Quote:
Originally Posted by morls
Does this mean a 2" diagonal and 2" eyepieces are essentially a waste of money?
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No, not at all. Personal experience is that it will usefully fill the field of 2" low power eyepieces with larger fields than what is possible in 1.25" barrels. As I indicated below your eye won't notice much until the vignetting exceeds 50% and that occurs when the field reaches about 40mm diameter.
For example the ProStar 38mm 70 degree UWA and Vixen LV50mm are both excellent in this scope.
But you are intent on using 2" eyepieces with no field stop at all, you will find the image is cut off by vignetting just inside the field stop. And example is the TMB Paragon 40mm which is also rebranded as various clone such as Titan II etc.
The same occurs in many newtonian telescopes - the size of the secondary mirror is often a compromise between the desire to deliver the full light cone over a reasonable field of view, vs the size of the central obstruction caused. The result is many opt for a diagonal that will cover a 20mm field but beyond that it starts to vignette.