Scorpius's Double Double, And The GRS!

[cloudsweeper]

Two fine spectacles!

21.46pm Monday, lightish sky, transparency not great, ED80 on GoTo.  Jupiter low in the south, with Io very close to the disc.  Mag was low since the view was unstable around x80, and I did not detect Io's shadow across Jove's face.  A little later however, I was delighted to get a brief but unmistakeable glimpse of the GRS - very pleasing under the prevailing conditions.

I aligned on Jupiter - a very handy reference before anything else was on show.  Then on to Sigma 1998 (51 Sco, Xi Sco, Grafias, SAO 159665).  GoTo (using x24) was spot on as expected, especially for a target close to the alignment object.  Same FOV - Sigma 1999.  These stars in Scorpius, close to the boundary with Ophiuchus, form a quintuple system: 1998 being a triple; 1999, a double.  Since the bright A and B stars of 1998 are hard to split at just 1" apart, the whole system generally appears as a quadruple - more specifically, a "double double".  1998's fainter C star is 6.9" away, then 1999 lies about 5' away, and its fainter components have a separation of 12".  See sketch.  (Incidentally, the details of this system are clearer and in better correspondence with observation using Sky Safari rather than Stellarium in this instance.)

I finished this very rewarding session after one hour, having achieved my aim, and seen the GRS as an unexpected bonus!

Doug.

 

Edited July 23, 2019 by cloudsweeper

[cotterless45]

Great session , useful targets at this time of year. The GRS never fails to surprise,

Nick.

[wookie1965]

If its not blocked by houses and does not go behind the nasty street light that will be a great view for me.

Thank you for the post great report.