Omni XLT max mag eye piece

cmblude · Guest

I recently purchased a Omni 102mm XLT telescope. The eye piece it came with works well, but I'm looking for an eye piece that will allow me to use the maximum magnification on this bad boy.

I've played with the numbers and for some reason nothing adds up to the 240X mark. Am I using the wrong formula? (focal length / eyepiece length). The closest one I came up with was to 250x that's with a 4mm eye piece. I've even try to throw in a Barlow 2x and the closes is 222x (9mm eyepiece).

I guess my question is; Is the 250x usable for astrophotography and deep space observation or should I stick with the 222x to be safe and not go over the recommend magnification?

Thanks
cmblude

Jne_K · Site Admin Joined: 24 Sep 2003 Posts: 4991

Hi

You're on the wrong track. You would use those magnifications for the moon and planets. For deep-sky, you will want lower and, sometimes, much lower magnifications. Deep-sky is about seeing faint objects and that means less magnification, not more, since image brightness decreases rapidly as magnification increases. This is especially true in a relatively small scope such as a 4" refractor. Keep the magnification down if you want to see more. For eyepieces, you should be thinking in terms to cover a low, medium and high range with 200x being plenty for high. Fact is, you'll be using the low and medium more often for deep-sky. Get two eyepieces and a barlow or three eyepieces without a barlow to cover all your bases.

Even for planets, 200x in that scope is pushing it, as much due to atmospheric conditions as the scope, itself. It's going to take an excellent night to use more than 200x in most locations and, to be honest, the XLT mount is not going to handle those kinds of magnifications, well.

Same applies for astrophotography and this assumes you have added a motor drive. (Astrophotography is not going to happen without a motor drive.) As magnification goes up, tracking errors become far more critical. Keep the magnification down if you are a beginner astrophotgrapher. Using those kinds of magnification in astrophotography takes a ton of patience and experience to get it right.
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cmblude · Guest

Thanks for the informative reply Joanie Very Happy

Jne_K · Site Admin Joined: 24 Sep 2003 Posts: 4991

You are very welcome. Enjoy your Omni. It will do a nice job and is much better than what most folks start with.
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Fax: 847-919-3003