VIEWING is a Web tool which determines when, or if, an astronomical position can be viewed by a given space telescope.
An example is determining when Cyg X-1 will be visible with Swift.
Use the VIEWING Web form.
The VIEWING output screen (see below) summarizes the input parameters and time when the object is visible from Swift.
Viewing Results +------------------------------------------------+ | Input equatorial coordinates: | | Cyg X-1, resolved by SIMBAD (local cache) to | | [299.5903, 35.2016], equinox J2000.0 | +------------------------------------------------+ Swift Double-check the latest TOO evaluation criteria at the Swift MOC. *** VIEWING Version 3.2 run on 2011 Jul 20 *** for the period 2011 Jul 20 to 2013 Jul 20 For Follow-up with Swift (Sun angle range = 46.0-180.0): (and Moon avoidance limit of 23.0 degrees) Observable throughout the specified period and is always far enough away from the Moon For preferred TOO observations with Swift (Sun angle range = 46.0-180.0): (and RA difference > 9.00 hours): (and Moon avoidance limit of 21.0 degrees) Observable between 2011 Jul 20 or before and 2011 Sep 06 and is always far enough away from the Moon Observable between 2012 Jun 06 and 2012 Sep 05 and is always far enough away from the Moon Observable between 2013 Jun 06 and 2013 Jul 20 or later and is always far enough away from the Moon