Astroblog

This post was inspired by an email from a reader. Having received a spanking new telescope for Christmas, and having successfully assembled it, despite the instructions looking like they were photocopied onto recycled rice paper using a 1980's photocopier. So there it is, bright, shiny, bursting with potential. What planet or star should you look at first?

The Moon. The Moon is big, bright easy to find, and has lots of interesting features. It is perfect for getting familiar with the intricacies of your new scope, and circumventing the problems that can cause people to hurl the scope into a garage and leave it to gather dust for the next century.

Actually, first off, take it out in the afternoon and set it up in the light where you can see all the bolts and cables, so you can see what you are doing. make sure you are somewhere where you can't accidentally see the Sun through your scope. Nothing ruins a Christmas present more than if it sends you blind.

Make sure you tighten up all the bolts especially those in the tripod mounting. A lot of frustration occurs when the telescope wobbles so much you can't focus or any time you look through the scope the objects jiggle to much see anything. Also make sure the knobs that hold the finderscope to the telescope tube are tight, if the finderscope moves around it can cause no end of grief. Then put the lowest power eyepiece in the scopes tube.

Now to tackle the thing that engenders the most frustration of all, aligning the finderscope with the telescope. Point the telescope more or less in the direction of something distant, like a telegraph pole. Look through the finder scope and adjust the alt-azimuth movement knobs until the telegraph pole is centered in the cross hairs, then look though the eyepiece (low power, remember). If you are lucky, then at least a bit of the telegraph pole is visible through the eyepiece, if so use the movement knobs to centre the telegraph pole in the eyepiece. Then use the adjustment knobs of the finderscope to get the telegraph pole in the centre of the finderscope again. This way, the next time you point the finderscope at something, it should be more or less centered in the low power eyepiece (make sure you don't bang the finderscope out of alignment now, or there will be a lot of weeping and wailing and gnashing of teeth).

Now wait for twilight to fall and the Moon to rise. The Moon is waxing at the moment, and there are lots of nice craters and so on to see.

Keep the low power eyepiece in. I know everyone one wants to go high first off, but trust me.

Point the telescope in the direction of the Moon. Look through the finder scope and adjust the alt-azimuth movement knobs until the Moon is centered in the cross hairs (just like you did with the telegrapgh pole), then look though the eyepiece.

If you are lucky, then the fiddling with the telegraph pole you did earlier will result in at least a bit of the Moon is visible through the eyepiece (it won't be exact because the telegraph pole is much closer then the Moon, and the parallax will be different), if so use the movement knobs to centre the Moon in the eyepiece. Then use the adjustment knobs of the finderscope to get the moon in the centre of the finderscope again. Now, when you next go out astronomical objects will be more or less centered in the low power eyepiece.

If, as more likely, the Moon is NOT in the eye piece, then take the eyepiece out and see if you can see any Moon light coming down the tube. If not, first check to see that the lens cap is off the working end, then use the movement control know to slowly scan across the sky in the
general direction of the Moon until you can see Moonlight coming down the tube. Once that's happened, put the low power eyepiece back in and use to movement knobs to centre the Moon. Then go back to the finderscope and centre the Moon in that (you may have to juggle back and forth between the eyepiece and the scope if the alignment is really out).

Once the low power eye piece is set up, enjoy the lowpower view of the moon and practice using the movement knobs and the focus knobs. Getting used to setting up the focus can take some time. Then put in the higher power eyepiece, note where the Moon is (it will probably be out of focus in the high power lens, you will have to adjust it). Play around with the low and high power views getting used to using the focus knobs and the movement knobs and the finderscope. In the high power eyepieces, you will also note that the Moon will slowly (or rapidly depending on how powerful it is) move out of the field, so you need to constantly adjust the movement knobs.

Once you have had a good play with the Moon, it is time to go planet hunting. Unfortunately, the only planet visible in the evening at the moment is Jupiter (unless you really feel like getting up at 4 am to see Mars and Saturn), and its is low on the horizon. By the time you have finished playing with the Moon, Jupiter may have set.

Don't despair, next night, go out and play with the Moon again (just to refresh yourself and check that the finderscope has not been knocked out of alignment). Now look west. The obvious bright object above the western horizon is Jupiter, get it into the finderscope, first with the low power lens to make sure it is in view, and enjoy.

Labels: telescope, where to look