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Rnc-color-stretch on a Mac

astrophotography dslr imaging
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8 replies to this topic

#1 fluyendophoto

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Posted 03 April 2020 - 05:41 AM

Good afternoon, I am quite new to astrophotography and really not much of a computer power user (I have a MacMini running OSX). I have been learning stacking and stretching using DSS and Photoshop, but I have come across Roger's website and wealth of information and have been blown away.

 

I also read about the rnc-color-stretch and hoped to give it a go, but because I am not very good with Terminal and programming, I have gotten stuck...

First, I tried to use it on OSX but got lost with all the command lines: I managed to install the file to the proper folder and Davinci, then I opened Terminal to to add
/Applications/davinci.app/Contents/Resources/bin to my path. I got this:

59070debec4a42adb51bf7f08a4eab7d.png

 

but then I was not able to proceed further (because i am a NOOB) because I do not know how to add /Applications/davinci.app/Contents/Resources/bin to the path.

I was able to open the Davinci exec on Terminal, which showed this:

 

e1081617bec044969b4be83c5928af53.png

 

but could not proceed any further to run rnc-color-stretch or locate my photo (which is in a folder in my desktop)

So I tried to run the GUI on my Mac enveloping it with Winebottler, and I got the program to open fine, I set up Davinci executable file and rnc-color-stretch script correctly, but when I press 'Stretch' I get this message:

 

b26ab660560b41c5a38f4a1fc2660ef6.png

 

Any help would be greatly appreciated, and apologies for the rookie mistakes I am probably doing... scripts and command lines are way above my level of knowledge, but I would love to see what Roger's method can do to improve my workflow and help me get better images

 

Thank you in Advance


Edited by fluyendophoto, 03 April 2020 - 05:45 AM.


#2 ChristopherBeere

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Posted 03 April 2020 - 06:06 AM

To be honest rnc-color-stretch isnt particularly user friendly, the (Windows) GUI is primitive and its a bit of a pain to setup.

 

The results can be pretty good (when it works) but if you are a Photoshop user then Mark Shelleys ArcsinH implementation is far superior.

 

https://www.cloudyni...rcsinh-stretch/


Edited by ChristopherBeere, 03 April 2020 - 06:08 AM.


#3 guidoforrier

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Posted 03 April 2020 - 06:15 AM

i can not help you . i am a Mac user to and went a long long time ago to this OSX to NOT to have to learn programming . this is also a reason why i stay away from Starnet ++ . i like to concentrate on the main goal : making good pics . you need already a lot of learning to achieve this . there is very good software with good GUI . i use APP , Gimp , capture one ....these work all very well and you need a lot of experience to use these software as good as possible . i also struggled with Terminal , github ... i now learning DaVinci resolve and for 3D is use Rhino .

thats enough !

hopefully you will helped on this forum .

greetings ,
Guido



#4 fluyendophoto

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Posted 03 April 2020 - 11:32 AM

Thank you for your replies.

 

I have just tried the Arcsinh curves in Photoshop and it works!

 

...I guess the first thing I need to work on is to get enough light captured by the sensor so I can stretch it out and process it!


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#5 ChristopherBeere

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Posted 04 April 2020 - 03:16 AM

Glad ArcsinH worked out smile.gif

 

Yes, increasing signal to noise ratio is the holy grail of astrophotography and enables you to stretch the data harder.

 

The best ways of achieving this are very dark skies, large aperture lenses, long integration and good calibration (dark frame subtraction and flat field correction).

 

Make sure the fundamentals of focus and tracking are locked down. 10 hours of data is no good if it is out of focus or tracked badly.



#6 fluyendophoto

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Posted 04 April 2020 - 12:51 PM

Glad ArcsinH worked out smile.gif

 

Yes, increasing signal to noise ratio is the holy grail of astrophotography and enables you to stretch the data harder.

 

The best ways of achieving this are very dark skies, large aperture lenses, long integration and good calibration (dark frame subtraction and flat field correction).

 

Make sure the fundamentals of focus and tracking are locked down. 10 hours of data is no good if it is out of focus or tracked badly.

 

thank you for your advice!

 

i am practicing from home, so hopefully by the time the lockdown is over I am able to take good astro photos!



#7 Lead_Weight

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Posted 04 April 2020 - 05:09 PM

This will not help you with your current issue. But have a look at my website linked in my signature for a list of available Mac software for processing and capture.


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#8 17.5Dob

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Posted 04 April 2020 - 06:53 PM

Don't even bother with rnc stretch, just use any variant of Arcsin stretch


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#9 fluyendophoto

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Posted 05 April 2020 - 07:32 AM

Andrew, that is a great resource I will look into in the next few days...

 

for the time being, I have started using Lightroom, Deep Sky Stacker and Photoshop. As suggested, I have abandoned the rnc stretch route and have downloaded Arcsinh, which is more user-friendly at least for my skillset

Also for the time being, my equipment consists of a Canon 90D unmodified and mostly a Canon 100-400mm that I mostly use for wildlife photography mounted on an Omegon LX3, so nothing professional. I am interested in nature photography in all its facets, and am curious to see how far I can go with the equipment that I have... 




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