Quote:
Originally Posted by Waxing_Gibbous
I diverge.
I find that they (XWs)positively demand correct eye position. I found them quite tiring and they gave me neck-ache.
I confess that I'm in the minority here and I am not really slagging them, as, when I did get them 'working', the views were outstanding.
Very high contrast and a nice flat field.
|
Hi Peter/Diver,
If you aren't used to using them and don't adjust the twist up eyecup correctly, they can be a little difficult to use. The long eye relief can make it difficult to hold the exit pupil. Once you get used to using them they are simplicity itself and very comfortable to use for long periods.
If you don't wear eye glasses the first thing to do is wind the eye cup right up to minimise the eye relief. You then need to learn to back off the eyepiece a little. Most people who haven't used them before just "mash" their eyeball hard up against the eye guard. The last thing you need to do is "learn to keep your head still" and not move it around like Noddy the Clown. You will get "blackouts" if you do.
I have 5 Pentax XW's (5,7,10,14 and 20) and an 8.5mm Pentax XF. The 14mm and 20mm need a paracorr (which I have) to deliver their best in a fast newtonian. The 5mm,7mm and 10mm XW's are outstanding in every respect and about as good as it gets IMO. The 8.5mm Pentax XF while cheaper than the XW's is also an excellent eyepiece.
And to prove I am not biased, I also have 9 Televue eyepieces and accessories. 31mm Nagler T5, 27mm Panoptic, 22mm Nagler T4, 17mm Nagler T4, 13mm ETHOS, 12mm Nagler T4, 8mm TV Radian, TV Paracorr, 2.5X TV Powermate, 1.8X TV Barlow.
At the 14mm and 20mm focal lengths if you don't have a paracorr their are better options IMO. At the shorter end of the scale, 5mm to 10mm and 8.5mm XF, they are exceptional eyepieces.
Cheers,
John B