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3 doubles + 1 triple in Corona Borealis

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#1 flt158

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Posted 25 June 2020 - 03:31 PM

Hello, everyone. 

 

After 2 weeks 2 days, I finally got a clear night!

And it is my 50th observing night of 2020. 

I find that very difficult to believe!

On the east coast of Dublin, Ireland our Sun sets at 21.57. 

But I did my utmost to set up my William Optics 158 mm apochromatic refractor in the back garden on its Berlebach alt-az mount on this particular evening. 

 

Having observed the Moon for over an hour, I set out to observe 3 doubles and 1 triple star all within the confines of Corona Borealis from 11 pm to midnight. 

Success was to be had with each one I observed. 

All are south of Iota Crb. 

 

All figures can be found on www.stelledoppie.it 

 

1. STF 2029 which is a true binary and is west of Upsilon Crb. Magnitudes: A = 8. B = 9.6. Sep = 6". PA = 187 degrees. Nice easy split at 112X of course. But I thereafter I found I easy split it at 40X. I did increase to 167X and I was soon to notice that B had an orange hue. A was white. This was the only time I saw an orange star during this hour. 

 

2. STF 2022 is also a true binary. Magnitudes: A = 6.5. B = 10. Sep = 2.5". PA = 153 degrees. This is a reasonably tough double to split. But 167X and 225X did it justice I am very happy to say. The delta mag of 3.5 had to be overcome. By the time I successfully split it there was already a decent black gap between the 2 stars. The colours are yellow-white and white. So nothing fancy here with the colours. However I did admire the view all the same. 

 

3. STF 2011 is the only triple of the night. And it seems that all 3 stars are uncertain binaries. Magnitudes: A = 7.9. B = 10.2. C = 9.5. Sep = 2.7" and 118.1". PA's = 67 and 350 degrees. A and C were easily split at 40X of course. But to see the B star 112X gave a good tight split. At 140X was a delightful split too. All 3 stars were white to me. 

 

4. Finally, I observed an uncertain double called AG 349. Magnitudes: A = 9.6. B = 10.9. Sep = 11.7". PA = 228 degrees. A dim pair but nicely split at 112X. AG stands for Astronomische Gesellschaft. 

 

So there you have it. Nothing terribly exciting this time. 

But I was so relieved to do some observing. 

 

Now our friend Rich observed a double called Lambda Crb recently. 

And I see where it is located. 

So I have since discovered there are 4 more doubles in Corona Borealis for me to seek out.  

After that the Northern Crown and I can go our separate ways. 

But what an amazing constellation it truly is!

 

Comments are very welcome. 

 

I wish you all clear skies from Aubrey.  


Edited by flt158, 26 June 2020 - 06:19 AM.

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#2 nerich

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Posted 25 June 2020 - 05:36 PM

Nice work Aubrey! I haven't observed any of these. 

Just wondering about your third item, though. You have STF 2022 listed twice. Is number three actually STF 2011? The numbers look correct. 


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#3 rugby

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Posted 25 June 2020 - 06:46 PM

Good to hear from you again Aubrey.  It's a pleasure to hear of your celestial travels. I have a challenge for both you and Nerich (and anyone else interested). Webb's COCT describes for STF2048 in Ophiuchus "Sm. notes deep or. star in field".  A further study of The Bedford Catalogue itself states it is to the n.p.

Now my problem is I am somehat colour blind. Nevertheless, I will try it tonite in a 140mm TEC. Let's see if we can match that observation from a long time ago.


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#4 nerich

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Posted 25 June 2020 - 07:08 PM

Good to hear from you again Aubrey.  It's a pleasure to hear of your celestial travels. I have a challenge for both you and Nerich (and anyone else interested). Webb's COCT describes for STF2048 in Ophiuchus "Sm. notes deep or. star in field".  A further study of The Bedford Catalogue itself states it is to the n.p.

Now my problem is I am somehat colour blind. Nevertheless, I will try it tonite in a 140mm TEC. Let's see if we can match that observation from a long time ago.

Sounds good. I'll add it in on my next clear night. 


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#5 river-z

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Posted 26 June 2020 - 03:36 AM

Good to hear from you again Aubrey.  It's a pleasure to hear of your celestial travels. I have a challenge for both you and Nerich (and anyone else interested). Webb's COCT describes for STF2048 in Ophiuchus "Sm. notes deep or. star in field".  A further study of The Bedford Catalogue itself states it is to the n.p.

Now my problem is I am somehat colour blind. Nevertheless, I will try it tonite in a 140mm TEC. Let's see if we can match that observation from a long time ago.

I took a look at STF 2048 tonight and tried to judge the color.  The primary star didn't look white to me, but wasn't very yellow either.  It was in between.  And the secondary looked quite pale.  I guess I'd say it looked bluish but when they're dim it's hard for me to tell.


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#6 flt158

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Posted 26 June 2020 - 06:22 AM

Nice work Aubrey! I haven't observed any of these. 

Just wondering about your third item, though. You have STF 2022 listed twice. Is number three actually STF 2011? The numbers look correct. 

Whoops! I'm not surprised I'm a bit rusty, Nick.  

I've just fixed that. 

The triple star should be STF 2011

Thank you for sorting me out!

 

Clear skies from Aubrey. 


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#7 flt158

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Posted 26 June 2020 - 06:30 AM

STF 2048 has a spectral class of F4V. 

That's according to www.stelledoppie.it 

I don't know what the V stands for. 

But the F means it ought to be yellow-white. 

I believe the 4 refers to temperature.

 

Best regards, 

 

Aubrey.  



#8 rugby

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Posted 26 June 2020 - 08:38 AM

I hope I haven't created confusion regarding STF2048. Apparently Smythe was describing a field star in the np quadrant that has a deep orange colour. I had a superbly still evening last night but it only lasted thirty minutes.


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#9 flt158

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Posted 27 June 2020 - 01:03 PM

Oh. It's just dawned on me. 

V stands for 5 in luminosity as in Roman numerals. 

 

Best regards, 

 

Aubrey. 


Edited by flt158, 27 June 2020 - 01:04 PM.


#10 fred1871

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Posted 27 June 2020 - 10:14 PM

The V is Roman numerals, as are I, II, III and IV, for other stars. V is for dwarf stars (like the Sun), Main Sequence. The other classifications are for sub-giants, giants, and super-giants. If you look at a detailed version of the Hertzsprung-Russell diagram it will provide details of absolute magnitude by spectral type for each class. The Roman numerals are for the MK, originally MKK, classification for the different types of stars (I to V, including sub-types). I'd recommend Jim Kaler's Stars and Their Spectra, 2nd edition, for a thorough over-view of spectral classification. There is, of course, a good amount of basic material available on the Net. Google can be useful. smile.gif

 

See, for example, http://stars.astro.i...du/sow/hrd.html

Diagram by Jim Kaler, plus text.


Edited by fred1871, 27 June 2020 - 10:18 PM.

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#11 flt158

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Posted 28 June 2020 - 07:10 AM

Thank you very much for sorting me out, Fred, once again. 

I have rechecked Robert Burnham's Celestial Handbook Volume 1 Page 85. 

 

His table of spectral classes are in complete agreement with Jim Kaler. 

 

Best regards from Aubrey. 


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