16mm Nagler Tpye 5

I have just received a 16mm Nagler Type 5. Which I thought would be wonderful. However, looking at the moon it gives off a very large and pronounced brown/yellow flare at the edge of the eyepiece, and a sharp blue flare above that. This does not happen with a 15mm Panoptic in the same scope (a 8 1/2 inch f7 newtonian with fine mirrors and perfect collimation). I notice that Todd Gross mentions that Televue admits to the blue flare (saying its a negative that they accept to avoid using another piece of glass). However, this is enormous chromatic aberation. Have others noticed the same problem, and what do you do about it please?

Well, I will tell you that the 31mm Nagler if used during the day for Terestrial viewing will give you a big Orange Ring around the image! Very unacceptable, however it was not designed for this use so I don't mind.
the 16mm T5 seems a bit much though, as you should be able to use it on any object at night without aberations that are distracting.
I can say that none of my Naglers have this aberation.
I would contact Al and ask about it, if he says this is normal I would tell him "Not for me it isn't" and I would return the EP for a refund. Most any distributor will allow a refund if you just recieved it unless they are not reputable. If you bought it used, then I don't know what to say except ask the man if he would consider refunding and a return of the EP.
This is my opinion. I do not pay large amounts of money for EPs unless they meet my expectations. I have returned a few because they did not meet them in the past.
Floyd

The first two are going to sound really stupid, but I mean them honestly.

1) Don't look at the moon with that eyepeice
2) I've found I tend to get used to things like that after a while, and they really don't bug me all that much in the long run - any chance of that happening for you?

If 1 or 2 are unacceptable,

3) Consider the 13mm t6 nagler or the 17mm t4 nagler.

FWIW, I've never bought the 16mm t5 because of the blue flare, and found both the 13mm t6 and 17mm t4 to be superb eyepieces. (You can also look for a 16mm type 2 if you prefer.)

Tom T.

Ed,

I can only agree with Floyd in calling Al or the vendor about this problem.

I have not had this problem with the one I own. In fact, this is the second one I have owned. It is typically the one I reach for when doing lunar and planetary observing with my NX11, as it gives about the best images when the atmosphere does not cooperate. When the atmosphere is cooperating I increase the mag and the 16T5 stays in the case. I also use this eyepiece in my FS-102. These are slower systems than your f/7, but I am not sure this should make that much difference.

Good luck,

Pernel

I've not seen this on my 16T5, but I've never used it on the moon either. It's mostly used for DSO work, but I have used it on planets, I have other ep's I prefer for planets, so I have not been particularly critical with the T5. For DSO work it is brilliant.
I might try it out tonight (on the moon) to see what happens.