M81 and 82 with integrated flux finally in colour

[MartinB]

In March 2010 I had the huge pleasure of spending a couple of weeks with Olly at Les Granges.  One of the goals of my trip was to capture the integrated flux around M81 and 82.  Integrated flux is extremely faint nebulosity produced by dust reflecting the light of the milky way itself (unlike normal reflection nebulosity produced by light from a near by bright star).  I did manage to capture the flux although the amount of stretching needed to show it created havoc with the rest of the image.  At the time, I didn't have any decent colour data and, after nearly 6 years (helped by my neighbour chopping down a couple of trees), I've finally got round to it. It's less than an hours worth in each colour channel but that's all that's been available for the past couple of months I've been set up and ready to go.

Scope: Tak FSQ 106 with 0.73 reducer (F3.6)

camera: QSI 532 wsg

filters: Baader

Luminence: about 10 hours mixture of 5 and 10 mins some with a cls filter and some without.

colour 9x6mins each channel

Captured, calibrated and stacked with Maxim.  Processed in PS

The processing was a bit of a challenge.  The flux is faint, the galaxies are bright and I've made a few compromises.  This isn't something I'd want to attempt with PixInsight.  I resorted to some pretty rough handling of the data!  But, there isn't a pixel in the image which was added inappropriately!!!

[MartinB]

Damn it!  Thats an uncompressed PNG file and much darker on here.  So here's a jpeg!

[abhoriel]

awesome images..

so this flux is dust reflecting light from the milky way. I guess its the whispy stuff amongst the blackness between the galaxies in your images? Is this dust intergalactic then or interstellar dust within our galaxy?

Apologies for the stupid questions.. I'm just curious!

[gorann]

Stunning image!

I guess we should be happy that there is not more of this dust since it would mess up galactic imaging

[MartinB]

It's dust in the Milky Way and not related to the galaxies.  The Milky Way is full of dust which is why we can't see to it's centre in the visible spectrum. Spring is the galaxy season because we are then looking out through the thin part of our galaxy

 

[laudropb]

Smashing image. 

[ollypenrice]

I remember your doing this one, Martin. Great to see it re-surface. In the last few years the village has been turning off its lights at 11.30 so the view to the north is now slightly improved. In truth the improvement is slight because the lights were few and quite well sheilded but, on something like this, it probably makes a difference.

As you say, the IFN does lead the imager into the strong-arm stuff but you've done your heavy lifting very discretely here.

Olly

[Mr Spock]

There's a lot of dust there and your image shows it well. Great stuff

[MartinB]

Thanks Olly and Michaell.  When I was at Les Granges shooting this there was a tiny bit of light coming from the village although, IIRC, the lights were well cowled.  Now that they get turned off things must be close to perfection.  

[Barry-Wilson]

The jpeg really displays the IFN. Good job to not leave an over processed image yet draw out the IFN.

[MartinB]

Thanks  Barry, M82 has a bit of a stuck on look which I was trying to avoid.  I have much higher resolution images of both galaxies but I didn't want to use those because it does start to look too artificial..  Also, there's some wispy stuff around M81 which is just from highly stretched outer galaxy layers that was too dim for the colour shots to pick up.  Never mind, every image I've looked at of IF in this region has "issues"!