My first DSI: M8 & M20

Last week the sky was exceptionally clear. I’ve been waited for clear skies for more than a half year. This was the first time I did DSI. This image was jointly taken with my friend. In fact he did most of the setting and the APM 80/600 and the 5DII were owned by him. The seeing was so so that night and the clouds were just running around and made us lost guiding star several times! We only shot one M8 & M20 before the moonrise. Although we have taken a few M8 & M20, I don’t know how to use DSS. I just use the PS to tune the Level & Curve. Here is the photographic detail:

APM-TMB 80/600
TS flattener (Zero Power)
350mm guide scope (A modified 9x50 finder scope)
ISO 1600
Single frame (180s)
No flat field and no dark frame
100% crop and 25% resize


  1. Nice. How do you like the APM 80/600? How is the color correction?

  2. The color correction of APM 80/600 is the best corrected telescope I have ever seen. Most APO or ED telescopes show no color fringe at the focus. But they show purple fringe in front of the focus & green fringe behind the focus. However APM 80/600 shows no hint of color fringe in both sides of the focus & at the focus.

  3. Hi Willis. Beautiful shot - hard to believe it is a first attempt! Do you use a modified 5DII? Have you run any more tests of the Borg 7887 focal reducer? Cheers, Peter.

  4. Sorry! overlook ur post! Yes! It is a modified 5DII. I tested the 7887 on APM 80/600. It works well even in full-film DSLR. I found that the APM 80/600 works well with SW 0.85x, Borg 7887 & TS 2.

  5. Hi Willis!
    Sorry for late question.
    I have LOMO 80/480 and finding reducer/flattener.
    How about APM 80/480 with Borg 7887 ?