What to Observe | Exoplanet Watch – Exoplanet Exploration: Planets Beyond our Solar System

What to Observe

Special Campaign April 2024:
HAT-P-23 b

No matter where you are on Earth, it's likely that at least a few transiting exoplanets will be visible TONIGHT! This page has tools and information to help you find where and when to point your telescope. Embedded below is the Swarthmore Transit Finder, an online tool for planning your own observations of any transiting exoplanet for advanced users.

Just getting started? Keep reading...

Exoplanet Watch Beginner Observation Campaigns
April 2024
Northern Hemisphere: HAT-P-22 b, TOI-1518 b
Southern Hemisphere: KELT-17 b, WASP-74 b

If you have a target that you would like Exoplanet Watch to observe for you, please reach out to us on Slack or email us at exoplanetwatch@jpl.nasa.gov. Each month, we highlight "beginner campaigns" above (frequent, relatively easy targets) as suggested starting points for new observers. However, Exoplanet Watchers are always welcome to observe any transits they wish!

See below for calendars of other recommended targets, but there are always more for the intrepid Watcher! Beware of weather that might disrupt your observations, as well as general safety of nightime observing. Remember that even partial transits due to daylight/moonlight/weather can still be useful.

Click your continent/region to expand the calendar, and click a calendar item to see Right Ascencion (hours:minutes:seconds) and Declination (degrees:minutes:seconds), as well as a link to a finding chart.

All times are in UTC and are approximate depending on your exact observing location

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For best results, check the exact timing for your latitude and longitude for any given transit down below. You can search upcoming transits so that you know when and where to look for them. Remember the above calendars are approximate depending on your exact location in your region, and are a simple tool for those who aren't sure how to start.

Transits typically last a couple of hours, with some extreme cases lasting upwards of six or more. Even partial transit observations can still be useful, but when possible, observing about an hour before and after the transit yields the best results.

Swarthmore Transit Finder:

This is an online tool to find out when and where to look for more exoplanets in your local area. Depending on your location within your continent, there may be other targets that are better and/or more challenging for advanced users than listed above (e.g. the complete transit occurs above your horizon, better airmass, smaller transits, dimmer objects, etc.). Remember that even gathering data on partial transits from your location can be useful. Wishing you clear skies!

How to use the Swarthmore Transit Finder (click to expand)

You can prioritize the Exoplanet Watch targets by selecting the “Exoplanet Watch targets” radio button at the top of the form.
Select an observatory near your location or choose “manual coordinate entry” at the end of the list.
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.
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.
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.