Hi Kirkus
Your 10" is maybe 1250mm focal length? The magnification with a 12.5mm eyepiece is 1250/12.5 = 100 times.
Keep looking for a couple of faint stars ("E" and "F") along with the four bright stars in the Trapezium (stars "A", "B", "C" and "D") - you'll see them when seeing is better. It's satisfying to see them. A bit of research on the internet will show you what to look for.
Eric
