OP­TICS

Sky at Night Magazine - - FIRST LIGHT -

The scope has a 90mm, two-el­e­ment, air-spaced ob­jec­tive lens and a fo­cal length 900mm, giv­ing a fo­cal ra­tio of f/10. The two air-spaced el­e­ments help to re­duce the ef­fect of colour fring­ing on tar­gets such as the Moon and bright stars. The dew shield also gave good pro­tec­tion to pre­vent the lens dew­ing up.

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