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Carina Nebula with the bright unstable star Eta Carinae in the centre of the image.
 
edit ( 27 March ):  Tweak to shadow levels to bring out more detail and also a slight reduction in the brightness of the highlights.  A much larger version ( 4562 x 3072 6062 x 4082) is available on my Flickr page.
 
C9A5A80B-ECC2-49FE-B5D1-3E336577B768.thumb.jpeg.b215a638e8c3fd7986d4e45e8283beab.jpeg
 
previous version:
FB1E9E98-0B2C-42F3-B88F-1D3264372A6C.thumb.jpeg.200adb7b970357f295688f3762a789b5.jpeg
 
Carinae Nebula ( NGC 3372 ) ( please click / tap on image to see larger and sharper )
 
From Wikipedia ...
"Eta Carinae is a highly luminous hypergiant star. Estimates of its mass range from 100 to 150 times the mass of the Sun, and its luminosity is about four million times that of the Sun."
This HDR image is constructed from 12 sets of exposures ranging from 1/8 sec ( to capture the bright centre of Eta Carinae ) through to 240 seconds.  Total exposure time around 13 hours
 
17-19 March 2018
 
 
Image details:
 

Objects in image:

  Hypergiant, Eta Carinae ( HD 93308 ) in the centre of the Homunculus Nebula

  Carina Nebula ( NGC 3372 )

  Keyhole Nebula

  Open Star Clusters:

    - Trumpler 14, 15, 16

    - Collinder  232

 
Field of view ..... 59' 18.2" x 39' 56.0"
Image centre ...... RA: 10 45 01.762  Dec: -59 40 52.87
Orientation: North is up
 
Telescope: Orion Optics CT12 Newtonian ( mirror 300mm, fl 1200mm, f4 ).
Corrector: ASA 2" Coma Corrector Quattro 1.175x.
Effective Focal Length / Aperture : 1470mm f4.7
 
Mount: Skywatcher EQ8
 
Guiding: TSOAG9 Off-Axis-Guider, Starlight Xpress Lodestar X2, PHD2
 
Camera:
Nikon D5300 (unmodified) (sensor 23.5 x 15.6mm, 6016x4016 3.9um pixels)
 
Location:
Blue Mountains, Australia
Moderate light pollution ( pale green zone on darksitefinder.com map )
 
Capture ( 17, 18 & 19 March 2018 ):
12 sets of sub-images with exposure duration for each set doubling ( 1/8s to 240s ) all at ISO250.
( 181 x 240sec + 10 to 20 each for the other durations )
 
Processing:
Calibration: master bias, master flat and master dark
Integration in 12 sets
HDR combination
 
Pixinsight March 2018
Edited by MikeODay
New tweaked version added at top of post
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On my Pixinsight screen this did not look too bad - on this forum, mmm, it looks, well, perhaps a tad overdone ...  :)

..........

I just replaced the image above with one a little less "electric".  What do you think, are the colours still too bright ?

This is what it used to look like ...

707B89A1-D215-41A6-875C-1C790059E5C8.jpeg.a75d4364ef639f678d40e89fb4140c62.jpeg

Edited by MikeODay
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Ok, I just realised what is going on ...

I processed the image on my calibrated wide gamut lcd panel with the colour profile set to Adobe RGB.  The site must be converting it to SRGB, which of course has a  far narrower colour range.  I willl have to do the conversion myself and see if I can produce an SRGB version that is closer to my original.

....

edit: not just the site - every app on my IPAD shows it the same - it is only on my 4k wide colour gamut monitor that it looks more subdued ...

Edited by MikeODay

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You fooled me cause i think it looks spectacular!!! thats something i'd be super proud to mount on a wall!

Edited by Sunshine
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Hi Mike

That's a cracking image :hello2:

I do prefer the one in the OP, although with an image this good we are largely splitting hairs.

I see that you also own a D5300. Can I ask why you choose to do a range of subexposures, even for an object such as this, which is not that bright? (certainly compared to say M42, or a big Globular Cluster).

Do you use the super-short exposures just for the star cores and nothing else? Your stars are gorgeous btw!

I'd love to hear how you go about compiling them all into your final stack. Even for those of us who don't own PixInsight, I'm sure a similar workflow would be possible in other software.

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36 minutes ago, Sunshine said:

You fooled me cause i think it looks spectacular!!! thats something i'd be super proud to mount on a wall!

Thanks that is very kind of you.  I have only spent a little time with the stretched image and I think I will end up tweaking it some more.  But yes, this is definitely a keeper :)

 

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35 minutes ago, Xiga said:

Hi Mike

That's a cracking image :hello2:

I do prefer the one in the OP, although with an image this good we are largely splitting hairs.

I see that you also own a D5300. Can I ask why you choose to do a range of subexposures, even for an object such as this, which is not that bright? (certainly compared to say M42, or a big Globular Cluster).

Do you use the super-short exposures just for the star cores and nothing else? Your stars are gorgeous btw!

I'd love to hear how you go about compiling them all into your final stack. Even for those of us who don't own PixInsight, I'm sure a similar workflow would be possible in other software.

Thanks, much appreciated :)

The HDR capture and processing is to keep colour and detail in the stars.  The 1/8 sec exposures @ ISO 250 just manage to capture the core of the central star "Eta Carinae".  The total dynamic range of the linear HDR image is 36bits !  There is no way any normal camera can record that in one exposure.

My workflow ...

- calibrate, debayer and alignment as a single group

- Integration in sets of like exposure - in this case 12 separate integrations

- remove pedestal from each integrated image ( I added this during the calibration stage to make sure that I did not clip the shadows )

- Combination in this case is by using Pixinsight's HDR tool, although I have often had trouble with it and usually I do manually using Pixinsight's pixelMath tool. 

- Divide each channel of the HDR image by the correct factor to achieve "daylight colour balance" ( for the D5300 that is approx.:  Red/1, G/2, B/1.4 )

- DynamicBackgroundExtraction tool to remove the colour cast in the shadows caused by light pollution

- MaskedStretch in multiple small steps to take the background level from around 5e-6 to around 1e-3 ( on a 0..1 scale ).  I double the background level at each step and also use the histogram tool at each step to clip away zero values as the peak slowly moves away from the left with each step.

- Either keep going with MaskedStretch until background level is about right or, as in this case, switch to ArcSinH for the final stretch from 1e-3 to 1.6 e-1

- Curve tool to tweak contrast

- And a final tweak of colour balance using the curves tool - usually, as in this case, I apply a small green reduction only ( ~ 1 to 3 % )

I hope that helps...

One day I will get around to doing a tutorial, one day ...

Cheers

Mike

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Some crops of interesting detail around the Eta Carina nebula ( please click / tap on each image to see larger and sharper )

0A8DD1D5-FF0B-4BE7-A7EC-676031248F67.thumb.jpeg.90182e0db02b736cd3da4c9c3ce26849.jpeg

9199CC5A-128D-48B0-9D79-E6ADF39C03BD.thumb.jpeg.ece3f5d33c7ab703f96865604d5afea3.jpeg

0315F8EA-D8B5-4DD7-A21F-E991652E9FD8.thumb.jpeg.10938bc98ae82f48347eb3acb6a1ba5c.jpeg

CF58ACC4-2EAF-46E8-9B7D-DDBC2148F027.thumb.jpeg.a9fa5b05a4952650f68741820515b3a5.jpeg

4824508A-ED1D-477D-8FFA-5EC969973973.thumb.jpeg.f7909dd6b1bb706a11d244b7e39f9a80.jpeg

942DD227-ADA7-4A64-9AEF-D02EE4CE2DD8.thumb.jpeg.85ad5d4a309d2bcc37b3d6b7d0a1ce22.jpeg

FCB43189-93CD-4063-A17F-C0F46075239D.jpeg.2da65dbe3e3d342283853a380e88ea67.jpeg

Edited by MikeODay
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0315F8EA-D8B5-4DD7-A21F-E991652E9FD8.jpeg

I love this image Mike, beautiful small cluster at the centre, very nice processing.

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Awesome result... the Carina Nebula is a awesome object to image

 

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24 minutes ago, Jkulin said:

I love this image Mike, beautiful small cluster at the centre, very nice processing.

Thanks John, that's my favourite of the crops as well.  

8C5F558E-2A3F-42F1-9D43-0EEB4F8D8B3C.jpeg.0e121a61dc0b3946830e248178fe0870.jpeg

The cluster is lovely and there is so much going in the clouds.  I am surprised ( and pleased :) ) that the detail holds up so well at this enlargement - I did not expect that.

Edited by MikeODay
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3 minutes ago, MarsG76 said:

Awesome result... the Carina Nebula is a awesome object to image

 

Thanks, much appreciated.  You are right, it is a great object - although this version is so much better than my first effort when I was just starting out; I will dig it out and post it here as a evidence that old dogs can indeed learn new tricks :)

 

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2 minutes ago, MikeODay said:

Thanks, much appreciated.  You are right, it is a great object - although this version is so much better than my first effort when I was just starting out; I will dig it out and post it here as a evidence that old dogs can indeed learn new tricks :)

 

Practise makes perfect... my first images were crp... but with time we all should and do improve

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Some more crops ...

DDCFC534-7AC1-460F-BE24-10E187BECCE7.jpeg.169bd632b713232e3b14e301de4f3c8b.jpeg

62212F4C-7B9B-453B-AC31-57B99A9AC4DF.jpeg.e8ae13aa758939d1e8d82ea23f77c9c2.jpeg

95194728-69F6-467B-BCF4-4AE4CC5F7F37.thumb.jpeg.9933831e00fcc96f819a60744278571a.jpeg

523BA55E-A67A-4334-BAA9-01579304FEF6.thumb.jpeg.810fc724e5a48af4e41c8f3c10b261bf.jpeg

9D04C99D-BC35-4626-B7E1-868D9A9C0BF3.thumb.jpeg.213f24b893d0f87d2bad1889eca869ad.jpeg

 

Edited by MikeODay
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12 hours ago, MikeODay said:

Some more crops ...

DDCFC534-7AC1-460F-BE24-10E187BECCE7.jpeg.169bd632b713232e3b14e301de4f3c8b.jpeg

62212F4C-7B9B-453B-AC31-57B99A9AC4DF.jpeg.e8ae13aa758939d1e8d82ea23f77c9c2.jpeg

95194728-69F6-467B-BCF4-4AE4CC5F7F37.thumb.jpeg.9933831e00fcc96f819a60744278571a.jpeg

523BA55E-A67A-4334-BAA9-01579304FEF6.thumb.jpeg.810fc724e5a48af4e41c8f3c10b261bf.jpeg

9D04C99D-BC35-4626-B7E1-868D9A9C0BF3.thumb.jpeg.213f24b893d0f87d2bad1889eca869ad.jpeg

 

Amazing resolution... that EQ8 has some good accurate tracking....

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Thanks...

Yes the tracking is pretty good and nights were reasonably sitll.  PHD was generally reporting RMS figures for both axis in the range 0.4 to 0.8 " which is around 1 pixel on my D5300.  

The end result is also improved by the number of subs I capture;.  20 to 30 each for exposures in the range 1/8 to 120 sec.  I then went sub by sub and chose the best 10 to 15 subs and discarded the rest.

Also, the crops above are not in fact 100%.  I produced them by croping the image I have on my IPAD which for some reason has been reduced by the app to  around 75% of the maximum image width of  6062 pixels.

Cheers

Mike

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And some more, because I'm travelling at the moment and I can't get to my pc to play with anything :)

6101B933-D18E-4C81-B99F-ED388EC12D83.thumb.jpeg.fc9d2397808e6731628f9b8d2e807ed8.jpeg

C4224117-87B3-4D0D-950D-CAF67D1B0A48.thumb.jpeg.e7dce2c57c84ecc09e6a0d94f82ede88.jpeg

EB32C42D-2EA0-43E4-B800-CFD52A96CBFE.thumb.jpeg.0ad03aaa82c50cf0d4905c424c7ad85d.jpeg

4FA34750-47A7-4F26-8E69-9AD2CB998428.thumb.jpeg.aea22aa02df6be43065a07e7877a579a.jpeg

And I'm quite pleased with how the Homunculus Nebula turned out; it's not Hubble but still ...

837A0219-164D-4B32-93D8-EE48F64E35B2.jpeg.3a65844703b232b2a64c57497b63aa8f.jpeg

Compare with ...

2DAF85B7-8C37-4543-8646-37D4D4A542D1.jpeg.09128b58f1f40fb9549397e37633191c.jpeg

Credit NASA Hubble

 

 

 

 

 

Edited by MikeODay
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23 hours ago, Allinthehead said:

Beautiful image Mike.

Thanks Richard.

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2 hours ago, stevewanstall said:

Awesome object, indeed

Thanks Steve.

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Fabulous images Mike. I wish I could get down to the Southern Hemisphere to image these wonderful objects.

Steve

 

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8 hours ago, sloz1664 said:

Fabulous images Mike. I wish I could get down to the Southern Hemisphere to image these wonderful objects.

Steve

 

Thanks Steve, much appreciated.

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21 hours ago, whatablanker said:

WOW I love this and I want to move down under.

:)

Thanks!

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