A Pair of Eyepieces

Hi all

I recently purchased a pair of second hand eyepieces, one from the US and the other from the UK, an Antares 25mm W70 and a Celestron 30mm Ultima.

I'll start with the Antares. This EP is a 1.25" barrel giving a magnification of 33X, I bought it more as a finder eyepiece following the sale of my Moonfish. I turned to Albireo and everything looked good, as I moved my eye towards the edge of the FOV from about 75% out the stars became soft, losing their shape, from 80% the situation deterioriated fast so that in the final 10% I was looking at boomerangs. As a wide field finder eyepiece this works fine with a 70 degree FOV it takes in a lot of sky, but if you like entire field of pinpoint stars, look elsewhere.

I saw the Ultima 30mm on Astrobuysell in the UK, I had a set of Ultimas many years ago, and stupidly sold them, so when I saw this I jumped. Keeping with Albireo everything looked sharp, unlike the Antares the Ultima kept the stars pinpoint until 10% from the edges where they became a little soft, though not too bad, but you had to look hard to see this, the Ultima gives excellent clear views, the stars are sharp across the the FOV and looking through this EP it makes me regret my previous sale even more. I highly recommend this eyepiece, if you can find one.

One thing of note about the Ultima, I wear spectacles, and I remove them for observing, lately I have been observing with Hyperions and the Moonfish, all giving wide fields of view, the Ultima is a Plossl with a 50 degree FOV, and I found with my glasses off I couldn't use it properly, my eye couldn't take the whole view in and I was getting blank spots. Putting my glasses on worked fine and the entire FOV was there. Anyone got an explanation for this.