Editing Great Red Spot (section)

=== First observations ===
[[File:Le osservazioni astronomiche - Giove.jpg|thumb|right|[[Donato Creti]]'s 1711 painting "Jupiter", the first depiction of a large spot on Jupiter as red]]
[[File:Jupiter Great Red Spot Elger November 1881.png|thumb|A sketch of Jupiter made by [[Thomas Gwyn Elger]] in November 1881, showing the Great Red Spot]]
The Great Red Spot may have existed before 1665, but it could be that the present spot was first seen only in 1830, and was well studied only after a prominent appearance in 1879. The storm that was seen in the 17th century may have been different from the storm that exists today.<ref>{{cite web |url=https://www.nasa.gov/feature/goddard/jupiter-s-great-red-spot-a-swirling-mystery |author=Karl Hille |date=2015-08-04 |title=Jupiter's Great Red Spot: A Swirling Mystery |website=[[NASA]] |access-date=2017-11-18}}</ref> A long gap separates its period of current study after 1830 from the 17th century discovery. It is unknown whether the original spot dissipated and reformed, whether it faded away, or whether observers simply failed to study and record it.{{sfnp|Beebe|1997|pp=38–41}}

The first sighting of the Great Red Spot is often credited to [[Robert Hooke]], who described a spot on the planet in May 1664.<ref name="aps-hooke-cassini"/> However, it is likely that Hooke's spot was not only in another belt altogether (the North Equatorial Belt, as opposed to the current Great Red Spot in the [[South Equatorial Belt]]), but also that it was in the shadow of a transiting moon, most likely [[Callisto (moon)|Callisto]].<ref name="aps-hooke-cassini">{{Cite web |title=May 1664: Hooke vs. Cassini: Who Discovered Jupiter's Red Spot? {{!}} This Month in Physics History |url=http://www.aps.org/publications/apsnews/202005/history.cfm |access-date=2021-12-29 |website=[[American Physical Society]] }}</ref> In the following year, [[Giovanni Cassini]] describes a "a permanent [spot] which was often seen to return in the same place with the same size and shape", calculating its rotation period to be {{nowrap|9 h 56 min}}.<ref name="aps-hooke-cassini"/>{{sfnp|Rogers|1995|p=6}} With fluctuations in visibility, Cassini's spot was observed from 1665 to 1713, but the 48-year observational gap makes the identity of the two spots inconclusive. Because of the older spot's shorter observational history and slower motion than the modern spot, it is difficult to conclude that they are the same.{{sfnp|Rogers|1995|p=188}}

A minor mystery concerns a Jovian spot depicted in a 1711 canvas by [[Donato Creti]], which is exhibited in the [[Vatican City|Vatican]].<ref>{{cite web |author=Staff |year=2003 |url=https://www.museivaticani.va/content/museivaticani/en/collezioni/musei/la-pinacoteca/sala-xv---secolo-xviii/donato-creti--osservazioni-astronomiche.html |title=Donato Creti, Astronomical observations |publisher=[[Vatican Museums]] |access-date=2019-12-16 }}</ref>{{sfnp|Hockey|1999|pp=40–41}} Part of a series of panels in which different (magnified) heavenly bodies serve as backdrops for various [[Italy|Italian]] scenes, and all overseen by the astronomer [[Eustachio Manfredi]] for accuracy, Creti's painting is the first known depiction of a large spot on Jupiter as red (albeit raised to the Jovian northern hemisphere due to an optical inversion inherent to the era's telescopes). No Jovian feature was explicitly described in writing as red before the late 19th century.{{sfnp|Hockey|1999|pp=40–41}}

The Great Red Spot has been frequently observed since 5 September 1831, with over 60 observations recorded by 1879, when it came into popular prominence.<ref name="Denning">{{cite journal |last1=Denning |first1=William Frederick |title=Early history of the great red spot on Jupiter |journal=Monthly Notices of the Royal Astronomical Society |date=June 1899 |volume=59 |issue=10 |page=574 |doi=10.1093/mnras/59.10.574 |publisher=Royal Astronomical Society |bibcode=1899MNRAS..59..574D|doi-access=free }}</ref> Since then, it has been under continuous observation.

A 2024 study of historical observations suggests that the "permanent spot" observed from 1665 to 1713 may not be the same as the modern Great Red Spot observed since 1831. It is suggested that the original spot disappeared, and later another spot formed, which is the one seen today.<ref name="Sánchez-Lavega2024"/>