My first Magazine Sky & Telescope - 02.2019 | Page 64

S&T Test Report
p The refractor produces an impressive 3½ °
fi eld at its native f/5.8 focal ratio. The red box
shows the fi eld size on an APS-C detector.
Inset: Stars near the very corners of the APS-C
fi eld show some elongation.
62
FE B RUA RY 2 019 • SK Y & TELESCOPE
q This image of NGC 6888, the Crescent Neb-
ula, taken through the Evostar 72 with reducer/
corrector shows pinpoint stars across the fi eld
of a Starlight Xpress Trius-SX694 CCD camera
equipped with a hydrogen-alpha fi lter.