Aligning Finderscopes

[title type=”modern-h2″ align=”center”]Aligning Finder Telescopes[/title]

Try getting a thin cardboard tube, perhaps from the inside of a kitchen role, close one eye and hold it up to the other. Now try walking around and I’m pretty sure you’ll keep bumping into things. Finding things through a telescope is just like this. Because a telescope has a very small field of view on the sky, its very hard to find your way around. That’s why all astronomical telescopes have some form of ‘finder telescope’ attached to the side.

There are a number of different types of finder telescope on the market from red dot finders to laser pointer finders but I shall focus on those that are like small telescopes made with with lenses.

The finder telescope has a much wider field of view on the sky and a much lower magnification than the telescope. In order for it to help you find your way around the sky, you need to align it to the main telescope. In other words, they both need to point in exactly the same direction. This may sound difficult to setup but is actually easier to setup than it sounds and the great thing is that you can do it in the warmth and light of the day.

Set the telescope up outside and find an object like a chimney or aerial, ideally the most distant object you can see. Trees don’t make great targets for this job as they tend to move in the wind and moving targets are the worse kind for finder telescope alignment. Now take the time to point and centre the object in the main telescope, this is the hardest bit. Once done, adjust the alignment screws on the finder scope to bring the same object to the centre of its view and you’re done. The finder telescope is aligned to the main telescope. Now if you want to find something in the sky, centre it in the finder telescope and it will be in the centre of the main telescope.

The principle is much the same with the red dot and laser finders although the procedure must be done at night. First align the telescope at a target object, then adjust the finder telescope to point at it.

Its worth taking time over doing this as time spent getting the alignment correct will make finding things a whole lot easier. Its also worth noting that you will have to keep checking the alignment, particularly if you move the telescope around a lot.

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