mosque etiquette/hours

What the locals do depends on their sect. Visitors do not need to tuck everything in. A hanky on your head won't cut the mustard. A longer scarf with the tails crossed under you chin and what's left tossed over your shoulders, even with bits of hair exposed, works fine. You haven't mentioned specific mosques, but if you're a bit off, somebody will correct you - - politely.

I can only speak for Turkey and Bosnia. Bangs are fine, but no bare legs, arms, or shoulders (I found it easiest to wear a long skirt and very light linen shirt with long sleeves, along with a scarf). You'll also have to leave shoes outside or carry them in with you in a bag. It will be obvious once you get there, so not to worry. I found it easier to visit when formal prayers are not going on because there is a separation of men and women and it's a little awkward to stand behind men as they're kneeling down (so I just stuck to the walls and was discrete).

Having visited several Moslem countries, it has been my experience that non-Moslems are not permitted to enter a mosque during prayer time.

There's no religious id card checker at the door. Moslems don't do anything secret, nor do they care if somebody watches them pray. Some mosques are so huge you could toss a football back and forth and not be noticed by those praying. I don't know how many times I've lurked around in the back or on the side while a friend tended to his religious business.

What you say is true, Ed, but my husband and I must have a very non-Moslem appearance, because in Cairo we were chased away by an officious young guy with a long stick which he had been using to round up a bunch of young boys into prayers. In Amman our guide told us we could not enter a particular mosque during prayers.

Could the OP clarify which countries she's visiting? Maybe in Jordan and Egypt mosques are off limits (and probably Morocco too, I think), it's not necessarily true of others.

In Turkey we were told by our Turkish Guide that it was not necessary to cover our hair when entering the Blue Mosque (but most of us did anyway). Shoes off - Blue Mosque provided bags so we could carry them. In Egypt at the Mosque in the Citaldal two members of our group who were wearing shorts (in spite of being told not to by our guide) were given long green robes to wear. The rest of us had dressed conservatively but were not required to cover our heads. In both cases, these visits were some time ago and things may have changed. But like visiting any church, temple or whatever, be respectful of any wishes expressed by locals and be discreet. Muslims are not required to attend the mosque to complete the five prayers required during the day - you will see people praying where and when it is convenient, for example in parks. Do not stare and do not take photographs of people praying. Friday morning is usually the big prayer meeting otherwise the mosques are open. It is possible, depending on which country you are in, that mosques may not be open to visitors.