Doubles - And Then Another!

[cloudsweeper]

Early evening, Thursday, set up the 8SE:

Sheliak - double in Lyra - a quintuple system, seen as a visual quadruple - easily spotted at x48 as an L-shape, one star dominant - took it to x303, but no difference.

Mu Herculis - a quadruple system - seen as a visual triple - again easy at x48 - small triangle, tighter than the above, one star dominant, appearing yellowish. Strange thing about one of the fainter stars: it seemed to change position when I returned to the EP.  I recently also noticed this effect with Enif (Pegasus), where the faint companion star seemed to change positions.  There is a "pendulum effect", but the movements in these cases were more than small apparent changes of position.  Any ideas/experience of this, anyone?

M29 - Cooling Tower, open cluster in Cygnus - quick glance at the characteristic shape.

M92 - globular cluster in Hercules - dense, with many stars resolved at x203 - a bit less clear at x231 - good compromise at x185.

Out again early morning, Friday:

M31 - quick look to check GoTo - quite clear on account darker sky and less light trespass.

C14 - Double Cluster in Perseus - always hard to resist - particularly this time, as I sat comfortaby on a stool and stared at it all, enjoying the ever fainter and closer stars there. Still good and more detailed at x85, 102, 145, but the wider view was best, with both cores in view.

Must try and get to bed some time.....

Doug.

 

[alan potts]

Nice report, did you by chance nudge the diagonal to cause the movement, I have done this myself and is easy to go unnoticed when changing eyepieces.

 

[Stu]

Nice Doug. I like the sound of those first two, will give them a shot. Thanks!

[Piero]

Great Stuff! 

It was a beautiful evening here too, lots of targets to see! 

[cloudsweeper]

7 hours ago, alan potts said:

Nice report, did you by chance nudge the diagonal to cause the movement, I have done this myself and is easy to go unnoticed when changing eyepieces.

 

Don't think it was that, Alan - sometimes I saw a change of position when returning to the same EP. 

I know there is a "pendulum effect" with for example Enif's fainter companion, whereby vibration makes it oscillate a little since its light stimulates the retina less, so its wobbling lags behind that of the other star.  But in the two examples given, the actual position seemed to be very different in relation to the brighter star - almost as if it was in rapid revolution!  Very odd, never seen it before.  Some kind of illusion?

Doug.

[alan potts]

Very odd, Dark forces maybe.

Alan