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Chromatic Aberration Correction is now available in SharpCap 4.1

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#101 Far_Southern_Skies

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Posted 20 March 2024 - 06:17 PM

Hi Mike
I am away camping to take advantage of some glorious Autumn weather. I’ll certainly be revisiting the Tarantula. My only feedback at the moment is this image was taken about five minutes after the Carina image without any changes to the white balance settings in the camera.
Many astrophotographers here express frustration with trying to produce a natural colour version of the Tarantula. It is a difficult target to get right.
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#102 Borodog

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Posted 21 March 2024 - 09:50 AM

More fooling around with chromatic aberration correction on fast achromats. The following images were shot with a 40mm f/4 guide scope and the SV305C under an 85% Moon. I shot sky flats, but I had taken them with the Moon just out of the frame and it was too close; the glow from the Moon ruined the flats, which became apparent after stretching. I also had problems with both darks and hot pixel removal. I believe the temperature fell too fast for my darks to work as they were causing black clipping, and hot pixel removal seems broken in the latest version; it was not working at all. I'll have to talk to Robin about that. I have an enhancement request there anyway.

 

In any event, M51. I think this was something like 37 minutes while I was inside talking to my wife.

 

M51_40mm_f4_chromatic_aberration_correction.png


Edited by Borodog, 21 March 2024 - 09:58 AM.

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#103 Borodog

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Posted 21 March 2024 - 09:54 AM

Horsie, 20 minutes.

 

HH.jpg

 

 


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#104 Borodog

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Posted 21 March 2024 - 09:56 AM

M42, 10 min.

 

M42.jpg


Edited by Borodog, 21 March 2024 - 09:58 AM.

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#105 Borodog

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Posted 21 March 2024 - 10:06 AM

This was shot in the clear blue sky. I put the Moon out of the frame and shot a "dark" to subtract off the blue sky & live stack a mineral Moon. Worked well enough.

 

40mm_Moon.jpg


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#106 Borodog

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Posted 21 March 2024 - 10:12 AM

By the way, I believe the aberrations on the bright stars were caused by my home made dew shield for the guide scope, which was just a piece of black plastic card stock rolled into a tube and stapled. The overlapping section was causing it to flatten out and the staple was visible to the aperture. Hopefully won't get those in the future now that I realize that.


Edited by Borodog, 21 March 2024 - 10:13 AM.

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#107 alphatripleplus

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Posted 21 March 2024 - 11:08 AM

Based on the tint in  the M51, Horsehead and Orion pics, were you using Deep Sky 1? (As a personal preference,  I tend to favour the colour with Deep Sky 2. )


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#108 Borodog

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Posted 21 March 2024 - 11:12 AM

Based on the tint in  the M51, Horsehead and Orion pics, were you using Deep Sky 1? (As a personal preference,  I tend to favour the colour with Deep Sky 2. )

Yep, DS1.


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#109 roncarr880

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Posted 22 March 2024 - 06:36 PM

Mike and others,

 

I have been experimenting with camera lenses in a quest for a wider field of view in the other thread with some disappointing results.  I thought this thread would be a better place for a discussion.  Camera lenses are expensive - I have been testing what I have - and they don't seem to do well on stars until the very expensive lens range.  I am beginning to think that a scope like the 40 mm guide scope you have with the #8 pale filter and CA removal is perhaps the way to go for a wider field of view.   I also just became aware that Svbony sells a 1.25mm 0.5 reducer for $20.  Coupled with my 60mm scope that would give me a 120mm focal length which I think may be about right ( for M31 size targets ).  I may buy one of the reducers and see if it looks promising.  It certainly is the less expensive option.   Any thoughts?


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#110 Borodog

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Posted 23 March 2024 - 12:56 PM

Ron,

 

I really like the 40mm SV165. It is SO much better than the 30mm version, which I would avoid like the plague except for guiding (it's fine for that). I'm excited to try it without the Moon blotting everything out.

 

Regarding the 0.5X reducer, it's worth a shot. I think you will get off-axis aberrations out of the reducer, but there's no way to say how bad until you try it. I would try to keep the reduction as mild as you can by keeping the reducer as close to the sensor as possible. I will be interested to see the results. I have a couple of those 0.5X reducers in a drawer somewhere, I may try one to get under f/4 and see how bad the aberrations are.

 

The CA correction really is a game changer for imaging with these fast little achromats imo.


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#111 Rgwood88

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Posted 31 March 2024 - 06:49 PM

Wonder why it is not available when restacking raw data from a folder? Folder Monitor Camera.

I had the same problem and I played a bit with things and discovered that the saved files in the folders must be de-bayered and then the CA Reduction option is available. I used PIPP to Debayer and save the subs as .TIF's, ran the Folder Monitor camera on these frames and the CA OPtion appeared and seemed to work. 

 

rw


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#112 Far_Southern_Skies

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Posted 13 April 2024 - 06:22 AM

It has been a frustrating several weeks with wanting to iron out the last little niggles in my attempt to convert my 140mm Vixen achromat into a fast f4 EAA scope. 

With virtually no clear nights, it has been difficult to verify some daytime fine tuning.

I have tracked down some tilt to a deformed 60mm to 42mm adaptor. This has been fixed. 

Back spacing is still not quite right - there is still some aberration when examined closely, but I am going to ignore this for now as I am not a pixel peeper.

I have re-checked the white balance settings - I suspect my earlier attempt to capture the Tarantula Nebula was spoilt by white balance settings done with the Fringe Killer filter in the light path.

 

Anyhow, a semi clear night tonight and I have managed to get a couple of new test images. Transparency amongst the clouds is poor and seeing is averaging about 5 arc sec. Constant passing cloud has meant I have had to limit the total exposures.

 

First up the Wishing Well open cluster in Carina. This was completed with The Solar System setting for chromatic aberration correction and a Baader Fringe Killer filter. The range of star colours in this field looks about right, although the hot young stars in the cluster are lacking that 'popping' blue-white appearance.

 

C91 (NGC 3532)_2024-04-12_NA140SS at f4_ASI585_SC_165X2.0s_330s_Gain210

 

C91 (NGC 3532)_2024-04-12_NA140SS at f4_ASI585_SC_165X2.0s_330s_Gain210_.jpg

 

Next up, the Carina Nebula. This was completed with the Deep Sky 2 setting for chromatic aberration correction and a Baader Fringe Killer filter. This could benefit from a longer total exposure, but at least the fundamentals are there.

 

C92 (NGC 3372,Eta Carina Nebula)_2024-04-13_NA140SS at f4_ASI585_SC_38X8.0s_304s_Gain210

 

C92 (NGC 3372,Eta Carina Nebula)_2024-04-13_NA140SS at f4_ASI585_SC_38X8.0s_304s_Gain210.jpg

 

Lastly, I managed a just two minutes on the Tarantula Nebula in Dorado before the sky clouded over completely. Again, this was completed with Deep Sky 2 setting for chromatic aberration correction and a Baader Fringe Killer filter. This is a much better result than my first attempt several weeks ago - I think having the right white balance settings plus using Deep Sky 2 has made the difference. Again, this could benefit from a longer total exposure.

 

C103 (NGC 2070,Tarantula Nebula)_2024-04-13_NA140SS at f4_ASI585_SC_16X8.0s_128s_Gain210

 

C103 (NGC 2070,Tarantula Nebula)_2024-04-13_NA140SS at f4_ASI585_SC_16X8.0s_128s_Gain210.jpg

 

 

For me, the Chromatic Aberration Correction tool has given me the opportunity to convert my existing visual only scope into a competent EAA performer. It has delivered a 140mm f4 refractor with a focal length of 560mm for EAA. Plus it has a few more tricks to offer. I have a complete second imaging train - I can simply unscrew the reducer and attached image train and screw in the second imaging train. This converts the scope to a 140mm f5.85 with a focal length of 800mm. This will be a better option for galaxies. I can also add a barlow for close up lunar live stacking.

 

Just need some clear nights!!

 

 

 

 

 

 

 


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#113 Borodog

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Posted 13 April 2024 - 10:13 PM

Those are amazing, FSS!

I can’t wait to see galaxies from that setup.

#114 roncarr880

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Posted 15 April 2024 - 10:13 PM

The 0.5 reducer was somewhat of a disappointment.  I didn't think it would be really great at f/2 but there seems to be a smear around all light sources, my guess is SA.   This is without the #8 yellow filter as there was an interference fit with the helical focuser and the amount of in travel was right on the edge for infinity focus.

 

svbony 60mm guide scope f/4, sv305c camera, svbony 0.5 reducer and CA removal Deep Sky 1.  This is M81 and M82 in case you can't tell.

 

 

Attached Thumbnails

  • M81_M82_42frames_441s.jpeg

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#115 Far_Southern_Skies

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Posted 16 April 2024 - 05:31 AM

Some final experiments that continue to demonstrate the power of the Chromatic Aberration Correction tool. I was also interested to gauge the speed of the F4 configuration so the following image of Orion is limited to 58 seconds to compare with my previous 100mm F5.5 system.

 

Both images are the same exposure and gain settings and all other enhancement setting were kept unchanged. The 58 seconds total exposure is a hybrid - 34 one second exposures (with dark) plus 3 eight second exposures (with dark). The stack is simply paused to change the settings. This helps preserve the four stars in the Trapezium.

 

Vixen NA140SS achromat at F4 and ASI585 OSC. No filters and colour balanced as best as possible in the circumstances:

 

M42 (NGC 1976,Great Orion Nebula)_2024-04-16_NA140SS at f4_ASI585_SC_(34X1s+3X8.0s)_58s_Gain210.jpg

 

Vixen NA140SS achromat at F4 and ASI585 OSC plus Baader Fringe Killer filter and processed with SharpCap Chromatic Aberration Correction Deep Sky 2 setting:

 

M42 (NGC 1976,Great Orion Nebula)_2024-04-16_NA140SS at f4_ASI585_SC_(34X1s+3X8.0s)_58s_Gain210_CAR-DS2.jpg

 

The result is extraordinary.

 

 


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#116 Far_Southern_Skies

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Posted 16 April 2024 - 06:44 AM

A quick 100 frame live stack of the Moon:

 

Vixen NA140SS achromat at F4 and ASI585 OSC. No filters and colour balanced as best as possible in the circumstances:

 

Snapshot of 2024-04-16-0946_5-Moon_00001_WithDisplayStretch.jpg

 

Vixen NA140SS achromat at F4 and ASI585 OSC plus Baader Fringe Killer filter and processed with SharpCap Chromatic Aberration Correction Solar System setting. No changes to other settings in the live stacks.

 

Snapshot of 2024-04-16-1013_1-Moon_00001_WithDisplayStretch.jpg


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#117 Borodog

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Posted 17 April 2024 - 09:10 AM

The 0.5 reducer was somewhat of a disappointment. I didn't think it would be really great at f/2 but there seems to be a smear around all light sources, my guess is SA. This is without the #8 yellow filter as there was an interference fit with the helical focuser and the amount of in travel was right on the edge for infinity focus.

svbony 60mm guide scope f/4, sv305c camera, svbony 0.5 reducer and CA removal Deep Sky 1. This is M81 and M82 in case you can't tell.



CA gets worse at shorter focal lengths. I suspect that defocused light is polluting the red and green channels.
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#118 Borodog

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Posted 17 April 2024 - 09:12 AM

Some final experiments that continue to demonstrate the power of the Chromatic Aberration Correction tool. I was also interested to gauge the speed of the F4 configuration so the following image of Orion is limited to 58 seconds to compare with my previous 100mm F5.5 system.

Both images are the same exposure and gain settings and all other enhancement setting were kept unchanged. The 58 seconds total exposure is a hybrid - 34 one second exposures (with dark) plus 3 eight second exposures (with dark). The stack is simply paused to change the settings. This helps preserve the four stars in the Trapezium.

Vixen NA140SS achromat at F4 and ASI585 OSC. No filters and colour balanced as best as possible in the circumstances:

M42 (NGC 1976,Great Orion Nebula)_2024-04-16_NA140SS at f4_ASI585_SC_(34X1s+3X8.0s)_58s_Gain210.jpg

Vixen NA140SS achromat at F4 and ASI585 OSC plus Baader Fringe Killer filter and processed with SharpCap Chromatic Aberration Correction Deep Sky 2 setting:

M42 (NGC 1976,Great Orion Nebula)_2024-04-16_NA140SS at f4_ASI585_SC_(34X1s+3X8.0s)_58s_Gain210_CAR-DS2.jpg

The result is extraordinary.



Agreed! I love how you live stacked the HDR.
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#119 steveincolo

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Posted 18 April 2024 - 07:48 PM

It has been a frustrating several weeks with wanting to iron out the last little niggles in my attempt to convert my 140mm Vixen achromat into a fast f4 EAA scope. 

With virtually no clear nights, it has been difficult to verify some daytime fine tuning.

I have tracked down some tilt to a deformed 60mm to 42mm adaptor. This has been fixed. 

Back spacing is still not quite right - there is still some aberration when examined closely, but I am going to ignore this for now as I am not a pixel peeper.

I have re-checked the white balance settings - I suspect my earlier attempt to capture the Tarantula Nebula was spoilt by white balance settings done with the Fringe Killer filter in the light path.

 

Anyhow, a semi clear night tonight and I have managed to get a couple of new test images. Transparency amongst the clouds is poor and seeing is averaging about 5 arc sec. Constant passing cloud has meant I have had to limit the total exposures.

 

First up the Wishing Well open cluster in Carina. This was completed with The Solar System setting for chromatic aberration correction and a Baader Fringe Killer filter. The range of star colours in this field looks about right, although the hot young stars in the cluster are lacking that 'popping' blue-white appearance.

 

C91 (NGC 3532)_2024-04-12_NA140SS at f4_ASI585_SC_165X2.0s_330s_Gain210

 

attachicon.gif C91 (NGC 3532)_2024-04-12_NA140SS at f4_ASI585_SC_165X2.0s_330s_Gain210_.jpg

 

Next up, the Carina Nebula. This was completed with the Deep Sky 2 setting for chromatic aberration correction and a Baader Fringe Killer filter. This could benefit from a longer total exposure, but at least the fundamentals are there.

 

C92 (NGC 3372,Eta Carina Nebula)_2024-04-13_NA140SS at f4_ASI585_SC_38X8.0s_304s_Gain210

 

attachicon.gif C92 (NGC 3372,Eta Carina Nebula)_2024-04-13_NA140SS at f4_ASI585_SC_38X8.0s_304s_Gain210.jpg

 

Lastly, I managed a just two minutes on the Tarantula Nebula in Dorado before the sky clouded over completely. Again, this was completed with Deep Sky 2 setting for chromatic aberration correction and a Baader Fringe Killer filter. This is a much better result than my first attempt several weeks ago - I think having the right white balance settings plus using Deep Sky 2 has made the difference. Again, this could benefit from a longer total exposure.

 

C103 (NGC 2070,Tarantula Nebula)_2024-04-13_NA140SS at f4_ASI585_SC_16X8.0s_128s_Gain210

 

attachicon.gif C103 (NGC 2070,Tarantula Nebula)_2024-04-13_NA140SS at f4_ASI585_SC_16X8.0s_128s_Gain210.jpg

 

 

For me, the Chromatic Aberration Correction tool has given me the opportunity to convert my existing visual only scope into a competent EAA performer. It has delivered a 140mm f4 refractor with a focal length of 560mm for EAA. Plus it has a few more tricks to offer. I have a complete second imaging train - I can simply unscrew the reducer and attached image train and screw in the second imaging train. This converts the scope to a 140mm f5.85 with a focal length of 800mm. This will be a better option for galaxies. I can also add a barlow for close up lunar live stacking.

 

Just need some clear nights!!

These are fabulous! The star colors in NGC 3532 are very nice, perhaps you could try shorter exposures with the nebulas as well to preserve star color.


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#120 roncarr880

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Posted 18 April 2024 - 08:42 PM

I made a stop for the scope reducing it to 30mm f/8.   The results are still  poor, so I think the svbony 0.5 reducer is a lost cause for EAA.  I am not sure I got my $20 worth of fun from this piece of glass. 

 

There were high clouds tonight illuminated by the moon.  Vignetting is most likely from the stop in the incorrect position, away from the lens and just inside the dew shield. 

 

 

Attached Thumbnails

  • M81_4_18_2024T20_43_26_G200_652s.jpeg

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#121 Borodog

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Posted 18 April 2024 - 10:29 PM

I made a stop for the scope reducing it to 30mm f/8.   The results are still  poor, so I think the svbony 0.5 reducer is a lost cause for EAA.  I am not sure I got my $20 worth of fun from this piece of glass. 

 

There were high clouds tonight illuminated by the moon.  Vignetting is most likely from the stop in the incorrect position, away from the lens and just inside the dew shield. 

Wow that's pretty bad all right.



#122 alphatripleplus

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Posted 19 April 2024 - 06:30 AM

I made a stop for the scope reducing it to 30mm f/8.   The results are still  poor, so I think the svbony 0.5 reducer is a lost cause for EAA.  I am not sure I got my $20 worth of fun from this piece of glass. 

 

Occasionally with the inexpensive 0.5x reducers, the manufacturer places the lens the wrong way in its cell, resulting in poor results. If you can reverse the lens orientation and test you may find that is the problem. Probably little to lose at this point in trying that.


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#123 roncarr880

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Posted 21 April 2024 - 04:39 PM

Occasionally with the inexpensive 0.5x reducers, the manufacturer places the lens the wrong way in its cell, resulting in poor results. If you can reverse the lens orientation and test you may find that is the problem. Probably little to lose at this point in trying that.

I do think this is the case with this reducer.   The lens as shipped had the flat side toward the objective lens.  I swapped it with some difficultly as the lens is a tight fit in the cell.  Unfortunately my far focus with my scope is now about 10 feet.   I found a short CS to 1.25 adapter on amazon and will probably get it with my next order whenever that will be.

 

I have a bunch of 50 - 80mm enlarger lenses.  They all focus an image ok either held correctly or reversed.  I have never seen a lens like the 0.5 reducer as when held one way it focuses an image of a light bulb just fine but when reversed the image is just a mess.

 

( I think I am getting off topic here, back to CA removal with blue channel replacement )



#124 roncarr880

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Posted 27 April 2024 - 08:44 AM

I have been having trouble with my darks removing two stubborn hot pixels.  I would guess they are green pixels and then the CA removal algorithm produces a hot blue pixel next to it, and then when debayered it produces a very large cyan hot pixel group.  Example cat's eye galaxy is CA deep sky 1 at gain 200.   I have made a new dark at the start of each evening.

 

Last night I tried CA deep sky 2 and gain 230 and a new dark.  I don't think the difference was CA 1 vs CA 2 but maybe the difference in gain.  One thought I had was maybe when Sharpcap changes the gain and exposure during a GOTO that the camera heats up and the dark no longer works.  Anyway, M53 is my first view of a globular cluster with EAA - much larger than I expected.  I used the Sharpcap sharpening tool with this image.

 

60 mm f/4 guide scope,   sv305c camera with #8 pale yellow filter.

Attached Thumbnails

  • HotPixels.jpeg
  • M53 (NGC 5024)_Stack_59frames_605s_1.jpeg



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