I have always been curious about binoviewers. Inspired by a
recent thread about "project refractors" where lady Frac was looking take a hacksaw to the focuser to make her binoviewers work without the Barlow, I decided to get a pair myself and see what this is all about.
The
WO package is great for starters, it comes with two 20 mm eyepieces and a 1.6x Barlow. My favorite shop Agena Astro did not disappoint and delivered the product with free shipping within a few days. I pulled my collapsible-converted Z12 out and, after collimating and aligning the
Telrad with the 30 mm 2"
GSO superview, my favorite eyepiece, I eventually found Polaris. I find Polaris all the time for
AP but I set up in a slightly different place and it was nearly blocked by a tree so I mistook some other star for Polaris.
My struts (three of them) have 2 sets of holes. The lower one is for standard viewing. I drilled it to make that possible. The upper holes are about 10 cm away. I added those for
AP since I still have that dual axis autoguided
EQ platform that I finished but never fully tested (because I won that 127 mm
ES Apo in a door prize lottery and moved to a motorized mount - long ago). I figured, I might be able to use those holes for the binoviewers without Barlow.
Indeed, I was able to reach focus with the standard viewing holes with the Barlow included, and with the
AP holes with the Barlow removed. Of course, switching between the two settings is not smooth because I drilled the holes manually so they point in slightly different directions. Not much but if you want to do it right you have to recollimate and recalibrate the viewfinder and/or Barlow (both in my case).
The stars were a bit fuzzy but that is partly because the magnification is higher. I am used to the 30 mm superview that delivers very nice crisp views of the stars. The magnification by a 20 mm is quite a bit higher. I tried it on Polaris, Spica and Mizar. I know the Polaris region very well because I use an
asterism for eyeballing the
NCP to about 1' accuracy. It was quite a bit larger than I was used to with the 30 mm. But, the
asterism was very clear.
One thing with Mizar was a bit odd. I always thought Mizar was a double star with Alcor that can be seen naked eye. I had seen it with 20x80 Skymasters, the Z12 and with
AP as well. With the binoviewers I noticed something odd, namely Mizar itself looked like a double star. I was wondering if that was an optical effect so I went inside and checked Stellarium and various
AP images but nothing showed the second star. Then I went to
Wikipedia and lo and behold, it is a double star!
So, these binoviewers are working great especially if you have a telescope with struts that have different settings so you can use it without the 1.6x Barlow. Maybe this will convince lady Frac to buy a light bucket with some struts so she doesn't have to cut up her fracs. Ok, I said it - time to duck for cover.
... Henk.
Telescopes: GSO 12" Astrograph, "Comet Hunter" MN152, ES ED127CF, ES ED80, WO Redcat51, Z12, AT6RC, Celestron Skymaster 20x80,
Mounts and tripod: Losmandy G11S with OnStep, AVX, Tiltall,
Cameras: ASI2600MC, ASI2600MM, ASI120 mini, Fuji X-a1, Canon XSi, T6, ELPH 100HS,
DIY: OnStep controller, Pi4b/power rig, Afocal adapter, Foldable Dob base, Az/Alt Dob setting circles,
Accessories: ZWO 36 mm filter wheel, TV Paracorr 2, Baader MPCC Mk III, ES FF, SSAG, QHY OAG-M, EAF electronic focuser, Plossls, Barlows, Telrad, Laser collimators (Seben LK1, Z12, Howie Glatter), Cheshire, 2 Orion RACIs 8x50,
Software: KStars-Ekos, DSS, PHD2, Nebulosity, Photo Gallery, Gimp, CHDK,
Computers:Pi4b, 2x running KStars/Ekos, Toshiba Satellite 17",
Website:Henk's astro images