Why didn't the Spitzer space telescope shoot images of (dwarf) planets around the Sun, or did it? Even though its primary goal was to detect (the characteristics of) exoplanets, it could have revealed something about Solar System Bodies as well, and perhaps discover new SSBs. The Webb telescope will be infrared too but will also study SSBs.


2 Answers 2


All "big" instruments have observation logs, so does Spitzer.

The complete logs are here but there's also a filtered log for solar system observations which shows basically all planets and especially many minor planets. That said, it's not a general sky survey telescope due to its FOV of 5' x 5', so it's not meant to discover objects in unsuspecting locations but to look at known objects in detail.

Find a list of officially released image on the Caltech website - which has separate 'planet' and 'interplanetary body' categories as well: https://www.spitzer.caltech.edu/images

  • $\begingroup$ this is an old answer, I know that, but let me just say, I don't think Spitzer was designed to look for stuff within our solar system. Most of what I would see out of the (now deactivated) Spitzer was mostly images made up of mosaics of galaxies and nebulas and whatnot. Spitzer's ability to "see" exoplanets was a shock to most astronomers, and it was this ability that made up the basis of the Kepler mission. @planetmaker $\endgroup$ Dec 6, 2022 at 16:22

In addition to the target list linked to by @planetmaker in their answer, there are two recently published review articles (from Nature Astronomy) summarizing the many different aspects of Solar System science that were done with Spitzer:

Lisse et al. (2020), "Spitzer's Solar System studies of comets, centaurs and Kuiper belt objects"

Trilling et al. (2020), "Spitzer's Solar System studies of asteroids, planets and the zodiacal cloud"

From the first paper, there's this comment about why not everything in the Solar System could be observed by Spitzer:

It has been said that Spitzer’s scientific forte was “the old, the cold, and the dusty” in our universe (Werner & Eisenhardt 2019). In its 5.5 years of 3-160 $\mu$m cryogenic operations and 10.8 years of subsequent warm era operations observing the Solar System from Aug 2003 to Jan 2020, Spitzer’s observing capabilities were mainly sensitive to small relic solids in interplanetary space, as its infrared sensors were so sensitive that it saturated on any large (i.e., radius > 300 km) moon or planet-like body inside the orbit of Uranus. But in order to keep sunlight from warming the spacecraft, Spitzer was also unable to look at objects closer to the Sun than 82.5$^{\circ}$ elongation, i.e., the inner system asteroids. Thus in the Solar System, we need to say that Spitzer’s scientific forte was “the old, the cold, the dusty, and the small or faraway”.


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