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Castor + 9 doubles in Cancer

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#1 flt158

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Posted 26 March 2020 - 09:31 AM

Hello everyone.

What a late afternoon and night I had last Wednesday 25th March in my back garden!

 

We seem to have plenty of clear skies over Ireland right now. 

I had set up my William Optics 158 mm F/7 apochromatic refractor and the usual WO 70 mm small apo at about 5 pm. Temperatures ranged from 9 to 4 degrees Celsius as the night wore on. There was no wind at all.

 

www.stelledoppie.it provides the figures for the doubles and triples.

 

1. I soon found orange Pollux and white Castor through my William Optics 70 mm small apo at 11X. Both stars were still invisible at 7 pm with my unaided eyes. In the main scope, I had that wonderful little black gap between A and B of Castor at 40X. Magnificent! Magnitudes: A = 1.9. B = 3. Sep = 5.4" and widening. PA = 52 degrees and lessening.

 

2. Where else was I going to go next? Only to Cancer. I soon found M44 in the 70 mm. I could barely see the open star cluster there and then. But it looked good at 40X in the main scope.

 

3. But what a momentous occasion was to occur next. I found Zeta Cancri (Tegmine) as a double star at 40X in the main scope. There are A and C components of course. But at 112X the scope was trying hard to split A and B. Then real personal history was made when I could see A and B split at 140X. Normally I require 167X or even 225X. The reason was the sky had not darkened enough; and that's why I was seeing all 3 stars cleanly separated at 140X. Still I was so full of joy swapping eyepieces to fully check I was not seeing things. For the record the magnitudes are: A = 5.3. B = 6.3. C = 5.9. Sep's = 1.14" and narrowing and 5.9". PA's = 5.2 degrees and lessening and 64 degrees. When will I do this feat again?

 

4. After dinner I headed north to Iota Cancri. I distinctly remember the late Sir Patrick Moore discussing this true binary on The Sky at Night TV show many years ago. He was very much charmed by it and rightly so. Magnitudes: A = 4.1. B = 6. Sep = 30.7". That's slightly more than Albireo. PA = 308 degrees. The spectral classes are G8 and A5. In my 158 mm apo A is strong yellow with a slight orange tint. B is a decent blue. At 40X the 2 stars have a very good gap in between. At 112X the gap is considerably wider of course. But the colours are much more vivid and are something to behold. It's a good double star for beginners.

5. Very near Iota Cnc we have a charming true binary called Stf 1266. It is a true binary. Magnitudes: A = 8.8. B = 10. Sep = 23.4". PA = 65 degrees. Barely visible and split at 40X. I noticed both stars are yellow-white particularly the brighter one at 112X and 140X.

 

6. I have an unusual designation for you next: CBL 32 which is a true binary. A = 7.4. B = 10.7. Sep = 41". PA = 174 degrees. I could see B at 40X. But 112X was much better. CBL refers to Roberto Caballero. I don't appear to have any information regarding him other then he is Spanish. Perhaps he is alive and well today. Could someone verify? He definitely was in 2015.

 

7. 57 Cancri is a glorious true binary. Magnitudes: A = 6.1. B = 6.4. Sep = 1.6". PA = 309 degrees. 10 years ago in 2010 I was in the Sugarloaf Car Park. My William Optics 158 mm apochromatic refractor was very new at the time. I sought out 57 Cnc using a very large Sky and Telescope Atlas and, after a very long time searching, I found this brilliant double star. I believe I cheered on that first night ( I had no Guide 9.1 DVD). 6 months later my wife and I were in French Polynesia to observe my 6th Total Solar Eclipse. The great TV astronomer Heather Couper was with us. I talked to her about 57 Cnc and how I greatly admired the colour of both stars: Yellow-orange. Heather Couper died 1 month ago at the age of 70. So I had a very great desire to revisit this stunning binary. This time I successfully split it at 140X. It truly is a wondrous sight. Please do check it out. You will be spoiling yourself! It also looks very good at 167X and higher. I'm sorry Heather is no longer with us.

 

8. 66 Cancri is a very nice double too. But it is optical. You won't think that when you view it. Magnitudes: A = 6. B = 8.6. Sep = 4.4". PA = 137 degrees. A is white. B is slight blue. I had no desire to go higher than 112X. The double star is simply stunning at that power.

 

9. Sigma 3 or 64 Cancri is not a particularly stunning triple star. It is an uncertain triple after all. Magnitudes: A = 5.3. B = 9. C = 10.1. Sep's = 90.3" & 160". PA's = 294 and 184 degrees. Very sprawled out at 40X and 112X. A is a reasonable yellow. B and C are slight yellow.

 

10. AG 159 is an optical double. Magnitudes: A = 10.8. B = 10.8 also. Sep = 6.8". PA = 101 degrees. So both stars very dim and very slightly yellow . I required 112X to see the 2 stars split. But I must say I did find it attractive in its own way.

 

11. Stf 1288 is another optical double. Magnitudes: A = 10.2. B = 10.2 also. Sep = 7.7". PA = 259 degrees. It is slightly brighter alright than AG 159. And it looked very good at 112X. No need to go higher.

 

There are some more doubles in Cancer the Crab which I was not successful in splitting on this night. Therefore I will return to this extraordinary constellation soon.

 

Thank you for reading.

 

Comments are always welcome.

 

Clear skies,

 

Aubrey.


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#2 deepwoods1

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Posted 26 March 2020 - 09:39 AM

Sounds like a nice night was had!


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#3 MP173

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Posted 26 March 2020 - 10:17 AM

You have provided quite a list for when the skys finally clear here.

 

It will be a few days.

 

Ed


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#4 c2m2t

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Posted 26 March 2020 - 10:45 AM

Hi Aubrey!

Another wonderful report. Judging from the frequency of these reports, Ireland sounds like a great destination for observing in the late winter months. smile.gif  Judging from the number of systems you are introducing in Cancer that have avoided detection in my original data search for doubles meeting by imaging requirements, I will have to build another list. I should do that soon given Cancer is ideally placed right now...but the clouds aren't!!

 

Cheers, Chris.



#5 flt158

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Posted 26 March 2020 - 10:51 AM

Thank you, Chris. 

 

I am amazed with all the "likes" too so soon after my report. 

 

Perhaps some of you would like to inform us what your least magnification is for splitting A and B of Zeta Cancri. 

Can anyone beat 140X? And I mean a black space in between! Wait till you see. Someone will say 139X. lol.gif lol.gif lol.gif  

Please feel free to add to this report. 

 

Clear skies, 

 

Aubrey. 


Edited by flt158, 26 March 2020 - 10:52 AM.


#6 c2m2t

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Posted 26 March 2020 - 11:33 AM

Hi Aubrey!

I suspect that with the world wide health situation we are all facing, many more of us are huddled around our computers with CN on the screen! lol.gif I suspect that most of us are dealing with clouds as well, so reading someone else's reports helps to transport ourselves to some dark skies.

 

Cheers, Chris.


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#7 tchandler

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Posted 26 March 2020 - 02:15 PM

Delightful report, as always. Iota Cnc is a personal favourite of mine. It was “second light” in my then new Takahashi 120 mm refractor several years ago. Really a fine double for a small telescope. Incidentally, first light with this refractor was Cor Caroli. 

 

CBL 32 is an interesting designation. In Sky Safari, I believe this star is listed as HD 74669. It’s almost one degree due south of iota,I think. Thank you for this wee dainty! 
 


Edited by tchandler, 26 March 2020 - 05:03 PM.

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#8 flt158

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Posted 26 March 2020 - 02:31 PM

That's the one, Trevor!

One degree south of Iota Cnc. 

I would say it's nice double. 

But Iota and 66 Cnc win the day. 

But Zeta is the best triple I know. 

 

Now it's clear again tonight Thursday. 

The skies will cloud over at some stage, right?

 

Kind regards, 

 

Aubrey. 


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#9 R Botero

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Posted 27 March 2020 - 06:41 AM

Excellent reports Aubrey. We have had very clear skies for a week in England also. Seeing only improved over the last 3 nights but transparency has dropped a little. I have been viewing a few doubles in your list as well as in Lynx, Leo (and Minor) and UMa.
Keep at it!
Roberto
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#10 flt158

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Posted 27 March 2020 - 08:11 AM

Hi Roberto. 

Please feel free to give us your observations. 

You can even "hijack" this current post. 

I am adding one more double here now. 

 

Stf 1294. Magnitudes: A = 9. B = 10.8. Sep = 15.6". PA = 341 degrees. Split at 112X. 

It's right next to Sigma 3 Cancri. 

Not exactly a wondrous double; but still good to tick it off.  

 

Cloudy skies have now resumed over Ireland. 

Never mind. I have enjoyed every minute of it while it lasted. 

 

Kind regards, 

 

Aubrey. 


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#11 Tyson M

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Posted 27 March 2020 - 11:59 AM

Hello everyone.

What a late afternoon and night I had last Wednesday 25th March in my back garden!

 

We seem to have plenty of clear skies over Ireland right now. 

I had set up my William Optics 158 mm F/7 apochromatic refractor and the usual WO 70 mm small apo at about 5 pm. Temperatures ranged from 9 to 4 degrees Celsius as the night wore on. There was no wind at all.

 

www.stelledoppie.it provides the figures for the doubles and triples.

 

1. I soon found orange Pollux and white Castor through my William Optics 70 mm small apo at 11X. Both stars were still invisible at 7 pm with my unaided eyes. In the main scope, I had that wonderful little black gap between A and B of Castor at 40X. Magnificent! Magnitudes: A = 1.9. B = 3. Sep = 5.4" and widening. PA = 52 degrees and lessening.

 

2. Where else was I going to go next? Only to Cancer. I soon found M44 in the 70 mm. I could barely see the open star cluster there and then. But it looked good at 40X in the main scope.

 

3. But what a momentous occasion was to occur next. I found Zeta Cancri (Tegmine) as a double star at 40X in the main scope. There are A and C components of course. But at 112X the scope was trying hard to split A and B. Then real personal history was made when I could see A and B split at 140X. Normally I require 167X or even 225X. The reason was the sky had not darkened enough; and that's why I was seeing all 3 stars cleanly separated at 140X. Still I was so full of joy swapping eyepieces to fully check I was not seeing things. For the record the magnitudes are: A = 5.3. B = 6.3. C = 5.9. Sep's = 1.14" and narrowing and 5.9". PA's = 5.2 degrees and lessening and 64 degrees. When will I do this feat again?

 

4. After dinner I headed north to Iota Cancri. I distinctly remember the late Sir Patrick Moore discussing this true binary on The Sky at Night TV show many years ago. He was very much charmed by it and rightly so. Magnitudes: A = 4.1. B = 6. Sep = 30.7". That's slightly more than Albireo. PA = 308 degrees. The spectral classes are G8 and A5. In my 158 mm apo A is strong yellow with a slight orange tint. B is a decent blue. At 40X the 2 stars have a very good gap in between. At 112X the gap is considerably wider of course. But the colours are much more vivid and are something to behold. It's a good double star for beginners.

5. Very near Iota Cnc we have a charming true binary called Stf 1266. It is a true binary. Magnitudes: A = 8.8. B = 10. Sep = 23.4". PA = 65 degrees. Barely visible and split at 40X. I noticed both stars are yellow-white particularly the brighter one at 112X and 140X.

 

6. I have an unusual designation for you next: CBL 32 which is a true binary. A = 7.4. B = 10.7. Sep = 41". PA = 174 degrees. I could see B at 40X. But 112X was much better. CBL refers to Roberto Caballero. I don't appear to have any information regarding him other then he is Spanish. Perhaps he is alive and well today. Could someone verify? He definitely was in 2015.

 

7. 57 Cancri is a glorious true binary. Magnitudes: A = 6.1. B = 6.4. Sep = 1.6". PA = 309 degrees. 10 years ago in 2010 I was in the Sugarloaf Car Park. My William Optics 158 mm apochromatic refractor was very new at the time. I sought out 57 Cnc using a very large Sky and Telescope Atlas and, after a very long time searching, I found this brilliant double star. I believe I cheered on that first night ( I had no Guide 9.1 DVD). 6 months later my wife and I were in French Polynesia to observe my 6th Total Solar Eclipse. The great TV astronomer Heather Couper was with us. I talked to her about 57 Cnc and how I greatly admired the colour of both stars: Yellow-orange. Heather Couper died 1 month ago at the age of 70. So I had a very great desire to revisit this stunning binary. This time I successfully split it at 140X. It truly is a wondrous sight. Please do check it out. You will be spoiling yourself! It also looks very good at 167X and higher. I'm sorry Heather is no longer with us.

 

8. 66 Cancri is a very nice double too. But it is optical. You won't think that when you view it. Magnitudes: A = 6. B = 8.6. Sep = 4.4". PA = 137 degrees. A is white. B is slight blue. I had no desire to go higher than 112X. The double star is simply stunning at that power.

 

9. Sigma 3 or 64 Cancri is not a particularly stunning triple star. It is an uncertain triple after all. Magnitudes: A = 5.3. B = 9. C = 10.1. Sep's = 90.3" & 160". PA's = 294 and 184 degrees. Very sprawled out at 40X and 112X. A is a reasonable yellow. B and C are slight yellow.

 

10. AG 159 is an optical double. Magnitudes: A = 10.8. B = 10.8 also. Sep = 6.8". PA = 101 degrees. So both stars very dim and very slightly yellow . I required 112X to see the 2 stars split. But I must say I did find it attractive in its own way.

 

11. Stf 1288 is another optical double. Magnitudes: A = 10.2. B = 10.2 also. Sep = 7.7". PA = 259 degrees. It is slightly brighter alright than AG 159. And it looked very good at 112X. No need to go higher.

 

There are some more doubles in Cancer the Crab which I was not successful in splitting on this night. Therefore I will return to this extraordinary constellation soon.

 

Thank you for reading.

 

Comments are always welcome.

 

Clear skies,

 

Aubrey.

I added a couple of these doubles to my Cancer observing list, that was initiated by Sue French's list. Thanks!


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#12 R Botero

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Posted 28 March 2020 - 03:17 AM

Hi Roberto. 

Please feel free to give us your observations. 

You can even "hijack" this current post. 

I am adding one more double here now. 

 

Stf 1294. Magnitudes: A = 9. B = 10.8. Sep = 15.6". PA = 341 degrees. Split at 112X. 

It's right next to Sigma 3 Cancri. 

Not exactly a wondrous double; but still good to tick it off.  

 

Cloudy skies have now resumed over Ireland. 

Never mind. I have enjoyed every minute of it while it lasted. 

 

Kind regards, 

 

Aubrey. 

Aubrey

 

I need to do a proper write up my recent sessions to contribute to the thread but if you get the chance, try and split Kappa Leonis (BU105, 09247+2611). It’s a tough cookie at 5 mag delta and only 2” separation. My most recent notes from 24 March are: “Clear split and lovely colours in good steady and transparent skies. Orange and pale blue. PA220. DR around primary.”

This at 320x using my 10” f/20 Mak. 

 

Roberto


Edited by R Botero, 28 March 2020 - 03:20 AM.

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#13 flt158

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Posted 28 March 2020 - 10:17 AM

Hi Roberto. 

I did successfully split Kappa Leonis but it was way back in time. 

It was not with my current William Optics apochromatic refractor. 

Instead it was with an 8.75" F/6 Newtonian reflector which weighed heavier than me. 

The date was 21st May 2001. 

The magnification was 195X. 

At the time my 3 volumes of Robert Burnham's Celestial Handbooks were my only source of information. 

Kappa Leonis is listed as having a separation of 2.1" and a PA of 208 degrees. 

It seems the double has not changed much throughout the intervening years. 

As it is very close to the eastern border of Cancer, It definitely is the right time to revisit this very fine double star with my newer refractor. 

I will need minimum wind and good seeing conditions.  

Right now it is very overcast and rather breezy as you probably know as you are in Kent. cloudy.gif  

 

But I do sincerely thank you for drawing my attention (and others) here on Cloudy Nights regarding Kappa Leonis.  

 

Clear skies,  

 

Aubrey.


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#14 R Botero

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Posted 29 March 2020 - 02:41 AM

...

It seems the double has not changed much throughout the intervening years. 

...

Clear skies,  

 

Aubrey.

Aubrey

 

Most likely it’s an optical pair - who knows - but separation and PA have barely changed since its discovery 150 yrs ago!

 

Roberto


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#15 flt158

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Posted 29 March 2020 - 06:12 PM

Hello Roberto. 

 

I have sad news from me personally regarding Kappa Leonis. 

I used magnifications 167X, 225X, 280X and 320X on it. 

I never saw B at any of these magnifications. 

Sky conditions were very good. 

I was splitting Zeta Cancri at 167X. 

But for some reason Kappa Leonis just would not split. 

I do consider it strange that B star would not "pop" out. 

I even tried going back to it an hour later. Still no go. 

Maybe bigger apertures would do better. 

My scope's aperture is 158 mm and F/7. 

 

All the best, 

 

Aubrey. 


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#16 fred1871

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Posted 30 March 2020 - 03:11 AM

Kappa Leonis is BU 105, discovered by SW Burnham with his 6-inch refractor as he states in his 1900 catalogue of all his double star discoveries. The measures he lists at that early date, from 1876 to 1898, he regarded as showing "no relative change" [within the errors of measuring]. He gives his reasons for thinking "the companion has the same proper motion" as the primary. 

 

Looking at the post-1900 measures I have current access to, it appears that despite the WDS showing the same separation for 1873 and 2015 (2.0"), that the pre-1900 measures were consistently wider than the recent ones, around 3.0" back then; the 1996 edition of WDS lists 2.4" for 1975; a 2005 measure on a 3.6-metre scope using adaptive optics, 2.2"; and the 2015 WDS listing of 2.0". 

 

The PA shows no sign of much, if any, variation. This suggests that we could have a gravitational pair in a near edge-on orbit. Over the period since discovery it's been closing in the line of sight. 

 

GAIA DR2 has a parallax for the primary star, giving a distance from us of ~60 parsecs (195 ly); at that distance the line of sight separation of the stars is 120AU at 2.0", and 180 AU at 3.0". So, if there is an orbit, it's a large one of long period. Gaia has no parallax yet for  the secondary, nor PM (proper motion) numbers for the secondary.

 

The WDS also has no PM numbers for the secondary star. The PM numbers for the primary star, around 33 and 48 mas per year (RA and Dec) do suggest that if the stars were unconnected, and with much smaller PM for the secondary, they would have drifted further in separation change than has occurred. The conclusion is that they're either a gravitational pair, or co-travelling in space with the secondary sufficiently further from us in space to not allow orbital motion. It could not be too much further away, however, or co-travelling speed would likely result in smaller PM rates hence more speed of change than is observed.

 

This favours but does not prove a gravitationally bound situation. Estimating the limits of gravitational binding could be calculated from the estimated Mass of the primary, and some guesses on the Mass of the secondary, combined with maximum distance possible for gravity to be effective. I'll think about crunching some numbers later. Meanwhile, it's open for anyone else to do some calculations. smile.gif


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#17 flt158

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Posted 30 March 2020 - 07:02 AM

Thank you very much for this vital information, Fred. 

Thank you most especially for giving us the history of the separation of Kappa Leonis even way back in 1876 when the Moons of Mars (Phobos and Deimos) had not been observed. 

It very much explains why I had a successful split in May 2001, albeit with a larger aperture, and not now some 19 years later in March 2020. 

Plus my eyes were that little bit better in 2001.(I was aged 40.)

Kappa Leonis might have had a separation of 2.3" then. 

That's only my guess estimate. 

 

Adaptive Optics is not an item of equipment I will ever have at my disposal. drool.gifIf only!

 

But I raise my hat to Roberto for seeing A and B split with his 10" f/20 Mak. applause.gif applause.gif

How this telescope looks I would love to know. 

Keep splitting those awkward doubles, Roberto. 

 

Clear skies from Aubrey. 


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#18 R Botero

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Posted 31 March 2020 - 09:53 AM

Hi Aubrey

 

Trying not to derail the topic but here's a picture of the scope (solar observing).  It is a Maksutov made by Yuri Petrunin and team at Telescope Engineering Company (TEC) in the US in the early 2000s.

Best wishes

 

Roberto

 

yp6n-XziyQXM_620x0_2naJ1p0L.jpg


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#19 flt158

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Posted 31 March 2020 - 01:52 PM

My goodness me!

 

What a telescope that is,Roberto. 

 

Back in May 2015 you did send into Cloudy Nights a most exquisite image of this telescope.

 

It is no wonder you had a successful separation of Kappa Leonis in recent times. 

 

What a joy to know some amateurs are true experts at resolving extremely tough double stars. 

 

Best regards, Roberto. 

 

Aubrey. 




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