Observation by Peter Tickner: Rare Callisto transit

Uploaded by

Peter Tickner

Observer

Peter Tickner

Observed

2021 Sep 17 - 19:57

Uploaded

2021 Sep 19 - 00:01

Objects

Jupiter

Equipment

ZWO ASI462MC
2.5x PowerMate + ADC
14inch f/10 LX200ACF SCT

Location

Urban Berkshire

Target name

Jupiter and Callisto

Title

Rare Callisto transit

About this image

Even when Jupiter is almost in the same plane to us as it is this year transits of Callisto are uncommon. Callisto has the longest orbit of the four Galilean moons so will transit the least often and except for the brief period when both planets are in line its distance from Jupiter means that the slightest angle and it transits above or below Jupiter from our perspective. The dark dot in this image is Callisto, not its shadow which passed close to the GRS some time after Callisto had cleared Jupiter and when I could no longer observe the event. Callisto has a low surface reflectivity meaning that against Jupiter it always appears as a dark object almost as dark as a Galilean moon's shadow.

Peter

Files associated with this observation

Callisto transit 17th Sept.png (413.3 kB)

Like this image

James Weightman, Alan Thomas, Geof Lewis, Peter Mulligan, Andrew Paterson

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