GSO ELLIPTICAL SECONDARY MIRROR 88mm Ring Here’s some examples

Here’s some examples

the small thickness of the mirror allows a much quicker cooling time compared to the standard monolithic mirrors

Length of the M69 thread

for example bring the optical system into the outside in an insulated box and allow it to cool down inside that box over the time of an hour

GSO ELLIPTICAL SECONDARY MIRROR 88mm Ring Here’s some examplesThe GSO 88mm elliptical secondary mirror is ideal for amateur telescope makers and is perfectly suited to the Geoptik Nadirus 16" Dobsonian. GSO secondary mirrors are offered in sizes from 62. 5 88mm to suit a variety of primary mirrors. Well known for their excellent quality, GSO mirrors are some of the best available in their price range. The secondary mirror does not come with a holder, but can be glued in place. The mirrors are made from BK 7