Hello,
I would like to share experience with this eyepiece.
I bought a 5mm Monocentric TMB eyepiece (in Paris). While image is very crisp and perfect at the center of field, eyepiece shows a serious astigmatism at the edge of the field and a mild one near half of the field (Sorry to say but exactly as described in Sky and Telescope). In fact only 15° (half of the field) is usable. This eyepiece is not unusable on the moon. Usable on planets if on optical axis (itself not perfectly centered).
Is that normal or a defect ? What is your experience ?
I am using it with F/7 scopes.
Regards, Laurent
I would like to share experience with this eyepiece.
I bought a 5mm Monocentric TMB eyepiece (in Paris). While image is very crisp and perfect at the center of field, eyepiece shows a serious astigmatism at the edge of the field and a mild one near half of the field (Sorry to say but exactly as described in Sky and Telescope). In fact only 15° (half of the field) is usable. This eyepiece is not unusable on the moon. Usable on planets if on optical axis (itself not perfectly centered).
Is that normal or a defect ? What is your experience ?
I am using it with F/7 scopes.
Regards, Laurent