What terms mean and how to do stuff?

[AppleGecko (Brent)]

Hey im new to astronomy and just got a new saxon 8" dobsonian

Ive gotten ahold of some star charts by Wil Tirion and i need to know some things.

- what does the M mean. For example M42 and why does each one have a number assigned.

- how do i find the diagrams of stars and things in the sky, do i just observe and find something i recognise and go from there with the charts.

- do galaxies rise and set?. Is there a time to see them and a time you cannot see them.

- What do filters do, they change the way you see obviously but are they a good add on to buy? Also how much can they range from.

- what does aligning the mirros mean?

- which is an easy galaxy to view and find, the orion nebulae perhaps?

That all the questions i can think of at the moment. Some one plz help

[Robh (Rob)]

Brent,

I'll try to be brief.
M is for Messier. His final catalog of some 103 objects was published in 1781. However, it now officially has 110 objects.
He was a comet hunter and made note of nebulous objects that might be mistaken for comets. We now know these objects include many nebulae, globular clusters and galaxies.
You need to start with the brighter stars and try to match these to your maps. A planisphere would help you to position the constellations in the sky at different times of the night and different times of the year. Once you can identify the major stars in a constellation you can star hop to a selected object.
The night sky appears to rotate from east to west, 15 degrees each hour, because of the rotation of the Earth. However, all stars and galaxies remain fixed relative to each other as the sky moves. Because they are closer to us, the planets can be seen to move across the background sky of stars over time.
A moon filter will reduce its light in a telescope for more comfortable viewing. Filters of different types can used to enhance features in an object e.g. nebular filter to enhance emissions. Some filters can be used to reduce skyglow. However, they won't make an object brighter but simply reduce the background light. I wouldn't bother with them until you are more experienced and know exactly what your needs are.
A telescope needs to have its mirrors aligned (not saying yours isn't) so that all incoming light is focussed to the eyepiece centre. If mirrors are misaligned then stars will not focus as nice points and objects will appear fuzzier. For example, close binary stars will be hard to split. A laser collimator or cheshire collimator can assist in the collimation (alignment) of optics.
A galaxy is a very large gravitationally bound system of stars. Our Milky Way is a spiral galaxy. The Orion Nebula is just a reflection and emission nebulae of dust and gases within our galaxy.
A bright galaxy is the Sombrero Galaxy in Virgo but more easily found from Corvus. You will need a map to find it.

Regards, Rob

[jjjnettie (Jeanette)]

Hi Brent, welcome to IIS.
It's all a bit confusing when you first start off. But don't worry you'll catch on soon enough.
Another prefix you'll come across is NGC = New General Catalogue.
eg. ngc253 is a nice bright galaxy also know as the "Silver Coin".
NGC104 is a globular cluster of stars which is also known as 47 Tucanae (abbreviated to 47 Tuc)
The Sombrero Galaxy that Rob mentioned is Messier 104 (M104).

What you really need to do is get yourself along to a star party.
It's the quickest way to learn.

[jjjnettie (Jeanette)]

Where abouts are you from Brent?

[astroron (Ron)]

Originally Posted by jjjnettie

Hi Brent, welcome to IIS.
It's all a bit confusing when you first start off. But don't worry you'll catch on soon enough.
Another prefix you'll come across is NGC = New General Catalogue.
eg. ngc253 is a nice bright galaxy also know as the "Silver Coin".
NGC104 is a globular cluster of stars which is also known as 47 Tucanae (abbreviated to 47 Tuc)
The Sombrero Galaxy that Rob mentioned is Messier 104 (M104).

What you really need to do is get yourself along to a star party.
It's the quickest way to learn.

"Silver coin"

[jjjnettie (Jeanette)]

Why do I always think of you Ron when I mention the Silver Coin Galaxy?

[Jen]

Hi Brent to IIS
Download this skymap it will help you get to know your way around the night sky
http://www.skymaps.com/skymaps/tesms0906.pdf

And i highly recommend you download Stellarium it is very helpful when you are just starting out and its free too

http://www.stellarium.org/

Cheers happy viewing

[AppleGecko (Brent)]

Thankyou everyone for your help. Only a few more questions should finish me off.

Is it possible to allign the mirros without a laser collimater and obviously it would be harder. Though how much would a laser collimater cost.

I have recently viewed a group of stars I think. There was a really bright star with 2 on one side and one on the other side. It looked like an average star through the finderscope but through the telescope it was round and different . Could this be a planet or something else or is there something wrong with my alligning.

Can i see nebulae and such galaxies with my telescope. And i live in Brisbane QLD. Im sorta not one for going out with other people to have a star party.

To view a galaxy such as sombrero would i have to allign the mirros correctly, find a dark spot on a dark night with no overcast obviously, and use my star charts to find it. I had my telescope outside earlier and was looking at the stars and could only see stars as they appeared as small dots with a little sparkle, i panned around casually and still only saw small stars excpet for when i found the round planet star thing. How do i find something that would blow me away. And is it possible to see a planet from my telescope and on a star charts what are they labbeled or can you not see any planets from Australia.

Also on my star charts each star in a constilation have letters from the greek alphabet beside them. What do these mean.

I think thats enough for the moment. Please dont hesitate in giving me more advice.

[M54 (Molly)]

Hi AppleGecko,

I'm reasonably new to this too.
I raided my local library and got out a pile of Astronomy books.
I'm currently reading 'Astronomy for Dummies'.
I'm sure your local library will have lots for you to read too.

That bright star that looked round in your telescope with two 'stars' on one side and one on the other was most likely Jupiter, the fifth planet in our solar system. The little stars on either side are its some of its moons. If you look at Jupiter each clear night, you'll notice the position of the moons changes as they orbit the planet.

I haven't collimated my mirrors yet so I can't help you with that (haven't had to so far).

When looking for nebulae and star clusters, so far I've just looked on the star charts to see their general position and then waited for that part of the sky to rise high enough to see them from my backyard and then searched for little fuzzy spots, which is what they (the bright ones) look like to the unaided eye. Then I just pan around with my scope till I find it.

Do you have a planetarium program? I have Orion's 'The Sky'. Its a big help in learning the positions of things, and how the sky changes over the course of the year.

As I said above, I raided the library. I also attended a Star Party held by the Astronomical Society of Victoria, which was open to the public. If you're a little nervous about going to a Star Party, drag a friend or relative along for moral support. There's no pressure and everyone lets you look through their telescope and answers any questions that you can dream up. I dragged my hubby along 'cos I was a little shy, and I was so glad I went. It was awesome.

The Brisbane Astronomical Society has public viewing nights, anyone can go along.
www.bas.asn.au

Hope this is a bit of a help to you.

[jjjnettie (Jeanette)]

Don't be shy, we've all been there and we know exactly what it's like in the beginning.
So keep asking questions.

If the sky is clear tonight, look to the east around 10pm and you'll see a very bright object rising. This is Jupiter.
Centre it in your field of view using your 30mm eyepiece, then change to a smaller eyepiece. You'll be able to see 3 or 4 of Jup's moons on either side of the planet.
If you have a barlow lens, use this to get in even closer to see surface details.

When I had my dob, I only ever used an old film cannister with a hole in the bottom to collimate.
But if your stars are pin points, I'd leave it for now.

[barx1963 (Malcolm)]

Just borrowed a laser collimator to see how it worked. Found I could do the secondary very easily with the laser, then did the primary by eye and fine tuned with the laser. Am now waitingf to test my collimation on the stars. Overall, I think learning to do it by eye will help to understand what you are trying to achieve, which is hard to get following instructions.
If your stars are showing as points your alignment should be good enough.
Galaxies such as the Sombrero are fairly hard to track down, start off with large bright nebula and clusters. Eta Carina and the Jewell Box in Crux are two very easy one visible clearly in early evenings. Try and learn where Scorpius and Sagittarius are and cruise around them, there are lots of clusters and nebs to see. Even a small scope will have no trouble finding these bright objects.
The Greek letters are an old way of classifying stars, in most constellations Alpha was the brightest star, Beta the second brightest etc. Usually only the brightest stars have these letters and due to changes in the constellations over the years, they are not always accurate guides to brightness. A good reference for the various constellations is Collins Stars and Planets which I use and find very helpful.
Star parties are not noisy affairs, usually very friendly places and most people there will be pleased to answer questions and show off their gear and show you what can be seen, get along to one, you will not regret it.

[ngcles]

Hi Apple Gecko,

Welcome to the wonderful world of amateur astronomy (and IIS). Amateur astronomy can as simple or as complicated as you like -- you are the one who determines that -- do it your way.

Originally Posted by AppleGecko

Is it possible to allign the mirros without a laser collimater and obviously it would be harder. Though how much would a laser collimater cost.

Yep, you can certainly align (collimate) a telescope's mirrors without a laser. The purpose of collimation is to align the optical axis of the big curved mirror down the bottom of the tube with the optical axis of the eyepiece you view through in the focuser. A star image near the centre of the eyepiece field of view should look very, very tiny and round with a little fuzz around them when the 'scope is focused. Diffraction spikes (look them up) are also normal in a newtonian. Planetary (Jupiter, Saurn etc) images should look small but really sharp. If the mirrors are not aligned properly you will get funny-looking star images that don't quite come to focus or have a flare out of one side and planets that look fuzzy and not crisp all of the time.

There are several methods to collimate a newtonian telescope. Some involve a laser and some a device called a "cheshire eyepiece". If you are experienced you can do a good rough job by eye.

Really top qualiy laser collimators cost maybe $200-. You'll get one that will do the job okay for the moment for about $100. A Cheshire will cost about $40-$100 and despite its "low-tech" appraoch I thnk is still the best way to collimate. It is one of those things that you need to learn to use well. Don't panic it isn't rocket surgery. Don't get to carried away by collimation for the moment -- enjoy the 'scope as is untill you start to become familiar with using it and seeing the night sky.

Do a search on "collimation" in the threads here and with a search engine. Learn the basics first. Don't get too anal about it in the meantime -- enjoy the 'scope.

Originally Posted by AppleGecko

I have recently viewed a group of stars I think. There was a really bright star with 2 on one side and one on the other side. It looked like an average star through the finderscope but through the telescope it was round and different . Could this be a planet or something else or is there something wrong with my alligning.

This was almost certainly Jupiter. It is low in the eastern sky late in the evening at the moment, very very bright compared to its surroundngs and gets higher as the night goes on.

Originally Posted by AppleGecko

Can i see nebulae and such galaxies with my telescope. And i live in Brisbane QLD. Im sorta not one for going out with other people to have a star party.

Yep, certainly. There are several hundred if not thousands of galaxies, star clusters and nebulae that can be seen with your 'scope. One thing you'll notice is that on these sorts of thngs, the vew is much, much better if you take the 'scope somewhere away from the city on a moonless night to somewhere nice and dark. You can also do "deep-sky" observing in the suburbs but the view isn't as good. This is one of the main reason amateurs organise "star-parties" and your local astronomy club will also probably hold observing nights.

Don't be intimidated by star-parties or observing nights. They are just are bunch of people interested in astronomy that meet to enjoy each other's company, share equipment and enjoy the sky together. Some of them are experienced, some have less experience and others are beginners like you.

One thing is for certain they all had to start somewhere and once upon a time they all stood in the shoes you are wearing now. These are a great way to meet other amateur astronomers, learn a lot of stuff and look through your own and each other's 'scopes. You'll learn that most amateur astronomers love to look through other people's 'scopes and have you look through theirs. We are an inherently friendly bunch of people who love to share our hobby (passion, obsession) with others.

Originally Posted by AppleGecko

To view a galaxy such as sombrero would i have to allign the mirros correctly, find a dark spot on a dark night with no overcast obviously, and use my star charts to find it.

Don't sweat too much on the collimation thing for the moment. Do some reading here and elsewhere first. As for the rest of the question -- yep, that is how most owners of telescopes similar to your's do it.

Originally Posted by AppleGecko

I had my telescope outside earlier and was looking at the stars and could only see stars as they appeared as small dots with a little sparkle, i panned around casually and still only saw small stars excpet for when i found the round planet star thing.

That's how stars should look. The stars are immesely big things. Even a medium-sized star like the Sun is 1.4 million kms diameter and can hold over 1,000,000 Earths inside. However all of the stars in the night sky are so incredibly far away that despite their size, they all look like tiny dots. That dot you see isn't even the surface of the star -- it's a product of the telescope's optical system. Individual stars through the telescope should look similar to the way they do with the naked eye. They obviously become more imteresting when there are lots of them together in a bunch (a star cluster) or with gas and dust around them (a nebula).

Originally Posted by AppleGecko

How do i find something that would blow me away. And is it possible to see a planet from my telescope and on a star charts what are they labbeled or can you not see any planets from Australia.

Planets are not usually labelled on star charts because they very slowly move among the background stars due to the Earth's rotation around the Sun, and the planet's movement around the Sun. It takes Jupiter abut a dozen years and Saturn about 29 years to do a whole lapa round the sky's background stars that for all intents and purposes do not move.

Venus, Mars, Jupiter and Saturn are easy to find because they are pretty bright to very bright. Mercury is a little more tricky because it is always near the Sun and the other two can't be seen naked eye. To know the position of the planets and where to find them you need an ephemeris like this one:

http://www.quasarastronomy.com.au/

and you'll also find a planisphere (an all-sky map where you can dial in a view of the sky above you for any night of the year) especially useful for learning the constellations and the night sky.

You might also strongly consider joining an astronomical society (club near you) where there will be lots of people who can answer questions.

There are also several magazines devoted to amateur astronomy and I'd suggest a trip to the paper-shop where you will probably find several. Some are American based (eg "Astronomy"), some European (eg Sky at Night") and at the moment one Australian based -- Australian Sky & Telescope. I'm sure you will find one or more that will meet your needs. They also have articles in them on where you can find the planets at present and other objects to track down with your telescope or binoculars.

Starting with something simple to "blow you away" -- see if you can find the southern cross in the southern sky. There are two bright pointer stars that point at the cross -- Alpha and Beta Centauri. Alpha Centauri is the closest star to our Sun about 4.3 light-years away (1 light-year is approx 9.6 billion km). Take a look at this star and you'll see not one star (like the naked eye view) but two very close stars. Alpha Centauri is a binary star.

Also see if you can fnd the "Jewel Box" star cluster" (NGC 4755) close-by to the 2nd brightest star in the southern cross itself. One of the very best star clusters in the skyand wonderful through an 8" 'scope. That ought to get you started.

I've attached a map you can print-out that shows the cross, the Jewel box (NGC 4755) and the two pointers.

Originally Posted by AppleGecko

Also on my star charts each star in a constilation have letters from the greek alphabet beside them. What do these mean.

This is one of the standard systems of labelling stars and a lot of the brighter stars will have these "Bayer/Ptolmey designations" beside them. Without going into the full history, they are old Greek letters that were assigned to stars within a constellation. Many of them run from brightest (Alpha, Beta, Gamma) to faintest (Omega) within that particular constellation, but for historical reasons don't expect them to be absolutely uniform.

I think thats enough for the moment. Please dont hesitate in giving me more advice.[/QUOTE]

And don't hesitate to ask more questions. Welcome to amateur astronomy. Don't forget to have fun. Don't stress too much over things -- you're a beginner.


Best,

Les D