opening hour gero onsens

I read the onsens in Gero are accessbile with Yu-meguri Tegata only in certain hours of the day. Can anybody help with the opening hours, in order to plan in advance which onsen to visit at what time? Is there any time limitation of Yu-meguri Tegata, or it can be used also the day after?

http://www.gero-spa.or.jp/yu_meguri/index.html

It says for 1,200 yen you can enter three of the baths at the inns listed on this page.The opening hours are stated for each. I read in someone's travel blog that it was valid for 6 months from the date of purchase, but I could not confirm it in the town spa website.

AK, thank you very much!this is exactly what I was looking for. It's a pity it's not available on the english version of the site..or at least I'm not able to find. But I'll try to manage. It's already a good result to have the hours.