Today I happily received a post package, flipped open my knife and opened it: haha, two night sky planisheres - one for 30-40 Degrees and another one for 40-50 Degrees North. They are made by David Chandler, P.O. Box 999, Sringville, CA 93265 USA. Copyright is 1992. But this planisphere will never need an update, literally until the end of the Universe. This is one of the differences to the iPad application "Pocket Universe" (which I also like, but in a different way). Another one is that the planispheres hold the instruction: read with red filtered flashlight at night. This is much milder to the eyes and helps adjusting to darkness. Of course you might say, the software covers more regions and you can select how deep you want to see into space. True, but the planispheres somehow make me think differently. Once you match date and time zone adjusted time, then you can literally "understand" how the whole thing works. Of course, in the software application you can do things like "fast forward" the star constellations and see them rush over the screen. But who wants to fast forward a night with a clear sky watching the stars? Personally, I think they go exactly at the speed I like it. And if you want to see what is coming behind the Eastern Horizon, just turn the ring of the planisihere a bit. Done!

Of course in Hong Kong I am South of 30 Degrees North and also have to twist the brain a bit on how much difference it will make. And for that little mental calibration process, the iPad application is perfect.

I had such a planisphere as a boy, which I bought when I was 10-ish from a museum shop in London. This was a big investment from my pocket money: 2.99 Pounds Sterling. Another 10 years later, I gave it away to somebody who joined me star watching one night. Perhaps her children are using it these days somewhere around 52 Degrees North, GMT + 1 hour. Then these 2.99 Pounds would have been one of the best investments I ever made. This makes me remember what I once read on a Powerpoint Slide of my colleague, Professor Patrick Gibbons, who shared kindly his teaching material with me to help me design my courses at the beginning of my University time. There were two questions: "1) What is the price of going to the British Museum on Sunday? and 2) "What is the value of going to the British Museum on Sunday?"

Damn, there is this Taifun passing through the South China Sea heading West towards Hainan. Hong Kong will be covered by the rain bands and heavy clouds during the next few days. Ha, but as soon as the sky clears up, I am ready to put the 30-40 Degree planisphere into practice. Of course, the Hong Kong sky is never as clear as I am used to. But let's hope for Southerly winds and a major power failure.