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ollypenrice

Another look at M101

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Posted (edited)

An interesting set of points made by Vlaiv on Rodd's M101 dataset thread sent me back to my own data to see if I was guility of making the spiral arms too blue. I think I was, but they refuse (by any reasonable means!) to become less blue than this. I had a lot of data, over thirty hours, from Yves Van den Broek's ODK14 and our TEC140. Ha LRGB. The reference image in the other thread was the Hubble Team's though it concentrates on the core. 

1736800697_M101HSTcolour30Hr.thumb.jpg.400baaf7a8c7b1cf0ab8688cfe2a8338.jpg

Olly

Edited by ollypenrice
typo
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Posted (edited)

I like it, Olly, a lot.  I think by holding back on the colour in the arms it almost makes your brain work to make it more blue if that is how you prefer to see it, but it doesn't smack you in the face as blue, drawing your eyes away from the whispy dust tentacles and core.

Whether Vlaiv's comments are seen as right or wrong when we are simply making pictures I believe is immaterial and for the imager or picture producer to decide, but for me I do think it lends itself to almost forcing you to look at more of the detail rather than just be taken in by the intensity of the colour.

Great image and excellent processing as always.

Edited by RayD
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A beautiful image there Olly, you always serve up the finest work. Briefly and as simple as you can how do you stack images from different scopes, I imagine you have to use the same camera but the FOV will be different, if the answer is complicated don't bother as i will never understand it.

Alan

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Posted (edited)
41 minutes ago, alan potts said:

A beautiful image there Olly, you always serve up the finest work. Briefly and as simple as you can how do you stack images from different scopes, I imagine you have to use the same camera but the FOV will be different, if the answer is complicated don't bother as i will never understand it.

Alan

If it were complicated it would be beyond me, Alan! I stack the images from the different scopes entirely separately so I end up with L from each, RGB from each and Ha from each. I then flatten the backgrounds of each of these separately in Pixinsight's DBE. Finally I open both Lums in Registar and combine them, then do the same with both RGBs and both Ha images. From then on it's the same as usual. (With an enormous amount of palaver it would be possible to align and calibrate every individual sub for subsequent stacking in a single run. I'll pass on that!!)

Olly

Edit: Registar is a doddle to use. It's expensive but saves me hours and hours since I'm always combining old and new data, data from different scopes, etc., and I use it for mosaics as well.

Edited by ollypenrice
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Looks good to me Olly. The speckled core of the arms are blue from star clusters while the fainter extensions are more neutral and I'm getting hints of yellow from older stars. I don't know what it really looks like but I suspect that's a good representation. Is the bright star on the right a little blown out and could it do with a tweak?

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Excellent image as always Olly.

Ive got about 12 hours worth of data on this from a week ago, but only got around to processing and posting the Lum so far.

Lee

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50 minutes ago, Knight of Clear Skies said:

Looks good to me Olly. The speckled core of the arms are blue from star clusters while the fainter extensions are more neutral and I'm getting hints of yellow from older stars. I don't know what it really looks like but I suspect that's a good representation. Is the bright star on the right a little blown out and could it do with a tweak?

It's already had an almighty tweak as it is! It was a whopper. I entirely deleted the reflector layer from it in order to lose the spikes. Unfortunately its halo swallowed up the smaller stars around it so any further restraint would produce a visual black hole around it. Indeed there already is one, unfortunately.

Olly

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I have to admit its nice not to have it screaming with saturated Blue, which I have done myself I must add.

Great job.

Tom.

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Very nicely done Olly. Compared to my own attempt at M101 (which also looks too cold in comparison), it shows just how much further the galaxy extends than I thought it did!

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Just Outstanding, great data expertly processed. I note that the HST image does have slightly bluer spiral arms further out from the core.
 

I think the FOV is perfect for this subject, you are far enough out to capture all the tenuous outer arms, but close enough to discern all of the intricate detail captured.

My Esprit 150/ASI 178 FOV combination is just too small to capture this in a single frame, a 4 panel mosaic would be needed, I also need more integration time, oh  and better skies wouldn’t go amiss either.  Plenty to go at for next season...

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Fabulous Olly!  I was going to say it was very natural looking but actually I haven't got a clue whether it is or it isn't!  I know the colours I like and this image ticks my boxes.  I tried to run pixinsights photometric colour calibration on your image but wasn't able to enter the correct capture parameters.  

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2 hours ago, MartinB said:

Fabulous Olly!  I was going to say it was very natural looking but actually I haven't got a clue whether it is or it isn't!  I know the colours I like and this image ticks my boxes.  I tried to run pixinsights photometric colour calibration on your image but wasn't able to enter the correct capture parameters.  

There are two sets of parameters in the image, Martin. I don't know how you'd factor them in. One set was at about 2.4 metres FL with 7 micron pixels and the other was at about 1 metre FL with 4.54 micron pixels. I can imagine the gurus of Pixinsight leaping to their feet and yelling ?Qué?????' The first question mark should, of course, be upside down but I can't do that...

Anyway, I'm glad you like it and we miss you.

Olly

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Posted (edited)
39 minutes ago, ollypenrice said:

The first question mark should, of course, be upside down but I can't do that...

Here's one of your very own to cut`n`paste Olly.

¿

Or if you want to get really funky.

 

I̪ä̴̫̲̗͕!͞ ͎̞̝̯̭̬̯S̬̼̜̖h̻u̳͚̫̭̰̟̘b̞̖̻-N̟͈̲͍̤͔i̹̲̥̱g͓͉̀g̸ur͝a͈͚͇̦͎̰̹t̤͍̦̤h̪̥!͔͔ T͏͖͖hḙ͟ ͝B͢la͇̮c̢k ̲̠̟͎͔Go҉̖a̗̲͉t̼͈͈̺̺̫̠ ͍o͏̯f͡ ̣̺͈̠͇ṱ̙̙̘̟̞ͅhe̸ W͡ͅo̹͈͍̺͞od̫̮̫̖͓̖̳s̡ w͓̮̪̠͟i̞̞̳͠t͏͎̤h ̢̳̹͓̳͓̲a ̷͇̲̬̟T͙͖͈̘̱̯̱͠ḫ̠̺͇̥̠͜o̹̰̪u͈͙sa̴͙̜nd͏ ́Yo̦̯̥͚̰̝̭u͔͍͈͞ng!͎͔̹͙

 

I'd like to reassure everyone that no internets were harmed in the making of that message.

 

Edited by Knight of Clear Skies
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3 hours ago, MartinB said:

I tried to run pixinsights photometric colour calibration on your image but wasn't able to enter the correct capture parameters.

If you use a FL of 468 and a pixel size of 4.54 it will solve. And guess what it does? Makes the image more blue!! LOL

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1 hour ago, Knight of Clear Skies said:

Here's one of your very own to cut`n`paste Olly.

¿

 

 

Gracias amigo!

59 minutes ago, Filroden said:

If you use a FL of 468 and a pixel size of 4.54 it will solve. And guess what it does? Makes the image more blue!! LOL

Get outta here! 🤣 Anyway, it's supposed to be applied to linear data, no? Think I'd be daft enough to give you that? No way, you'd expose all my bungles!

😁lly

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This is stupendously good Olly, even by your own lofty standards. 

At this scale, it certainly needs no more blue. It looks pretty much perfect as it is. Touché! 

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