I bought my first Celestron Luminos eyepiece around four years ago. Primarily for a high magnification in a small Maksutov. The thinking was that 82° of FOV would allow me more time to track a planet or the Moon before compensating for right ascension with the slow motion control. This wasn’t a bad plan and more or less worked with my 10mm Luminos. That is until one day I discovered a large piece of visible debris in the field of view. At the time I didn’t realise that the Luminos has a detachable negative Smyth lens in its drawtube. The entire drawtube can be unthreaded revealing the large field lens to facilitate cleaning. I managed to clean the 10mm. Later I acquired 15mm and 19mm Luminos EP’s. The 19mm has a 2” barrel and is a veritable ‘hand grenade’ weighing in at nearly half a kilo (490 g). The field stop is an equally large and impressive 30mm.



The Luminos series (formerly known as Axiom) generally have a bad reputation for astigmatism and often some mysterious and inexplicable edge of field brightness. The aberrations are supposedly particularly prevalent in fast astrograph Newtonians, where they also have a tendency to produce glare. A couple of nights ago I gave my rarely used 19mm a bit of a session in an f/5.8, 72ED Evostar. It is one of two 19mm eyepieces I own (OK, three if you include the second Panoptic that makes a bino pair). I wondered just how bad it could possibly be compared to the 1.25” 19mm TeleVue Panoptic. The Luminos gives about 22x for 3° 42’ TFOV and a 3.2mm exit pupil in the Evostar. The 68° Panoptic produces about 3° of TFOV and has a 21.3mm field stop. The 19mm Panoptic is one of my favourite eyepieces of all time and gets a lot of use. Ergonomically the Panoptic has the overall feel of a much larger eyepiece and I can't fault its performance.



I don’t doubt the Panoptic has better quality glass but the 19mm Luminos accounted for itself pretty admirably. The field stop is nearly a centimetre (9mm) wider and the fourteen extra arc degrees of field are definitely noticeable. The 490 g weight was not really a problem as the ED72 is nicely balanced on the AZ5 mount and tripod combination. I had no sensation of the strange EOFB that apparently mysteriously disappears when you try to look at it directly. Off-axis is pretty good and the seagulls were only making an appearance right at the edge of field. They were there, but 82° combined with a three centimetre field stop sort of compensated for it. I probably got the best view of the Andromeda Galaxy with it that night in a shootout between the Luminos, Panoptic, and a 36mm Baader Hyperion Aspheric. Luminos eyepieces can start long debates on some forums, I know they don't work well in fast Newtonians. But in my experience they seem to do pretty well in fast short tube refractors. I never expected it to be a Nagler (or Panoptic for that matter) and there are a few things that bug me about it. For some reason the Luminos draw tube barrel doesn't secure well in most click lock adapters and relies on the tightening of the click lock safety screw. I'm not over impressed with the mechanical roll up eyeguard either which seems designed for its aesthetic rather than as a practical application. Of course, the real difference is that the nearest equivalent Nagler, which I believe would be a a 17mm Type 4, is £349 (Sterling) and 726 g while the lighter 19mm Luminos is £140 with a bigger field stop.


So, what is your experience of the Luminos, lemon or luxury?