Wedge or Equatorial

[chouet]

Hi all

I bought my first scope earlier this year, mainly for planetary imaging. It's a CPC925, which I bought second hand. I've also acquired a Bresser R152S refractor on a driven CG5 mount (the one which looks like an EQ5).

I've now really got the bug for deep sky imaging (I've had a few attempts at M13 and M31) and am up against field rotation with the CPC and tracking errors over time with both.

I know that I need to start auto guiding, but much of what I've read recommends starting with a short focal length apo refractor.

What is the next best step for me? A wedge for the CPC (and possibly piggy back an apo) or an equatorial mount and apo that can be guided, e.g. a HEQ5 Pro or CGEM? Or indeed, something else entirely!

In addition to the scopes, useful kit I have includes a Crayford for the SCT, focal reducer, a Canon EOS40D (not modified), a Neximage, 17Ah powertank, netbook and camera control software.

[ollypenrice]

Wedges have their followers but I am not one of them! If you are not observatory mounted then forget it, itinerant polar aligning of wedges is not bearable. They are also absurdly expensive by comparison with EQ mounts.

Imaging with the 9.25 (excellent scope in many ways) is not going to be easy because the long focal length will require very very good autoguiding. Neither its own mount nor an EQ5 or 6 can be guaranteed to be good enough for reliable captures, though they might deliver with luck and care in the fine tuning and balance. I would not, personally, want to image on our EQ sixes at much more than a metre but I do need to make sure I can deliver. Someone imaging for themselves alone can take more risks, if they want to.

With an EQ6 you might get reults t f6.3 with the SCT or you could just go for a small apo on HEQ5 or 6 with any old guidescope. The SCT, by the way, might guide better with an Off Axis Guider because of mirror flop.

Whoever said to start with a small apo and HEQ mount was right!!!

Olly