I have come to love lunar observation with my APM 100 ED BT. I normally observe with a 5mm ED Starguider eyepiece set. These are by no means premium eyepieces but I have been extremely satisfied with the views so far. While I understand 110x is not considered very high-detail observation, there is enough to be seen in Luna at this power to keep you busy.
However, last night sky was great and felt I could “squeeze” some more out of it. The 5mm are my shortest eyepieces so I decided to try some barlowing. I have two Orion “shorty” barlows that allow unthreading the lens cell from the Barlow body, which can in turn be threaded directly to the eyepiece giving you an estimated 1.5x mag. So if I’m not mistaken I must have been somewhere in the 150-165x neighborhood. Wow! Two things struck me: first that the binos held collimation at all. Collimation was just perfect. I did have to fiddle with the eyepiece a bit rotating it in order to merge images, but they merged perfectly. Secondly, how much detail is still preserved at this magnification. Resolution obviously suffers a bit, and floaters start to be a real nuisance for sure at this exit pupil, but if you relax and learn to look “through” them, the image was still very sharp and made for a very pleasant session. A lot of detail!
There was a little bit of color on the limb, but really not a lot. The Barlow lens configuration is, I presume, not perfect and I’m sure quality and ghosting would be greatly improved by using a dedicated eyepiece. Even though I rarely go over 40x for DSO and star sweeping, this has opened a door and I’m considering getting a shorter eyepiece just for lunar observation.
Would love to hear your experiences, how far have you pushed your BT. Any issues with collimation and where is your “comfort limit”? Any shorter eyepieces you use that work well with the BT100 and that you would recommend, again, just for the purpose of lunar (and I might have to give it a try for planeatary) observation?
Edited by ERHAD, 12 October 2019 - 05:03 AM.