Meade LXD75 SN size

[Siguy]

I would like to know how big of an advantage there is in getting an eight inch LXD75 Schmidt Newtonian over a six inch or a ten inch over either of those. I might be able to get one of those models, and I want the best I can get for the price, but I don't want to pay too much for a small difference. The scope will be used for astrophotography, so if there's a difference on how suitable each size is for astrophotography, such as a larger size having a wobblier mount, please tell me.

[Kaptain K]

Optically, the relationships are fairly straight forward:

1) Resolution is linearly related to aperture. If the 10 inch can resolve two stars that are 1 arc second apart, then the 8 inch will resolve 1.25 arc seconds and the 6 inch, 1.6 arc seconds.

2) Light gathering goes up with the square of the diameter of the objective. The 8 will take in over 1 3/4 times as much light as the 6 inch and the 10, 2 3/4 times the 6 inch (1 1/2 times the 8).

I can not comment on the mounts, having no personal experience with them, but I'm sure that others will chime in.

[Dave Mitsky]

From all accounts, the mount for the 10" is inadequate for prime focus astrophotography.

Dave Mitsky

[Siguy]

So that eliminates the 10''. Is the 6'' mount even stabler than the 8''?