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

Some double and multiple stars for my 4.7" APO

  • Please log in to reply
9 replies to this topic

#1 JuergenB

JuergenB

    Mariner 2

  • -----
  • topic starter
  • Posts: 209
  • Joined: 15 Nov 2015
  • Loc: Lilienthal, Germany

Posted 22 February 2021 - 09:15 AM

Dear fellow observers,

 

I have to confess that I generally do more astrophotography than visual observing. Yesterday, the bright moon would have interfered with deep-sky AP and the seeing forecast seemed to be favorable for visual observing, so I set up my TSA-120.

 

Indeed, during dusk, the seeing was quite good, therefore, I chose the moon as my first target. I had hoped to see the craterlets on the floor of Plato, but I could only detect the most prominent one at the very center of Plato. Quickly I moved to some binaries and started with Rigel. Normally not a big deal for a 4 to 5 inch APO, but we are at 53° N, where the maximum elevation of Rigel is about 28 degrees only. More often than not, bad seeing is unfavorable. When I started watching yesterday, the sky brightness was a tad too high, which prevented from seeing Rigel B. One hour later, the dim companion was easily visible already at medium magnification (90x).

 

Next target was the trapezium inside M 42. Although the seeing was still good and there was a lot of space beween the A, B, C and D components, I got the impression that the sky brightness, caused by the moon, was too high to see the fainter E and F components. There also was slight haze which did not help at all.

 

Unfortunately, temperatures started to drop fast, which resulted in deteriorated seeing. On the Pickering scale, it must have been 5 only. I could not remember ever having observed iota Cancri, so I moved to ths wide pair. Indeed, it is a spring version of Albireo, with striking color contrast. The nicest view is of course at low magnification (64x in my case). Another prominent one in the constellation of Cancer is Zeta. I was very amazed that I could split the Zeta 1 (or AB), where the separation at present is 1.1". The C component, which in reality is a binary or a triple itself, could of course be seen well at a separation of 7", if I am correct. It forms roughly an 120° angle with the connection line between A and B components. For this, I used a magnification of up to 180x.

 

After that I targeted my personal nemesis, eta Geminorum (Propus), which I never managed to split clearly. Even at highest magnification (432x), I could not detect it for sure because the first diffraction ring was always broken and speckles were dancing around. I doubt whether the companion of eta can be seen with 4 to 5 inch aperture, when the seeing is rated 5 on the Pickering scale.

 

One last try at Sirius B shortly after meridian transit was also unsuccessful. Nevertheless, I am quite happy having observed the nice objects in Cancer.

 

Juergen 


  • payner, Mike G., chrysalis and 7 others like this

#2 Stellar1

Stellar1

    Apollo

  • -----
  • Posts: 1,076
  • Joined: 08 Dec 2018
  • Loc: Ontario, Canada

Posted 22 February 2021 - 10:35 AM

Sounds like a great time splitting some challenging doubles, I too find that when the moon is out it makes it more difficult to spot some of those faint small components. This past year after trying for almost three months, I was finally able to split  Zeta Her, cant wait for some of my fav summertime doubles like the double double. 

 

Clear Skies!


  • flt158 and JuergenB like this

#3 Spikey131

Spikey131

    Surveyor 1

  • *****
  • Posts: 1,981
  • Joined: 07 Feb 2017

Posted 22 February 2021 - 10:47 AM

I have trouble splitting Tegmine (Zeta Cancri) with my 4” refractor, but it is no trouble for my C8.  One of my favorite multiples.  Next time out, take a look at 12 Lyncis, another nice triple and of course Beta Monoceros, maybe the best triple of all.

 

The other night the seeing was excellent and Sirius B was just obvious in the C8, but I still could not see it in the 4”.


  • flt158, JuergenB and Stellar1 like this

#4 c2m2t

c2m2t

    Viking 1

  • -----
  • Posts: 568
  • Joined: 03 Oct 2017
  • Loc: Pembroke, Ont.

Posted 22 February 2021 - 01:38 PM

Hi Jurgen!

Excellent report! I thought I might share a couple of your targets from this session. Unfortunately, the singular 30 second exposure does not render the colours of Iota Cancri (STF 1268) very well, but this pair dominates the field it occupies...not many distractions in way of additional resolved stars.

 

On the other hand, Zeta2 Cnc (STF 1196) contains several visible companions spread out in a fairly wide field...something for a variety of different sized optics to appreciate.

 

Cheers, Chris.

Attached Thumbnails

  • STF 1268-8559-ns-ID.jpg
  • STF 1196-1831-pt-ns-ID-Notes.jpg

  • chrysalis, Magnus Ahrling, flt158 and 1 other like this

#5 JuergenB

JuergenB

    Mariner 2

  • -----
  • topic starter
  • Posts: 209
  • Joined: 15 Nov 2015
  • Loc: Lilienthal, Germany

Posted 23 February 2021 - 04:36 AM

Hi Chris,

 

Thank you for posting the nice photos. Of course the resolution is not high enough for splitting the A-B components of STF 1196. I was a bit confused at first about your labeling D, E, F and G. Those are of course field stars which do not belong to the system. Isn't "D" also a designation of the M-type dwarf (or dwarf pair) circling around the C component in a close orbit?

 

I find it very interesting to follow new research data about the true nature of this amazing multiple system.

 

Jürgen


  • flt158 and c2m2t like this

#6 c2m2t

c2m2t

    Viking 1

  • -----
  • Posts: 568
  • Joined: 03 Oct 2017
  • Loc: Pembroke, Ont.

Posted 23 February 2021 - 08:55 AM

Hi Jurgen!

You are quite right...they are field stars but they are listed as stars that have been measured through the years and are listed in the WDS. In the fact, the E & F stars have been flying through this star field rather quickly...I remember doing a little study about them some time ago. I like to include all stars that are identified in the records...makes the story complete, so to speak. I am not aware of any special nature of "D". I focus most of my time on the imaging and learning some new astro-physical characteristics about these systems is a bonus. If you have a link to some data regarding the M-type dwarf nature, I will be sure to read it.

 

Cheers, Chris.


  • JuergenB likes this

#7 JuergenB

JuergenB

    Mariner 2

  • -----
  • topic starter
  • Posts: 209
  • Joined: 15 Nov 2015
  • Loc: Lilienthal, Germany

Posted 24 February 2021 - 07:16 AM

Hi Chris,

 

When looking for scientific papers on astronomical objects, I usually go to the SIMBAD astronomical database first (simbad.u-strasbg.fr/simbad/). There you can find publications starting from the year 1850, if available. My search about zeta02 Cancri revealed a reference to the following paper:

 

HUTCHINGS J.B., GRIFFIN R.F. and MENARD F., "Direct observation of the fourth star in the ζ Cancri system", Publ. Astron. Soc. Pac., 112, 833-836 (2000/June-0).

 

This paper of June 2000 mentions the detection of either one or two M2 class stars orbiting around ζ Cancri C. You might want to download the full paper from there.

 

Cheers, Jürgen



#8 c2m2t

c2m2t

    Viking 1

  • -----
  • Posts: 568
  • Joined: 03 Oct 2017
  • Loc: Pembroke, Ont.

Posted 24 February 2021 - 10:20 AM

Hi Jurgen!

What a fabulous paper...I need to get a telescope like that!!...next lifetime!! lol.gif  What I find truly amazing is that both Sir William Hershel and Otto Struve were able to detect the subtle changes in the orbital pattern...more amazing for Herschel given the home built equipment that he fashioned to complete his research. I would recommend it as "Great Reading" for everyone. Here is the link to the actual paper via Simbad.

 

https://iopscience.i.../10.1086/316587

 

Thanks Jurgen!!

 

Cheers, Chris.


  • JuergenB and Voyager 3 like this

#9 flt158

flt158

    Vanguard

  • *****
  • Posts: 2,137
  • Joined: 11 Aug 2014
  • Loc: Dublin, Republic of Ireland

Posted 24 February 2021 - 02:23 PM

Hello, Juergen. 

 

I'm finally getting around to replying to your fabulous report!

My favourite triple star is Tegmine STF 1196 or Zeta Cancri. 

And it has been since I first observed for the very first time on Sunday 31st March 2013. 

However on Wednesday 25th March 2020, I had the greatest thrill when I split A & B with my oldest eyepiece which is an 8 mm eyepiece which gives me a paltry 140X. 

The trick on that occasion was to star hop from M44 about half an hour after sunset. 

I then had cleanly separated Zeta Cancri into 3 stars when very few 1st magnitude stars were visible with my unaided eyes. 

 

Well done on persisting on seeing Rigel B. 

Perhaps you will try Eta Geminorum another time. 

I managed to split at cleanly at 167X 4 to 5 years ago. 

I normally require 225X. 

 

Clear skies from your fellow European, Aubrey. 


  • Magnus Ahrling, JuergenB and Voyager 3 like this

#10 JuergenB

JuergenB

    Mariner 2

  • -----
  • topic starter
  • Posts: 209
  • Joined: 15 Nov 2015
  • Loc: Lilienthal, Germany

Posted 25 February 2021 - 05:11 AM

Hello, Juergen. 

 

I'm finally getting around to replying to your fabulous report!

My favourite triple star is Tegmine STF 1196 or Zeta Cancri. 

And it has been since I first observed for the very first time on Sunday 31st March 2013. 

However on Wednesday 25th March 2020, I had the greatest thrill when I split A & B with my oldest eyepiece which is an 8 mm eyepiece which gives me a paltry 140X. 

The trick on that occasion was to star hop from M44 about half an hour after sunset. 

I then had cleanly separated Zeta Cancri into 3 stars when very few 1st magnitude stars were visible with my unaided eyes. 

 

Well done on persisting on seeing Rigel B. 

Perhaps you will try Eta Geminorum another time. 

I managed to split at cleanly at 167X 4 to 5 years ago. 

I normally require 225X. 

 

Clear skies from your fellow European, Aubrey. 

Hello Aubrey,

 

Thank you very much for your kind reply and suggestions. Did you already split the A-B components of Tegmine in 2013? If so, you might remember that the angle between  A-B-C is changing quite a bit because of the short revolution period of the A-B pair. It can be seen very well when comparing photographs from 20 years ago with recents ones.

 

Clear skies from the plagued continent

 

Juergen 


  • flt158 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