take two

[muletopia (Chris)]

year I put up an image of ngc 2070, my first attempt. Raymo kindly made criticism and has given me more help by private communication, many thanks Raymo.

These images are again from a Canon 60DA at prime focus of a Tak Mewlon 210.

The major problems were tracking,noise and loss of detail in reducing the image for this site.
The steps taken were:-
Guiding: went to off axis pulse guiding with an Orion thin OAG and a ZWO 120mm.
Noise : stacked 4 4 minute shots at ISO 640
Image reduction: still a a problem, these are small but at least clearer

The camera stored jpeg and raw images.
The link below gives the steps I followed to process the raw images, and the jpegs without the demosaic step.

Despite the assurances in the tutorial the colour is missing in the final raw shot

So two immediate questions.
How to produce colour in the raw processing
and
the best way to reduce images for this forum

Chris

http://northlincsastro.org/images/A%...Nebulosity.pdf

[raymo]

Good job Chris, sorry I can't help with your current problems.
raymo

[PKay (Peter)]

Originally Posted by muletopia

...

So two immediate questions.
How to produce colour in the raw processing
and
the best way to reduce images for this forum

Chris

http://northlincsastro.org/images/A%...Nebulosity.pdf

I don't use nebulosity however the principles are the same.

Study and learn the following:

1:The difference between 'Linear and Non Linear'.
2: What a histogram is telling you
3: What 'stretching an image' does. Also called 'developing', or 'histogram transformation'.
3: What 'curves transformation' does.
4: Play with 'saturation' and 'hue' controls.

And finally, if you over expose an image, no colour at all

Question 2 is a hard one and in the nearby thread.

Have fun!