Like the old Sara Lee adverts - "layer upon layer upon layer". I'm a multiple layer person - also gives me lots of pockets for all those keys, phone, torches, laser pointer, glasses, eyepiece caps, odds and ends.... But I start with thermal underwear - check out the outdoor stores - Anaconda etc. Hands - start with woollen mittens (Edit - woops - I meant "fingerless gloves"). Then add a set of thin thermal gloves as the temperature drops, then add bulky gloves below about -4 deg! Head - usually beannie until it drops below zero, then a fur lined "flying cap". Boots - these ones:-
http://www.iceinspace.com.au/forum/s...ad.php?t=46307
I max out at three layers on hands; five layers up top and three layers around legs. But this is for -6 deg observing!
Unless you want just the one layer - many are big fans of the Freezer Suit! Some refuse anything else next to their skin
http://www.gtbastrowise.com.au/ - goto "Freezer Wear".