Using the AstroTrac TT320X and Canon 40D for deep-sky imaging

Well I managed to get out and try the kit even though earlier in the day I had a 4 and a half hour traffic nightmare coming back from the West Country – managed to hit the Bank Holiday traffic.  Never mind, got out with the AstroTrac TT320X, the Canon 40D and a 28-200 mm zoom lens.

Polar aligning the AstroTrac with the Polar scope was pretty straightforward, helped enormously by a Manfrotto 405 geared head system which works beautifully!  Focusing was a bit of a problem – the screen on the back of the camera was too small for me even with x10 magnification, and my clumsy paws on the focusing ring had stars jumping all over the place.  I had to bring out the laptop and remote controlled the camera (for focusing only) from that.  The big laptop screen using “Live View” and x10 magnification had the stars clearly visible.  I then focused the zoom lens from the laptop by clicking on the focusing arrows until I minimised the star diameter.  When I got good focus I flicked the lens from automatic focus to manual focus and uncoupled the laptop.  I then connected up the Canon Timer Remote Controller, set off the TT320X and left the kit to do its thing for 1 and a half hours.

 Result?  Well absolutely no complaints about the TT320 – tracking looked pretty much spot on at 28 mm focal length.  A half Moon peaking over the N.E. horizon didn’t help the LP any, and the zoom lens has fairly bad radial distortion, although the centre 2/3 of the FOV was reasonable.

 It will be a fairly long learning curve to get the best out of this new system, but already it is clear that the potential is enormous.  I don’t fancy having all this expensive kit out during the Winter months collecting dew, so this will be a Summer months project, plus the take-away system for imaging while on holiday.

 I will keep you posted on any progress made 🙂

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4 Responses to Using the AstroTrac TT320X and Canon 40D for deep-sky imaging

  1. Dave says:

    Your post is very helpful. Regarding the focusing operation that you did on the laptop, what software did you use for that, and what kind of video adapter were you using? (I assume for live view you are using the video out plug, not USB?) Thanks,

  2. Greg Parker says:

    I used the Canon remote camera control software and the USB port. You view the x10 image on the computer monitor not the camera.

  3. Dave says:

    Great. After reading your post I installed all the remote control software from the CD that came with the 40D. The remote control software does just what you describe. I had no idea you could do remote focusing or get video out over USB. Thanks.

  4. Greg Parker says:

    Glad it worked for you 🙂 I can’t remember how I found out about this, I think I had nothing better to do one afternoon and just hooked the 40D up to a laptop and played with the Canon software to see what each bit did. I don’t think they do a very good job selling the software and hardware capabilities of the 40D.

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