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f/3.3 focal reducer or not??


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#1 SparkyHT

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Posted 25 June 2012 - 10:25 AM

I've got a 8" LX200R (now the 8"ACF??) with the microfocuser and a DSI Pro with the LRGB filter set. I am starting to dabble in astrophotography and my researching has led me to think that if I want to capture deep-sky objects, I will have to get a focal reducer to get those images to fit on the tiny chip that the DSI Pro has. I'm not sure if the f/6.3 will be enough or if I should get the f/3.3? Another factor is whether I can still use the microfocuser with one or both reducers or will I have to remove it and attach the reducer right to the threads on the back of the telescope (which kind of negates the advantage of HAVING the microfocuser)? I also read from the astronomics.com website product description for the f/3.3 reducer that having a color wheel in between the f/3.3 reducer and the camera will prevent proper focus...I don't have the wheel, just the sliding filter holder.

I'm confused. What CAN and CAN'T I do?? I can't seem to find a Meade-specific answer from other forums, so hopefully someone here can set me straight. I just want to prepared when I DO start shooting larger, more elusive objects. Ultimately my goal is to photograph deep sky objects using a reducer, microfocuser, and the LRGB filters IF that is possible. If not that, I want the second best solution.

Thanks

#2 Mark Sibole

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Posted 25 June 2012 - 07:32 PM

the 3.3 focal reducer was designed for a small chip years ago.Dont bother with it.Get a 6.3 focal reducer and it should work fine
Mark Sibole
MTSO Observatory
Fife Lake, Mi.

http://astronomy.qteaser.com

#3 JohnGraham

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Posted 27 June 2012 - 06:35 PM

I agree. I've used both an f/3.3 and f/6.3 focal reducer on my SC8 with a DSI Pro. The f/3.3 is too finicky and by the time you've got the spacing set to reduce coma it's stretched out to about f/5.

If you are using the Meade LRGB filter set I'd also suggest getting a second IR blocking filter. This will let you keep the Meade IR filter is the filter slide (or wheel) and eliminate the need to refocus between the L and RGB images. I used an imaginf skyglow filter as my IR prefilter in the nose piece and that solved two issues with one filter.

-John




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