A little story:
I like ST-80s, they're simple, inexpensive and versatile and I think they make good beginners scopes, they're about one half binocular and one half telescope. They're not very good planetary-double star scopes but they're passable and show the moon reasonably well. I buy them used and give them away..
The best one I've ever had is an older Celestron version that came on an EQ mount. I've owned a couple of them but this one was different, it has a metal objective cell that threads to the tube and a metal dew shield. I fitted it with a 2 inch focuser and my recollection is that I was able to split delta Cygni with it. I had loaned it out about a year ago and I just received it back in the mail on Monday. In light of this thread, I was eager to see if I could split delta Cygni...
I probably spent about an hour swapping eyepieces, seeing if I could eek out the split. I went as high as 230 x and there were times when I thought I might be seeing something but I never made the split.
Over to the double-double, I could split the one but not the other. Frustrated, I went inside and got my WO 80mm F/7 FD and pointed it at delta Cygni.. No split. No Cassini division. This was very unusual, these are normally easy. I went inside and got the 120mm F/7.5 ED, it normally provides clean, crisp views and has an easy time of delta Cygni.. No split, barely see the Cassini.
Bad seeing. Delta Cygni in the ST-80 will have to wait.