Share this postThe Classroom Astronomer Newsletter #20 - February 24, 2022 (21st delayed)classroomastronomer.substack.comCopy linkTwitterFacebookEmailThe Classroom Astronomer Newsletter #20 - February 24, 2022 (21st delayed)Eyeballing Stellar Spectral Types, Astronomy Cafés for Students and Teachers, Jelly Prisms for Gravitational Lensing DemonstrationsFeb 24CommentShareThis post is for paid subscribersSubscribeAlready a paid subscriber? Sign in