Comet C/2013 A1 (Siding Spring) July 07/08

[cometcatcher (Kevin)]

And... a comparison shot with M42, same scale. The trailed pic is 97 x 1 minutes, ED100, Pentax K-5. The comparison shot is a single minute sub for each, just to give some perspective.

[StephenM (Stephen)]

Interesting comparison pic, Kevin. It will be interesting to see how this one shapes up in a couple of months time!

[doppler (Rick)]

I think it is amazing that you even find these comets with a 4" scope. Well done.

[cometcatcher (Kevin)]

Thanks Stephen. Unfortunately latest predictions are a bit glum, with a max magnitude of 9 for it.... but you never know comets.

Thanks Rick, like I was saying the other night, I'm very happy with this little 4" ED refractor. It seems to perform like a bigger scope. I've retired my 6" F5 Newtonian because of it.

[doppler (Rick)]

I think refractors are under rated for their size. Reflectors loose a lot of appeture from the secondary mirror and spider obstruction.

[cometcatcher (Kevin)]

Well, my reflector is old. Maybe the mirror is not as reflective as it used to be. The image it produces is "bright" but on camera it doesn't show fainter stars than the 4" refractor. Tube currents are bad with the Newt in this weather too where the refractor is less bothered by them.