Celestial hemisphere:  Northern  ·  Constellation: Ursa Major (UMa)  ·  Contains:  Bode's Galaxy  ·  Cigar Galaxy  ·  HD85161  ·  HD85458  ·  HD86574  ·  M 81  ·  M 82  ·  NGC 3031  ·  NGC 3034  ·  NGC 3077  ·  PGC 2719634  ·  PGC 2720796  ·  PGC 2721118  ·  PGC 2722319  ·  PGC 2723482  ·  PGC 2723731  ·  PGC 2724146  ·  PGC 2725076  ·  PGC 2725421  ·  PGC 2726432  ·  PGC 2726822  ·  PGC 2727224  ·  PGC 2727315  ·  PGC 2728713  ·  PGC 2728721  ·  PGC 2729331  ·  PGC 2729390  ·  PGC 2730097  ·  PGC 2730379  ·  PGC 2730409  ·  And 37 more.
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M81 (Bode's Galaxy), M82 (Cigar Galaxy) & Friends, Alan Brunelle
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M81 (Bode's Galaxy), M82 (Cigar Galaxy) & Friends

Revision title: Higher Contrast Revision to enhance M 81 Arm Stucture

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M81 (Bode's Galaxy), M82 (Cigar Galaxy) & Friends, Alan Brunelle
Powered byPixInsight

M81 (Bode's Galaxy), M82 (Cigar Galaxy) & Friends

Revision title: Higher Contrast Revision to enhance M 81 Arm Stucture

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Description

Revised Description 1/30/2023:
No new data.  But processing started with a fresh stack via WBPP in PI.  This revision is the result of processing with new tools in PI.  But as is obvious, I rotated this to closely match how it appears in Aladin, with North up and east left.  This was a bugger.  A flaw in the data left me with moderate to strong stars often with what looked like a stem.  Must have been an issue with my cable routing on the RASA.  I was still figuring things out at the time.  I also reduced the noise, stretched a little different and saturated the colors more to make the scene look even more dramatic.  Especially with the dramatic contrasting colors of M 82 with the blues from the many blue stars driving the outflow of red gas from the center of the galaxy.  Maybe I over did it a bit, but what the heck!  It could be argued that the original M 81 is better because the dark clouds are more pronounced than the version...

Original Description:
I was not expecting much from this given the very sizeable moon hanging in the east sky during the full shoot of this target. But this was about as far in the opposite direction from the moon as I could get. Even so, I still had some serious gradient to deal with, which I partially solved by cropping! Also, a new camera and uncertainty as to exposure setting, etc., offered me little hope as to great success. However, I was able to get a lot of subs, for sure. For me, that is. But one night out of the last 5 months, what is one to do!

In the end, I am pleasantly surprised, because all the indications from software assessment of the subs was for a very high sky background. I was surprised to even detect what I first thought was a faint IFN signal across much of the frame. I did not process this image in a way to preserve much of the IFN signal since I was more interested in the galaxies themselves. But I will elaborate more on this "IFN" below. In any case, I have to say that I am pleased with my new QHY268c. Given the chance, I will have to revisit this field of view with much darker skies. But first I need to deal with the tilt issue when the skies clear!

As I looked at my subs, stacked, and partially processed image, I noted a faint image of IFN-like signal across much of the field. Striking to me, was that this signal appeared to be somewhat circum-galaxial (a word?) around M81, as if M81 had cleared out a spot. If this is IFN, it could only be a coincidence. IFN is Milky Way stuff only. This whole area certainly has a lot of IFN, without a doubt. Very widefield images demonstrate that fact. But I actually believe that some of this signal may be galactic halo stars. I think that M81 is much larger in extent than the bright visible body of the spiral. I would also argue that M81 has much longer arm extensions than are easily seen. I offer that two blue stellar clusters one at 5 o'clock (listed as galaxy PGC28757) and a much smaller one at 10 o'clock (See my additional photo and near the center of the yellow circle) correlate with the extension of each of the two main galaxy arms. PGC28757 is presumed a satellite galaxy of M81. The smaller blue stellar cluster seems to be uncatalogued and, as far as I have seen, unnoticed, yet is interesting because it has a longer axis that seems to follow the contour of what one would imagine an extension of the lower M81 arm as should it wrap around and above M81. PGC28757 has no such symmetry, however, being closer to the end of the upper arm, it makes sense for it to be that much more substantial. As seen in other's photos, just beyond PGC28757, there is IFN-like density that is rather disrupted and may be a stellar halo arm extension that is gravitationally affected by M82. Whether PGC28757 is a true galaxy or part of M81's arm may be semantics, since it is believe that that all larger galaxies are the result of an accumulation of small galaxies. But a differentiating property might be an analysis of PGC28757's rate of motion relative to M81. If it is found to be rotating in a manner consistent with the rest of the galaxy at that distance from the center, then one has to consider it already merged or just a clumpy part of the existing arm. This in contrast to the Milky Way's own LMC and SMC, which are now known to be zipping past us at too high a speed to ever merge with the Milky Way.

For QHY268c users: Mode 0, gain 28, Offset 10 @ 90 seconds. I consider this a somewhat Low Dynamic Range object, which may seem counter since these are galaxies and they do get bright.

But I did not saturate much on these 90 second subs. Seemed to work well, considering the big moon.

Comments

Revisions

  • M81 (Bode's Galaxy), M82 (Cigar Galaxy) & Friends, Alan Brunelle
    Original
  • M81 (Bode's Galaxy), M82 (Cigar Galaxy) & Friends, Alan Brunelle
    B
  • M81 (Bode's Galaxy), M82 (Cigar Galaxy) & Friends, Alan Brunelle
    C
  • Final
    M81 (Bode's Galaxy), M82 (Cigar Galaxy) & Friends, Alan Brunelle
    D

B

Description: Here is the slightly cropped unmolested view. The other revision has the highlighted area discussed in the text.

Uploaded: ...

C

Title: Revision 1/30/2023: M81 (Bode's Galaxy), M82 (Cigar Galaxy) & Friends

Description: See main Description for details.

Uploaded: ...

D

Title: Higher Contrast Revision to enhance M 81 Arm Stucture

Description: This I am adding to highlight the spiral arm structure of M 81. I felt that these were a bit swamped by the starfield haze between arms in my stretch to bring out the IFN and stellar streams surrounding M 81. So a masked contrast with CT.

Uploaded: ...

Sky plot

Sky plot

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M81 (Bode's Galaxy), M82 (Cigar Galaxy) & Friends, Alan Brunelle