Making MOST

As part of our Space Exploration Badge we built a full scale model of a satellite! Here are some pictures of our model.

Canada and Canadians have a history of innovation and success in space exploration. From Alouette 1 to the Canadarm and Canadarm2 used aboard the Space Shuttle and International Space Station. By 2006, Canada had over 33 payloads in orbit. One of these is a tiny observatory called Microvariability & Oscillations of STars (MOST) that is making a big splash in the field of astronomy.

Most is a micro-satellite, about the size of a large suitcase, that was launched by Canada on an Russian rocket in 2003. Launched on a modest (for space exploration) budget, MOST has been called the Humble Space Telescope in reference to its much larger and more expensive predecessor the Hubble.

MOST orbits the earth from pole to pole in perpetual darkness and can keep its cameras focused on stars for almost two months! Because it can pick up small variations in light from the stars it observes, MOST can be used to study planets orbiting other stars and variations in the star's atmosphere (a bit like studying earthquakes). MOST hopes to answer questions about how the Sun may evolve and even how stars contributed to the formation of solar systems.

Expected to operate for about one year, it's still going. In fact, the science team has opened up to the public to propose observing targets through the My Own Space Telescope project!

MOST is unusual for a space telescope in that it uses an unusual lens design. The Fabry microlens array spreads light from target stars over a large number of pixels to achieve high resolutions.

The 433rd has contributed too. Mitchell's dad is part of the operations team, Mang has proposed a couple of targets. Here's a chart showing the parts of the sky MOST can see and some of the official candidate and selected targets.

The chart shows the sky mapped out against the coordinates used by astronomers. The x-axis is the Right Ascension (in hours) and the y-axis is the Declination (in degrees).

There are three zones that are important to MOST. The CVZ (Continuous Viewing Zone) is where MOST can keep itself focused for up to about 60 days at a time! There are two SS (Sun Sensor) zones. Targets within the SS zones represent the extreme range of the telescope and can be focused on for shorter time periods. If you are really interested in a star in the SS zones, one trick is to pick a second star and switch between the two. These are called "switch targets".

These targets are all taken from the official web site for MOST. One thing that may be of interest is that some of the candidate stars were chosen before the operational parameters of MOST were well understood. If you look, you will see candidates well outside the SS zones.

This particular chart shows two stars that I proposed for observation. One is a switch target. Can you figure out what they are? And why I picked them?

Another surprise for me was that I could actually get Excel to produce a chart like this!

More information on MOST can be found at

• Wikipedia
• The Canadian Space Agency, and Most @ the CSA.