1. Eat healthy...
Nobody likes a guy who's eating Dinky Donuts for breakfast like there's no tomorrow. "I eat 10 carrots a day. Does this mean I can see better than the rest?" How often does this come up in astronomy forums? We all know that vitamin A is something we basically need to keep going as the retina needs it for scotopic and color vision. Simply eating a carrot (β-carotene) a day keeps you fit and well supplied with vitamin A that is enough for your body functions. Eating more than what your body needs isn't necessary. The body takes what it needs and discards the rest. So, no matter how many carrots your eat, it won't improve your night vision beyond the normal point. This same goes for bilberry, blueberry and whatnotberry.
It is also important to remember that for example fatty tissue (if you have any you big playboy!) in your body has reserves for vitamin A for many months. Interesting enough, eating too much of "pure" vitamin A (A1) can actually cause overdose leading to liver damage amongst others. And vitamin A or β-carotene taken from supplements is never as good or safe as what mother nature can produce.
Also while observing, keep your body hydrated and blood pressure up by eating at least once every 3 hours. This keeps you sharper and is something you'd do when doing a lot of exercise or something similar during the day.
|Stay in shape & use sunglasses!|
3. Avoid sunlight exposure
Simply put, keep your eyes shielded from the sun - always use sunglasses when the weather so demands. Too much light in the eye during the day can impair night vision for up to two days. Your eyes also get tired a faster at night when spending too much time - unprotected - in the sun.
|If drunk, try to appear sober.|
Image courtesy of Iiro Sairanen. 2008.
Truth is, no serious, hardcore observer drinks alcohol while he is observing. We all know alcohol slows you down, specifically slowing down your brain functions which is something you don't want when you're supposed to be using your eye(s). Even small amounts of alcohol in your blood are known to lessen the muscular control of your eye affecting night vision, color perception and peripheral vision. So don't drink and observe and most importantly do not try to tell jokes when intoxicated. They usually suck. Bad.
It is a good day when you can complain about smoking. For a start, recent studies have shown that tobacco increases your chance of getting one of those very nice diseases caused by smoking for example AMD (Age related Macular Degeneration). Then there's nicotine. The nicotine from the tobacco you're sucking down is one of the least favorites of your optical nerve. In fact, continuous use of nicotine is actually so nice to your little eye that is actually slowly destroying your optical nerve. And that's not all. Nicotine slows down the production of rhodopsin (visual purple) and blood circulation which is vital for your body in general and especially your eyes. Smoking also reduces your color perception (especially green and red). The last one is a good one if you're all about the ego. 2010 study on more than 20 000 Israeli soldiers concluded that smokers have a lower I.Q. than non-smokers. So, stop smoking if you want to appear smart and all knowing in public and star parties! And if you HAVE to smoke, do it in private - most of us don't want to be passive smokers.