Going H-alpha: T-S binoviewer first review II.

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The next greater distance was much more difficult. I hung my inverted piece of printed paper from a tree along the drive at 80 yards. Now I was struggling to read the 3mm [1/8"] high bold text headings due to local thermal effects. The sun was bright but quite invisible behind the thick cloud but still warmed the intervening, overgrown lawn and the air above it. There was a ripple to the edges of everything including my printed piece of white paper.

The cantilevered binoviewer really needs a diagonal brace to support it on top of the PST filter stack and eyepiece holder. But where to fix such a brace?

I could easily see the text, but was unable to read it until I inserted a very odd pair of no-name 20mm eyepieces. One presumed Plossl and a plastic one one marked R-K. Possibly from a Bresser Skylux 70mm refractor.

Now the bold text was legible but I could not read the 2mm high text and figures in normal weight of type. Though, I repeat, all the text was easily visible. A fly became interested in the paper and was easily seen at this distance as it flew around.

I had to work much harder now to get the images focused for each individual eye. Clarity was very much better using both eyes. There was also a much wider apparent field of view with these 20mm compared to the Meade 4000s. Which were rather like looking through a tunnel in comparison. 20mm gives 50x magnification and would make a great birding telescope on a pond. Though the long and rather heavy Vixen hardly lends itself to portability and needs a really sturdy stand. I have used a video tripod with this telescope to take handheld snaps of eclipses with a 20mm eyepiece.

Attempts to use an Orion Shorty-Plus 2x Barlow were disappointing. Dim and fuzzy was the best description even with the 32mm Plossls. Bright sunlight might have helped but all my targets were north facing under a resolutely, overcast sky.

The Orion's optical nose-piece would have shortened the distance and resulting magnification. But the thread size was much greater than the T-S binoviewer body with its own 1.25" nose-piece removed.

My 45° Baader erect image diagonal used up too much light path, in combination with the binoviewer, to allow its use. Which is a shame because it has a nice compression band eyepiece holder. Which provided a much better grip on the binoviewer's nose piece. It would require the telescope's main tube was physically shortened. Or a Barlow lens used to gain some path length.

I have a T-S 1.6x glass path correcter with Barlow in the post. Due to the distance to the eyepiece the resulting power will lie between 2.6x and 2.8x. So a 32mm EP will effectively become a 12mm. Whether the PST filter stack adds further power, due to path length, is still an unknown. More on this later.

The S-T GPC+Barlow duly arrived in the post. Another utterly wasted opportunity! Firstly, it is smaller in outside diameter than the 1.25" fitting. Had it been the same size it would have provided valuable support for times when the binoviewer cannot be pushed right into a fitting.

Secondly, the S-T binoviewer has an undersized body thread for the nose piece. Imagine if they had the imagination and daring to have fitted a standard filter thread in the body. Now anything and everything will fit the body.

The empty nose piece can be simply unscrewed and the GPC or Barlow[s] with 1.25" OD fitted directly to the body. Instead of which the daft GPC will not fit into a standard 1.25 star diagonal! How crazy is that! Nor will it fit into the blind end of the PST eyepiece holder! Now what?!!?

How utterly futile! They chose a non-standard, undersized thread for the body which cripples all the huge potential had it been a standard 1.25" filter thread. Argh!! Ooh, it does make you cross. Well me, anyway.

Click on any image for an enlargement.

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