A little history for those interested on the D&G.

In the early 90's Barry Greiner of D&G and his partner at the time decided to take a stab at the APO market and the end result was the APO 130. It was an ED doublet that operated at f9. Unfortunately there was a problem with some of the glass and only around 10 were ever made. That was a shame as it was an excellent performer. Maybe not as great for photographic use, but I'm not certain as I never tried to use it to take pictures. But on nights of steady seeing it made me a true believer in what a good refractor is capable of.
I was really sorry to see it go, but to make the A/P deal a reality ...well you know the story.

Hope this helps.