[astro744]

Note the Tele Vue 32mm Widefield eyepiece is an early design that did suffer from mild astigmatism. Consider the Wide Field as a better corrected Erfle eyepiece. Consider the Panoptic as a better corrected Wide Field eyepiece with the residual astigmatism of the Wide Field series removed. Tele Vue took the Wide Field eyepiece series to Nagler like performance levels in their Panoptic series of eyepieces. You can use the Panoptic and Nagler as a baseline to test your telescope for aberrations down to f4 as Tele Vue designed in these large apparent field offerings. I would not be so confident in testing with a ‘clone’ and in your case the Wide Field although a much improved design over anything else offered at the time (I think around 1982), is not as well corrected as the Panoptic and Nagler series with the Nagler with its wider field being an excellent test eyepiece.

Note also that you are observing with a larger exit pupil with the 32mm and if the sky is dark your eye will open up and any edge defects in your eye will me more pronounced. I think you are correct in thinking that this is an eyepiece and perhaps eye combination problem rather than a primary mirror issue. If there were astigmatism in the mirror then what you would see is stars that are elongated across the field and this elongation would shift 90 deg when going in or out if focus. At best focus stars would be square.

There could be field curvature but this would not cause distortion only a focus shift between centre of field and out field. I detest field curvature in cheap wide apparent field ‘clone attempt’ eyepieces. What is the point of a wide field if the outer portion is out of focus. It’s useless as a finder eyepiece since any faint fuzzy DSO at the edge of field will most likely be invisible. It was a cheap 80 deg ‘clone’ that got me onto Tele Vue and I have never looked back.

To test if your eye is causing an issue look through the eyepiece and note any aberration. Then turn your head 90 deg, not the eyepiece or the telescope and see if the aberration rotates. If it does it is your eye. Note though it will be most people’s eye especially at a wide exit pupil so try this at different magnifications. Pick a target full of stars such as a large open cluster in Carina. This way you can observe from centre to edge from lower to higher powers, (preferably tracked so the object doesn’t move).

What is the longest focal length ES eyepiece you have? Of the ‘clones’ the ES are well regarded by many and you may find the 82 deg ES perhaps better corrected as the Wide Field but unless it is of long focal length probably not a good comparison with the 32mm because of exit pupil differences.

I have a couple of ES 82 but only in the very short focal length and I bought them used to compare against the Tele Vue (curiosity) and because eyepiece reviews online are often given by people who have never used the eyepiece they are praising or not praising as the case may be nor stating which telescope they used the eyepiece in. (For the record it was not an ES clone that got me onto Tele Vue but a cheap 30mm/80 deg offering that is sold under many names).

I would like to add that for the record I have not looked through a 32mm Wide Field but have looked through a 24mm Wide Field quite a few times but that too was in the late 1980s, (6” f5.5 and 14” f5 Newt). I just remember the views were WOW and if there was any astigmatism I cannot remember seeing it and certainly not like in my 32mm Celestron 2” Erfle. Information I have stated on the mild astigmatism of the Wide Field and correction in later series, I remember reading on the Tele Vue web site a few years ago. Note the Tele Vue Wide Field was a considerable improvement over other offerings at the time and still regarded as a fine eyepiece amongst today’s offerings on the market.