Steve’s Virtual Planet

What planet, where planet?

When you plan your upcoming sky viewing, it’s always a good idea to check what planets are going to be visible. There are a number of ways to layout a plan for the constellations and because they are regular and predictable, it’s easy to get prepared. “Well”, you might say, “planets are regular and predictable, too.” Yes, true, but our solar system neighbors have their own rhythms that don’t coincide with Earth’s yearly cycle.

After searching the internet for some time, I have found a very useful tool for planning your planet watching called AstroViewer. This is an online tool and it is found at www.astroviewer.com. There is a free interactive version of the program that can be used as long as you have a live internet connection. There is also a download version and a license key that can be purchased for about $15US. Chances are you are planning weeks or even months in advance, so the online version should be adequate.

When you go to the web site, you will see a group of tabs across the top of the main page. Click the second tab marked “Interactive Night Sky Map”. It takes a few minutes after that, but you will soon see a grey button appear that says “Start AstroViewer”. (If you don’t see the button, refer to my notes at the end). Click that button and you will get a new browser window with the actual tool inside. The main display will appear with an easy to use sky map that’s very intuitive to use. There is also a view of the solar system in the second tab which you may wish to check out, but the point of this post is on the third tab - “Planets’ Visibility”.

The display may look a little odd at first but when you study it for a moment, you’ll see it’s a 24 hour timeline with a horizontal line for each planet and the moon. Notice the scale below the planet lines; this is the time of day. You will need to set the location over in the left hand side control panel to be in sync. But once you do that, you can then determine when each planet will be visible in relation to the time of day. The view defaults to the current time, but if you adjust the dates using the controls to the left, the real usefulness of this display becomes apparent. You can use the control panel to skip forward in time by weeks or even months or years to see when you favorite planet is up. You will still need a planetarium program or online tool to see exactly where the planet will be, but you will know when to look.

Enjoy!

Notes: AstroViewer relies on Java and need to have an addin for your browser for the tool to work. That’s really beyond the scope of this post, but if Java is missing, your browser will likely prompt you to download the addin. Java is a very useful component and has it’s own internal security so you shouldn’t worry about adding that to your browser.