Is there an error in the program?

[Grace Travesser]

A search of when Jupiter goes into Cancer comes up with June 9, 2025 on the internet, but

according to Stellarium,  on June 9th, Jupiter enters the outskirts of Gemini and is there with Mercury and is still there on July 18th.

Why are the answers different?

[Georg Zotti]

The program is arguably more correct than a random search on "the internet", but both can be argued to be correct in a way. Just one answer is scientifically more meaningful than the other.

Jupiter will reach ecliptical longitude of 90 degrees (the sun's summer solstice point) on June 9th. This is the begin of the region along the ecliptic that extends from 90 to 120° longitude. In ancient times up to the early modern era, the ecliptic was not counted 0...360° but split into twelve 30-degree sections named after the constellations (starry patterns) that were roughly aligned there about 2000 years ago. The region 90...120° is called the Zodiacal Sign of Cancer, which Jupiter reaches on that date. However, on the observable sky, Jupiter on that day is short of entering the astronomical area of the constellation Gemini. The observable, visible constellations have moved about a full 30-degree section since the names were given due to precession.

Now, whatever part of "the Internet" you have found, when they write today about "Jupiter enters Cancer" sounds like somebody referring to the ancient gibberish of astrology, where these "Zodiacal signs" are still used. The mathematic-historical core of it just uses the twelve zodiacal signs (or 30-degree sections) as coordinate.

[Alexandros Kosiaris]

Cause the first one is from Astrology and the second one from Astronomy.
Despite sharing the prefix "Astro", the name of the constellations and a
couple of other things, due to some common history, these days they have
nothing to do with each other. These days, the former is a practice (an
ideology if you will), the other a science. To avoid all kinds of
confusion (and derision in some cases), it's best to not conflate them.
There's a lot of articles on the internet that talk more about the
subject (it's a recurring one), here's the first one I found Googling
https://www.astronomy.com/science/your-zodiac-sign-is-probably-wrong/

[Grace Travesser]

Thank you. Your description I appreciated.

Grace

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