5MM LUNT XWA - 110°

5mm Lunt HDC XWA - 110° - REVIEW

After submitting my review on the APM 100 degree eyepieces, I forgot to include this eyepiece in the review. I did not have a full set at the time, but before I had bought the 20mm, 13mm, 9mm and 7mm APM 100's, I bought this eyepiece and I eventually sold it. So, here is my brief review of the 5mm Lunt HDC XWA 110° eyepiece. (It is actually a 4.77mm FL eyepiece). Comments here were taken from audio reports from Sept to October / 2021.

First Impression in Semi-Dark Skies

After letting my telescope cool down for at least two hours, I put the 5mm into the focuser and I checked out a few things and made audio reports on the eye relief, eye positioning, and a general "feel" to this eyepiece. It has a bit of a steep learning curve to it. This is mainly because the supplied rubber eye cup is too long when folded out. You can't really see the entire 110 degrees when it is folded out. You have to fold down the rubber eye cup in order to see the full 100 degrees, but then eye placement becomes somewhat of a chore and is more critical. A shorter rubber eye cup would be so much better, IMO. After a bit of time, I just left it folded in the down position and I cupped my eye with both hands to hold the exit pupil.

Second Impression - Same Skies - Different Night

The AFOV, (apparent field of view), is MASSIVE to say the least. This is a strong point of this eyepiece. You can frame things at high power and still have some room to spare. I compared it to a barlowed 9mm Baader Morpheus, (245x). The 5mm gave me 240x, so I felt that was close enough for a quick comparison. Both showed the same amount of detail on some globular clusters, and planetary nebulae and more. I observed M-92, M-15, M-13, M-2, NGC-7331, Epsilon Lyrae, M-57, NGC-6826, Albiero, M-76, M-11, then Saturn and Jupiter. It served well as a planetary eyepiece too. The only downside to this eyepiece, as well as the 13mm, 9mm and 7mm APM's was the short eye relief if you need to wear glasses. The other downside, that I found, was that taking in the full 110 degrees was hard to do. I had to tilt my head sideways every time. I did not have to do that when I used the 100 degree APM's. I also saw another strange phenomenon. Every time I viewed into this eyepiece, I always saw my eyelashes in my peripheral vision. I found it really distracting.
A positive thing I will note is that when viewing into this eyepiece, stray light was not leaking into the sides like longer eye relief eyepieces tend to do. I just cup my hands around the eyepiece when that happens, and I normally do this anyways for a darker outside background. I also use a hoodie whan I observe to keep the perspective as dark as possible because I do not view in super dark skies.
I was able to compare this to the 4.7mm Ethos that a friend of mine owned. I actually found the eye placement on the 5mm Lunt XWA a bit easier IIRC. Eye relief on the Ethos definitely felt shorter as well. It was brief, so I cannot comment on what we both compared it on.

Final Thoughts

These are pretty impressive for light transmission considering the amount of glass involved, but after trying this one out over the course of about two months or so, I found that the eye placement was still tricky and finicky. Just not my cup of tea I guess. Some really like 110 degrees AFOV, which is a personal preference and in no way makes this a "bad" eyepiece. YMMV, so they say...I just think that a shorter rubber eye cup would have been ideal for this to hold the exit pupil better. The other negative for me was the sheer L E N G T H of this eyepiece, which is really long. If you don't mind about 6.5 inches of eyepiece protruding out from your focuer, then you'll be ok, lol.
Overall, smaller deep sky objects like smaller planetary nebulae are perfect for this EP. Double stars are also ok, but simple glass would be far better because of less "scattering" from so many lenses. (This one has 9 lenses in 6 groups). Planets were also ok, but other eyepieces with less glass would be better for the same reasons I just mentioned.

Well, that's my story, and I am sticking to it, LOL. Please feel free to add any comments you like to this brief review.

Cheers and Clear Skies to All !!! (Merry Christmas to All as well).

-Mark