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  #41  
Old 24-12-2014, 06:23 AM
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Attaching reducers/correctors on any CCD cam would go directly on the filter wheel with an adapter of the correct width to match the distance required by reducers (flatteners seem more flexible).

Not sure what you mean by removing the nosepiece reduces cooling power. The air in the enclosed CCD chamber is the only air being cooled.

Greg.
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  #42  
Old 24-12-2014, 08:45 AM
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Hi Greg,
Removing the nose piece allows the air inside the filter wheel to heat the CCD chamber.




For anyone who wants to help?


Getting back to this Newt:
http://www.teleskop-express.de/shop/...fertigung.html

I am trying to see if it would actually work with my QHY9 camera & a 2” focuser?
The QHY9 has only a 22 mm diagonal – quite a small frame.
That would save me a lot of money as I have all the 2” accessories: OAG, coma corrector etc

I used this program on the web:
http://stellafane.org/tm/newt-web/newt-web.html

Please see the attached picture – see that there are many problems..
I don’t have all the right dimensions to plug into the calculator so I had to guess some e.g
tube inside diameter
tube thickness.

I need the right dimensions to use the 2” focuser?
I have asked TS.



Starlight 2" Feather Touch with dual speed ... no price change

http://www.teleskop-express.de/shop/...ges/5383_0.jpg

That focuser made in the USA is one of the best and most stable focusers for Newtonian telescopes in 2" with a very low profile. We recommend that masterpiece of engineering for the use with heavier cameras and accessories. The overall height of the focuser including the basis is only 45 mm which results in perfect illumination of standard camera sensors.
Maybe I can get away with the 2" focuser?

cheers
Allan
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  #43  
Old 24-12-2014, 10:16 PM
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I have discovered something about the 10" f/4 Newt. design:

There is a Russian guy on the Cloudy Nights forum who wins many competition called Oleg Bryzgalov.
He is using a Tevevue Paracorr-2 coma corrector with 55mm of back focus on a 10” f/4 Newt.
It shows that a 2” focuser can be used for a KAF8300 sensor..
He has a 79 mm secondary mirror. ( 3.1” )
see here:
http://www.cloudynights.com/topic/48...t-submissions/

https://www.flickr.com/photos/olegbr/15987950961/

The RCC1 that I want to use is not quite as good but may still work.
At least it has a longer back focus.

It would not be as good as an ASA Newt. with a 3" focuser.

Now - back to the 12" f/4 -
still studying that.

cheers
Allan
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  #44  
Old 24-12-2014, 11:55 PM
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hi al,

are you looking at 12" f3 or f4?
if you were looking at f4 cf have you seen this?

http://www.teleskop-express.de/shop/...n-Germany.html

cheers


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  #45  
Old 25-12-2014, 01:05 AM
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Quote:
Originally Posted by rustigsmed View Post
hi al,

are you looking at 12" f3 or f4?
if you were looking at f4 cf have you seen this?

http://www.teleskop-express.de/shop/...n-Germany.html

cheers

Yes - the 12" f/4 is too heavy for my mount - for imaging.
A 10" f/4 is lighter than what I have now.

I think my plan would be to get a sandwich mirror for a 10" f/4 then have
the ultimate modern assembly.
It would be ahead of anything else for sale.

cheers
Allan
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  #46  
Old 25-12-2014, 01:22 AM
glend (Glen)
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If your looking at a 10" f4 why all the research on the 12" f3? Is that topic now closed?
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  #47  
Old 25-12-2014, 06:25 AM
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Quote:
Originally Posted by glend View Post
If your looking at a 10" f4 why all the research on the 12" f3? Is that topic now closed?
No - the original idea was to get a review on the 12" f/3.

It later seems that a 10" f/4 would be a safer bet.

What is your opinion?

cheers
Allan
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  #48  
Old 25-12-2014, 05:03 PM
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Well given all the issues raised and discussed re the12" yes I believe the 10" f/4 is more mainstream and easier to setup - thus the 'safe' bet.

Last edited by glend; 25-12-2014 at 05:54 PM.
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  #49  
Old 26-12-2014, 10:36 AM
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Quote:
Originally Posted by glend View Post
Well given all the issues raised and discussed re the12" yes I believe the 10" f/4 is more mainstream and easier to setup - thus the 'safe' bet.

Hi Glend,
This thread is now finished.
The 12" f/3 was too much of a gamble.

I have ordered the cheaper Carbon fiber 10" f/4 Newt. with the electric focuser option.
see here:
http://www.teleskop-express.de/shop/...rbon-tube.html

I believe it only has GSO mirrors but they are checked.
I intend to upgrade the mirror to a 10" f/4 sandwich or honeycomb mirror from Hubble optics
but that will take up to 6 months delivery.

That way I get a carbon fiber Newt. with low weight & low coefficient of expansion
& up to 10 x faster cool down to ensure the boundary layer of air is at the same temp as the mirror.
The 10" f/4 is 3 Kg lighter than my 8" f/6 Newt so very nice on my modded EQ6 mount.

If I find there is too much vignetting of the flats then I may change to a 3" focuser & the ASA coma corrector:

http://www.teleskop-express.de/shop/...orr--Feld.html


This will be a nice upgrade from an 8" f/6 Newt.
I have calculated - considering the size of the secondary mirrors that I will
have system where the 10" f/4 will collect 3.35 times the light per unit area in the same time.
That means 3 minute sub frames now in 54 seconds with only a slightly shorter focal length : 1200mm to 1016mm.



cheers
Allan & thanks to everyone for all your help.
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  #50  
Old 27-12-2014, 06:05 AM
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If you want a good 10" f4 mirror then look at a Royce conical. No mirror cell and super stable. I use one with a Televue Paracorr 2.
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  #51  
Old 27-12-2014, 08:34 AM
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Quote:
Originally Posted by Rac View Post
If you want a good 10" f4 mirror then look at a Royce conical. No mirror cell and super stable. I use one with a Televue Paracorr 2.

I want to try a sandwich mirror which is not available from Royce -
see here:
http://www.iceinspace.com.au/forum/s...d.php?t=129366

cheers
Allan
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