15 Bootis problem

Hello double star admirers.

I have a problem with a double star in Bootes. Last Monday night, I was using my 158 mm apochromatic refractor seeking out some lovely double stars. I split Izar at 140X, Xi Bootis at 40X and Stf 1835 also at 40X. This last double is highlighted in the June issue of Astronomy Now -it is a beauty. Do enjoy it when you can. However a few degrees northwest of Stf 1835 is another double star 15 Bootis. It is an extremely tight -it is only 1 arc second in separation. By the way, it is mentioned in the same article in Astronomy Now as Stf 1835. It is very easy to find. Simply point your scopes at Arcturus and head south to 20 Bootis. Then head further south to 14 and 18 Bootis and about 3 degrees south again and you will come to 15 Bootis. Easy-Peasy.
I did use a Guide 8 map to pinpoint 15 Bootis and I definitely was observing it. Component A is magnitude 5.4, and B is 8.4. My telescope has north at the top; but my east is to the right at all times thanks to its mirror diagonals. This is most important to remember. The problem I have is the Position Angle of the B component (PA).
According to Guide 8, the PA is 114 degrees. This ought to mean I should see B in the 4 o'clock position. However, I see B in the 10 o'clock position, and I have observed 15 Bootis once on Saturday night and now again on Monday night. So you can see that this is a complete mystery to me. I was using high magnifications -280X, 320X and 374X. All 3 eyepieces showed B in the same position. I was delighted to split it at these high powers. And I even called on my wife Valerie to verify the PA of component B and she agreed it is in the 10 o'clock position.
Robert Burnham's Celestial Handbook Volume 1 states B's PA is 120 degrees -again 4 o'clock. stelledoppie.goaction.it (which is very much up to date) says the PA is 108. Sissy Haas does not list 15 Bootis. The famous double star website Eagle Creek Observatory says the PA is 120 degrees.
How can they be all wrong? I reckon the B component should have a PA of something like 280 to 300 degrees. It is faint -I agree with that and I totally agree with the magnitudes of both stars and the separation. I can only separate very tight doubles at high magnifications -especially ones with 1 arc second separations. I have been successful in splitting Lambda Cygni, 32 Orionis, 52 Orionis and recently Stt 186 in Cancer. So I feel I do know what I am talking about.

So can anybody help me out? All opinions are very welcome to help me solve my mystery. Perhaps Mike Casey, Paul Byrne or Dave Lillis could observe 15 Bootis some time soon.

Thank you for reading.

Clear skies,

Aubrey.

Stellarium seems to agree with you Aubrey, just click on this screenshot and the B companion looks like it's at 10 o'c. Maybe the catalogues are confusing the respective components?

Good grief, Fermidox. I am greatly surprised at the image you have sent me. So I am right, and all the current and past records appear to be wrong. How is that possible? I am especially surprised that stelledoppie.goaction.it are incorrect. They have been extremely reliable for many years to me.
I have asked a close mate to have a look at 15 Bootis. He is looking tonight all being well. He has a 9.25" SCT with a mirror diagonal.

By the way, Fermidox, does Stellarium give a position angle? It does not state it on the image. But I do thank you very much for this most interesting information.

Aubrey.

flt158 wrote: By the way, Fermidox, does Stellarium give a position angle?

I'm afraid it doesn't Aubrey. But I've looked up several other sources and they all give the PA in or around 108° so we're being outnumbered here...

Finbarr.

That's really intriguing Aubrey.

First, congratulations on splitting such a difficult double, the large difference in the magnitudes exacerbates the difficulty posed by the small separation.

I looked at some of the original papers and the data are from professional labs using excellent equipment. Some examples:

1968: 1.08 117
articles.adsabs.harvard.edu//full/1974Ap...13V/0000432.000.html (van Biesbroeck's last paper reporting observations made in his late 80s!)

2002: 0.98 106
arxiv.org/pdf/1012.3383.pdf

2003: 0.72 109
cdsarc.u-strasbg.fr/viz-bin/nph-Cat/html...28%2F3012/table2.dat

Finbarr's theory that the primary and secondary were confused, so the position angle is in error by 180 degrees, seems plausible. On the other hand, it seems unlikely that experienced professional observers would repeatedly make such a mistake.

I will definitely take a look at the first opportunity, though, to be honest, I am not confident that I will be able to resolve this double. It will certainly require very good seeing.

Thanks for pointing out this fascinating puzzle Aubrey.

Mike

Hello, Fermidox. From the Stellarium image can you tell me which way is east? I take it north is up.

Mike, I see from your profile that you own a 280 mm SCT. I own a 158 mm apo. Surely your scope would have an easier time splitting tight doubles.

I observed 15 Bootis yet again on Tuesday night. This time Valerie and I could see component B in the 10 o'clock position at the much lower magnification of 167X! But 225X is more suitable for my apo.

Thank you, Mike, for sending the 3 links. I agree they all show me I am wrong with the PA. However, I am not letting this one go. I do not think it is all that difficult to see a 8.4 magnitude star close to 5.4 mag star -even though in this case they are 1 arc second apart.

So my strong advice is that as many telescope observers spend about 15 minutes of their time checking out 15 Bootis. It is very easy to find. My friend Liam Smyth hopes to split it tonight with a 12" reflector. And I too will look at it again tonight for the 4th night since the weekend. Tomorrow we may know what its actual PA is.

By the way, Stf 1823 double is nearby. A is +9.2, B is 9.8. Separation is 3.8" with a PA of 147 degrees. My north is up and my east is to the right. So that is at 5 o'clock in the apo.

Clear skies,

Aubrey.