What lenses should I get for my telescope?
Friday, November 26th, 2010 at
9:15 pm
I have a Galileo FS-135DX Reflector and I want some new lenses. I have two lenses, galileo astroscopic 25mm and then a zoom lense that says F6.8mm and F16mm. This is like jiberish to me but i've been able to just put the lenses on the telescope and see the moon really close. I can see the craters and the beautiful surface. But i'd like to be able to see much more. If theres any other lenses anyone could suggest, I'd love to hear about them!
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US $.01
If you want to see the moon closer, you need a better telescope. Lenses are just for viewing angle (wide, narrow, etc). Mainly just changes focus. The one (telescope) you have is just a general view of the sky. You need a refractor type telescope to see closer, along with some good lenses.
1. These are called “eyepieces” not “lenses.”
2. You calculate the magnification of any eyepiece by dividing the focal length of the telescope (1100 mm I believe) by the focal length of the eyepieces (25 mm = 44 power) and (16 mm to 6.8 mm = 69 power to 162 power). This is pretty much the maximum magnification you can get from this size of telescope without the image getting hopelessly fuzzy.
3. These two eyepieces cover just about all the magnifications you need for observing most objects: the Moon, the planets, double stars, star clusters, nebulae, and galaxies.Learn how to use the eyepieces you have before adding more.
4. If you don’t know how to find interesting objects to look at, I’d recommend “NightWatch” by Terence Dickinson (Firefly).
What you have is actually a good set. 25mm is a standard eyepiece in everyone’s collection. The zoom eyepiece probably isn’t the best quality optics (unless you paid several hundred $$ for it), but it covers the range of eyepieces that you should otherwise have.
For example: I have: 25 mm, 15 mm, 9 mm, 6 mm. I also have a 32 mm wide angle that I use alot.
The only thing I would suggest (and possibly make some other astronomer types, here, cringe) is to buy a good Barlow 2X magnifier. Like Geoff says, with a Barlow and maximum zoom the image will probably be too fuzzy, but you can zoom out until it gets clear — and that’s as good as it gets with your ’scope.