No matter where you are on Earth, it's likely that at least a few transiting exoplanets will be visible tonight. You can look up upcoming transits so that you know when and where to look for them. Transits can last anywhere from an hour to five or six hours, and some are even longer. When observing an exoplanet transit, it's important to capture the star's baseline brightness before the exoplanet starts passing in front of it, then capture the transit as well as an hour or two after the transit ends, so that the baseline brightness of the star can be measured again.

Swarthmore Transit Finder
Swarthmore Transit Finder

Embedded below is the Swarthmore Transit Finder, a helpful tool for planning your own observations of any transiting exoplanet.

  1. You can prioritize the Exoplanet Watch targets by selecting the “Exoplanet Watch targets” radio button at the top of the form.
  2. Select an observatory near your location or choose “manual coordinate entry” at the end of the list.
  3. Under “Date window” select the “base date” that you would like to begin scheduling and fill in the appropriate number of days before and/or after this base date. In addition, you can optionally include constraints on the target’s elevation during the transit if your horizon has limited visibility.
  4. Once you hit the “Submit” button, the service might take a few seconds to minutes to load, depending on the number of days you have requested.
  5. On the page that does open, you can sort the planets according to their “Exoplanet Watch rank” where a low number (e.g., 1) is higher priority than a larger number (e.g., 1000). You can also filter your targets based upon the host star’s V-magnitude (“V_max”) and the expected transit depth (“Depth_min” in units of parts per thousand ppt). You can sort the list by the date, by the name of the exoplanet, or by the Exoplanet Watch rank, as well as by the magnitude of the star or the amount of starlight the exoplanet blocks.

Please note that it can take a few moments to query the Swarthmore Transit Finder service, particularly if you are looking up targets over multiple days. Please be patient or restrict your search to fewer days or fewer targets.

Exoplanet Watch Observation Campaign for February 2023:

If you have suggestions for observing campaigns, please reach out to us on Slack to suggest them, and we will post them here.

Recommended Targets for February 2023:

North America: HAT-P-30 b (February 2), K2-229 b (February 2, 9, 12, 16, 19, 26), KELT-17 b (February 3), HAT-P-22 b (February 3, 19), HAT-P-56 b (February 4, 18), WASP-180 A b (February 6), KELT-23 A b (February 6, 15), KELT-19 A b (February 7), XO-6 b (February 8), WASP-14 b (February 13, 22), HAT-P-30 b (February 16), K2-229 c (February 16), WASP-84 b (February 17)

South America: K2-229 b (February 1, 4, 11, 18, 21, 25, 28), WASP-121 b (February 2, 16), WASP-62 b (February 4), HAT-P-30 b (February 5, 19), HAT-P-56 b (February 7), WASP-180 A b (February 13), TOI 1478 b (February 26), WASP-15 b (February 26)

Europe: WASP-33 b (February 2, 13), XO-7 b (February 6, 9, 26), K2-229 b (February 7, 24), K2-229 c (February 8), HAT-P-56 b (February 10), XO-6 b (February 12, 27), HAT-P-22 b (February 13), WASP-180 A b (February 20), KELT-23 A b (February 20), HAT-P-30 b (February 22), KELT-17 b (February 25)

South Africa: K2-229 b (February 3, 10, 17, 20, 24, 27), WASP-121 b (February 6), WASP-34 b (February 12, 25), WASP-62 b (February 13), TOI-1478 b (February 16), WASP-180 A b (February 20), WASP-121 b (February 20), HAT-P-30 b (February 22), KELT-17 b (February 25)

Australia/New Zealand: K2-229 b (February 1, 8, 11, 15, 18, 22, 25), WASP-121 b (February 5, 14, 28), WASP-34 b (February 8, 21), WASP-101 b (February 11), KELT-17 b (February 13), WASP-127 b (February 26), HAT-P-30 b (February 28)

To find out when to look for these exoplanets, you can use the Swarthmore Transit Finder. Depending on your location within your continent, there may be other tartets that are better (in which the complete transit occurs above your horizon).

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