from another topic:
www.astropixel.org/astropixel_modif_pst.htm
www.astropixel.org/images/pstmodif-1_20 ... 9_1024.jpg
The PST can be easily dismatled:
http://astrosurf.com/re/pst_dismantle_20060617-01.jpg
http://astrosurf.com/re/pst_dismantle_20060617-02.jpg
http://astrosurf.com/re/pst_dismantle_20060617-03.jpg
(some parts are glued so you will have to use some torque)
http://astrosurf.com/re/pst_dslr_20050505-02.jpg
http://astrosurf.com/re/pst_dslr_20050505-01.jpg
best
Fast f/5 and telecentric for a f/10 PST mod?
Re: Fast f/5 and telecentric for a f/10 PST mod?
Very interesting mod. You still will have to deal with the BF5 of the PST (limited field of view)
I am certain it will reach focus. Please keep us posted
best regards
I am certain it will reach focus. Please keep us posted
best regards
Re: Fast f/5 and telecentric for a f/10 PST mod?
Common barlows don't have a constant 2x factor when you move further away, so I guess it must be the telecentric type.
Check the Powermate ones .
They are the only one that provide info on their real focal length and there is a a chart with the mag. factor according to the distance .
Check the Powermate ones .
They are the only one that provide info on their real focal length and there is a a chart with the mag. factor according to the distance .
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Re: Fast f/5 and telecentric for a f/10 PST mod?
Don't know the answer to your question Neo, but I will certainly follow this with interest...
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: Fast f/5 and telecentric for a f/10 PST mod?
Hello Neo! Thanks for your link to this great forum!
I was thinking: I see your PST etalon is behind the focuser. Therefore changing focus means moving the etalon away from the ideal position of 200mm inside focus. Your current setup may keep the etalon pretty much at a right position, but mounting a Barlow directly in front of the etalon might cause a "etalon ideal position" issue, resulting in a low detail image. You might check if everything works out ok by adding a barlow in front of the setup you already have, before cutting up a new refractor.
I was thinking: I see your PST etalon is behind the focuser. Therefore changing focus means moving the etalon away from the ideal position of 200mm inside focus. Your current setup may keep the etalon pretty much at a right position, but mounting a Barlow directly in front of the etalon might cause a "etalon ideal position" issue, resulting in a low detail image. You might check if everything works out ok by adding a barlow in front of the setup you already have, before cutting up a new refractor.
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Re: Fast f/5 and telecentric for a f/10 PST mod?
Hi guys,
I've done and assist with my fair share of PST mods, over forty successes at the last count....
The reason for the "majic number" 200mm is very straight forward.
The front of the PST etalon has a barlow lens which is....you guessed it -200mm focal length; this means to present a collimated parallel beam through the etalon it MUST be placed 200mm inside the prime focus.
On the rear of the etalon...there's a positive lens (yes you guessed correctly!) which is 200mm focal length.
So, if the final focus is 200mm behind the etalon you'll be pretty much assured that the etalon is in the correct position.
(I have a PST Mod write up available (6.5Mb) just drop me an email address and I'll send a copy)
If you do want a challenge try a double stacked PST etalon design!!
I've done and assist with my fair share of PST mods, over forty successes at the last count....
The reason for the "majic number" 200mm is very straight forward.
The front of the PST etalon has a barlow lens which is....you guessed it -200mm focal length; this means to present a collimated parallel beam through the etalon it MUST be placed 200mm inside the prime focus.
On the rear of the etalon...there's a positive lens (yes you guessed correctly!) which is 200mm focal length.
So, if the final focus is 200mm behind the etalon you'll be pretty much assured that the etalon is in the correct position.
(I have a PST Mod write up available (6.5Mb) just drop me an email address and I'll send a copy)
If you do want a challenge try a double stacked PST etalon design!!
"Astronomical Spectroscopy - The Final Frontier" - to boldly go where few amateurs have gone before
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http://astronomicalspectroscopy.com
"Astronomical Spectroscopy for Amateurs" and
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https://groups.io/g/astronomicalspectroscopy
http://astronomicalspectroscopy.com
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer
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Re: Fast f/5 and telecentric for a f/10 PST mod?
Hi Ken
thank you very much. I would like to have your essai.
You just have no email adress listed in your profile, you will see mine in my the profile
thank you very much. I would like to have your essai.
You just have no email adress listed in your profile, you will see mine in my the profile
Only stardust in the wind, some fine and some less fine scopes, filters and adapters as well. Switzerland 47 N, 9 E, in the heart of EUROPE
from 7 am - 7 pm http://www.nanosys.ch
from 7.01 pm - 6.59 am http://www.wastronomiko.com some times vice versa
from 7 am - 7 pm http://www.nanosys.ch
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Re: Fast f/5 and telecentric for a f/10 PST mod?
I thought my email was in the profile data???
Anyway here it is:
kenm(dot)harrison(at)gmail(dot)com
Anyway here it is:
kenm(dot)harrison(at)gmail(dot)com
"Astronomical Spectroscopy - The Final Frontier" - to boldly go where few amateurs have gone before
https://groups.io/g/astronomicalspectroscopy
http://astronomicalspectroscopy.com
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer
https://groups.io/g/astronomicalspectroscopy
http://astronomicalspectroscopy.com
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer
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Re: Fast f/5 and telecentric for a f/10 PST mod?
based on the mods done to date, there seems to be about a 3-5mm tolerance band before you get collimation problems with the etalon.
"Astronomical Spectroscopy - The Final Frontier" - to boldly go where few amateurs have gone before
https://groups.io/g/astronomicalspectroscopy
http://astronomicalspectroscopy.com
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer
https://groups.io/g/astronomicalspectroscopy
http://astronomicalspectroscopy.com
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer