RC for planetary imaging

[Sreesha74]

While I am aware of the general theory that RCs may not be great for Planetary, and are mostly often used for Deepsky imaging, I wanted some advice on whether these can be used for planetary imaging, especially with 2x / 3x Barlows.  Anyone here has experiences, please share:

 

Orion 8-Inch F/8 Ritchey-Chretien Astrograph

 

GSO 8" F/8 Ritchey-Chrétien Telescope.

 

I know SCTs are far better suited for planetary, but am trying to see best leverage possible with above, since it can double-up the needs. 

 

[johninderby]

You should add the 8” Classical Cassegrain f/12 to the list which is an ideal planetray scope although not limited to planetary.  use mine for visual and prefer it to the 8” SCT I had for lunar / planetary.. Much easier than an RC to collimate as well although holds collimation so well haven’t had to collimate it again after receiving it.

Edited May 18, 2020 by johninderby

[kirkster501]

Not ideal due to the large central obstruction compared to an "ordinary" SCT but they do work.

[lukebl]

I've had some reasonable results imaging Venus with my Omegon RC8 coupled with a 3x Televue barlow. Unfotunately, the other planets will be poorly placed for some time yet.

[johninderby]

The central obstruction of an 8” Classical Cassegrain is about the same as an SCT which makes it more suitable to planetary work. Unlike the huge RC central obstruction.

Edited May 18, 2020 by johninderby

[CraigT82]

For planetary imaging you can pretty much ignore the central obstruction size.

The effect of a large CO is to reduce contrast, which is bad for visual use but for imaging this contrast is restored in the image processing. 

An 8" RC should make a good planetary imaging scope if you can reliably keep it well collimated. The open front will help to reduce tube currents somewhat but you still want to pay attention to what the air is doing inside the tube. 

Damian Peach now mostly uses the Chilescope RC for his planetary imaging... don't hear anyone complaining about his images! Attached below