astro.n-minus

Filter

Astronomik ProPlanet 642 BP 1.25" (M28.5)

Key specifications

Filter typeOther
Passband642-840nm (IR bandpass)
Filter size1.25"
MountedYes

About

An infrared bandpass filter opening at 642 nm and closing at about 842 nm — unlike the other ProPlanet filters it blocks the longer IR. Astronomik pitches it as three filters in one: daylight IR photography, seeing-reduced lunar and planetary imaging, and an affordable entry to H-alpha deep-sky work, since it reaches nearly full transmission at 656 nm. 1.25" M28.5 mount.