Image of the day

Captured by
Evan Miller

Veil Nebula NGC6992

My Account

New to Astromart?

Register an account...

Need Help?

40mm Pentax XW - My Review

Posted by Mark Gemmell   12/07/2022 09:49PM

40mm Pentax XW - My Review

40mm Pentax XW - A MINI REVIEW 

I borrowed this eyepiece from a good friend of mine, (Thanks John G !), October/20/2022 and have had it for a few months now. I've tried it a few times in darker skies. It gives me 30x magnification and an exit pupil of 8.5mm, which is too big for my particular telescope. However, it frames M-45 really nicely, with room to spare. I also checked out IC-4665 in Ophiuchus, and it also fits nicely with room to spare. Other open clusters were also really good in this eyepiece. The 30mm Pentax XW would be a much better fit for my telescope at 40x, having an exit pupil of 6.35mm. The 40mm would be more of a "novelty" eyepiece for the two objects I mentioned, and maybe a few more. It would also make for a really nice "sky sweeper", when searching for objects, but the 30mm is the one I want.


1.5 Lbs on my scale I have here, which is not too bad considering the sheer size of it. It looks heavier, but it is 1.5 Lbs / 24 Oz. No balance problems on my 10" dob from this one.


Very easy to handle in colder weather. The top screws off if you want to get in a bit closer, but I find that isn't needed even when wearing glasses. The top half has a nice texture to it.

Correction in my Fast Scope:

Edge correction in my telescope, (no coma corrector), is excellent from what I can see. No field curvature and maybe just a "touch" of astigmatism near the edges from my old eyes, lol. Stars appeared very round and pinpoint. The central area sharp as a tack, which is well known with Pentax XW's. I have also owned the 5mm, 7mm, 10mm, 14mm and 20mm versions, with the 7mm and the 10mm being my favourites.

Star Colors:

Star colors appear very true to form with this eyepiece. The others I had were also good in this regard. A bit of a "cooler" tone, as compared with other brands, but still good.

Closing Thoughts:

If your exit pupil is smaller than what I was getting, this eyepiece is a real winner! I can highly recommend it from what I have seen with it. It just doesn't get any better than this one, if it fits your needs.

Thanks for reading, and keep looking onwards and upwards! And a BIG THANK YOU to John G for letting me borrow it, YOU ROCK !!!