Getting to grips with star charts: by a novice for novices
Venus and Jupiter are unmissable and unforgettable sights in the night sky when they are in the right part of their orbit.. Jupiter with its 4 Galilean moons is my all-time favourite through a telescope. But when trying to find fainter objects, how do you know where to look if you can’t see what you’re looking for ?
For those of us without a GoTo telescope, the answer, given in a one of our meeting talks, seems to rely on star charts which you use to “star-hop” from one visible feature to the next until you arrive, you hope, at your chosen position. The big problem with star charts – at least, it sounded like a big problem for me – is that star charts always show a section of the night sky as it really is, ie as you see it visually. Then when you look through your telescope, the optics will flip things horizontally and/ or vertically. Tricky !
Perhaps there is a website which provides star charts in the correct orientation for your telescope view. I didn’t find one ( though I’m sure there must be one !) but I did come across a handy hint. If you have or can make a copy of a normal star chart, try saving it as an image (or if it is a hard copy, scanning in and then saving). Now use an image manipulation programme and flip it horizontally and vertically as needed to make it show the same orientation as your telescope view. I assume you’d need the normal star chart on an observing session so you could get your telescope pointing in roughly the right direction and then use your adapted chart to do the fine-tuning.
If you are not sure about what the optics of your telescope does to the orientation of things, Click here This shows the moons of Jupiter and allows you to select the orientation by either just horizontal flipping (mirror-reversed) or horizontal and vertical (inverted view). If you can find Jupiter through your telescope and can compare what you are seeing with the various versions from this website, you’ll be able to work out what your telescope is doing.
(I assume you could achieve the same effect by looking at the Moon visually and then through your telescope)By Katherine Rusbridge
Mar 2012