I know that my Field of View is 80 minutes. (52 degree Ploessel 17 mm with F=660 mm; so 52 / 38.84 = 80 minutes arc)
I used the
Burnham's (page 1274) shows Sigma at
So, the math seems to work out. I drew this. Sigma Orionis group is at the bottom.
17 March 2021
I went back on the 17th because just scanning the Belt area earlier, I sketched this. 17mm with 2X Barlow.