Izar (Epsilon [ε] Boötis) (Σ 1877) (AB is H I 1) HIP: 72105 SAO: 83500
RA: 14h 45.0m Dec: +27° 04′
Magnitudes AB: 2.6, 4.8 AC: 2.6, 12.0
Separation AB: 3.0″ AC: 175.5″
Position Angle: AB: 345° (WDS 2011) AC: 255° (WDS 2001)
Distance: 210 Light Years
Spectral Type: K0
Located to the northeast of Arcturus, Izar is the first of the stars that forms the east side of the kite-shaped asterism of Boötes — and it can be a very frustrating little devil to split. On a rare night of stable seeing it can easily be done in a 60mm scope with good optics. But on a night of poor seeing (more common it seems), you’ll find it hopeless in an eleven inch SCT. But regardless of what you finally pry it apart with, you’ll find the time has been well spent. The reward comes in the form of a very small secondary nestled right up against a much larger, colorful primary.
If you attempt it with a small scope of between sixty and eighty millimeters, you’ll find the very small companion is often hiding in the diffraction ring. In that case, I’ve found that varying the magnification will usually bring it out. In Double Stars for Small Telescopes, Sissy Haas describes the primary as amber-yellow and the secondary as deep blue. She credits Admiral William Henry Smyth with “pale orange; sea green,” which pretty well describes the colors I see, although I lean more toward gold than green in the secondary — but I can clearly see the green tint most of the time.
Now if you’ve never looked at Izar, you’re very likely to discover that once you’ve split it, it’s siren call will keep luring you back for another view. I’ve lost track of both the number of times I’ve pointed a scope at it, as well as the amount of time I’ve lingered over it admiring the view ………………………..
and wondering if any Izar-ians were looking back at me. 😯
Since Boötes is a spring and summer constellation, most of your observations of it are likely to be in reasonably warm and comfortable weather, as was the case with the one described above on a sixty degree evening in April of 2010. But if you’re an adventurous type, and like to observe in the early hours of the morning, you can catch it in the brisk winter air. Which, in defiance of good sense, is what I did on the following occasion.
Here’s the scene:
It’s 2AM on the morning of February 19th (2011), the sky is clear and, thanks to a barely waning moon that is about 97% full, it’s also bright. It’s 35 degrees and there’s a cold — very cold — wind blowing at me from the northeast. And the stars in the sky that I can see are twinkling like they’re all about to explode.
But I can’t resist. The lure of those twinkling white dots of light up there in that pale blue sky is not meant to be missed.
My deck is out of the question because it’s got a thin coat of ice on it — not the place for a star-splitter who is focused on splitting stars instead of paying attention to his footing.
So out into the drive I go with my 63mm Zeiss — facing almost directly into that chilling north wind that is determined to freeze me in place in my chair.
But good sense will only get me a warm bed with an absence of starlight.
My view of the sky is limited from here, so I spend some time on Algieba — quite a lot of time, actually — then look at Saturn for a bit, and finally turn the Zeiss to face the Izarian music.
The seeing has improved a bit by now, which I was hoping for — but not much. When I came outside, it was so bad even Izar was twinkling.
So, the question confronting the lens at the end of the 63mm f 13.3 Zeiss is: Can you split this one in these confounded conditions?
We — which is me and Herr Zeiss — start with an 18mm Tak (47x), not with the intention of carving out a split, but just to survey the surrounding stellar neighborhood. Not bad, things looks reasonably stable.
Next move: a 15mm TV Plössl (56x), which just did a great job on Saturn and was breath-taking on Algieba. Not quite a split now, but it’s close.
So Herr Zeiss and I confer and decide to make a forward leap of faith into the middle of a 12.5mm Tak (67x). Now that may not seem like a lot of magnification, but in this seeing, it’s about the limit of what will work.
In it goes, and after several attempts to catch a sharp focus while the image is bouncing around, the devious little dot of a secondary pops into view — and out of view — and into view — etc, etc, etc.
But — we got it! Herr Zeiss und Herr Nanson.
We stayed with it for about fifteen minutes, which was all I could take. At times the image was nice and sharp, at other times it would suddenly balloon up as if someone was holding a match beneath it, and most of that time it was bouncing around so much it made me think I was being tossed around the deck of a small boat on a storm ravaged sea. So enough was enough.
And anyway, my fingers were now ice, and my toes were edging toward the negative side of the Centigrade scale — but Herr Zeiss didn’t seem the least bit perturbed.
I think he was hypnotized by the strange stellar tones of that Izarian Musik. Fortunately it wasn’t penetrating my numbed mind.
So, we called it ein gutes Nacht and headed for the Haus, accompanied by our four-legged companion, Herr Klaus.