The inverse function of the secant; the angle that has a secant equal to a given number.
1Its disc spans 18 arcsec, with bands of cloud that are a pale imitation of those of Jupiter.
2Viewed telescopically, it shrinks from 7.5 to 6.5 arcsec wide.
3Catch them below-left of the Moon on the 15th when the cloud-swathed planet appears 41 arcsec wide.
4Shrinking in width from 41 to 37 arcsec, it stands near the Moon on the 3rd and 30th.
5The unrivalled rings, though, stretch for 41 arcsec and are wide open with their N face tipped 27° towards us.