Andrew's Binoviwewer.

[vespine]

Does anyone own one of these and have an opinion? I have the 12" lightbridge and was NOT considering a bino viewer, mainly only because of the cost. But seeing this!:

Binoviewer, Andrews - Scoop purchase!$269.00

http://www.andrewscom.com.au/site-section-10.htm

I would consider it, I'd probably only be able to use the generic plossls for now too. Has anyone bought one of these? What do people think? Seems like a decent deal if they are half good. Obviously people are going to say that the binoviewers that are 2x - 4x the price are better but are these usable with generic plossls or are they a waste of time?

[ving]

i have heard some good things about them... but as you say, ppl will prolly tell you to save up for a $10,000 pair :)

how bout you try them and do a review for here?

[janoskiss]

Unlike some of the other budget units around the Andrews ones are not fully multi-coated. This is important IMO for maintaining good contrast. I would get the William Optics package instead from Frontier Optics (www.frontieroptics.com). Does not cost much more but you get a better binoviewer, a pair of eyepieces, and a 1.6x corrector. But unless you can lower the secondary cage, you will most likely need another corrector lens or an extension piece between the WO 1.6x and the binoviewer in order to reach focus in the 12" Dob. A long barrel 2x barlow would work also (my 2" 2x works) but the magnification will be very high.

[astroboy]

I agree , I've compared the WO's with my TV's and found it hard to see a difference on Jupiter with the 12" SCT.
Only ever looked through the Andrews once and didn't like them.
The WO's are a great buy:thumbsup:

Zane

[janoskiss]

Do you mean the new Andrews one, or the Saxon one which Andrews had for a while now?

[astroboy]

Err sorry didn't know there was a new version:doh: this was about 12 months ago .

Zane

[g__day]

I got the Andrews one a few weeks ago. like em alot on a 5" MAK (so focusing ing is no issue.) I want another Vixen LV-W 22mm to really test them out; stay tuned!

[janoskiss]

This binoviewer won't have enough clear aperture to fully illuminate the full field of a 22mm LVW. 25mm plossls are probably the widest you can go without noticeable vignetting.

[g__day]

The Andrews binoviewers say they are multi-coated BAK4 prisms (pg 35, Australian Sky & Telescope May 2006)

Janokiss,

Thanks for telling me first! How much "clear aperature" (?) do you need to fully illuminate the full field of a 22mm LVW? Could you please explain this in laymans terms a bit more fully for me. How much field of view will you lose from the 65 degree FOV?

[janoskiss]

try with the one eyepiece you have already. during the day is best, to pick up any darkening around the edges. amongst the lower cost units, the yet-to-be-released BV24 binoviewers from Burgess should be able to handle the FOV of the 22mm lvw. clear aperture = size of aperture (cross section) of the unobstructed light path through the binoviewer.

[g__day]

Tried it yesterday, and for the life of me couldn't see any darkening at the edges or anywhere comming from the centre to the circumference (during the day). Will do a night time test shortly.

I am kinda surprised at what binoviewers that cost less than $300 can do.

[Argonavis]

The ad said "multicoated", not "fully multicoated". The difference between expensive and cheap binoviewers is the extent of coating (if I look into my Zeiss binoviewers during daylight, I don't see a thing - all that glass just disappears from the excellent coatings) and the other factor that determines cost is the size of the field lens. The field lens is at the opposite end of the binoviewer to the oculars and if you use any oculars with field lenses bigger than it it will vignette. My Zeiss has a field lens of 28 mm so if I use eyepieces with more than a 28mm field stop I will lose some of the field of view to vignetting. This can all be measured with a ruler.

[janoskiss]

Sounds like they might be alright then. But such expensive EPs for such cheap binoviewers... :shrug: Unless you are thinking of upgrading later on. ;)