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Rusty Strings

Focal reducers

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I understand what focal reducers do I'm just unsure which I need. I have a 200p and a C80ED, is there one reducer that will do both?

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What do you want to use the reducer with John?

For the video cameras the 1.25" 0.5x work well and they are cheap :) you can alter the reduction ratio by using 1.25" extension tubes of different lengths

Bern sell them at Modern Astronomy...

http://www.modernastronomy.com/camerasAstroVideo.html

I use the Teleskop Service one...

Edited by Psychobilly

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Hi

You may have problems with inward focus travel on the 200p when you use a reduce - not from personal experience rather gather from this and other forums. Any reducer moves the focus point towards the main lens/mirror - usually not a problem on refractors of MAK/SCT but can be an issue on newts.

Bern at modern astronomy is very helpful so I'd suggest giving him a call.

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Thanks chaps

Inward focus shouldn't be a problem as the newt has a moonlite focuser with spacers fitted. I can remove a spacer to give me more in focus

Peter

I'm using it with a SCB 4000

Edited by Rusty Strings

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Hi, has anyone used the Meade 3.3 FR with the Atik Infinity, I have one to try that has been loaned to me, but , due to the weather not had chance as yet.

Currently I use the Celestron 6.3 FR and I am getting decent image captures with this, just wondering if the Meade 3.3 will make all that difference to my FOV etc. 

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Hi

I have both the F6.3 and F3.3 reducers and use them with my C8 and Lodestar - to be honest the F6.3 does not get much use as the FoV and speed with the F3.3 suits me.

Note that the reducer to CCD spacing is quite critical with the F3.3 - get it wrong and you'll get bad distortion.

 

HTH

Paul

  • Like 1

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3 hours ago, 2STAR said:

Hi, has anyone used the Meade 3.3 FR with the Atik Infinity, I have one to try that has been loaned to me, but , due to the weather not had chance as yet.

Currently I use the Celestron 6.3 FR and I am getting decent image captures with this, just wondering if the Meade 3.3 will make all that difference to my FOV etc. 

I've used the Meade 3.3 with an Ultrastar that has the same sensor as your Infinity.  At 11mm diagonal, you will get some vigneting and coma in the corners, but it is usable.  You FOV will be significantly increased over the 6.3, almost cutting your focal length in half.  Doc is correct that you need to get the spacing correct.  Here's a handy site to calculate the correct spacing.  For an SCT, use the moving mirror formula.

http://www.wilmslowastro.com/software/formulae.htm#FR

Don

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