Speers-Waler 5-8mm Zoom

iceman (Mike) · #1 06-10-2005, 08:05 AM

Does anyone own one of these, or has anyone tried them?

They don't seem to be that common in Australia.

They're made by Antares, and i'm contemplating the 5-8 SW Zoom for my premium planetary eyepiece. The 5-8mm zoom would allow use in average and good seeing, and by all reports, they also barlow very well for use in very good seeing.

Some vital stats:

- 9 (!) element design
- 89-84 deg AFOV
- 12mm ER
- 1.25" barrel

They go for about US$239 or CDN$299 or approx AU$315, not including any shipping, customs or GST charges.

Some more info is on Phil Harrington's site if you scroll down.

They are big! (image from Phill Harrington's site)

Anyone used them?

They'd be a bit cheaper than a televue nagler or radian in the same focal length, and with the zoom you effectively have multiple eyepieces in one.

h0ughy (David) · #2 06-10-2005, 08:12 AM

gee mike you would need a few speaker magnets to balance that! Best of luck tracking one down.

ving (David) · #3 06-10-2005, 09:15 AM

not seen them before mike but I have been looking into the vixen zoom EP... havent seen any reviews tho.
the FOV on that SW is great tho hey

mickoking · #4 06-10-2005, 09:47 AM

9 elements, Me thinks thats too many.

asimov (John) · #5 06-10-2005, 06:48 PM

9 elements hey? Not to my liking I'm afraid..

iceman (Mike) · #6 06-10-2005, 06:50 PM

Why not? Please explain..

ving (David) · #7 06-10-2005, 07:07 PM

theres a review for the SW zoom on CN mike... go have a look

gtg, the sky becons!

asimov (John) · #8 06-10-2005, 07:41 PM

I don't know......Just what I was taught back in the old days: too many elements = less light transmission. But perhaps these days that 'theory' no longer holds true due to advances in optical design?

Starkler (Geoff) · #9 06-10-2005, 08:31 PM

The issue is that the more glass to air surfaces, the more opportunity for light scatter and ghosting. Coatings will have to be A-1 to prevent ghost images.

One issue I have heard mentioned about this eyepiece is that dirt can easily get inside the slot for the sliding barlow adjuster.

Read user reviews here

asimov (John) · #10 06-10-2005, 08:38 PM

Interesting......

iceman (Mike) · #11 07-10-2005, 06:10 AM

There's a review by well respected amateur David Knisley over on CN, here:

http://www.cloudynights.com/item.php...=331&pr=2x7x32

davidpretorius · #12 07-10-2005, 06:48 AM

that is a good recommendation, so mike, will you have the eyepiece at snake valley??

iceman (Mike) · #13 07-10-2005, 06:58 AM

Unlikely, unfortunately.