Preventing fog on lens
 

Just came back from an island called Pulau Ubin in Singapore where it is reputely the best place for stargazing.
Tried to get a timelapse of the stars but the lens kept getting fogged up througout the night.
Anyone encountered or have any solutions? I'm thinking of taping a heat pack onto the camera.

Various riflescope "safe" defoggers should work
 

http://www.cabelas.com/cabelas/en/te...exId=cat200007

EK Scope Dope USD $3.99 Used for hunting rifle scopes.
Cabelas has a good reputation in USA and this item is very light, so won't cost very much to ship, even to Asia.

They have other items too...

did you allow your camera time to get to outside temperature or take it from a cool place to hot and start videoing or hot to cold too quickly. If so set your camera in the temperature you will be videoing in for at least 30 minutes to allow the camera to get accustomed to the temp difference.

I don't think it is a matter of letting the camera acclimate. The changing conditions during the night will cause dew and a camera lens pointing up will catch that dew. A can of compressed "air" may help dry the lens, but a hair dryer or heat pack might be better. I think a gentle blast from the hair dryer every once in a while might be easiest to implement. The compressed "air" cans may cool the lens which could make the problem worse. Don't use a fueled heat source since their exhaust contains a lot of water which may initially condense on the lens. Obviously, don't apply significant heat as it may adversly effect the camera.

Marcus has it right....except I wouldn't use a can of air. Too often something nasty comes out that you don't want on your lens. I am an amateur astrophotographer(in addition to playing at video during the day). The problem is indeed dew....formed by the lens being at a different temp than the air. When I am in my observatory I can use a hair dryer as Marcus suggested if it is really heavy dew. When out in the boonies(we sometimes pick up and go to darker skies) I use a "heat rope" attached to a battery. You can get this "heat rope" at American Science and Surplus. I believe they are on the web. They have a store in Wisconsin. It's basically nichrome wire in a cloth sleeve. You wrap it around the end of your lens. The DC current heats it just enough so it warms the lens. You don't need much heat...just a degree or two above ambient is enough. It's best to turn it on at the start and leave it on. Once dew forms it takes forever to get rid of it with the heat rope. Another option is to take a look at Kendrick Dew Heaters. They make a very nice system for telescopes that are easilly adapted to any size lens. It's what I use on my 12 inch scope in the observatory when the dew isn't heavy. Works a charm.
Mark