Which Telescope is best for me?
Binoculars are a very good start to astronomy but eventually you will be drawn into telescopes. Beware, not all telescopes are born equal! There are different types. If you imagine a traditional telescope it will be a refractor. However, there are other types of telescopes which are reflectors, where light is collected by one mirror that reflects it onto a second mirror, then into an eyepiece. It doesn’t stop there. You could even have a mixture of the two types which use a combination of mirrors and lens called a catadioptric or compound scope. They all do a good job but binoculars will be better that a cheap telescope.
If you want to observe planets, get a telescope that has a long focal length or a high focal ratio (f/10 will be stamped on it somewhere). This is called a ‘slow’ telescope. ‘Faster’ ones, better suited to fainter objects, have a lower focal ratio, eg f/5. An important first job after acquiring a telescope is to line-up your finder-scope so that it has the same view as your main telescope. This is best done during the day, by focusing on a distant object. This is really a key job and will save you a great deal of frustration later on, as trying to do this at night is ten times harder! Also choose the best nights for those very faint objects, when the Moon is not spoiling the show.
If your telescope is indoors it takes up to an hour to cool down when you take it outside. Any earlier and you may find the lens covered in mist or your view wavy from the warm air trapped inside. While that is cooling down, you will need to give your eyes a chance to adapt by using a torch with a red filter as you set things up. This may take about 20 minutes. In my opinion, at low power the best direction to view is the South because you have access to the planets. In general, don’t be tempted to use your most powerful eyepieces. Measure the diameter of the end of your telescope in mm (aperture) and don’t exceed more than double this in terms of magnification. There are many reasons for this but here are two very good ones. Unless you have paid a great deal of money for a quality telescope then the optics may not be good enough at high power. You may be able to tell its quality by seeing if the manufacturer has put a restriction (like a plate with a hole) inside the tube. If there is one there, then the quality of your optics may not be too good. Secondly, when you look through a telescope at high power it is very difficult to point it and find objects, even the biggest of objects (like the moon!). When you do have it in your sights then things very quickly drift out of view at this power.
When (not if!) you get hooked you will realise that you need to plan ahead. As your set-up becomes more complex you need to allow more time. Your tripod or mount may need to be aligned in a special way. You may need to heat your telescope to stop it freezing up. A tripod will only take you so far in this hobby until you will need a motorised mount. If you are controlling your telescope by computer, your exact location on the earth needs to be factored in. Then there is the software and cables…. the list goes on! There is something to be said for keeping it simple and just scanning the night sky. But after a while you will get drawn in by an irresistible force to seek out objects and try to image them. Try to resist if you want a simple life!
This hobby is not for the faint hearted and will test your patience and optimism, then burn a hole in your pocket. It will stretch your sanity and disappoint you relentlessly. But when it all comes together it gives you a massive sense of achievement and satisfaction that is hard to match.
What to look out for in February.
Looking North
The view on 9th Feb at 9pm Looking North from Embsay
Half way up in the west is the faint fuzzy patch of the Andromeda Galaxy, Look to the left of the ‘W’ shape of Cassiopeia as a guide. This is the most distant object visible with your naked eye. It is a spiral galaxy just like our own. Edwin Hubble proved that this patch was in fact not part of our Milky Way Galaxy and opened up the idea that not everything close was the limit to our Universe. Here was something we could see far beyond. Suddenly the Universe was viewed as something far bigger. For example, if you look due east you will be able to see the constellation of Leo. Hidden here is the Leo Triplet, 3 spiral galaxies grouped together (known as the M66 group).Below is a picture of them taken from Embsay. Each of the spiral galaxies just like our own.
Photo: Milan Davidovic (March 2017)
Looking South
The view on 9th Feb at 9pm Looking South from Embsay
Orion dominates due South with its unmistakable hour glass shape as well as Jupiter, (see last month’s article). You will also see close to the horizon a very bright star. This is Sirius, also known as the Dog Star; called this because it is part of the constellation Canis Major, Latin for greater dog. It is the brightest star in the night sky. It has been a useful pointer for navigation as you can use it to locate south by drawing an imaginary line from Sirius to the horizon and that point will be south. There are many more facts and myths about this special star. https://www.astronomytrek.com/interesting-facts-about-sirius-the-dog-star/
If you have enjoyed reading this article, don’t forget you can refer to previous ones on my blog at:
Clear Skies.
Milan Davidovic
