Anyone own an aluminium GSO RC8?

[spymaster]

Hi,

I've read some great reviews and discussion here on the 8, 10, and 12 inch GSO Ritchie Chretien scopes. Some seriously impressive images captured by y'all!

I'm looking at getting an RC8, but it appears that the only models in the country at the moment are the aluminium tube models. CFs won't be available until perhaps June/July.

So, while I've read much discussion on the theory behind the focus shift difference between CF and aluminium, the only real comparisons I've seen are between a CF RC8 and a aluminium RC12.

Does anyone have hands-on experience with the aluminium RC8? I'm interested in knowing whether focus shift really is a big deal. I can handle focusing after an initial cool down (the mirror has to cool down anyway before using it), but frequent adjustments throughout the night could be a hassle with longer exposures.

Thanks!

Matt.

[allan gould]

Matt
I've got a 10" GSO RC and to be honest it holds collimation and focus exceptionally well. Sure the CF scopes look really schmick but remember both the 8" and the 10" have large aluminium rails top and bottom. So no matter if you have a CF tube you have these "expanding" aluminium bands on your scope, theoretically. I find I would need to re-focus maybe 2 - 3 times if doing it manually during the night with dropping temperatures but now I have it all done by software doing autofocus each degree drop of temperature and on filter changes. The software is cheap ($100) for full camera, scope, filter and mount control as well as the focuser and a lot more.
Allan

[spymaster]

Thanks Allan!

That doesn't sound so bad. Cosmetically, I'm not worried that CF will look "nicer", I can console myself with the fact that the white will match my new mount ;)
I'm hoping for evidence to push me in the direction of getting the aluminium tube, this has certainly helped!

Matt.

[allan gould]

Ok let's put this plainly. For the extra cost of the CF tube you could upgrade the focuser to a MoonLight focuser with a stepper motor which would then give you temperature control, automatic focusing and all the automatic goodies that go with that. Since I've gone down this route I've never had such sharp stars across the field of view, consistently from frame to frame.
Makes imaging more of a pleasure.
Allan