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NGC 457 the ET, Owl or number 5 is Alive! cluster

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#1 Starobserver


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Posted 07 September 2009 - 09:11 AM

When you look through the Cassiopeia window you see a lot of open clusters, which actually belong to the Perseus arm, the next spiral arm when looking outwards, away from the galactic centre. One of the clusters is NGC 457, also known as the ET cluster, the Owl cluster and for me personally as the "Number 5 is Alive" cluster.

Observing report
This striking open cluster is very easy to find and identify. Even with the lowest magnification possible, the 35mm Panoptic (46x and true field of view 89'), it is completely detached from the background. I first tried all possible magnifications but in the end I like the looks through the 22mm Nagler best. It shows NGC 457 nicely with some space left around it. This eyepiece was also used for the sketch.

NGC 457 looks like a little "stick-figure" with its arms spread out widely, and he welcomes me to visit his wonderful world. It looks like a very warm welcome. A nice way to start the observation! The shape of the little figure is very obvious. In my 300mm Dobson he stands right up with his feet down in the north and his head with two glittering eyes up in the south. He spreads his arms out to the east and west. A lot of observers refer to NGC 457 as the ET- or Owl cluster, and I understand why, but to me personally, NGC 457 reminds me very much of Johnny, the friendly robot from the movie "Short Circuit" (Number 5 is alive!). On the movie poster he stands with his mechanical arms stretched out to the heavens, while being struck by lightning, and that's exactly the pose I recognize in the star pattern of NGC 457.

A pair of bright stars represents the eyes of Johnny. One is definitely yellow with a hint of orange, the other looks plain white with a suspected very faint yellowish hue, but I'm not 100% sure about this. I know there is a magnitude 9 M class star somewhere in this cluster, which should be "red", though I cannot find it. There is no real "central star". However, I do see two small asterisms inside the "body" of NGC 457, which jump right out at me. First of all, going north from the eyes I see three stars forming a little triangle. A bit more to the north, somewhere on Johnny's chest, I see a group of six stars forming a large question mark.

There are several chains of stars forming the arms and feet, but there are also dark and empty patches. I see no glow of unresolved stars or nebulosity. It is a sparkling bright cluster but not very rich in stars. While sketching the cluster I counted about 45 to 50 stars, some of them popping in and out of view. I didn't include all of these stars in my sketch. The two bright eyes of Johnny are of magnitude 5 and 7. The other stars magnitudes range from 8 to 13, so there's quite a large range of magnitudes visible.

The Cassiopeia window and Phi Cassiopeia
If you are interested in a little more background info about the Cassiopeia window and Phi Cassiopeia, maybe the brightest star (or not?) of NGC 457, please follow this link.

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#2 JakeSaloranta



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Posted 07 September 2009 - 12:18 PM

I sketched this very same cluster Friday, the 5th of September! My sketch is just rotated north up. A splendid cluster!

Instrument: 8" Orion DSE
Observing place: Koivukylä, Vantaa, Finland
Date: 4./5.9.2009
Bortle class: Class 5 (suburban sky)
NE Lim.mag: 5.4 (UMi)
SQM-L reading: 18.07 (UMi)
Background sky: 5
Seeing: 3
Transparency: -
Weather: +12.0°C, humidity ~94%, air pressure 1005.1 HPa, S wind 4.0 m/s. 99% moon in Aquarius.
Posted Image

#3 JayinUT


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Posted 07 September 2009 - 12:30 PM

Nicely drawn cluster by both of you. One of falls finest in my opinion.

#4 kraterkid


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Posted 07 September 2009 - 01:13 PM

Math and Jake,

These are superb sketches! :waytogo:

#5 Edwin Quiroga

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Posted 07 September 2009 - 03:49 PM

Very striking sketches!!! To me, this object remember the mythical "Mothman" from Western Virginia.

#6 frank5817



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Posted 08 September 2009 - 05:29 AM

Math and Jake,
Excellent sketches of a fine open cluster with a comfortable number of stars to sketch.:waytogo:

Frank :)

#7 JimPie


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Posted 08 September 2009 - 11:36 AM

Math & Jake
Very nice sketches .
I like the "#5 is alive" Ive never herd that name before.

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