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Posts Tagged ‘Double Double’s Double’

No kidding. (Yeah, I think all those apostrophes make sense 😉

One of my favorite destinations in the summer skies – or early mornng skies these March days – is the well-known Double Double. This multiple star is not only beautiful and charming, but is frequently a bit of a challenge and seeing what power it takes to split it cleanly is a good indicator of how good the seeing is at that moment.

What I didn’t know after all these years was that the Double Double has  an easy alternative – sort of a Double Double with training wheels attached – for those who want a warm-up exercise – or just a fun side trip. It’s neither as charming nor demanding as the Double Double, and it is not a true binary system where all the stars are related and in one another’s gravity field. But – it’s got it’s own charm and it is easy. I learned about it from “Turn Left at Orion,” the great little observer’s guide from Guy Consolmagno and Dan Davis.  I was checking the distance to the Double Double stars before going out (200 light years) and saw under “also in the neighborhood” directions for finding the Double Double’s Double.

Finding Iota.

Finding Iota.

I won’t give all the details. Essentially you go to Iota Lyrae, a 5th magnitude star that’s easy to star hop to from Vega. (It’s barely visible to the naked eye here on the best nights, but bright in the finder.)  See chart above.

Moving Iota to the top right of this 2-degree field I was easily able to see the pair of 7th magnitude stars that make up the Double Double's Double.

Moving Iota to the top right of this 2-degree field I was easily able to see the pair of 7th magnitude stars that make up the Double Double's Double.

A degree and a half due south of Iota (see chart above)  are two seventh magnitude stars – a nice, wide pair like the  two primary  stars of the Double Double.  (Actually, these two are about three times as far apart as the two primary stars in the Double Double.) They are  Struve 2470 and 2474. The first one has  an 8.4 magnitude companion a generous 14 seconds west of it. The second has an 8.1 magnitude companion 16 seconds west of it. (To put those distances into perspective, the separation of the close pairs in the Double Double are 2.8 and 2.3 seconds – much more challenging.)

This was easy to split with the 80mm Eon and 13mm Nagler eyepiece yielding about 46X. (The same scope split the Double Double this morning, but needed 171X to do it and gave the cleanest split at 240X – a magnification I was surprised the little scope handled so well.)  I’m sure the wider Double Double’s Double will split with low  power and a smaller scope. It will be fun to check out in the “Little Rascal” – if it ever arrives. (Seems they sent it to the worng lace, so maybe I’ll get it next week.)

So – I find this all a little tongue twisting, but fun, and a good exercise in star hopping and splitting.

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