I know I'm late to this party, but I read about these stars with interest and last night finally had a chance to check them out with my 155mm refractor. The seeing was rough, and Struve 1400 was flickering. I looked for a while and saw nothing, then checked the stats with the Sky Safari app on my phone. After that I began to see the faint companion pretty consistently (I had been expecting a closer, more equal pair). I'm not sure it's as bright as mag 9.8. It looked fainter to me.
I also looked at 1398, but did not split that, though it seems to be a similar pair.
--- In email@example.com, Brian Skiff <bas@...> wrote:
> Both pairs near NGC 3077 are Struve doubles, and are similar
> enough in specs that measures of them have been mixed-up in the
> literature. The one to the west is Struve 1398 and the one north
> is Struve 1400. Both have recent observations in the WDS, and both
> are physical pairs. Indeed Struve 1400 has a third
> common-proper-motion companion located about 10' NW as well.
> The WDS lists the magnitudes, cribbed from Tycho-2, as 8.0 and 9.8
> for Struve 1400 (to the north), and 8.1 and 11.4 for Struve 1398.
> Current separation and position-angles are:
> Struve 1400: 3".2 in pa 226 (2011)
> Struve 1398: 3".6 in pa 106 (2006)
> Struve discovered the pairs with a 9-inch refractor, and Struve 1400
> was at only 1".8 separation back then (1832), so they can't be
> too hard to resolve visually. Struve 1398 definitely has larger
> delta-magnitude, and a good way to overcome that is simply to use
> higher power.