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Another WDS Mystery Solved

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lunator

lunator

Posted
Posted

I have been investigating a few more neglected doubles

I was looking at BOT 3 with was supposedly an easy pair 45" apart with both components bright.

It only had a single observation which is why it was on the neglected list.

I observed the pair the Primary is H 5 137 and I could split that easily. By comparing the image in my eyepeice with the CduC image on the laptop I realised that the C component lay 450" away and not 45".

I submiteed my findings to Brian Mason and got a reply back today.

I think Bango is the same as Bingo ;)

Cheers

Ian

---------------------------------------------------------------------------------------------------------------------

Bango!

The Bottger paper had separations of 100.766" in Dec and 432.98" in RA.

That works out to 444.55" @ 76.9 degrees. I checked and AB gives the values determined from his offsets: 38.568" @ 26.3 degrees. Somebody at Lick missed a decimal.

Excellent detective work!

Brian

> ______________________________________________________________________

> From: Ian Coster [mailto:ian.coster@homechoice.co.uk]

> Sent: 26 August 2007 17:14

> To: 'Brian D. Mason'

> Cc: 'Bob Argyle'; 'Chris Lord'

> Subject: BOT 3

>

> Hi Brian

>

> I wanted to run some analysis of this neglected double past you.

>

> I was quite surprised to find this in the neglected list as ‘on paper’

> it should be a fairly easy catch.

>

> The pair H 5 137 was an easy target but there was no star close to the

> BOT 3AC position for the C component.

>

> The nearest star was a >12th magnitude star more than 100” to the

> East. The star does not appear to have a Tycho number but has a 2MASS

> designation of 19455808+3500162

>

> The Bmag was 13.6 and the Rmag 12.6.

>

> Whilst studying my telescopes 1 degree FOV and the Cartes du Ciel

> display on my laptop. I noted that the line designating the BOT 3AC

> pair was pointing at BD +34 3706/HD187037.

>

> Due to the distance between the pair I was not able to use my usual

> set up for measuring the pair. I had to use my microguide eyepiece

> without the Barlow which meant my focal length was only 1200mm well

> short of that recommend by Bob.

>

> Measuring the pair has given me preliminary results of (only taken on

> one night [25/08/2007] )

>

> PA 76.5

> Separation 450”

> This afternoon I checked this against the Aladin database and the

> measurements were

>

> PA 76.9

> Separation 451” (1995.713) POSSII.N.DSS2.398

> The WDS data for this pair is for one observation in 1958

>

> 19459+3501BOT 3AC 1958 1958 1 77 77 44.6 44.6 6.10 8.5

>

> Comparing this to my analysis below show a close match in PA &

> Apparent magnitude, the difference being the separation error of 10x

>

> 1958 1 77 77 44.6 44.6 6.10 8.5

> 1995 1 77 451 6.10 8.26

> 2007 1 77 450 6.10 8.26

>

> My initial conclusion is that this is the pair BOT 3AC. The most

> likely explanation is the insertion of a decimal point between the 4 &

> 6 and that the WDS entry for BOT 3AC should read

>

> 19459+3501BOT 3AC 1958 1958 1 77 77 446 446 6.10 8.5

>

> I am analysing proper motions of the A & C components to see how this

> may affect the results.

>

> Regards

>

> Ian

>

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lunator

lunator

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Posted

Here is the latest update

Looks like I'm going to get a couple of doubles to myself :lol:

Cheers

Ian

--------------------------------------------------------------------------------------------------

Hi Ian!

I actually was ready to respond to this over the weekend, but I knew the prospects for me observing Monday night were quite good, so I have even more to report.

First of all, I found HJ 3027 at about the position you cited. I will be updating the precise position of the pair to 211947.12+711017.0 and the magnitudes to 10.5 and 10.6. We will have a 2007 measure of the pair in our measurement series. I got about 126 degrees for the position angle. Rough scale calibration gives about 30 arcseconds sep.

Secondly, I looked for SHR 1, which was already on our observing

list. Looking over your email today, it looks like I neglected to check

the 21288+7034 pair you cite as the likely SHR 1. The 21275+7024 pair

you describe as 279 deg and 7.5" I measure as 282 deg and 7.5". This one

is the closest to the alleged position of SHR 1. The other possible

new pair, 21309+7020 (66 deg @ 11.4") I measure at 71 deg and 11.4".

All of my position angle and separation estimates are preliminary and quite rough.

I'll look into the other possible location of SHR 1 you mention on

Thursday or over the weekend. The Moon will be bright, so observing to the north is ideal. In any event, it looks like at least one new CSR pair, and likely two.

Finally, I'm glad to give any support I can to folks doing double star work. All of the above observations, of pairs ~10th mag or fainter, were obtained at the US Naval Observatory directly adjacent to the British Embassy in Washington, DC. I'll be glad to field any questions via email or our comment page and will gladly send out copies of the new Double Star CD to anyone interested. They can fill out the web form, or you can collect addresses and send them to me. If you do this in the future, let me know a month or so ahead of time and I'll send you a box of CDs you can give away as door prizes!

Clear skies!

Brian

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