California Nebula 300mm tele mosaic

[gorann]

This is a two panel mosaic (with central overlap) that has been waiting to get processed - for some reason my first attempt to process it reached a dead end where I was rather disappointed with the results and gave up. But with clouds and moon conspiring I have made a new attempt from scratch. Taken with my Canon 300 mm f/4 (@f/4) on my triple rig on the same night as the previously posted Samyang 135 and ES 127ED images, so 21 Dec 2017. Like my Samyang mosaic, this is an accidental mosaic created by a shift in framing after the meridian flip, resulting in a somewhat unusual framing. Stacked in PI and processed in PS. 76x3min @ ISO1600.

Here is my previous post with the little Samyang and 5" refractor:

Comments & suggestions most welcome

Cheers

Göran

 

 

 

 

[wimvb]

Excellent image, Göran. I especially like the framing.

[Adreneline]

Hi Göran,

The only problem I have with your image is that it makes my efforts to image this nebula look woefully inadequate. I think it is amazing! The more widefield images I see the more I like them and I really like yours. Thank you for sharing.

Adrian

[gorann]

Thanks Wim!

Yes I think the accidental framing turned out quite ok

[gorann]

13 hours ago, Adreneline said:

Hi Göran,

The only problem I have with your image is that it makes my efforts to image this nebula look woefully inadequate. I think it is amazing! The more widefield images I see the more I like them and I really like yours. Thank you for sharing.

Adrian

Hi Adrian,

Thank you very much! I am sure you will get there. Your WO ZS71 connected to the 70D should be able to grab this nebula. It is relatively featureless in RGB so I have worked on the contrast quite a bit on the nebula. Ha would bring out much more detail so collecting Ha is on my list.

[gorann]

PS. I just edited the post by putting on a more fiery version of the nebula created by tweaking the curve a bit

[Adreneline]

29 minutes ago, gorann said:

Your WO ZS71 connected to the 70D should be able to grab this nebula.

Hi Göran.

I've not tried the 70D on the ZS71 to date; my efforts have all been with the ZS71 and 428ex. Mosaics are amongst the many skills I still have to master in AP -  I've just about managed to cobble together a four-frame Ha of this nebula but it is a bit random! Maybe Registar could work wonders with an image from the 70D and my random mosaic.

Now my son has just bought a Sony A7s - putting that on the end of the ZS71 might be fun!

[gorann]

4 minutes ago, Adreneline said:

Hi Göran.

I've not tried the 70D on the ZS71 to date; my efforts have all been with the ZS71 and 428ex. Mosaics are amongst the many skills I still have to master in AP -  I've just about managed to cobble together a four-frame Ha of this nebula but it is a bit random! Maybe Registar could work wonders with an image from the 70D and my random mosaic.

Now my son has just bought a Sony A7s - putting that on the end of the ZS71 might be fun!

Well, this was a very primitive mosaic. Just two frames. So I put them together in PS and the major effort was to make minute rotations of one of the frames to make the stars align. One problem I experience with stacking in PI (as I now usually do) is that its star alignment procedure distorts the image in subtle ways, which makes stitching two images together a tedious task and I could not allow much overlap before I started to get double stars. As you say Registar may be the way to go, but I do my processing on a Mac and I think Registar if only for Windows. I guess I could do the alignment on a Windows machine and do the rest on my Mac.

[Adreneline]

2 minutes ago, gorann said:

Registar may be the way to go, but I do my processing on a Mac and I think Registar if only for Windows.

I have a Win10 install on my MBP running under Parallels and it works a treat and is a much cheaper option than buying a dedicated laptop. It also means that my Pictures subdirectory is common to both machines so no messing around with usb drives etc.; I can easily move image files into PI or PS on the Mac. In fact I also have EQMOD, SGPro, BYEoS and PHD all running under Parallels but tend to use a dedicated Intel NUC for driving the scopes and collecting images.

One of the advantage of running Win10 under Parallels is that Win10 will never do a 'random shutdown / update' in the middle of night - unlike Win10 on the NUC. You can definitely go to bed and know it will keep going; in fact Win10 crashes are almost non-existent under Parallels. Explain that one!

Good luck!

Adrian

[gorann]

9 minutes ago, Adreneline said:

I have a Win10 install on my MBP running under Parallels and it works a treat and is a much cheaper option than buying a dedicated laptop. It also means that my Pictures subdirectory is common to both machines so no messing around with usb drives etc.; I can easily move image files into PI or PS on the Mac. In fact I also have EQMOD, SGPro, BYEoS and PHD all running under Parallels but tend to use a dedicated Intel NUC for driving the scopes and collecting images.

One of the advantage of running Win10 under Parallels is that Win10 will never do a 'random shutdown / update' in the middle of night - unlike Win10 on the NUC. You can definitely go to bed and know it will keep going; in fact Win10 crashes are almost non-existent under Parallels. Explain that one!

Good luck!

Adrian

Sound like a very goo idea Adrian!

I should look into it - I have heard of this type of programs for Mac but never given it a serious thought. One problem with my MBP is that I bought it with a 256 Gb solid state hard drive - sounded like a lot but I soon found out that I was running out of space (I usually only have about 30 Gb free space on it). So I have all my images on external hard drives. Adding Win10 and Parallels to it may take up too much space but probably not. I do have a Windows laptop that I use for PHD2 so I could also put Registar on that.

[Filroden]

34 minutes ago, gorann said:

One problem I experience with stacking in PI (as I now usually do) is that its star alignment procedure distorts the image in subtle ways, which makes stitching two images together a tedious task and I could not allow much overlap before I started to get double stars.

You know PI does mosaics really well? StarAlign will work out the geometries across multiple overlapping images and there is one process and one script that then do good jobs at stitching them seamlessly. There is a good tutorial in the PI book. 

[gorann]

2 hours ago, Filroden said:

You know PI does mosaics really well? StarAlign will work out the geometries across multiple overlapping images and there is one process and one script that then do good jobs at stitching them seamlessly. There is a good tutorial in the PI book. 

Thanks Ken - I suspected this but was unsure how to do it. I will give it a try next time.

[wimvb]

3 hours ago, Filroden said:

You know PI does mosaics really well? StarAlign will work out the geometries across multiple overlapping images and there is one process and one script that then do good jobs at stitching them seamlessly. There is a good tutorial in the PI book. 

 

1 hour ago, gorann said:

Thanks Ken - I suspected this but was unsure how to do it. I will give it a try next time.

There are more ways than one to mess up a mosac in PI. ImageRegistration with mosaic options selected, combined with GradientMergeMosaic is one. 

[Adreneline]

3 hours ago, gorann said:

Well, this was a very primitive mosaic. Just two frames. So I put them together in PS and the major effort was to make minute rotations of one of the frames to make the stars align.

Hi Göran,

I got to say that if you want a quick result that is surprisingly good then it is worth a look at Microsoft ICE. I messed around with a four frame mosaic of the Flame and Horsehead in PI for ages and although I am sure that in experienced hands the results are excellent if you want a "quick look" result to see if it is worth further work then ICE produces an amazing result with no effort at all - feed in the separate frames, press 'Go' and bingo - out pops a finished end result and I am blowed if I can see the joins! No need to mess around with LinearFit - ICE sorts it all out.

This is the tif I produced with no further processing. The 'seeing' was terrible the night I did this and it was another 'random' mosaic; as an image it has everything wrong with it but it shows what ICE can do and whether it is worth investing lots of effort in PI.

Hope you don't mind me adding it to your thread; I've uploaded it as a tif so the image does not confuse your NGC1699 thread.

Adrian

Flame-ICE-four-frame-stitch.tif

 

 

[Rodd]

Nice wide field.  rare to get all of this one.  Are the stars in this region on the blue side?  At first glance they seem a tad blue--but there are blue stars so I am not sure about it.  Works well with the red of the nebula regardless.

Rodd

[gorann]

1 hour ago, Rodd said:

Nice wide field.  rare to get all of this one.  Are the stars in this region on the blue side?  At first glance they seem a tad blue--but there are blue stars so I am not sure about it.  Works well with the red of the nebula regardless.

Rodd

Thanks Rodd. I have to say i was more preoccupied with the nebulosities than star colour while processing so star colour may have accidentally drifted off, but I trust that no one will use this image scientifically. I am not as advanced in my processing as using any star colour calibration protocol. Maybe I should. One thing I noticed is that when I use "Selective Colour" to adjust the reds and magenta in the nebulosity it may have rather strong effects on star colour. Maybe I should take more care?

[Rodd]

44 minutes ago, gorann said:

Thanks Rodd. I have to say i was more preoccupied with the nebulosities than star colour while processing so star colour may have accidentally drifted off, but I trust that no one will use this image scientifically. I am not as advanced in my processing as using any star colour calibration protocol. Maybe I should. One thing I noticed is that when I use "Selective Colour" to adjust the reds and magenta in the nebulosity it may have rather strong effects on star colour. Maybe I should take more care?

Well--in PI its a simple thing to process the stars and nebula separately.  Not sure about PS.  I usually find I usually have too little color in my stars and need to add some t the end.

Rodd

[gorann]

8 hours ago, Rodd said:

Well--in PI its a simple thing to process the stars and nebula separately.  Not sure about PS.  I usually find I usually have too little color in my stars and need to add some t the end.

Rodd

Rodd, I had a look at the stacked image before any processing and these blue stars are blue to violet also there so apparently my camera sees them as blue. Found this image on Flickr taken with similar equipment and there are plenty of blue stars also there. In any case I think they make a nice contrast to all the red and brown nebulosity, but maybe mine is a bit over the top and I could reduce the blue saturation a bit

https://www.flickr.com/photos/fotopholio/10766377595

 

Cheers

Göran

[Rodd]

4 hours ago, gorann said:

Rodd, I had a look at the stacked image before any processing and these blue stars are blue to violet also there so apparently my camera sees them as blue. Found this image on Flickr taken with similar equipment and there are plenty of blue stars also there. In any case I think they make a nice contrast to all the red and brown nebulosity, but maybe mine is a bit over the top and I could reduce the blue saturation a bit

https://www.flickr.com/photos/fotopholio/10766377595

 

Cheers

Göran

I had a second look at the image and its not the stars that are blue--the stars have blue halos.  Probably amounts to the same thing.  Anyway, right after stacking is a very bad time to make a color judgement, as the image has not yet been color calibrated, degradiented, or background neutralized.  Right after integration the palette can be like Salvador Dali.  Perhaps speaking in terms of intensity rather than color would be better in this case.  The stars may in fact be blue--but perhaps not quite so blue?

Rodd

[wimvb]

This is one weak point of osc/dslr combined with a refractor. Lenses (in scopes) are rarely parfocal, and the blue part of the spectrum has another focus point than red and green. Maybe you remember the marker on photographic lenses that indicated the focus settings for IR. I believe I have that on a few of my old lenses.

[gorann]

4 hours ago, wimvb said:

This is one weak point of osc/dslr combined with a refractor. Lenses (in scopes) are rarely parfocal, and the blue part of the spectrum has another focus point than red and green. Maybe you remember the marker on photographic lenses that indicated the focus settings for IR. I believe I have that on a few of my old lenses.

Yes Wim, but I thought the whole idea with an apochromatic refractor like my ES 127ED triplet is that it focuses all visible wavelengths at the same focal plane - so that there is no chromatic aberration. With mirrors this is not a problem but as soon as you introduce lenses in the pathway (including coma correctors in Newtoneans) you run the risk of chromatic aberration but an apo refractor is designed to keep this to a minimum.

[gorann]

On 2/5/2018 at 13:05, Rodd said:

I had a second look at the image and its not the stars that are blue--the stars have blue halos.  Probably amounts to the same thing.  Anyway, right after stacking is a very bad time to make a color judgement, as the image has not yet been color calibrated, degradiented, or background neutralized.  Right after integration the palette can be like Salvador Dali.  Perhaps speaking in terms of intensity rather than color would be better in this case.  The stars may in fact be blue--but perhaps not quite so blue?

Rodd

I also had another look and started to agree with you Rodd, so I have tuned down the blue/magenta saturation in the halos around the stars and blurred them a bit to make them look softer. Also stepped back a bit on the sky background that appeared a bit too dark and maybe even clipped (copied the background from an earlier version using the magic wand and pasted it in as a layer).

Thanks!

 

[Rodd]

4 hours ago, gorann said:

I also had another look and started to agree with you Rodd, so I have tuned down the blue/magenta saturation in the halos around the stars and blurred them a bit to make them look softer. Also stepped back a bit on the sky background that appeared a bit too dark and maybe even clipped (copied the background from an earlier version using the magic wand and pasted it in as a layer).

Thanks!

Looks Great!  I find myself resorting to using the background of an earlier version quite frequently now.   Nice job.

Rodd

[gorann]

6 minutes ago, Rodd said:

Looks Great!  I find myself resorting to using the background of an earlier version quite frequently now.   Nice job.

Rodd

Thanks!

Yes, it is so easy to lose track of some aspect of the image while working on another, and especially the sky and stars can easily suffer, so it is a great comfort to have saved previous versions at your rescue.