Eyepiece - extra long eyerelief - cheap

[pjifl]

Some people may be interested in a the super long eyerelief eyepiece I concocted for a shooter friend.

He wanted to be able to wear special prescription safety lenses and still
look through his spotting scope which is a small Pentax.

Anyway, I decided there was nothing to lose by trying the combination of a long FL Ploessl eyepiece + Barlow lens.

Cheap - total about $40 for a set which is 1/10 price of some high quality big name equivalents. And many of these really do not have enough relief for the job.

The compromise - there always is a compromise - is a narrower field. But this is not as bad as it seems because expensive wide field eyepieces lose field when used a distance from the eye. And the longer eyerelief is sometimes more important.

Tried the combinations of

http://www.ebay.com/itm/31-7mm-1-25-Ach ... 588729a41b

plus

http://www.ebay.com/itm/Orbinar-Plossl- ... 5893fd1b86

or

http://www.ebay.com/itm/Orbinar-Plossl- ... 5893fd15b9


The results are surprising good with oodles of eyerelief - even the 30 mm
eyepiece. In fact, perhaps too much relief with the 40mm one.

One thing to watch is that the eyepiece used in combination with the Barlow lens is a simple Ploessl. Not a Super Ploessl or some other such stupid name beloved by advertisers which is 5 element and small relief. Sometimes they are labeled wrongly on eBay, but I know the ones mentioned above are true simple very long eyerelief symmetrical eyepieces. Obviously, other brand equivalents would be as good.

In use, the Barlow lens is inserted in the telescope and the actual eyepiece is plugged into it. The end result is rather long but still usable.

Some spotting scopes have a focal plane which is too far forward for this to focus properly but it does work in many. For example, the small Pentax often used as a spotting scope will just focus with it.

Peter Smith.

[RDavies]

Thanks for the tips. My Pentax broke apart recently, but when I glue it together I would like to get something with more eye relief for it. I rarely shoot without shooting glasses, but these often get in the way of an eye piece, so a longer eye relief would be handy.