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To invert or not?

Erika Rix discusses when to invert your celestial sketches and turn your dark markings back into bright stars.
RELATED TOPICS: ASTROSKETCHING
Erika-Rix
Graphite pencils on white paper produce negative astronomical drawings. That means that any rendered starlight appears dark against a light background. If you plan to scan and publicize your sketch, you have the option to leave it as is or invert the image to create a realistic portrayal of the eyepiece view. Often the brightness of the object becomes the deciding factor.

A negative sketch can make difficult-to-see details stand out more clearly. I’ll use NGC 2090, a spiral galaxy in the constellation Columba, to demonstrate. This object has a magnitude of 11.3, a low surface brightness, and is 4.9' by 2.4' in size. It’ll be a challenging target for observers in the Northern Hemisphere due to its low altitude. To locate it, point your telescope toward the southern sky near midnight. It lies 1.5° east of Alpha (α) Columbae.

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