Focal reducer problem

[martin_h]

I have the focal reducers for the ED80 and the ED100 and my problem is that with a filter wheel inline there is no way I can get the 55mm spacing required - I'm about 9.5 mm to long. The only thing I can remove from the chain is my LP filter...so given that one can process out LP how detrimental would it realy be to remove it, otherwise I have two very expensive door stops if anyone is interested.

[BlueAstra]

I use a OpticStar 0.63FR (same as Celestron) with my C8. The data states that it is 0.63 @ 105mm, or 0.7 @ 50mm or 0.5 @ 225mm. So I presume you can use them at separations other than the optimum, with a changed FR ratio and perhaps some degradation in image quality. I do not use mine at exactly the specified distance, and have not noticed any significant image quality degradation. So, may be worth trying at the increased distance to see if it usable. My other FR is a 0.8TVue, which states 56 +/- 4 mm. At the moment I'm using it at 48mm while I wait for a spacer, but it doesn't look too bad.

[Hawklord]

The Teleskop-service flattener has a back focus of around 100mm so that would help. Worth emailing them to see if they can help out. The flattener's not cheap, but most reviews say it is excellent.