Please confirm me: Will the Omni 1.25 in – 4mm eyepiece fit into my Celestron Astromaster 130eq telescope?
Yes. Any decent telescope manufactured today will take 1.25″ eyepieces. However, you should be aware that a Plössl eyepiece with this short a focal length will have an uncomfortably short eye relief, forcing you to cram your eye against the eyepiece to see anything. A preferable way of getting such a magnification would be to use a good quality Barlow lens with a longer focal length eyepiece, or to use a more modern eyepiece design with a longer eye relief.
