Orion’s Arrow

[David Basey]

Denis Buczynski has recently posted on his member’s page a very nice image of Orion here.

One part of the image leaped out at me and was a reminder of something that changed the way that I look at Orion.

Several years ago my wife Ishbel and I returned home late one November evening, Orion was well above the horizon and I remarked on this to Ishbel, saying how its appearance in the late evening sky was a sure sign that winter was on the way.

Ishbel who is a non-astronomer replied “Orion? Oh you mean the arrow?”.

Now this threw me. I’ve always assumed that the pattern of Orion was self evident, indeed it was picking out this constellation some 50+ years ago that first started my interest in astronomy. In all those years I had never seen an arrow in Orion. However, once pointed out it is quite obvious. The tip of the arrow is Delta with the belt forming one side of the point and the line Delta to Eta the other. The sword of Orion forms the shaft. I have delineated it on my rather poor image at right. Denis’ image shows it much better.

There is nothing about it in Burnham’s extensive section on Orion and a Google search only turns up one reference. Apparently it is moderately well known in the Caribbean, particularly Trinidad, and may be used as an aid to navigation as it points roughly due North.

I had always thought that pattern recognition would be standard across humanity and that like myself, people would see Orion as the belt and the four bright outer stars forming the rough rectangle. Apparently that is not the case.

While photographs can enhance the appearance of stellar patterns (mine fails miserably at this) the arrow once seen is quite obvious to the naked eye. The faintest star, Eta, is magnitude 3.4 and is consequently visible under reasonable skies.

Should the clouds ever part again, have a look and see what you think.

Happy New Year,

David.

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[Dr Andrew Smith]

I think what you see is very much determined by your environment and culture. I can’t “see” the classical constellations. I see geometric  figures, straight lines, circles etc. Haveing had the arrow pointed out it now seems obvious.

Regards Andrew 

[David Swan]

Thanks David. The clouds are forecast to part this evening…. If they do, I will look for the arrow asterism. I have never thought this myself or even been told about it prior to your post.

[Alan Thomas]

That’s interesting, David. I had never seen it that way myself. I think we are conditioned to see patterns which can then be quite difficult to see in any other way. But I will look out for it next time I see Orion.

Elsewhere, I have not always been able to see the expected patterns. For example, the Owl Cluster (NGC457) looks more like a lobster to me than an owl! And with images of the Moon’s craters, they will often become ‘ambiguous figures’ in which they sometimes appear as depressions but will suddenly switch and look like raised areas. I’m not sure how common this experience is. Is it just me?!

Seasons Greetings

Alan

[Peter Mulligan]

Hi David

Its unbelievable that this has never been noticed by Amateurs.  But like you say your wife spotted it.  Its probable that we are so used to the bright star pattern of Orion that the arrow as gone unnoticed, I bet there’s lots of these asterisms to be discovered. I will have a look next clear night but might struggle with eta with the light pollution around here. Might take my wife out to a dark sight and see if she can spot anything! 

Peter

 

[David Swan]

It just doesn’t jump out of my skies. Whilst eta Ori is visible, it is so much less prominent than the belt stars that the arrow pattern does not emerge naturally in my mind. I think that Betelgeuse, Bellatrix and Rigel also frame the middle stars to be perceived as a belt.

[James Lancashire]

With a moonless and very transparent sky last night, I also didn’t think the ‘arrow’ asterism obvious as a ‘pointer’.

Maybe if you *needed* a direction but then why not stick to the usual end of the Plough?

I wondered if eta Ori might be variable and its eclipsing nature gives an 8-day period from mag 3.26 to 3.48

[Gary Poyner]

eta Ori is also a pulsating non supergiant star of the BCEP sub group.  Amplitude is quite small though; 0.01 to 0.3, so at it’s extreme upper limit, I guess it could be noticed visually .

Gary

[Jeremy Shears]

I enjoy hearing about what other’s make of star patterns. There is a lovely chapter in Skylight Nights where the young Leslie Peltier gets up in the small hours to view an unfamiliar region of the night sky. He makes up his own constellations, but none coincide with the “standard” ones. 

I tried to find Orion’s Arrow the other night, but even knowing what to look for, I struggled. Clearly I lack Mrs Basey’s imagination! Or perhaps it was that I was distracted by Betelgeuse’s faintness and that it might go supernova.

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