Celestron Travelscope and ASI120MC

[Rumbold2010]

Hi all,

I'd love to get a couple of single frame shots of Andromeda , but my CPC925, even with reducer fitted has far too much focal length to see anything other than the core. Is it feasible to try and image it through my Travelscope 70? I know I have no tracking ability with this so I'd like to know roughly how long an exposure I might be able to get away with? As it's a fairly bright object , I'd assume I wouldn't need too long? Failing that, might even try my Canon SX40 at 35x optical zoom but I'd have a harder time ensuring framing was correct with the camera I guess? Thoughts on a postcard please?

[JamesF]

The problem with the ASI120 for this job is the sensor size.  It's just under 5mm by 4mm and you'd only be able to get at most three quarters of a degree across the long size of the sensor with the Travelscope, so you'd probably need at least a twelve pane mosaic to get the entire thing in.

A crop-sensor or full frame DSLR might be a better bet.

James

[Rumbold2010]

Nice one James, thanks for the heads up mate :-) I'll have a pop with the camera instead. It's a balancing act isn't it? Short of a lottery win, trying to cover all bases properly in AP is beyond the means of most. I think a DSLR would maybe be a good next investment.

[JamesF]

It is tricky.  M31 is, frankly, enormous.  Six times wider than the Moon.  Give it a billion years or so and it will look fantastic in our night sky.  But many DSOs are so much smaller that you want more focal length that is ideal for M31.  Hacking the lottery is the only obvious solution

James