Celestron Ultima-LX 5mm / 8mm Review

By: Vlad Fedosov


Celestron’s original Ultima eyepieces are well regarded as good performers. The Celestron Ultima-LX promises the same great performance but with a 70° FOV. These eyepieces have both a 1.25” and 2” barrel design and are rather large and heavy in size. The eyepieces weigh in at about 1.25lb and have about 15mm of eye relief. I had the opportunity to try out the 5mm and 8mm of the line.


This review of the Ultima-LX is based on my time spent with them over several observing sessions(used in comparing to the Panoptic 19mm and in my Celestron 102GT reviews). Starting with the overall physical aspects of the eyepiece I will say that these are large eyepieces especially considering the lower focal length versions that I had. These are physically much larger than the TeleVue Panoptic and the Explore Scientific 68° eyepieces. They are not a bad looking eyepiece but the plastic used in the construction defiantly makes the eyepiece look somewhat cheap compared to the all-metal design of premium eyepieces.

Putting the eyepiece in the diagonal you will immediately find that you will need to re-balance your scope as these eyepieces weigh in at more than a pound. This can either be a good thing or not. As I found out in while testing the Celestron 102GT, you really cannot use the eyepiece with the Nexstar mount as you cannot balance it. I usually use Explore Scientific 100° eyepieces in the longer focal lengths so my normal scopes are already balanced fairly well when switching in one of these Ultimas.

Optically I found the Ultima-LX to be quite good. The eye relief for me was very comfortable considering the short focal length and the eye placement was very forgiving with these eyepieces. Comparing the performance to a Panoptic I noted that the Ultimas held their own quite well with perhaps a hair better edge correction but not as sharp of a view at the center. The differences were quite minimal and honestly, I think that I would never notice these differences in normal observing. I’m a fan!


I was pleasantly surprised by the Ultima-LX eyepieces. They are a good performer opticly and constructed well if you overlook the plastic. If you are willing to live with the weight of these guys I would seriously recommend considering them as they are an excellent value on the used market.