DID WILLIAM HERSCHEL DISCOVER THE RINGS OF URANUS IN THE 18TH CENTURY?

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Everything I need to know I learned through Googling.

IIRC, this discussion has come up occasionally for a very long time, at least since the rings were discovered. I think it's unlikely in the extreme; visible light images of Uranus from HST, and nontargeted near-encounter Voyager imagery show absolutely no trace of the rings; god bless Herschel, but I think his telescopes using circa 1800 technology were hardly better, and the though that the rings could change so radically in just 200 years is a little hard to swallow.

Just my two bits.

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"Call me old-fashioned, but I think fire is magic. And it scares me a lot."

--The State

Was that only Voyager 1 as Voyager 2 was quite revealing in Jan. 1986.

I used Starry Night Pro Plus to see if the ring orientation from Earth might have helped Herschell. Assuming the software is accurate enough, it shows that the ring would have had only a slight inclination, so, perhaps it would have appeared to him with nearly maximum surface brightness, whatever that might be.

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Lighten up! This is a stellar board!

Here is an amateur approach that may still be effective....

I drew to scale the ring system. They are only about 2600 km wide and 0.1km thick. After giving the rings an inclination, roughly, that Starry Nights says existed in Herschell's year, I determined, approximately, the cross sectional area of the outer portion which would have been the easiest for him to see. I computed the apparent magnitude for this region to be 16.8 in the upper drawing, with more inclination than would have been in 1797, and 17.5 mag. for the lower drawing which approximates more closely the actual 1797 inclination.

I used 0.03 albedo and ignored reflectance from Uranus itself off the rings. I also ignored any magnitude loss as a result of greater inclination, too. [Uranus is about 6 in apparent magnitude.]



What was his magnitude limitation?

If this has been helpful to the advancement of planetary science, I suggest we rename the rings to the original name Herschell gave to our 7th planet. [Don't you think the name would have a nice ring to it. Ok, forget it. ]

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Lighten up! This is a stellar board!