Eyepiece help

[JackieW]

My husband bought a telescope at a garage sale, with no book, and we set it up and started looking around. Actually found some constellations and such, but the eye piece looked like you were looking through a spider web. So, he took it inside and ran water over it to clean it, left it on the counter overnight to dry (cause we didn't want to rub it with anything and scratch it) and now we can't see anything out of it.

So, to make a bad situation worse, we decided to take a closer look, and try to clean the lens. Two lenses fell out of the eye piece and now we don't know how to put it back together correctly. I thought I'd ask here first, before I took it to the local camera shop to have them fix it. If it was just a simple matter of placing the lens' back in the right order....

Dumb mistake, but hopefully you won't laugh at us too hard and give us a few suggestions. :doh:

[redshifter]

It sounds like the eyepeice may be damaged, not just dirty. After your mishap, you may have damaged the antireflection coatings (if the eyepeice had any to begin with).

What kind of telescope and eyepiece are we talking about here? You might check the lens/mirror (depending on what type of scope) to make sure those aren't damaged as well.

Eyepeices should really only be cleaned sparingly and with cloth/tissue and fluid designed for eyepieces/camera lenses, and shouldn't be disassembled -- yeah I know, too late now...

[JackieW]

It's a Tasco 11T-R 450x114mm. It was only $20, so it might not have been us that did it. :lol: The lens that is under question is the SR 4mm lens. Will we really use that one a lot? We used one of the other lens' to look at the moon that first night, and things were really clear and distinct.

What I really want is one of the telescopes that has the viewing software and the auto-track.

[redshifter]

Hmmm...yes, it's quite possible that scope was 'pre-damaged'. Tasco scopes aren't the greatest, but for $20, it's no biggie. The eyepieces that ship with the Tasco scopes are typically of very low quality, the SR and H designs aren't very good to be honest. What I'd recommend is first measuring the diameter of the focuser (where the eyepiece goes), it'll be either 1.25" or .965". Hopefully it's 1.25" as that is a standard size for eyepeices and you can easily get good quality eyepeices. If it's a .965" focuser, it's a little more problematic but decent eyepieces can be found for that size focuser. I'd recommend a low power eyepiece, say 20 mm or so, a higher power eyepiece, say 7 mm or so, and a barlow lens which doubles the power of an eyepiece, that will give you a decent range of magnifications. Look for eyepieces that are a plossl design, those usually are of reasonable quality, certainly a giant step forward from the Tasco eyepeices.

I'm assuming the 450 in the 450X114 nomenclature means that the scope in question has a 450mm focal length. That mean that the 20mm eyepiece will give you 22.5 power and 45 power with the barlow in place. The 7mm will give you roughly 65 power and 130 with the barlow.

Here's an example of decent quality eyepieces for that scope: http://www.telescope.com/shopping/product/detailmain.jsp?itemID=264&itemType=PRODUCT&iMainCat=6&iSubCat=36&iProductID=264

[JackieW]

RedShifter, you've been tremendous help! I don't feel so bad about the lens now. It sounds like we'll be using the other two lens' more often than the 4mm. This will get us started and experienced enough to warrent the more expensive scope. Do you have a suggestion for a good star book that a beginner can use? We'd like to be able to find, and recognize, more than just the moon! :lol:

[Dave Mitsky]

Jackie,

A few of the books that I heartily recommend for novices are NightWatch: A Practical Guide to Viewing the Universe by Terence Dickinson, Phil Harrington's Star Watch: The Amateur Astronomer's Guide to Finding, Observing, and Learning About over 125 Celestial Objects, Turn Left at Orion: A Hundred Night Sky Objects to See in a Small Telescope--and How to Find Them by Dan M. Davis and Guy Consolmagno, and A Field Guide to Stars and Planets (Peterson Field Guides) by Jay M. Pasachoff.

Sky & Telescope and Astronomy are the two major astronomy magazines in the United States.

You should also consider purchasing a planisphere (star wheel) and an introductory star atlas such as the Bright Star Atlas 2000.0 by Tirion and Skiff or Sky & Telescope's Pocket Star Atlas.

http://www.willbell.com/atlas/atlas1.htm

http://www.shopatsky.com/index.asp?PageAction=VIEWPROD&ProdID=1159

Free monthly star charts are available at http://www.skymaps.com/downloads.html

This site (http://freeware.intrastar.net/astronmy.htm) lists good astronomy freeware programs available for download.

Dave Mitsky

[redshifter]

Glad I could help! Dave give excellent recommendations for books, I can't add anything to that. It sounds like you're taking the approach of getting your feet wet with the Tasco, then when the time comes, upgrade to a better scope and/or eyepieces, which is a good approach to take. At some point, I'd suggest a visit to a star party which will give you exposure to many types of scopes and their pros and cons.

[Charlie in Dayton]

If you want to stock up on some inexpensive .965's, try here... (http://www.surplusshed.com/pages/category/eyepiecessets_1.html)
I've picked up some from them to round out a cheapo scope's selection, and they weren't too bad.