Leveling a Dob with DSCs: Is it needed?

I have an Obsession 20 equipped with the old JMI NGC-MAX DSC unit. Following the practice I’ve seen others use I’ve always spent 10 minutes or so struggling to level the mirror box with a bubble level and little wood shims each time I’ve set up the scope under the assumption that this is needed for accurate pointing. However the manual does not discuss this at all. Has anyone tested to see if very accurate leveling is needed for DSC accuracy with a Dob?

George N

I've heard it both ways, ie you must level with these units and you don't have to bother doing it. It's been my experience that you get better results(better "warp factor" and accuracy) if the scope is level before you proceed with the vertical alignment or initialization. I've got the JMI minimax unit on a 10" dob and leveling it first seems to help a lot.
No problems with the sky commander and I was glad I used the latter on my 16" f4.5 dob when I was setup on rough terrain at the base of Pinos a few months ago when the parking lot was closed with snow. I was basically setup on what appeared to be a piece of lunar surface and I couldn't imagine a JMI unit working very well on it.
Give your unit a try without leveling at see how it works...

George Normandin said:

I have an Obsession 20 equipped with the old JMI NGC-MAX DSC unit. Following the practice I’ve seen others use I’ve always spent 10 minutes or so struggling to level the mirror box with a bubble level and little wood shims each time I’ve set up the scope under the assumption that this is needed for accurate pointing. However the manual does not discuss this at all. Has anyone tested to see if very accurate leveling is needed for DSC accuracy with a Dob?

George N

I have never levelled the scope or needed to with the Sky Commander.

8)

George,
While I wouldn't want to set up on a 30 percent grade,
it isn't at all neccesary to level your rocker box.
I used to fuss with it a bit, but I got over it.
Much more important is a stable surface and a good star alignment.
I use both Sky Commander and Argo Navis. (not at the same time)
Linton