Alstar Stereo Binocular Viewer for Telescopes - Stereoscopic Viewer Offers a Immersive, Almost 3D Viewing Experience, Featuring an Adapted 1.25" Barrel and Two 32mm Plossl Eyepieces

I purchased this in January so I have not had a chance to use it on the moon due to the moon positioning and weather but I have used it during the daytime and it works great. No problem merging views. I did a lot of research before choosing this one. I wanted to make sure it was available through Amazon Prime and there are not a lot of choices for Amazon Prime. The one from William Optics was highly recommended but it was almost $100 more and not Amazon Prime. Orion was on sale but not Amazon Prime. I basically had to choose between Alstar, Astromania or Celestron if I wanted the Amazon Prime feature. Celestron and Orion use screws while the rest use self centering compression rings. I prefer to use the self centering compression rings to avoid merging issues. All three (Alstar, Astromania and Celestron) would cost basically the same price of $187. I think the one sold by Alstar and Astromania are the same as the Arcturus Binoviewer that I read many reviews on the cloudynights website. Just type cloudynights Arcturus Binoviewer in your search engine and you can read many reviews on this. I chose Alstar over Astromania because Alstar included the eyepieces and Astromania did not. Astromania does sell it with included eyepieces but it was not available through Amazon Prime. So, it basically came down to a decision between Celestron and Alstar. It was a tough choice because Celestron is a well known name but I took my chances on Alstar because I wanted the self centering compression rings for the eyepieces to avoid merging view problems.I am happy with my decision. I REALLY LIKE THE INCLUDED EYEPIECES and I have no problems merging views. The package does include a 1.85 and 3x barlow but I really don't see much of a difference between the two. It looks to me more like 1.85 and a 2x barlow. I will probably not use either and use my Celestron 2x barlow and Astromania 3x barlow which both can either be unscrewed to use the lens or just put the whole thing in the diagonal. I will probably just do the latter because it is much easier.I read many reviews on Cloudynights website about the Arcturus binoviewer having problems with undercuts on eyepieces (the indention on some eyepieces). I found that to be true. Your eyepieces will be loose but there is an easy fix, which I found no mention of on the Cloudynights website. Just buy some parfocal rings and slide them all the way up as high up on the nose of the eyepiece as you can and that will solve the problem. Works great for any eyepieces with undercuts.