Roll Angle & Visibility Calculator

This tool shows the default roll angle and allowed range (min and max) for a target at a given J2000 RA and declination over an entire year. All values are calculated at 12:00 UT for each day.

• Only periods where the source is outside the Sun constraint are shown.
• Moon distance is highlighted in red when the source is too close to observe.
• Pole constraints are not shown — all values are estimates and must be validated by the Swift planners.