Zeta Cancri (Tegmine) -triple star

5 months 2 weeks ago - 5 months 2 weeks ago #107614 by flt158
Zeta Cancri (Tegmine) -triple star was created by flt158
Hello everyone.

I thought it was high time to highlight Tegmine (pronounced Teg-MEEN-e) as it is wonderfully positioned in the southern sky at present from my vantage point.
We finally had a clear night in Ireland on Tuesday 26th March 2019 with no wind and no dew.
My William Optics 158 mm apochromatic refractor was set up in the back garden to have a go at splitting Zeta Cancri into 3 components.
After observing M44 which is the brilliant open cluster in the centre of Cancer and Theta Cancri (a tough wide optical double -mags: 5.5 and 11.8 with a separation of 74.5" and PA of 62 degrees at 112X), I was eagerly waiting to try the very fine triple.
I was not disappointed. Even at 140X I could see there are 3 stars alright. But A and B were not split.
But at 167X I could see a very slender black gap.
What a glorious sight!
At 225X in my Nagler 5 mm I also welcomed its magnificence.
All my measurements are obtained on the famous website www.stelledoppie.it
The magnitudes are: A=5.3, B=6.3 and C= 5.9 give or take 0.05.
The position angle (PA) of A and B is now only 8 degrees. It keeps decreasing year after year by about 3 degrees. What fun is that?
A and B's PA is 64 degrees.
The separation  of A and B is 1.1. A and C is 6.2". 
A and C can be split at 40X or less. 
All 3 stars are a true triple. No optical doubles here.

Also directly north of Tegmine is a very faint double Struve 1191.
I split it at 112X with a Pentax 10 mm.
How faint can you go?
Its magnitudes are 10.3 and 10.8. Sep: 3.6". PA: 77 degrees.
There is a good red star to its north.

Clear skies to you all,

Aubrey.
The following user(s) said Thank You: michael_murphy, mykc, Fermidox, astronomeratnight

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