Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Zeta Cancri (Tegmine) -triple star

  • Please log in to reply
12 replies to this topic

#1 flt158

flt158

    Apollo

  • -----
  • topic starter
  • Posts: 1,302
  • Joined: 11 Aug 2014
  • Loc: Dublin, Republic of Ireland

Posted 28 March 2019 - 09:18 AM

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 from 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 separations for A and B are 1.1" and A and C are 6.2" apart. 

A and C are easily 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. 


Edited by flt158, 28 March 2019 - 09:37 AM.

  • nirvanix, R Botero, Francopoli and 1 other like this

#2 gfeulner

gfeulner

    Viking 1

  • *****
  • Posts: 914
  • Joined: 23 Nov 2007
  • Loc: Bergen county, New Jersey

Posted 28 March 2019 - 12:37 PM

Tegmine is one of my favorite triples along with Beta Monoceros. Two nights ago I viewed it through my friends new and excellent Orion 127 Mak. Last night I viewed it with my 140 refractor. It's a magnificent sight. Thanks for the info on Struve 1191. If it's clear tonight I'll have to check it out.

Gerry


  • nirvanix and flt158 like this

#3 R Botero

R Botero

    Vanguard

  • -----
  • Posts: 2,349
  • Joined: 02 Jan 2009
  • Loc: Kent, England

Posted 29 March 2019 - 02:44 AM

Nice one Aubrey! Here are my notes from 25 February when I observed it last: “Beautiful triple. AB yellow. C white-blue. PA15 and 30. ”
Roberto

#4 flt158

flt158

    Apollo

  • -----
  • topic starter
  • Posts: 1,302
  • Joined: 11 Aug 2014
  • Loc: Dublin, Republic of Ireland

Posted 29 March 2019 - 01:03 PM

You're a good man on the colours, Roberto. 

I'm sure they are correct as I have seen them in the recent past. 

I did try to consider them but to no avail. 

They appear to be quite subtle or slight generally speaking. 

 

I trust www.stelledoppie.it for the PA's.

Which means that the B is component is "straight up" from A, 

Precisely what I saw on 26th March. (8 degrees). 

In 2017, A and B had a PA of 15 degrees.

Maybe your estimate comes from a different source.

You might check your 30 degree PA for AB to C. 

It is a bit different to Stelle Doppie. 

 

Anyway I have very pleased you clearly saw all 3 components and those colours, Roberto. 

Well done! 

 

Good seeing from Aubrey.


  • R Botero likes this

#5 Kon Dealer

Kon Dealer

    Apollo

  • -----
  • Posts: 1,008
  • Joined: 05 Jan 2011
  • Loc: Cambridge UK

Posted 29 March 2019 - 06:28 PM

Split it last night with my SE6. Quite easy at x150. Got an elongated peanut at x170 using my 90mm TS90.

sky was the steadiest I’ve seen in about 6 months


  • flt158 likes this

#6 R Botero

R Botero

    Vanguard

  • -----
  • Posts: 2,349
  • Joined: 02 Jan 2009
  • Loc: Kent, England

Posted 30 March 2019 - 02:06 AM

...

 

I trust www.stelledoppie.it for the PA's.

Which means that the B is component is "straight up" from A, 

Precisely what I saw on 26th March. (8 degrees). 

In 2017, A and B had a PA of 15 degrees.

Maybe your estimate comes from a different source.

You might check your 30 degree PA for AB to C. 

It is a bit different to Stelle Doppie. 

 

...

You are absolutely right Aubrey! Although my last visit to Tegmine was on 25 Feb this year, my notes are from 17 February 2017 (at 21:30)! I had to go back and properly check my log!

My PA numbers are all visual estimates. I sometimes measure but not for this one. 

Roberto


  • flt158 likes this

#7 flt158

flt158

    Apollo

  • -----
  • topic starter
  • Posts: 1,302
  • Joined: 11 Aug 2014
  • Loc: Dublin, Republic of Ireland

Posted 30 March 2019 - 05:25 AM

You are absolutely right Aubrey! Although my last visit to Tegmine was on 25 Feb this year, my notes are from 17 February 2017 (at 21:30)! I had to go back and properly check my log!

My PA numbers are all visual estimates. I sometimes measure but not for this one. 

Roberto

 

You are absolutely right Aubrey! Although my last visit to Tegmine was on 25 Feb this year, my notes are from 17 February 2017 (at 21:30)! I had to go back and properly check my log!

My PA numbers are all visual estimates. I sometimes measure but not for this one. 

Roberto

Gosh Roberto!

You must be a highly skilled observer if you measure your own separations and position angles. 

I know one or two who do this over here in Ireland, but that's all!

They use protractors and reticle eyepieces. 

I take the lazy way out and head straight for www.stelledoppie.it  

 

Thank you for your honesty, Roberto. 

 

Kindest regards from Aubrey. 



#8 R Botero

R Botero

    Vanguard

  • -----
  • Posts: 2,349
  • Joined: 02 Jan 2009
  • Loc: Kent, England

Posted 30 March 2019 - 07:11 AM

Aubrey
They are only estimates and not very good at that! Position angles are easier than separations.
Cheers
Roberto
  • flt158 likes this

#9 hasebergen

hasebergen

    Sputnik

  • -----
  • Posts: 39
  • Joined: 04 Mar 2016
  • Loc: Stuttgart, Europe

Posted 25 April 2019 - 03:39 AM

Hi people,

I could split z Cnc 1"1 Components with an 35-40 years old Vixen-Pulsar 102/1300mm refractor. Eyepiece: 5mm Nagler/260x. A wonderful triple system.

Some years ago I splitted z Cnc with a chinese 114/500mm parabolic Newtonian - forgot the magnification ;-)

@Aubrey - thanks for the information about Struve 1191. If it will happen, today will arrive an old Zeiss AS63/840mm refractor ... this can be a famous "entry-double" for this - I hope - famous scope.

 

Best regards Hannes


  • nirvanix and flt158 like this

#10 flt158

flt158

    Apollo

  • -----
  • topic starter
  • Posts: 1,302
  • Joined: 11 Aug 2014
  • Loc: Dublin, Republic of Ireland

Posted 25 April 2019 - 08:22 AM

What a lovely long focal length you have on that Vixen -Pulsar refractor, Hannes. 

I would imagine it takes time to assemble it.

I am very pleased you had a great success splitting Tegmine with it and your other Newtonian. 

And I wish you the very best if you should split Struve 1191 at any time in the future, Hannes!

 

Clear skies from Aubrey. 



#11 Magnus Ahrling

Magnus Ahrling

    Mariner 2

  • -----
  • Posts: 297
  • Joined: 07 Mar 2014
  • Loc: Visby, Sweden 57:30N.

Posted 03 December 2019 - 07:29 PM

I had a very fine split of this marvelous triple last night 2-3/12 with my C8. I never stop to enjoy this awesome binary. To me A and B appears yellow and C bluish. I used 160X and up...

 

By the way I also had  a view of "e" and "f" in Trapizium. At 142X both stars were steady and easy to see. At 160X they were also easy to observe but at 183X I began to need adverted seeing to notice the "f" star.. It´s far from always I can observe "e" and "f" stars. I live at 57N.

 

-Magnus


  • CharlieB, R Botero, flt158 and 1 other like this

#12 nirvanix

nirvanix

    Vanguard

  • -----
  • Posts: 2,122
  • Joined: 07 Jun 2007
  • Loc: Medicine Hat, AB

Posted 04 December 2019 - 05:03 PM

Nice reports!

 

I split Tegmine A-B January 2019 with a 4" refractor in Pickering 9 seeing. 280x magnification, and I need every bit of that to score black space between them.  Would love to see it more often if I could get the seeing conditions. Beta Mons is easy in comparison.

 

I'll check out Struve 1191 soon.


Edited by nirvanix, 04 December 2019 - 05:04 PM.

  • flt158 likes this

#13 flt158

flt158

    Apollo

  • -----
  • topic starter
  • Posts: 1,302
  • Joined: 11 Aug 2014
  • Loc: Dublin, Republic of Ireland

Posted 05 December 2019 - 02:39 PM

Gosh! It is going to be March or April 2020 when I get around to observe my favourite triple star. 

I was wonderfully surprised to see on this forum that some good folk have already observed Zeta Cancri before the end of 2019. 

Well done, Magnus and Nirvanix!

It whets my appetite to split Tegmine again in a few months. 

 

Clear skies from Aubrey. 


  • Magnus Ahrling likes this


CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics