LRGBHa workflow - am I on the right lines?

[Willi1972]

Hi all,

I am just getting started with DSLR imaging, but in the cloudy nights of the last 6 weeks, I was tempted to open an iTelescope account and try some LRGB imaging, with a Ha thrown in for good measure. I set up an imaging run pointing at M42 and downloaded the files an hour or so later. I have had a go at processing in PS (CC) and have come up with a reasonable (for me) image as a first draft. However, I suspect my workflow is inefficient to say the least, so I would appreciate any comments.

1. Download all images as FITS files. These are already calibrated. The R,G,B and Ha are binned x2

2. Stack each channel separately in DSS, using 1 of the L images as a reference frame.

3. Save as a FITS file. I need to do this so that I can get an acceptable stretch using FITS Liberator. If I save as a TIFF, I can't seem to stretch satisfactorily in PS. It gets very spiky very quickly. Any advice here would be very welcome. I suspect longer subs would help.

4. Stretch using FITS Liberator using a log (log) profile, and save as a TIFF

5. Resize the colour channels to be the same size as the Lum channel

6. Tweak the alignment manually

7. Add layer adjustments to each of the colour layers and reduce the unused colours to zero. I will also try doing this in the channels, but I figured this way would give me more control.

8. Set the colour layers to screen mode, and the Lum layer to Luminosity

9. Tweak the curves of each layer to taste. I am still in the process of trying to get the colour balance correct, I suspect working with the colours in channels would be better for this.

10. The Lum layer is made up of 240s subs. I also have a 30s layer to blend into it when I have time.

Any comments would be appreciated. I had only 5x 120s Lum, 5x 40s R, G and B (binned 2x), 5x 120s Ha, but this was more for practice on the processing side of things. I was pleasantly surprised at this result, even though it still has more work to go into it. I suspect that if I blend out the Lum layer in the blown out bits, this would help as well.

Regards

Richard

[Willi1972]

Anyone? Anyone at all?

[Scott]

Sorry Richard, I can't help you I'm afraid but heres hoping someone will be along soon. I'm planning to capture my first set of LRGBHa tonight so would be interested in advise also .

You've given me some tips to start with so thank-you 

[Willi1972]

I now have a new version of this where I have adopted my new workflow of opening the DSS 32bit TIFF file in CS. Then change mode to 16 bit, with the setting "equalise histogram". This gives me data that are much more stretchable. The result is more subtle and pastel.

I spent a long time playing with the different layers, and found that by making the curve for a particular colour a bulge rather than a single curve, I could affect a specific portion of the nebula. By careful manipulation of the colours of certain layers, I could get more of a 3D effect. I still kept my colours in layers rather than channels, as I could have a fine degree of control that I don't think is available in channels. For example, the red layer could be made into an orange layer.

I played around with shorter subs for the blown out region, but I decided that the image looked more complete and "active" with the intense brightness there. Not to everyone's taste, I realise.

This is getting far from a faithful representation of real life, but it still looks nice.

Regards