Monday January 01, 2007

Thanks to Darryl for his recent blog entry on Stellarium, open-source and free planetarium software that's available for Mac OS X, Linux, and Windows.

I'm using the Mac OS X version. It has a few user-interface quirks, but those are minor when compared against the wonderful visuals this program offers. Stellarium gives you a real-time view of the sky at your latitude and longitude and lets you run time at different speeds so you might, for example, watch an evening's worth of sky motion in just a few minutes. You can interactively change your direction and field of view using the keyboard and mouse.

I've included a few screen dumps below, which don't really do justice to the software, but they'll give you an idea of what the package can do.

A basic view of the sky, looking south at 9:21pm from the Boston area on December 31st. Stellarium has labeled several large stars and prominent nebulae.



Here I've added constellation labels and constellation drawings to the basic display. I've chosen Western constellations, though Stellarium supports several others (Polynesian, Chinese, Egyptian, etc.)



I've now added constellation art, which I think is quite attractive and helps me remember the constellations.

If you are interested in learning your constellations or just want to identify a particular object in your night sky, Stellarium is the perfect tool. It is available for download here.

Late last night, after the set-back thermometer had dropped the house temperature to about 65 degrees F, I had occasion to use the toilet. As I was sitting there, I realized my array of proximate biological sensors was detecting an unexpected warmth from the water beneath me. A subsequent check with my Raytek non-contact infrared thermometer (everyone should own one of these--you will be amazed at how often you use it), confirmed my suspicion. For some reason, the water in the toilet bowl was a balmy 81 degrees F. I started tracing water lines in the basement, but as it was well after midnight, I decided to explore the issue in more detail this morning.

It didn't take me long to find that the water line filling the toilet is fed by hot and cold water lines that join at a mixing valve in the basement. So the plumbing was set up deliberately to allow the toilet to be filled with warm water. Huh, I thought. Interesting. But why would anyone go to such trouble?

A little web searching turned up the answer. Mixing some hot water into the toilet intake will prevent condensation from forming on the toilet tank and the toilet bowl. Condensation can harm the flooring under the toilet if the problem is persistent. It's mostly an issue in warm, humid weather, or if one frequently takes hot, steamy showers in the bathroom. When I explained this to my wife, she recalled the previous owners had mentioned problems with the flooring under the toilet in this bathroom. Presumably, the mixing valve had been installed to mitigate the problem. Mystery solved.

Perhaps because of this incident, my wife tells me it is good that my vacation is almost over.