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Visibility Challenge
90 seconds. Pick the smallest aperture that reaches the Medium band — wrong answers burn time.
Score
0
Best
0
Time
90.0
Each round shows a deep-sky object, the Bortle class, and four Newtonian reflector apertures. Pick the smallest one that can show the target.
All choices are Newtonian reflectors at the shown Bortle. No filters.
−5s
Bortle
What's the smallest aperture that can show this object?
Time's up!
Score:
0
Best:
0
