Steve’s Virtual Planet

SVC Tip #4 - Going in circles with the Big Dipper

The northern sky has several memorable asterisms and the favorite one is probably the Big Dipper. It’s actually only part of Ursa Major, the Great Bear. It’s easy to spot when it swings into view in the early evening this time of year. And the further you are to the north when observing, the better the view will be.

The Big Dipper will contain stars which will be visible at some time on most nights. As those stars move counterclockwise around the northern polar star Polaris, they are said to be “circumpolar”. In other words, if we are at a certain minimum latitude (around 41 degrees), a specific star in the dipper will make a great circle in the sky and never go below the horizon.

Of course, around the suburbs you might be dealing with the tree line but not to worry. You can plan for this using Sky View Cafe (SVC) and on of its options on the Sky tab - the Horizon to Zenith view. Look for the list of options over on the right hand side when using the Sky tab. The first option is probably set to a full sky view, but click the don arrow to list the others and choose Horizon to Zenith. Then, look for the “Select a direction …” button near the Insolation tab and change it to N, for north.

Now you’re looking at a full slice of the northern sky from the horizon to the zenith. By adjusting the time and date values up in the time field, you can preview what your view of the dippers will be. If you also mark the names of the stars for the constellations, you can refer to the chart made in the previous blog on the dippers. And remember, you can print from Sky View Cafe and get a simple chart to use in the field for the exact time and date you’ve selected.

Have a great time with SVC and check out the other tips here SVC Tip #1 & SVC Tip #2 & SVC Tip #3.