Archive for the 'Astronomy' Category

A resurgence in Lunar Exploration

November 12, 2007


Is there a race heating up with lunar orbiters suddenly becoming the focus of several nations around the globe?

The Chang’e 1 is an unmanned lunar orbiter from China’s CLEP that entered its one-year long lunar orbit early Monday. The $187 million mission is a key stepping stone in China’s quest to develop a lunar exploration program that includes a lunar rover and a probe to return soil samples from the moon’s surface. The spacecraft is named after the Chinese goddess of the Moon, Chang’e.

Only a month back, Japan completed the launch of its own lunar orbiter – Kaguya. KAGUYA consists of a Main Orbiter at 100km altitude and two small satellites (Relay Satellite and VRAD Satellite) in polar orbit. The scientific instruments on board the Main Orbiter will be used for the global mapping of lunar surface, magnetic field measurement, and gravity field measurement. According to JAXA, the name Kaguya was inspirted by the Tale of the Bamboo Cutter.

The name KAGUYA originates from “Kaguya-hime (Princess Kaguya)” in The Tale of the Bamboo Cutter (Taketori Monogatari). and many people overlapped the images of SELENE going to the Moon on an exploration mission and Kaguya-hime going back to the Moon.

India is also planning its own launch of a lunar orbiter in April of 2008 – named Chandrayaan. Over a two-year period, it is intended to survey the lunar surface to produce a complete map of its chemical characteristics and 3-dimensional topography. Chandrayaan literally means moon-craft in sanskrit.

And finally, USA is planning to put the Lunar Reconnaisance Orbiter around the moon in October 2008. The first mission of NASA’s Robotic Lunar Exploration Program, it is designed to map the surface of the Moon and characterize future landing sites in terms of terrain roughness, usable resources, and radiation environment with the ultimate goal of facilitating the return of humans to the Moon.

Space race or not, these missions do add to the nation’s credibility for putting satellites in orbit. Apart from scouting for resources in Moon, these missions are also prove the technical merit of the nations involved, and could be a great source for technology exports.



October 31, 2007


Stellarium is a free open source planetarium for your computer. It shows a realistic sky in 3D, just like what you see with the naked eye, binoculars or a telescope. It is being used in planetarium projectors. Just set your coordinates and go.

That is from the home page. The way I stumbled on this software is because of an Indian festival that requires wifey to fast until she has seen the moon. A quick Google search to find the trajectory of the moon led me to this blog entry, and eerily the author of this article had also found the software for the same reason.

Now you might think why I need a software to locate the rising of the moon. After all, the moon follows the sun in its rise and set pattern, so moon should just rise in the east right? Wrong! One of the tidbits I remember from my astronomy club at school is that the lunar orbit is elliptical, which causes a daily variation in the directional orbit of the moon for an observer in the earth. Here is what Wikipedia has to say…

The orbit of the Moon is distinctly elliptical with an average eccentricity of 0.0549. The non-circular form of the lunar orbit causes variations in the Moon’s angular speed and apparent size as it moves towards and away from an observer on Earth. The mean angular daily movement relative to an imaginary observer at the barycentre is 13.176358° to the east. The orientation of the orbit is not fixed in space, but precesses over time.

Anyways, I have used a few planetarium software in my school days from being in the astronomy club. And this tool has pretty much everything you need for an amateur astronomer. The user interface is also very slick.

You basically specify your location in terms of latitude and longtitude, and can look at the object in the sky. You can pan and zoom around. It also has a neat search feature, where you type in a celestial object, and it would pan, in a Google-earth-stlye, to that object. It also has quite a few interesting layers for constellations, azimuthal grids and so on.

The only problem I have had so far is the ability to retrieve a saved location. The software always seems to start up in the last location, and I cannot seem to find a way to list and use a previously saved location.