 »

MAURITS wrote: Fri Jun 24, 2022 8:37 am Looks really nice Mathieu.
Thank you Maurits :-)


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Re: First light PST mod : how to fine tune Etalon?

Post by Mathieu80 »

robert wrote: Fri Jun 24, 2022 9:03 am Tilting the ERF gets rid of internal relections that may cause ghost images of the sun. Tilting the camera can get rid of Newton rings.

Great images

Robert
Thanks for your answer Robert. We don’t care of how much the ERF is tilted? I mean it will not affect any thing else than getting rid of reflections?

Mathieu


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Re: First light PST mod : how to fine tune Etalon?

Post by ffellah »

Welcome to the group, Mathieu. Your images look great to me: you hit the floor running !

Franco


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Re: First light PST mod : how to fine tune Etalon?

Post by rsfoto »

Hi,

I am not an expert but the images look excellent.

I can not judge if they are Ellerman bombs or the beginning of Flares but if it is working do not repair it :mrgreen:


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Re: First light PST mod : how to fine tune Etalon?

Post by Petrus »

Very impressive first light and nice setup! Welcome to SolarChat Mathieu :)


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Re: First light PST mod : how to fine tune Etalon?

Post by Rusted »

Superb images! :bow

They look fine for tuning. Very even brightness and detail. :bow

Ellerman bombs tend to be very small, round white spots on my 150/10 PST mod.

As Mark says: Aim for the darkest, most evenly lit and evenly detailed image on your monitor.
Increasing the gain, or the exposure, will produce uneven brightness across the field if the etalon tuning or distance from focus is wrong.

As has already been said. "If it's not broke[n.] Don't mend it!" ;)


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Re: First light PST mod : how to fine tune Etalon?

Post by robert »

Mathieu80 wrote: Fri Jun 24, 2022 9:17 am
robert wrote: Fri Jun 24, 2022 9:03 am Tilting the ERF gets rid of internal relections that may cause ghost images of the sun.
Thanks for your answer Robert. We don’t care of how much the ERF is tilted? I mean it will not affect any thing else than getting rid of reflections?

Mathieu
I don't think it makes much difference once the ghosts are out of the field of view. Too much ERF tilt could degrade the image... too long a path through the glass and creating an uneven image, possibly a banded focus effect across the field.

Your present setup gives great results in my opinion
Robert


images and animations http://tinyurl.com/h5bgoso
2024 images https://www.flickr.com/photos/69734017@ ... 0313830045
2023 images https://www.flickr.com/photos/69734017@ ... 0304905278
2022 images https://www.flickr.com/photos/69734017@ ... 0295810277
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Re: First light PST mod : how to fine tune Etalon?

Post by Mathieu80 »

ffellah wrote: Fri Jun 24, 2022 10:56 am Welcome to the group, Mathieu. Your images look great to me: you hit the floor running !

Franco
Thank you very much Ffellah :-)


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Re: First light PST mod : how to fine tune Etalon?

Post by Mathieu80 »

rsfoto wrote: Fri Jun 24, 2022 2:11 pm Hi,

I am not an expert but the images look excellent.

I can not judge if they are Ellerman bombs or the beginning of Flares but if it is working do not repair it :mrgreen:
Thank you rsfoto :-) yes sure it is working, just wanted to be sure i am going in the right way and how to maybe improve ;-)


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Re: First light PST mod : how to fine tune Etalon?

Post by Mathieu80 »

SassySun wrote: Fri Jun 24, 2022 2:53 pm Very impressive first light and nice setup! Welcome to SolarChat Mathieu :)
Thank you Sassy! :-)


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Re: First light PST mod : how to fine tune Etalon?

Post by Mathieu80 »

Rusted wrote: Fri Jun 24, 2022 3:41 pm Superb images! :bow

They look fine for tuning. Very even brightness and detail. :bow

Ellerman bombs tend to be very small, round white spots on my 150/10 PST mod.

As Mark says: Aim for the darkest, most evenly lit and evenly detailed image on your monitor.
Increasing the gain, or the exposure, will produce uneven brightness across the field if the etalon tuning or distance from focus is wrong.

As has already been said. "If it's not broke[n.] Don't mend it!" ;)
Thank you rusted, actually there is an uneven brightness across my field, in each position of the etalon tuning ring. I deal with that thanks to flats, but this uneven brightness makes quite hard to find the good tuning


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Re: First light PST mod : how to fine tune Etalon?

Post by Mathieu80 »

robert wrote: Sat Jun 25, 2022 9:55 am
Mathieu80 wrote: Fri Jun 24, 2022 9:17 am
robert wrote: Fri Jun 24, 2022 9:03 am Tilting the ERF gets rid of internal relections that may cause ghost images of the sun.
Thanks for your answer Robert. We don’t care of how much the ERF is tilted? I mean it will not affect any thing else than getting rid of reflections?

Mathieu
I don't think it makes much difference once the ghosts are out of the field of view. Too much ERF tilt could degrade the image... too long a path through the glass and creating an uneven image, possibly a banded focus effect across the field.

Your present setup gives great results in my opinion
Robert

Ok Robert thank you for these informations and thanks to all for your nice help! :-)


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Re: First light PST mod : how to fine tune Etalon?

Post by Rusted »

Mathieu80 wrote: Tue Jun 28, 2022 3:29 pm
Thank you rusted, actually there is an uneven brightness across my field, in each position of the etalon tuning ring.
I deal with that thanks to flats, but this uneven brightness makes quite hard to find the good tuning
Sorry, I didn't know you were using flats to even out the PST imbalances.

I presume you have heard of the PST etalon "sweet spot?"
This is the negative side of using a small aperture etalon with a larger aperture telescope.
Some of our experts here have discussed etalon sweet spots not long ago.

My own PST etalon varies from day to day.
I have removed the outer, ribbed, rubber band and its metal supporting shell.
So that I can physically tilt the etalon itself with an extended rod.
Which is crewed into the hole where the hidden locking screw usually fits.

I also "clock" or rotate my Lunt Blocking Filter relative to the etalon.
I have stuck red tape as a marker to ensure correct alignment each time I set up to image.
I am often adjusting the etalon's position, tuning and tilt throughout an imaging session.
Always aiming for the most even, darkest and most detailed image right across the frame.


http://fullerscopes.blogspot.dk/

H-alpha: Baader 160mm D-ERF, iStar 150/10 H-alpha objective, 2" Baader 35nm H-a, 2" Beloptik KG3,
Lunt 60MT etalon, Lunt B1200S2 BF, Assorted T-S GPCs or 2x "Shorty" Barlow, ZWO ASI174.
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Re: First light PST mod : how to fine tune Etalon?

Post by eroel »

Mathieu:
Super results from your PST etalon, that is a very good one, just try to turn the etalon or the BF15 on its axis 1/4th of a turn and then check for the best position. (contrast and even field)
Best wishes and thanks for sharing your work.
Eric.


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Re: First light PST mod : how to fine tune Etalon?

Post by Mathieu80 »

Rusted wrote: Tue Jun 28, 2022 4:57 pm
Mathieu80 wrote: Tue Jun 28, 2022 3:29 pm
Thank you rusted, actually there is an uneven brightness across my field, in each position of the etalon tuning ring.
I deal with that thanks to flats, but this uneven brightness makes quite hard to find the good tuning
Sorry, I didn't know you were using flats to even out the PST imbalances.

I presume you have heard of the PST etalon "sweet spot?"
This is the negative side of using a small aperture etalon with a larger aperture telescope.
Some of our experts here have discussed etalon sweet spots not long ago.

My own PST etalon varies from day to day.
I have removed the outer, ribbed, rubber band and its metal supporting shell.
So that I can physically tilt the etalon itself with an extended rod.
Which is crewed into the hole where the hidden locking screw usually fits.

I also "clock" or rotate my Lunt Blocking Filter relative to the etalon.
I have stuck red tape as a marker to ensure correct alignment each time I set up to image.
I am often adjusting the etalon's position, tuning and tilt throughout an imaging session.
Always aiming for the most even, darkest and most detailed image right across the frame.

Thanks for your message Rusted. Yes i have heard about it but with mythe telecentric system i don’t have any sweet spot, not like in a collimated system with the lenses of the etalon.
Mathieu


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Re: First light PST mod : how to fine tune Etalon?

Post by Mathieu80 »

eroel wrote: Tue Jun 28, 2022 5:08 pm Mathieu:
Super results from your PST etalon, that is a very good one, just try to turn the etalon or the BF15 on its axis 1/4th of a turn and then check for the best position. (contrast and even field)
Best wishes and thanks for sharing your work.
Eric.
Hi Eroel, thank you for the tip, i did not try to turn the BF15, i will do next time :-)


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