By: Vlad Fedosov
01/10/2024

Intro:

A 1.25″ illuminated reticle eyepiece not enough for you? The Stellarvue 26mm Illuminated eyepiece has you covered! It’s a 2-inch, 70° field of view eyepiece with an optional illuminated reticle. The eyepiece has a five-element design and multi-coated optics for sharp, clear views. The reticle is adjustable in brightness and can be turned on or off as needed. The eyepiece also has a generous 20mm of eye relief. As kin from the same manufacturer, I also had the 7mm and 4mm 82° EUWA wide fields that I wanted to check out while evaluating the 26mm. So should we get this trio under the night sky and test it out?

Testing:

Before I get into the testing of the eyepiece I will be honest that I was a bit confused why someone would want a 2″ crosshair eyepiece??? But onto the testing and perhaps we will discover the purpose of this fairly unique offering. I did the testing of the eyepieces from my Mag 5 fairly dark sky backyard with about a half moon in the sky. The scope used was an excellent Stellarvue 70mm Triplet APO refractor on a Stellarvue M2 alt-az mount.

I first turned the 26mm eyepiece to the Moon with the illuminated reticle turned off. The view was nice. It was sharp in the center and the contrast was good. I wanted to start with the moon to determine if this eyepiece can double as a good wide-field eyepiece for general with the possibility of ignoring the reticle. There was no mistaking that the reticle was there, but in a way, it kind of gave the view a more scientific view(think the moon landing cameras) of the moon! I did not find it very distracting which was pretty reassuring. Eye relief was actually pretty nice on this one and I could use the eyepiece with the eyecup up(though still preferred it down after some use so my face did not hit it).

Switching over to the 7mm and 4mm EUWA’s I was greeted with a much higher power view and a somewhat wider FOV! The moon really filled the view of the wider FOV at a higher power. The image was overall pleasant and I had no major complaints besides that the eye relief was pretty tight. In my common fashion with put the eyecup down(eyepieces use a nice screw up/down eyecup) on both the eyepieces to be able to actually see the entire FOV all at the same time. These claim a 12mm eye relief from the manufacturer’s specs. It felt a bit tighter than that to me but I did not measure it. I will note that for me even with the eyecup all the way down I did touch my face on the eyecup because of how unnecessarily wide it is. Not a fan of this design.

Moving onto some deep sky objects I decided to take a look at some open star clusters considering that these objects should display well with the equipment I was running this night. I took a look at m45 and m37 with all three eyepieces. Starting with the 26mm I was greeted with a FOV that was wide enough to fit all of m45. Pleasant presentation and I enjoyed the view of this old friend for a short while. The reticles when turned off were really not visible too much but I would prefer them not to be there at all in all honesty, especially for DSO. Turned on I will say that they are one the most precise cross presentations I have ever seen in an eyepiece! So far so good. Turning the reticle off I did examin the view a bit more. Studying the area on the outer FOV I could see a fairly severe coma(where stars start to look more like comets) at the edge. From my estimate in the modestly fast f/7 little APO only about 50% of the FOV was sharp and after that, the star shape started to degrade more and more out toward the field stop of the eyepiece. Contrast and sharpness did seem fairly good. 

Moving onto m37 I decided to take a closer look with the 7mm and 4mm EUWA’s. Overall a nice presentation in the eyepieces of this amazing open star cluster. I did note coma starting at about 70% of the outer FOV but certainly significantly better than with the 26mm. Strangly contrast did seem worst in the EUWA’s. This night did have some haze in the sky, and maybe that is why the sky did not look quite as dark as I would expect but the 26mm did seem better in the contrast department.

Even though overall I enjoyed using the 26mm it was still a puzzle to me. For most applications in an illuminated reticle eyepiece, you actually benefit from higher powers. This is the realm of 1.25″ eyepieces that are 12mm or lower. I was actually so intrigued by why Stelervue felt that they needed to bring a 2″ crosshair eyepiece to market that I looked into it on their website. It turns out that this eyepiece pairs with their F060M3 and F090M3 straight-through finderscopes. In that application, it makes much more sense! With a finder having the wider FOV is generally quite desirable and this eyepiece would still double well for the traditional role of precise GOTO alignment aid.

Conclusion:

In conclusion, I will say that the 7mm and 4mm EUWA’s performed about how I would expect, but honestly did feel like my Explore Scientifics(which are supposed to be very similar and some claim produced by the same manufacturer in China) do perform better. The 26mm for me is a petty cool piece of glass, but I would really only recommend it if you had an application that needed a wide FOV with a crosshair such as the F060M3 and F090M3 straight trough finderscopes. For any other application where a crosshair is useful, you would really be better off with a higher power 1.25″ eyepiece.