Pentax 5mm XO Eyepiece


Pentax XO 5mm


I finally received my long awaited Pentax 5mm XO eyepiece with much anticipation and excitement! The strong seasonal trade winds that disturb steady seeing were forecasted to be absent and portended fair to good seeing for the evening. I started to cool my 16" Newtonian just as the sun went down before leaving for a dinner engagement with some friends. I got back home and to the observatory by 11pm with Mars high and near the meridian. The sky was perfectly transparent and the stars were twinkling lazily instead of excitedly as they usually do. It looked like a perfect night to welcome and test the XO.

I centered the N16 on the red planet with a Telrad, then viewed through a medium power 20mm TeleVue Plossl. The seeing was indeed quite steady so I plopped in my higher power Celestron 10mm Plossl. The views of Mars with this eyepiece are quite good. The north polar cap and Sytris Major could be easily discerned. Encouraged by the seeing, I then deployed my high power Celestron 5mm Orthoscopic. The view through this old eyepiece was familiar and trusty. Styris Major became larger and more defined. The north polar cap showed hints of definition. I then decided to finally try out the new 5mm XO. I noticed that it slid with nearly a perfect pneumatic fit into my focuser. Nice. The next thing I immediately noticed was that snapped in to focus. There was nothing vague or mushy about focusing. Excellent! Then what I beheld for the first time through that eyepiece literally made me hold my breath and nearly weep with joy. Mars appeared as I never in my long life had seen it. There were so many fine details that I got disoriented at first. What immediately grabbed my attention were the well defined serrations on the edge of Utopia. Never had I see these before. The polar cap was not just easily visible, but also exhibited a clear area where the ice is receding. Sytris Major was magnificent! The fangs of Mare Cimmerium stood out in easy contrast to the lighter hued plains of Elysium. Nodus Alcyonius was also easy and clear to see. I then realized that for the first time ever, my visual view of Mars was better and more detailed than any high resolution CCD image I had ever had the pleasure of viewing before. This, to me, is the Holy Grail of visual observation.