rogerg
23-04-2007, 02:23 PM
I have a friend who is considering a guidescope for her 12" LX200. It appears the general consensus amongst the masses is that an Orion 80mm ED is the best choice.
I don't understand that choice for several reasons:
Only 600mm focal length vs minimum 1900mm of the LX200.
No focus lock (only focus tension, which from my use of an Orion 80mm ED is not enough to hold a SBIG, large eyepiece, or similar.
The Orion costs about $675 when a 70x700, 70x900 or 9x900 Skywatcher costs significantly less.
The Orion weighs more than a longer focal length 70x700 or 70x900.
A wide field refractors just doesn't make sense to me, for guiding. If choosing purely for guiding why not long focal length? F/10 or F/12 won't matter with a SIBG or long exp modified ToUCam for guiding.
Skywatchers have longer focal length, focus lock and are lighter.
The choice seems plain to me. You don't need the optical quality of the ED (who cares about false colour in a guide image) and you do need long focal length and light weight.
Yet people get the Orion ED. Is that just because they want to photograph through it also and are happy to sacrifice guiding accuracy for that?
Thanks,
Roger.
I don't understand that choice for several reasons:
Only 600mm focal length vs minimum 1900mm of the LX200.
No focus lock (only focus tension, which from my use of an Orion 80mm ED is not enough to hold a SBIG, large eyepiece, or similar.
The Orion costs about $675 when a 70x700, 70x900 or 9x900 Skywatcher costs significantly less.
The Orion weighs more than a longer focal length 70x700 or 70x900.
A wide field refractors just doesn't make sense to me, for guiding. If choosing purely for guiding why not long focal length? F/10 or F/12 won't matter with a SIBG or long exp modified ToUCam for guiding.
Skywatchers have longer focal length, focus lock and are lighter.
The choice seems plain to me. You don't need the optical quality of the ED (who cares about false colour in a guide image) and you do need long focal length and light weight.
Yet people get the Orion ED. Is that just because they want to photograph through it also and are happy to sacrifice guiding accuracy for that?
Thanks,
Roger.