Advantages of Stage I and Stage II

Frankenscope? Let's see it!***be advised that NOTHING in this forum has been safety tested and you are reading and using these posts at your own peril. blah, blah, blah... dont mess around with your eyesight when it comes to solar astronomy. Use appropriate filtration at all times...
Post Reply
vikeljay

Advantages of Stage I and Stage II

Post by vikeljay »

Since you are not changing the size of the etalon, what advantages are there to the Stage I and Stage II mods? Thanks.


User avatar
Merlin66
Librarian
Librarian
Posts: 3970
Joined: Tue Dec 13, 2011 1:23 pm
Location: Junortoun, Australia
Has thanked: 173 times
Been thanked: 615 times
Contact:

Re: Advantages of Stage I and Stage II

Post by Merlin66 »

You're increasing the effective aperture which gives better surface resolution...
The Stage 2 mod also dumps the problematic penta prism, improves the backfocus to accommodate cameras and allows the introduction of larger blocking filter for a better FOV.


"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
User avatar
marktownley
Librarian
Librarian
Posts: 42274
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Has thanked: 20442 times
Been thanked: 10247 times
Contact:

Re: Advantages of Stage I and Stage II

Post by marktownley »

Exactly what Ken says!


Image
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!
User avatar
keithatrochdale
Ohhhhhh My!
Ohhhhhh My!
Posts: 71
Joined: Wed Mar 21, 2012 11:16 am

Re: Advantages of Stage I and Stage II

Post by keithatrochdale »

I do not see any advantage between them if your PST is working well; it is another story if the PST is not giving of it's best.


Nothing is foolproof to a sufficiently talented fool!

http://www.astronomycentre.org.uk
JohnM
Im an EXPERT!
Im an EXPERT!
Posts: 410
Joined: Fri Apr 20, 2012 2:06 pm

Re: Advantages of Stage I and Stage II

Post by JohnM »

I do not see any advantage between them if your PST is working well; it is another story if the PST is not giving of it's best.

There's one major advantage. It opens you up to the world of large aperture Ha telescopes. :)


User avatar
keithatrochdale
Ohhhhhh My!
Ohhhhhh My!
Posts: 71
Joined: Wed Mar 21, 2012 11:16 am

Re: Advantages of Stage I and Stage II

Post by keithatrochdale »

Ok let me rephrase it, I cannot see any advantage of a TAL100/PST stage 1 conversion over a Tal100/PST stage 2 conversion.


Nothing is foolproof to a sufficiently talented fool!

http://www.astronomycentre.org.uk
JohnM
Im an EXPERT!
Im an EXPERT!
Posts: 410
Joined: Fri Apr 20, 2012 2:06 pm

Re: Advantages of Stage I and Stage II

Post by JohnM »

OK, there's a major advantage to getting rid of the Black Box of the PST and in particular getting that penta-prism out of the light train.


User avatar
keithatrochdale
Ohhhhhh My!
Ohhhhhh My!
Posts: 71
Joined: Wed Mar 21, 2012 11:16 am

Re: Advantages of Stage I and Stage II

Post by keithatrochdale »

OK, there's a major advantage to getting rid of the Black Box of the PST and in particular getting that penta-prism out of the light train.

And they are what exactly?

Having used both side by side and bigger scope conversions I would be interested.


Nothing is foolproof to a sufficiently talented fool!

http://www.astronomycentre.org.uk
JohnM
Im an EXPERT!
Im an EXPERT!
Posts: 410
Joined: Fri Apr 20, 2012 2:06 pm

Re: Advantages of Stage I and Stage II

Post by JohnM »

If you used both and couldn't see the difference, I'll leave it to others to carry on.


MjrTom

Re: Advantages of Stage I and Stage II

Post by MjrTom »

If you used both and couldn't see the difference, I'll leave it to others to carry on.

Yeah a huge difference in practice ;)


Solarhound
Ohhhhhh My!
Ohhhhhh My!
Posts: 132
Joined: Sun Jul 28, 2013 4:51 pm

Re: Advantages of Stage I and Stage II

Post by Solarhound »

Having used both configurations I have to agree with Mlr Tom above , there is a huge difference . Personally I would not consider a stage 1 mod after seeing how the stage II opens up the view . The big advantage in my opinion is being able to use bigger blocking filters . Going from the 5mm BF in the PST to a BF 15 compares like looking through a straw to looking through a telescope . My next move is to try a Lunt 2" - 18mm straight through .


peter drew

Re: Advantages of Stage I and Stage II

Post by peter drew »

A BF15 is a direct swapover from the standard PST BF5, you just unscrew both for the switch. Both the PST BF5 and the BF15 use the same supplied 15mm ITF so there is no issue there. :)


vikeljay

Re: Advantages of Stage I and Stage II

Post by vikeljay »

Is there a detailed description of how to perform a stage 2 mod including the parts necessary and where to purchase them? It sounds like a stage 2 is the way to go. I already have a diagonal with a BF 10 blocking filter. Thanks.
Jim


JohnM
Im an EXPERT!
Im an EXPERT!
Posts: 410
Joined: Fri Apr 20, 2012 2:06 pm

Re: Advantages of Stage I and Stage II

Post by JohnM »

I've only ever seen one person who swears there no difference between a stage 1 and a stage 2, I have better things to do than deal with that.


User avatar
keithatrochdale
Ohhhhhh My!
Ohhhhhh My!
Posts: 71
Joined: Wed Mar 21, 2012 11:16 am

Re: Advantages of Stage I and Stage II

Post by keithatrochdale »

I've only ever seen one person who swears there no difference between a stage 1 and a stage 2, I have better things to do than deal with that.

Well JohnM some side by side testing was done with 2 TAL/PST stage 1 and a Vixon florite/PST stage 2 and the three testers favored the stage 1.

I hope some of the testers who visit this site will add their comments.


Nothing is foolproof to a sufficiently talented fool!

http://www.astronomycentre.org.uk
Solarhound
Ohhhhhh My!
Ohhhhhh My!
Posts: 132
Joined: Sun Jul 28, 2013 4:51 pm

Re: Advantages of Stage I and Stage II

Post by Solarhound »

My testing was done with the same donor scope and the same PST . Celestron 102 OMNI XLT with stage I mod and followed by the same XLT scope using the sams etalon from the PST . The big difference was the Coronado BF 15 I used for the stage II . After comparing the views there was no desire what so ever to go back to the stage I configuration , in fact I plan to move up to a Lunt B 1800 2" straight through for this scope in the near future .

These are just my findings and opinions on what I have done . For imaging I actually prefer my stage II mod to my SM 60 II


User avatar
marktownley
Librarian
Librarian
Posts: 42274
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Has thanked: 20442 times
Been thanked: 10247 times
Contact:

Re: Advantages of Stage I and Stage II

Post by marktownley »

Visually (with perfect aligned black box PSTs) I could 'see' no difference with the stage 1 and stage 2 mods, and in this context happily see the argument. However from a critical imaging point of view, with that penta prism in place sharpening soon shows the astigmatism it introduces and with it a relative lack of contrast and definition.


Image
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!
JohnM
Im an EXPERT!
Im an EXPERT!
Posts: 410
Joined: Fri Apr 20, 2012 2:06 pm

Re: Advantages of Stage I and Stage II

Post by JohnM »

Yes, probably important to emphasize the difference between visual and photographic uses.
The human eye is much more forgiving than a camera chip.


User avatar
keithatrochdale
Ohhhhhh My!
Ohhhhhh My!
Posts: 71
Joined: Wed Mar 21, 2012 11:16 am

Re: Advantages of Stage I and Stage II

Post by keithatrochdale »

Not having progressed to serious imaging yet, all my comments and the three tester were using standard
Mk 1 eyeball.

So I think we can agree that for visual there is little to justify the extra costs of stage 2, but there may well be advantages for imaging, which I have yet to do/assess?


Nothing is foolproof to a sufficiently talented fool!

http://www.astronomycentre.org.uk
User avatar
swisswalter
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 17948
Joined: Thu Feb 06, 2014 4:28 am
Location: Switzerland
Been thanked: 1 time
Contact:

Re: Advantages of Stage I and Stage II

Post by swisswalter »

Not having progressed to serious imaging yet, all my comments and the three tester were using standard
Mk 1 eyeball.



:lol:


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 ;)
Post Reply