6. Finding stuff in the night sky
(part 2, using starcharts)
Earlier we learned how to find stuff that we can see with our eyes using simple charts. But how do you find something you can't see with your eyes? Now we move up to the more detailed charts which are usually big books. Unfortunately, there are lots of choices out there and they are at different levels of complexity and scales.
Fig 1: Two of the many available chartbooks.
The trick is to be aware of the scales of the charts. Have a simple printout or planisphere along with the more detailed chart. It will be very useful if you've already become familiar with the constellations and asterisms in the night sky. Find a simple pattern, say the bucket of the Big Dipper. On the simple chart or planisphere, there's just the four stars. Those are easy to see. If you're observing from a darker site, you may see some stars in the bucket. Let's look at the more detailed chart. First find the bucket of the Big Dipper on one of the pages. Because of the scale of the more detailed chartbook, you can't do the same kind of orientation because the one page of the chartbook is looking at a very small chunk of the sky whereas in Section 4 we had a starchart that showed the whole sky. But it's pretty simple... Just turn the chart so that the rectangle of the bucket is oriented to the way you see it in the sky. Now if you see some stars in the bucket with your eyes alone, match them up to the ones in the chart. The chart still shows more stars, so use binoculars to pinpoint the others. Make sure you are very comfortable with matching up what you are seeing in the binoculars to what you see with your eyes and on the charts. Being familiar with how many fields of views to move over from one star to another will be handy in trying to find your target (asteroid or comet) later on.
Fig 2: These two images show the same small patch of sky as represented by two different chartbooks.
Note the difference in detail.
[Region around Spica from the Sky Atlas 2000 (left) and The Cambridge Star Atlas (right).]
Sometimes you might have a chart like our binocular views of the comet that don't show the whole constellation. That's okay. Some stars should be labeled so you can use those to match the view up to a an even more detailed chart in a chartbook.
With a pair of binoculars, practice finding stars that you see with your eyes that are on the chart. In the binoculars, you'll see more stars than are marked on the chart or that you can see with your eyes alone. Reconciling the binocular view with these simple charts is not easy but it is not too hard. It just takes practice! Once you are comfortable using binoculars and basic charts, try starhopping with your telescope. On the detailed charts, find a bright star near the target. Then make a note of any star patterns or strings of stars leading to the target. Using the telescope, find your bright star starting point and then try to find the patterns or star strings that you noted on the chart.
In late August, Hartley 2 can be found just above the Great Square of Pegasus and moving into Lacerta. Through September, the comet makes its through Andromeda and Cassiopeia. It spends October drfiting through the stars of Perseus, Auriga and Gemini. It is in Monoceros when the Deep Impact Flyby spacecraft flies past in early November, crosses into Canis Minor and back into Monoceros during November before drifiting through Puppis. It is over towards Canis Major at the end of the year.
Archive: Dawn -- Vesta
2007: Vesta is just east of Scorpius. Check out the Starcharts to find Vesta. And later on, we'll have information about Ceres.
Archive: Deep Impact -- Tempel 1
Tempel 1 moved through the constellation of Virgo throughout 2005. In mid-January (2005), Tempel 1 was near epsilon Virginis. By early July, Tempel 1 was near Spica, the brightest star in Virgo.