Transcript: The sequence of stellar spectral classes is another example of the historical baggage that astronomers carry around. It’s hard to remember, so generations of students have dreamt up mnemonics to help them remember the unusual sequence of letters. For example: Old Boring Astronomers Find Great Kicks Mustily Regaling Napping Students. Or try this one: Overseas Broadcast, A Flash Godzilla Kills Mothra, Rodan Named Successor. Or perhaps this one, oven Baked Ants, Fried Gently, Kept Moist Retain Natural Substance.