Analysing the Evidence

Take the following steps . . .

LTImage Screenshot

1. Using image processing software

   Run LTImage in a new window on your computer desktop alongside this planet investigation.

   Load your image data files of two planets by selecting FILE (menu) and then OPEN DATA IMAGE (option) for two seperate image stores.

   If you have not downloaded, or are not sure how to use LTImage, click HERE.

   For each image file identify the time the observation was carried out by the telscope.

   To do this click on Astro (menu), Image Properties (option) and Calibration (button on right) and you will be able to find out this information.

2. Comparing planets

   With both planets displayed, you will immediately notice marked differences between your two chosen planets.

   This part of the investigation is all about describing the similarities and differences you can see between the planets you have observed.

   To record these you should devise a table similar to the one shown here.

   Comparisons	Planet A	Planet B
   Diameter
   Size of a large feature
   Ring system (Yes/No)
   Clouds and storms
   Oblateness
   Phasing
   Moons
   Other

Here are a few pointers . . .

• Look at the surfaces of your two planets and describe each.

  To pick out more detail and to help you identify different types of surface feature, try experimenting with false colour processing by selecting the Colour (menu) and Colour Select (option).

• If you can see one, pick a surface feature and try to measure its size.

  If you are not sure how to measure the size of a planetary surface feature or the planet's diameter click HERE.

• Look to see if the planet is surrounded by a ring system.
• Atmospheric storms change surface features on planets.

  Do you think that you can see any atmospheric activity?

  You can often see spots on Jupiter and, if you request a number of observations of the planet over a period of time, you can follow these as they move across the surface of the planet.

• Oblateness is a measure of the amount by which a rotating object such as a planet (or star) departs from a perfectly spherical shape. This is most clearly seen on Jupiter and Saturn.

  Check to see if you can see if the planet is spherical or not.

  Why not measure the diameter of your planets from north to south as well as from east to west.

• Like the Moon, some planets show a phase - a darkening seen down one edge of the planet. Again, the planet does not appear perfectly spherical.

  A good example is Venus, although it is possible sometimes to see Mars showing a slight phase.

  Can you see phasing?

• Most of the planets do have moons and these can often be seen.

  Do you think that you can see any moons?

  Because planets are so bright compared with their moons a telescope has to be given a different exposure setting before moons can be photographed properly.

  The best way to detect moons, which look like stars in a telescope, is to request a number of observations over a period of time. In this way you will be able to see their movement against the star background.

• In the Other section write down any similarities or differences you can see between your two planets that have not already been described.

  Now you must evaluate your evidence . . .