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Author Topic: PST prism  (Read 2170 times)

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Offline Geoff_k

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PST prism
« on: 12:53:38, 05 March, 2011 »
Got this scope in July and due to varying circumstances have hardly used it a lot. It has probably spent more time in its box than out of it.

Managed some images yesterday (the first in quite a while) and it was suggested that the prism might be out of alignment.

Being a relative beginner to solar imaging I thought it would be prudent to open it up and take a picture which is attached. Do I need to do anything or is it fine as it is?

Geoff

Offline Merlin66

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Re: PST prism
« Reply #1 on: 13:48:00, 05 March, 2011 »
I've actually seen MUCH worse... the images will probably be very usable.
(The top edge of the prism should be square to the eyepiece holder ie parallel to the underside of the PST black box...yours looks slightly tilted towards the front which is pretty usual.)
C11, C9.25 SCT, 4" Genesis, NEQ6pro, modded 1000D,  ATik314L+, DMK41AF04, SM60DS/BF15, and Spectroscopes (many!).
http://tech.groups.yahoo.com/group/astronomical_spectroscopy/
"Astronomical Spectroscopy for Amateurs", "Grating Spectroscopes-How to Use them" -Springer

Offline Geoff_k

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Re: PST prism
« Reply #2 on: 14:02:00, 05 March, 2011 »
Merlin66

Thanks. I did look at some on the Web and based on that rather unscientific survey, mine seemed as good as any.

In that case, I reckon it would probably be advisable to let sleeping prisms lie.

I feel it has more to do with the cameras and having the time and opportunity to sort out the focus issue properly.


Geoff

Offline Merlin66

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Re: PST prism
« Reply #3 on: 14:26:47, 05 March, 2011 »
Certainly give it a go!
If you see astigmatism in your images - you know what to fix!
C11, C9.25 SCT, 4" Genesis, NEQ6pro, modded 1000D,  ATik314L+, DMK41AF04, SM60DS/BF15, and Spectroscopes (many!).
http://tech.groups.yahoo.com/group/astronomical_spectroscopy/
"Astronomical Spectroscopy for Amateurs", "Grating Spectroscopes-How to Use them" -Springer

Offline firmament

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Re: PST prism
« Reply #4 on: 11:42:14, 07 March, 2011 »
Hi Geoff

I agree with Ken: your prism is slightly tilted, but only slightly and I would recommend to leave it as it is.
Unless you have an urge to tweak of course :o)))

However when imaging do tweak the Etalon Tuner to get the best image, and of course focus and focus again. I prefer to tweak and focus on the granulation of the solar disk; this goes best when you enlarge the live video feed say 2x or more, e.g. with ScreenVision (see my software page)
Groetjes/greetings from The FIRMAMENT Observatory

Jan Timmermans N 51.363 E 5.4622 (Valkenswaard - The Netherlands) <><
Astro website http://www.thefirmament.nl
PST + 2.5 PowerMate + Philips Vesta SC3 webcam

Offline Geoff_k

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Re: PST prism
« Reply #5 on: 20:48:37, 07 March, 2011 »
Jan

Thanks. I had come to much the same conclusion. I'm not one for tweaking things as disaster can strike.

At the moment, I am trying to work out the best camera/scope/(and barlow sometimes) combination to get the best results. Hopefully, I will get more time as the weather improves. So far I have found that my venerable old Toucam is the easiest to reach focus but when it does is not as sensitive as the Philips SP900 which is proving more difficult to focus.

I'll get there in the end.


Geoff

Offline joncarruthers

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Re: PST prism
« Reply #6 on: 08:45:51, 15 January, 2013 »
the prism is only stuck to the carrier by double sided tape. My pst was found in a skip with no prism, I fitted a 90 degree prism from a binocular which had the advantage of reducing the light path so enabling easier camera focus.

Offline colinsk

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Re: PST prism
« Reply #7 on: 15:00:45, 20 March, 2016 »
Many years ago I owned a PST and was able to make a simple laser alignment setup. It improved my focus greatly.

 

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