Unfortunately the Meade Series 5000 version of this Tele-extender is no longer available new, but does pop up on the s/h market.
https://www.bhphotovideo.com/c/produ...tender_3x.html
The ES x3 is readily available from many sources.
https://agenaastro.com/explore-scien...-fe03-125.html
Both these Units are tele-extenders, in effect giving telecentric operation (field rays leave parallel to optical axis, unlike Barlow lenses which diverge rays)
This means basically the magnification doesn't vary (much) with rear spacing (to camera or eyepiece). They should be compared to the TV Powermate rather than a "standard" Barlow lens.
http://www.televue.com/engine/TV3b_p...=_app#MagChart
It has been said on other forums that the Meade Series 5000 x3 and the ES x3 are very similar..... Is this true??
I now have one of each of these tele-extenders and decided to do a comparison.
Verdict: They are identical and were made in the same factory in China, the only difference besides the decal is the choice of the locking screw!!
They are physically identical, same size, same shape, same finish.
Optically, testing with a couple of scopes, looking over the Bay towards Frankston they gave identical performance.
Any questions let me know.
ken
