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Melotte 15, IC 1805, Sh2-190, The Heart and and an Open Cluster C 0225+615, in OSC, Alan Brunelle
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Melotte 15, IC 1805, Sh2-190, The Heart and and an Open Cluster C 0225+615, in OSC

Revision title: Melotte 15, IC 1805, Sh2-190, Reprocessed

Getting plate-solving status, please wait...
Melotte 15, IC 1805, Sh2-190, The Heart and and an Open Cluster C 0225+615, in OSC, Alan Brunelle
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Melotte 15, IC 1805, Sh2-190, The Heart and and an Open Cluster C 0225+615, in OSC

Revision title: Melotte 15, IC 1805, Sh2-190, Reprocessed

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Description

Melotte 15 was my primary objective, but given my wide field and camera I get the most of the rest.  I have provided a mouse-over sub frame of the central part of the larger image.  I have always admired the dust/gas cloud structures that this cluster of young intense stars has sculpted.  It sits right in the middle of IC 1805, common name The Heart.  It is very likely that the whole of IC 1895 is a local bubble cleared out by the intense UV irradiation from these stars.  But the structures that appear closest to the cluster are the most dramatic.  I deduce they are closest, but instead, we may be looking at the tip of a cloud column that falls away from us, from our perspective with the cluster superimposed.  Who knows?  But there are other clues, I think.  The spiral and bifurcating column seems illuminated the very brightest when compared to the perimeter "Heart", which seems to glow mostly in excited hydrogen with a bit of blue component evident in some areas inside the perimeter.  The dramatic columns appear embedded within a diffuse reflection component that seems to include some of the stars.  Reflection nebulae usually are more closely associated with their source of illumination, something that hydrogen excitation does not suffer so much from.  I will go with the theory that we are looking down at the top of a dust/gas cloud that closely approaches near or through the cluster and extends beyond, visually appearing to the lower left.  I say this because the arrow shaped shadowed portion of this cloud belies its position above most of the bright stars (hence the reason it is not illuminated).  As such, the whole column may actually continue, broken up, all the way to the dark nebulae at roughly 7 o'clock, which show us their shaded, unilluminated sides in rather dramatic fashion.

I have done a fair amount of star reduction of the image to highlight the outer reaches of the Heart.  However, I tried to leave a light touch with the bright stars in Melotte 15, since I wanted to leave the impression that there is obvious impact of the brightness of these stars on the formation of the structures.  Its hard for me to make sense visually of reflection nebulae being brighter than the stars that illuminate them!  

It is not surprising that this whole area is filled with young stellar objects.  In fact many of the very brightest stars seen here are listed as YSO.  This information I gathered from Simbad.  I should be careful when I describe an area as a hotbed of star formation because what is reported by Simbad is often findings from astonomers having concentrated their efforts in a particular area.  You see these astronomer-studied hot spots often, with a telltale signature when the area of hot activity is all concentrated in the shape of a square, or perfect circle.  So just because other areas displayed by Aladin may not list a lot of activity, it may actually be due to the fact that the professionals have yet to turn their gear on those areas yet and/or just not reported it yet.

For QHY 268C users, I chose extended deep well mode #3, and used a gain of 0, offset 8.  All hoping to not saturate bright stars.  ~90,000 e-, if you believe the numbers...

Comments

Revisions

  • Melotte 15, IC 1805, Sh2-190, The Heart and and an Open Cluster C 0225+615, in OSC, Alan Brunelle
    Original
  • Melotte 15, IC 1805, Sh2-190, The Heart and and an Open Cluster C 0225+615, in OSC, Alan Brunelle
    B
  • Melotte 15, IC 1805, Sh2-190, The Heart and and an Open Cluster C 0225+615, in OSC, Alan Brunelle
    C
  • Final
    Melotte 15, IC 1805, Sh2-190, The Heart and and an Open Cluster C 0225+615, in OSC, Alan Brunelle
    D

B

Description: Crop for Mouse-over

Uploaded: ...

C

Title: Melotte 15, Cropped

Description: For the mouseover, this is a cropped image of Melotte 15 proper. The old one is still in the list, and in some respects the contrast within that central section is stronger and therefore maybe more pleasing to some. But I believe the stars and some detail are better in this newly processed version.

Uploaded: ...

D

Title: Melotte 15, IC 1805, Sh2-190, Reprocessed

Description: This image is reprocessed from scratch, including better choices (I believe) made with settings in WBPP. But with the new tools for star reduction, star removal and noise reduction, I am happier. This version tries to render the deeper darker sections as brighter (really brighter overall) to show detail that was lost in the earlier version. The artifacts and defects in the stars from the previous version are gone, though I did not try to round the stars on the periphery. I felt this unncessary since the scale of view is intended to not be such that you would notice. Also the treatment for noise, using NoiseXterminator is so much better and causes less artifacts throughout. Processing is getting much simpler!

Uploaded: ...

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Melotte 15, IC 1805, Sh2-190, The Heart and and an Open Cluster C 0225+615, in OSC, Alan Brunelle