Talk:Comet Donati

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Photographed?

If it was photographed, then surely any copyright on that pic is long expired. Is the photo available anywhere? Mdotley 00:48, 31 May 2007 (UTC)[reply]

I know this is seven years late, but - it is, in "The Earliest Comet Photographs: Usherwood, Bond, and Donati 1858" by Pasachoff, Olson and Hazen in the "Journal for the History of Astronomy" - a google will get you to the article.

The surviving picture (by Bond) is very poor, hence seldom reproduced, and was regarded as such at the time. I have never understood why he did not have another go - or why no-one has applied enhancing software to see if something can be extracted. There was a better picture by Usherwood, which impressed Bond, but that, tragically, has long been lost :( Jellyandjocko (talk) 17:33, 13 January 2014 (UTC)[reply]

Next perihelion

What reference do you have that Comet Donati will come to perihelion in the specific year 3811? Have you accounted for perturbations in the orbit? A barycentric calculation of the orbital period (unperturbed and with the comet currently outside of the inner solar system) comes up with 6.35E+5 days (or 1739 years). Add that to the last perihelion date (1858) and you get a crude estimated return year of 3597. I must revert you edit as unreferenced. -- Kheider (talk) 01:16, 14 February 2011 (UTC)[reply]

Even comet 177P/Barnard with a much shorter orbital period of 119 years has somewhat different solutions to the next perihelion date. -- Kheider (talk) 16:34, 15 March 2011 (UTC)[reply]

Three tails?

It looks like there are two ion tails and one dust tail. Is that correct? If so, why are there two ion tails? — Preceding unsigned comment added by 2001:8003:E414:3A01:BCF7:EA8C:97FC:DF9D (talk) 09:01, 2 June 2020 (UTC)[reply]