THE TAL SUPER & ULTRA WIDE ANGLE EYEPIECES
Posted 27 October 2013 - 07:42 AM
By William Paolini
Posted 31 October 2013 - 10:49 AM
I have one of Tal's UWA eyepieces. The 2" 24mm. An early version, bought sometime before '04. Not 100% sure, but I think 2003 rings a bell?
Two points -
1/ I've no idea why early users reported poor build quality, as mine is perfect, with solid Russian build, engraved lettering and visually identical to the one shown in the review.
2/ I star tested mine last year and found out that the stated 80 degree AFOV was grossly under. I reckon mine to be in the 93-95 degree region.
Posted 01 November 2013 - 03:05 AM
I would be interested in knowing how they compare to the Televues, which are the "gold standard" here. Particularly the 25mm UWA piqued my interest, until I discovered it cost $400, or more than a 35 Panoptic.
Granted it is optically comparable to the Nagler (and not the Panoptic), and the 31 Nagler is over $600. but $400 is still a considerable amount to pay for an eyepiece, particularly one that is not considered one of the "class leaders."
Posted 01 November 2013 - 04:27 PM
Clarity, brightness, contrast, color range and fullness seem to be equivalent between both. In terms of magnification, the TV Delos 8 mm is closest to the TAL 10mm SWA and 10mm Plossl. Both of these TALs have smaller FOV. The Plossl FOV edge is perfectly sharp, my SWA sample is not - due to some vignetting in the outer 5%, the TV Delos 8mm has a sharp edge.
The TALs have much shorter eye relief than the Delos, but the TALs do not black out. The Televue blacks out easily, but is somewhat mitigated by careful extension of the eyepiece outer sheath and/or eyecup. Still, I have to devote considerable attention to eye and head placement with the Televue, and am finding out increasingly that it is not a comfortable piece to use. The TALs are comfortable.
Prior to obtaining the Televue, I recently acquired an Explore Scientific 82* 6.7mm. It blacked out uncontrollably, and had no choice but to return it to the vendor for a refund. It was unusable for me, particularly in daytime observations. I use the TALs exclusively during day, no black outs whatsoever. The Delos blacks out more during day, and cannot use it then - only at night.
Another observation gained through testing by viewing graph paper is that there is noticeably more rectilinear and angular distortion with the Delos than in any of my TALS. However, there is slightly more field curvature in the TALs than in the Delos.
Some time ago I field tested my TALs with someone else's Naglers, and we both came to the following identical conclusions:
1. Both sets had equivalent sharpness, clarity, contrast, color fullness and range.
2. The TALs had tighter eye relief.
3. The Naglers blacked out much more easily.
Hope this helps,