Printable finder charts for 21P/Giacobini-Zinner
| Color schemes | |||||
| Date span | Estimated date when brightest | Date of perigee | Date of perihelion | Dark on light | Light on dark |
| Apr 1992 – Oct 1992 | 28 Jul | 20 Jul | 30 Jul | PNGPDF-RGBPDF-CMYKSVG | PNGPDF-RGBPDF-CMYKSVG |
| May 2005 – Nov 2005 | 19 Aug | 16 Aug | 21 Aug | PNGPDF-RGBPDF-CMYKSVG | PNGPDF-RGBPDF-CMYKSVG |
| Jun 2018 – Dec 2018 | 13 Sep | 14 Sep | 13 Sep | PNGPDF-RGBPDF-CMYKSVG | PNGPDF-RGBPDF-CMYKSVG |
| Dec 2024 – Jun 2025 | 24 Mar | 21 Mar | 25 Mar | PNGPDF-RGBPDF-CMYKSVG | PNGPDF-RGBPDF-CMYKSVG |
Credits
The charts above were generated using StarCharter, a command-line tool for producing vector-graphics charts of the night sky, written by the author and freely available for download.
The paths of the planets are taken from the DE430 planetary ephemeris computed by the Jet Propulsion Laboratory (JPL). Planetary positions were extracted from the DE430 files using EphemerisCompute, which was also written by the author, and is also freely available for download.
The positions of asteroids are calculated from orbital elements published by Ted Bowell of the Lowell Observatory. Comet positions are computed from orbital elements published by the Minor Planet Center (MPC).
Star positions and magnitudes were taken from the Hipparcos, Tycho, Tycho-2 and Gaia EDR3 catalogs.