I have a new Skywatcher 8" collapsible Dob with a max useable magnification of 406X. I purchased a 3.2 TMB Planetary eyepiece in the hope of seeing some detail on Jupiter. This morning had the first clear skies since the eyepiece arrived and the view was less than startling! The calcs gave a magnification of 375X but the image was fuzzy to useless.
Is this due to 1. the magnification limitations of the scope, 2. poor collimation ( I thought I had done a pretty good job using the tutorial on this site), 3. something else I haven't thought of , or 4. a crook eyepiece?
Cheers
Graeme
Optimal magnification for an 8" on the planets is probably about X200 to X250, where the image will be bright enough and floaters in your eye don't start to become objectionable. If you aren't already seeing detail a wealth of detail at X250 you won't see it suddenly at X380.
Its highly unlikely you have a bad eyepiece. When you defocus a star a little, is the secondary mirror shadow centered> Are there fine dark rings that are clear and sharp ( the fresnel rings) against the bright background of the defocused star. If these rings are not visible its unlikely you will see much planetary detail do to bad atmosphere, poor optics, inadequate cooling or some combination.
Planetary observing takes time and practice. Don't be in a hurry and you'll get there.
Too much power for conditions. The telescope needs to cool and the air needs to be steady. Even so 200-250x is more than enough to see detail when conditions permit.
Try the eyepiece on the Moon as it is far more forgiving. 375x will make you feel like your in orbit.
