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The Proud Head of Orion: Marching with Meissa (Lambda [λ] Orionis) and OΣ 111

Majestic Orion! Click on this and any of the following images for a larger view, and then click a second time to enlarge the view once more. (Stellarium screen image with labels added)

Situated halfway between bright orange Betelgeuse and blue-white Bellatrix  and about three degrees to the north, Meissa is a busy little devil.  It anchors a large open cluster, Collinder 69, and illuminates a large ring of gas 150 light years in diameter.  Meissa “A” is a very hot star sporting a sizzling temperature measured at 35,000 Kelvin, and Meissa “B” is just barely cooler at 27,000 Kelvin.  At those temperatures, they each send a tremendous amount of energy into that cloud of gas. “A” radiates 65,000 times more than the sun and “B” drops down to a comparatively smaller, but still considerable,  5500 times more than our own star.  The source of the name is somewhat vague, but James Kaler’s best guess is it’s from the Arabic for “the Proudly Marching One.”

A closer look at the Betelgeuse-Bellatrix-Meissa area. (Stellarium screen image with labels added)

In a telescope, Meissa and the surrounding area is a beautiful sight at any time, but especially for my photon deprived eyes after a lengthy run of rotten viewing weather.  South of Meissa are two fourth magnitude stars, Phi-1 (Φ-1) and Phi-2 (Φ-2).  This pair combines with Meissa to form a slightly tilted irregular triangle.    Phi-1 is a class B0 star located at a distance of 985 light years, and Phi-2, which to my eyes has a very distinctive reddish-orange flavor to it, is a G8 star at a much closer 116 light years. Inside that triangle is a line of three north-south aligned stars.  The northernmost has a magnitude of 7.6,  and the next one to the south is at 7.5.   The southernmost one, HIP 26212, is a class B2 star with a magnitude of 6.7 sitting way out there at the sizable distance of 1388 light years.  Burnham comments that the moon would actually fit within this triangle, which measures twenty-seven arc minutes on the west side and thirty-three along the south edge.  Completing the telescopic scene is OΣ 111 (STT 111), sitting about 14 arcminutes north of Meissa.  This one is another double, with magnitudes of 5.6 and 9.7 separated by 2.9″, positioned at a distance of 1463 light years from us.

So as should be rather obvious from this long introduction,  pleasing photonic opportunities abound in this very small area.  And as I alluded to earlier, my opportunities have been severely curtailed for the past five weeks due to a parade of very wet clouds that were considerate enough to drop thirty-three inches of rain on my observing sight as they passed through.  I tried several times to get a peek at Meissa through sucker holes, but as usual, the clouds waited until I was lined up and then leaped back across my view.  I even managed to get rained on twice during those futile frustrating attempts.  So pull up a chair and make yourself comfortable, because we’re going to spend some time here — no looking and leaving, no viewing and vamoosing — we’re going to sit and stay!  My goal is to become so familiar with this wonderful area of sky that I can call up an image of it in my memory quicker than you can swap browser screens.

Finding this area is easy – as described above, from a point midway between Betelgeuse and Bellatrix, move north a few degrees.  If you have reasonably dark skies, you’ll see a faint triangle of three stars just north of that line, which represents the head of Orion.  Moving from east to west and then north, these stars are Phi-1, Phi-2, and Meissa.  In a finder with a four or five degree field of view, this entire area — from the Phi twins up to OΣ 111 — is a an eye-catching open cluster known as Collinder 69, and it’s especially attractive due to the three north-south aligned stars between Phi-1 and Meissa.   I dropped a 26mm Plossl (30x) into the focuser of my AT-111, which gave me a reasonably wide 1.7 degree field of view —— and I could feel all the rusty corroded connections in the dim recesses of my astronomical memory coming to life once again as the photons flew through them!  What a sight for star starved eyes!  The Stellarium screen image below gives you a hint of what it’s like, but don’t take my word for it — go out and take a look!

Image as seen in the eyepiece of the AT111 at 56x - note that east and west are reversed. (Stellarium screen image with labels added)

Image as seen in the eyepiece of the AT111 at 56x – note that east and west are reversed. (Stellarium screen image with labels added)

So, on to the serious stuff — Star Splitting!!!

Meissa  (Lambda [λ] Orionis)   (Σ 738)  (AB is H II 9)       HIP: 26207    SAO: 112921
RA: 5h 35.1m  Dec: +09° 56′
Magnitudes    A: 3.5     B: 5.5     C: 10.7     D: 9.6    E: 9.2
Separation     AB: 4.2″      AC: 28.7″      AD: 78.0″    AE: 150.4″
PA    AB: 44° (WDS 2011)   AC: 185°   AD: 272°   AE: 279°  (C, D, & E all WDS 2008)
Distance:  1056 Light Years
Spectral Classification    A: O8    B: BO.5

Now Meissa “B” is not particularly difficult to see, so I started with a 14mm Radian (56x) in the AT 111 and was just able to glimpse it clinging to the side of the primary, and about an arc minute off to the west, “D” was also easy to pick out of the glare, and “E” is easy to see hovering all by itself out beyond “D”.  Out with the 14mm and in with a 12mm version (65x) and “B” became a perfectly round white dot of light just out of hugging range of “A,” and “C” now came into view with averted vision.  I’m not in a hurry here ;), so the next move was to a 10mm Radian (78x) which gave me a slightly larger, but essentially similar view.  Still savoring the moment, I reached for the 8mm Radian (97x) — which allowed me to pick out “C” with direct vision, although it was difficult to hold for long.  One more magnified leap forward, to a 6mm Radian (130x), and I was able to hold “C” with direct vision for long periods of time.   Searching for an aesthetic alternative, I dropped back to a 7.5mm Tak LE (104x) and was surprised at how steady “C” was in it.  And then, backing away from my focus on the four Meissa components, I went back to the 14mm Radian and took in the entire field of view once more.  As I sat there for several minutes absorbing the beauty of it, I noticed “C” was occasionally visible out of the corner of my eye.

The primary I saw as white and “B” I would call gray, but Haas saw “lemony white and ashy blue-violet,” which are the colors hinted at in the sketch.  (East & west reversed to match the refractor view, click to lose this caption).

Two nights later I returned with a Tasco 60mm f/16.7 for another look, mainly curious about the different perspective provided by the smaller aperture and the longer focal length.  With a 26mm Plössl (39x) I needed averted vision to pick out “D,” but was able to see it with direct vision when I moved up to a 20mm Plössl (50x) — and “E” was obvious, thanks to it’s greater distance from all the glowing that was going on closer in.  With 15mm (67x) and 11mm Plössls (91x) I was able to glimpse “C,” but it was difficult because of the cloud of gas which is illuminated by Meissa “A.”

There was something noticeably different about this view, though.  Of course, it wasn’t as bright and the stars were slightly dimmer in comparison to the four inch aperture of the scope I used two nights earlier, but those weren’t surprises.  Instead, it was the compactness of the view that intrigued me.  The field of view in the AT111 using the 14mm Radian comes in at 1.06 degrees, while the 20mm Plössl in the Tasco gave me .98 degrees — so, from a numbers standpoint, they’re essentially the same.  But the entire field in the Tasco was just “neater,” as in “freshly pressed” (with a stellar iron)  — which I’m pretty sure was just a result of the smaller image scale resulting from the smaller aperture.  That’s not to say the view in the AT111 was lacking in any way — just that it was not the same.  Everyone has their preferences, and those will change over time.  On that night, I preferred the view in the 60mm.  Next week — if it’s clear (!) — I may lean back to the AT111.

Now about that gas cloud that Meissa illuminates with so much energy: I can’t honestly say I’ve ever noticed it prior to these two nights, but it really was not difficult to see in either the 111mm or the 60mm refractor.  If you look right at Meissa “A,” you won’t see it — but if you avert your vision just a bit, it pops right into view.  I could see it quite easily at both low and high magnifications that way.  Most of the time it had an oval shape, extending about an arc minute to the east of “A” and as far west as “D.”  And I noticed in an 8×50 finder it appears slightly larger than that.

OΣ 111 (STT 111)         HIP: 26215    SAO: 94671
RA: 5h 35.2m  Dec: +10° 14′
Magnitudes: 5.6, 9.7
Separation:  2.8″
Position Angle:  351°  (WDS 2003)
Spectral Classification: B9
Distance: 1463 Light Years

Up to this point, I’ve neglected poor old OΣ 111, which sits on the north fringe of this cluster of stars.  Looking at the statistics, I could see this was going to be a difficult one to split, but based on experience, it certainly didn’t strike me as being out of range.  Both nights I was out, the seeing was below average — well below on the first night with the AT111, just on the negative side of average on the second night when I tried with an AR-5.  On that first night of no luck, I stopped with a 5mm Tak LE (155x) because the image was bouncing around so badly I couldn’t hold it in view for more than a fraction of a second.  I was sure I could nail it, though, the next time out with the five inch AR-5.  Again, no luck, and again, I had to give up because the image was bouncing around so badly I would have needed half a dozen motion sickness pills to keep at it.  I may have had a glimpse of it with the 5mm Tak (236x), but it was so fleeting it was impossible to be sure.  I gave a 4mm Plössl (295x) a try, but it bounced out of the field of view more than it was in it.

I’ll come back to this one on a night when the seeing is better.  I suspect what I’ll find is the companion is a very small pinpoint of light.   If you, the reader, happen to split this elusive little devil, by all means post a comment here and let us know.  We would be honored to have it on this site.

These observations were made on the evenings of two different years:  December 30th, 2010, and Jan 1st, 2011.  🙂   Data on Meissa is from Jim Kaler’s web site, which is highly recommended!

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7 Responses

  1. Thanks for a great read i can examine all too leisurely at cloud central. I was dimly aware of an interesting backround to Meissa -one of the first doubles i looked at and still enjoy when the big O rides in the sky. Apologies to Roy Orbison -i still remember where i was when i heard his amazing voice had died. what a tragic life he had. Now i have another piece of sky to roam around where before i just looked at an easy and pretty double. All i need is something less than 100% cloud. regards, rich.

  2. Agreed John: “Phi-2, which to my eyes has a very distinctive reddish-orange flavor to it. ” my notes put it as orange and this is a delightful area. I was using the the Tasco 76/1200 and the 6X30 finder showed a wonderful, strong lightning bolt of six stars. When I dropped in the 30mm Tak LE I counted 40 stars in the field and that was before my eyes dark adapted! What’s more, there was asix-day old Moon still about 22 degrees above the western horizon offering a little competition.

    Not sure, but that Moon might have made it difficult for me to locate “C.” The “B” and “D” component popped right out with a 12.5 Tak (96X). I saw “B” as distinctively orange. But finding “C” was a battle. I tried the 7.5mm Celestron Plossl (160x) but seeing was still a bit below average and at that power there was a lot of light being thrown into the quadrant of the diffraction rings nearest to the PA of “C.”

    I switched to the 10mm Tak and that did the trick. It quieted down just enough for me to glimpse “C” from time to time with averted vision. Boy, I want that 4-inch F12.5! It’s on the way – so is the 4-inch F10. I think either would have made “C” easy,

    One Interesting note – not sure if you mentioned this – but there’s a star that is almost the same PA as “D,” but nearly twice as far away and significantly brighter – still, someone might mistake it for “D.”

    I took a quick look at OΣ 111 and could see something at about the right PA, but I didn’t have much confidence in it. I would call that a “maybe.” I did not see the gas cloud you mentioned – but then I didn’t look for it and my skies, even without the Moon, are not as dark as yours.

    • Yes, there is a star beyond “D” that can be confusing – it confused me! I show it in the sketch above at the location you’ve described.

      (Update 3/4/2012): That star out there past “D” turns out to be the “E” component of this system. It’s listed in the WDS as GUI 9, so it isn’t immediately obvious unless you look closer and see the coordinates are the same as the other stars in the system. I’ve updated the sketch and labeled that star now).

      After I was able to get a glimpse of “C,” I had a means of estimating the 78 arcsecond distance to determine which one was the correct star.

      Short distances like that are tough to estimate as you change eyepieces, even when you know the field of view for the one you’re using. Of course, if your seeing can stand it, the solution is to use a 2.5mm eyepiece with a 10 arcminute field!

  3. January 19th, 10PM

    The moon was about 99.95% full tonight and positioned high in the sky – which means the sky was bright blue, and the few high clouds in it were very busy bouncing all that light all over the place.

    But not one to miss a clear night – the first one in about ten days – I turned a 72mm AT ED scope on Meissa to see what could be seen.

    Wide field view with a 20mm Plossl (23x) – OK, but not outstanding. The image was too bright with that moonlight meandering through it.

    10mm Tak LE (43x) – holy Meissan miracle! I could NOT believe this. Meissa “B” was a very small, very sharp, pinpoint of light nestled up so close to Meissa “A” that if it was any closer, it would have been invisible. But that little point of light was etched against the sky as if it had been put there by an expert jeweler. It was hard to believe that something that small could be so close to it’s primary and still be seen as clearly separated from it.

    Two words describe it: “Delicately delicious!”

    I will never cease to be amazed by the surprises that lurk in an eyepiece.

  4. Well, I at last got a good look at “C” – but I’m afraid I couldn’t describe it as “delicately delicious” 😉

    I tried the 8-inch Celestron Edge on Meissa and got rewarded with a clear, steady look at C using 10mm Tak (200X), but everything was very mushy at that power in that scope. Transparency was below normal and I would say seeing was below normal – well below I hope because I switched to the 105/1250 and was extremely disappointed. I couldn’t get above 100X without everything becoming a mess and no chance of seeing “C.”

    Interesting. Here was an example of the 8-inch actually outperforming the 4-inch because of seeing. Either that or the lens on the 4-inch has suddenly gone to hell. ) really don’t know what to make of it – and the clouds came in before I could decide,

    Bottom line – view in the 8-inch was mushy, but acceptable. The view in the 4-inch was only good at about 70X. If I had had time I would have put the 8-inch back on the mount. Maybe while I was switching, seeing got worse.

    But – while I had barely detected “C” before I at least got a very good look at it. So good a look that I made careful notes about its position because as I remembered your drawing I thought you had it off by a bit. Nope -we both have it in exactly the same spot. What was off was my memory. No surprise there 😉

  5. Out with the ETX-90 for a brief evening spin. Castor was nice in a 10 mm Tak especially – but optics still cooling.

    Seeing and optics were better by the time I got to Meissa after a stop at M35 which was impressive. But Meissa really blew me away. I love the A/B split – D just sort of hangs out there looking on – but C is the shy one, visible only because she blushes once in a while and glows enough to catch your averted vision.

    Best view was in the 5mm Nagler (250X) – I’m talking absolutely perfect stars all around, though perhaps a little too much light in the diffraction rings. 7.5 Nagler was nice, but you lost C with that one. Need the higher power to darken the sky background.

  6. Ah, the elusive OΣ 111.

    I’ve tried and I’ve tried and I’ve tried to split this diminutive little devil but it keeps dodging my determined efforts.

    I’ve tried with the AR-5 at least half a dozen times, and I tried two nights ago with my six inch f10 refractor. I was SURE I would capture it that time. I wasn’t even concerned about it. Just point the scope at Meissa, get a very exact focus on it, then pan north to OΣ 111. Piece of cake.

    Wrong. Not the least luck.

    OK, maybe more aperture. These are the vital statisics: magnitudes of 5.6 and 9.7 separated by 2.9″.

    I made up my mind to forget about it for a while and come back some other night with the C9.25.

    But I was out last night with a four inch f10 Celestron refractor I was coaxing along with exhortations about living up to optical expectations, and it was responding rather well.

    So I repeated the exercise I had used with the six inch refractor.

    Go to Meissa, get a very sharp, precise focus, and then pan north to OΣ 111.

    So I did.

    And there it was.

    Immediately.

    As I moved it into the center of the field of view with the slow motion knob on the mount it came into sight immediately!

    No searching, no straining …. not even any swearing. Honest.

    Very faint, but sitting at the top (north) of the primary grinning back at me just like it had been there all the time. Which, of course, it had. But not for me to see.

    I was using a 14mm Radian, which gave me 71x, so we’re not talking about a lot of magnification.

    But it was enough. In fact to be precise, it was the perfect choice.

    So the moment was too good to let pass. I sat and absorbed that view for a good 20 minutes. Most of the time I could hold that 9.7 magnitude secondary in sight with no problem. Every ten or fifteen seconds, it would disappear — as if to remind me I was fortunate to be seeing it — but it always came back quickly.

    The seeing was about a 3.5 on a scale of five (five being unbelievably great and unfortunately rare), and transparency was a four on the same scale. So those conditions played a huge part here. The evening I had the six inch out, both seeing and transparency were about 2 on a five scale.

    Anyway, I just sat and watched and sat some more and grinned a lot.

    That very fine point of white light — a hair’s distance away from it’s big brother.

    I’ll dream about it for weeks.

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