Wednesday, May 05, 2021

tried to help Chris

I was tired so I crawled into bed. Oddly early for me. And I really wanted to sleep shift... But then again I had pushed my training course 3 hours earlier so I wouldn't be able to sleep in. I was about to return to Babel-17 by Mr Delany when I noticed a pending text message.

Chris V had pinged me in the afternoon.

He asked, "Do you have notes on HD 198626, the foreground double star in the middle of the Cygnus Loop?" Was he observing now? Was Cygnus up?!

With my phone, I checked my double star life list. No hits. I looked up the DS in Stelle Doppie. Burnham (BU) 67. Looked to me like a tight double of unequal stars. Simple double. No other stars. I pinged back, a little late.

Chris agreed. But he encouraged me to centre on it in Stellarium. "You'd be left with the impression that there's a great DS there." Now I was intrigued. I hopped out from my toasty covers and grabbed John Gomez. 

Searched by the Henry Draper number. Landed in the middle of the Veil supernova remnant. Chris had said the star was labelled B67 but I noted β 67. Beta, followed by a number, so BU or Burnham.

I zoomed to half a degree and saw a pleasing double. Yellow and blue stars. But I had a feeling that was not what Chris was after. Zoom in more and the HD star split. Ah ha. There was the true double. The Stellarium application showed a position angle of 311° and a separation of 1.48". This closely matched the data in SD. The B star was to the north-west.

A very tight double. Three magnitudes different in brightness.

Chris said, "I was going to highlight it. Not now."

Oh. It sounded like he was writing an article and looking for a fun double.

He went on to say that "SkySafari looked correct." I knew he had the Pro but I still fired up the free basic SS on the motorola. And zoomed in tight. I was not surprised that it didn't show all the stars. But the data for the double was in the Object Info panel and, again, aligned.

Chris shared, "I checked WDS and your life list this afternoon, after sending you that message." 

It dawned on me after a moment. Holy moley. Somebody actually used my double star life list table. Wow!

I relayed my findings in Stellarium. "Zooming on Burnham 67, I see the tight double at 1.5 arc seconds. I also see at about a 90° angle another star but it's 26 arc seconds away."

He said, "In Stellarium it's labelled with a Greek Beta. Not at the computer right now, but Stellarium seemed to have a nicely resolved close pair, uneven mags, oriented 11-5." 

Sounded like the β was throwing Chris. And the 11-5 reference was without context. Was this equatorial or real-time?

In equatorial orientation, HD 198626 A and B were to the north while the distant star, unlabelled in Stellarium, was to the south. Almost 12 and 6. Maybe 11:30 and 5:30.

He added, "SkySafari doesn't show them as that pair." I think he meant the distant star at 26 arc-seconds. 

Then, "It's moot, I think. I decided to delete the reference to it in my Veil piece. I was curious if you had seen it."

For some possibly easier targets, easier than BU 67, I suggested 52 Cygni. Or HD 198627.


Today I followed up. 

Confirmed my suspicion this was for a magazine article.

Ensured Chris was clear about the use of beta. Shared other odd designations with symbols. Sent wide field snap shots from SkyTools. No bright easy doubles in the Loop. Echoed my experience 10 years prior with Stellarium...

And finally did a deep dive with SkyTools 4 Visual Pro. There was no star shown 26" away and south of HD 198626. So doubly bad (no pun intended) for Stellarium.

I checked Aladin too. No mag 9 star south of the HD pair...

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