Finding stuff to see in the eyepiece

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In yesterday’s post we looked at the things you can do to get your new telescope ready before taking it outside, a kind of check list to make sure you’re safe and the telescope won’t fall about around you. This article is all about finding stuff in the night sky, once you’ve taken the telescope outside. What I’m not going to cover is the pros and cons of goto setups versus setups that you have to manually drive, the reason is because I’ve never owned a goto setup so I have no idea how to set them up. Plus I know a lot of setups are all manual and this should be the first logical step to know in mastering your telescope. There’s lots of ways to find stuff in the night sky and if you’re using a manual setup then you’re going to have to convert the knowledge of what you want to look at into a physical direction the telescope is pointing. We’ll have a look at answering some common questions.

How do I find out about interesting things to look at through a telescope?

Read Milky-Way.Kiwi!!!! Ok seriously….. read Milky-Way.Kiwi!!!!! Ok, now seriously, there are heaps of resources on the internet, in astronomy books, on apps and in people’s heads (ask before you go looking in someone’s head).  I reckon the best stuff to look at first is the bright stuff, like the Moon and the planets. Right now it’s a smorgasbord of great stuff to look at because Jupiter is easy to spot and is very bright and a little later in the night Saturn and Mars appear. Next week the Moon will be back as well, which is always a fantastic first object to look at, basically because you can’t really miss it, unless it’s cloudy. Stellarium is a free application for looking at the stars and it is very easy to use and a great resource. I recommend downloading this and having a good look at it to familiarise yourself with how it works so you can convert the information on the screen into what you’ll be seeing in the sky.

Orion Nebula looks a bit like this in a telescope (Credit: Me)

How should I set my telescope up to use?

The answer to this depends on what sort of telescope you have. If is a Dobsonian mounted reflector then you can plonk in on the ground, as long as the surface is reasonably flat. For an equatorial mounted (EQ) telescope then the main axis of the mount needs to point at the south celestial pole (the north celestial pole for the Northern Hemisphere because they are upside down). It is a bit tricky to get an EQ mount pointing in the right direction because you have to also make sure the altitude is correct (the angle that it’s pointing up). In the Northern Hemisphere you basically point the mount main axis at the North Star, it’s close enough to the North Celestial Pole. No such luck in the Southern Hemisphere.

Why does an EQ mount have to point at the celestial pole?

Basically you need the EQ mount to be lined up so you can easily track what’s in the eyepiece. This is really handy if you’re looking at planets and the Moon because tracking means you don’t have to keep nudging the telescope to keep the object in the eyepiece, the telescope moves with the sky.

How do I get the thing I want to look at in the eyepiece?

You have to point the telescope in the right direction. There’s a number of ways of helping this happen. If you read this post then you’ll have you finderscope perfectly lined up with the main telescope so what you’re looking at in the finderscope will also be in the eyepiece on your focuser. Some telescopes have red dot finders which are also really easy to use, I used to have one on my 16” Dobsonian mounted reflector and it made it quite easy to find stuff. So line up what it is you want to look at in the finderscope and make sure you have a large eyepiece in the focuser, at least a 20mm eyepiece, because the that view will be considerable more zoomed in than the view in the finderscope. If everything has gone to plan then you should have the object in the eyepiece. It will probably be out of focus so you’ll need to adjust the focuser.

What’s the big donut shaped blob in the eyepiece?

That’s a defocused star, so you will need to adjust the focuser to make the bright blob as small as possible. Remember if it’s a planet it may not resolve to a bright point but you might actually see the disk of the planet, which is very cool to see for the first time.

Why does Saturn not look like the images from Cassini?

Visual astronomy requires quite a bit of expectation management. When you view something you are looking through the Earth’s atmosphere and many millions of kilometres of space (even billions for the outer planets). The atmosphere is the biggest problem as it really distorts and messes around with the details you can see through the telescope. It’s not all bad though as you can see some really amazing things through a telescope, not quite like being in orbit around another planet and not like the Hubble Space Telescope. On a good night that is nice and cool, with a clear atmosphere you can see the dark bit in Saturn’s rings called the Cassini Division and the banding on the planet’s disk.

Saturn looks a bit like this in the eyepiece on an average day (Credit: Me)

How come I can’t see the Apollo landers on the Moon?

The smallest object I think I have seen on the Moon is some of the small craters on the floor of Clavius, some of them are around 5km in diameter, so seeing something as small as a lander which is is only a few metres across is virtually impossible from our vantage point on the Earth’s surface.

This is the sort of detail you can see on the Moon (Credit: Me)

So get out there with you telescope and enjoy!