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Hi Chris,
Just a thought regarding the 5x Powermate, you can have to much of a good thing, depending on how you intend using it. Sounds like double dutch, doesn't it.
With my imaging setup I was after about 5x and tried a 5x Powermate. The image scale it provided was enormous, Jupiter no longer fitted on my CCD chip. I use a filter wheel, that combined with the nose ring adapter for my DMK had the surface of the CCD chip 70mm from the top surface of the 5x Powermate. For your interest I have attached the Nagler graph for the performance curves of their Powermates.
You will notice that at 70mm from the top surface of the 5x Powermate it is delivering 7x.
As the 5x Powermate was not suitable for my system I thought about a 4x Powermate, however if you look at the curve for that, any extension from the top surface has very little effect and at 70mm above its top surface it is only delivering 4.5x.
Eventually I settled on a Televue 3x Barlow, I have attached the Nagler performance graph for the TV Barlows for your interest.
Note that at 70mm from its top surface it is delivering 4.5x and at 100mm a little over 5x. I have turned up on my lathe a 30mm extension to give me that 100mm overall from the top surface. This allows me to image Jupiter with enough of the CCD chip unused above and below the planet to allow me to image it and keep it on the chip quite easily.
All of the images I have been posting over the past month or so have been with this setup, Given good seeing the images are sharp as a tack with stunning resolution.
I know a lot of people with 10 and 12" Newts are using the 5x Powermate, but it was not suitable for my system a 16" F4.5 scope with a DMK.
Just some food for thought.
Regards
Trevor
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