Historical solar Ca II K observations at the Rome and Catania observatories. (arXiv:1902.07483v1 [astro-ph.SR])

Historical solar Ca II K observations at the Rome and Catania observatories. (arXiv:1902.07483v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Chatzistergos_T/0/1/0/all/0/1">Theodosios Chatzistergos</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ermolli_I/0/1/0/all/0/1">Ilaria Ermolli</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Falco_M/0/1/0/all/0/1">Mariachiara Falco</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Giorgi_F/0/1/0/all/0/1">Fabrizio Giorgi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Guglielmino_S/0/1/0/all/0/1">Salvo L. Guglielmino</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Krivova_N/0/1/0/all/0/1">Natalie A. Krivova</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Romano_P/0/1/0/all/0/1">Paolo Romano</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Solanki_S/0/1/0/all/0/1">Sami K. Solanki</a>

Here we present the little explored Ca II K archives from the Rome and the
Catania observatories and analyse the digitised images from these archives to
derive plage areas.

Here we present the little explored Ca II K archives from the Rome and the
Catania observatories and analyse the digitised images from these archives to
derive plage areas.

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