Hubble Palette and Star Colors

[hoa101]

I had a quick question, which is probably trivial for the more experienced people. My main problem is that I did not come to Startools with any other software under my belt.

Using the layers and/or the LRGB tools I can do just about any palette I want with emission-line data.

Say, for example, I am doing plain old Hubble palette. Also assume that I have a very small amount of RGB data (short exposures) to capture star colors only. SNR in the DSO will be non-existent. What is the best way to combine that star data with my Hubble palette narrowband data?

I imagine some operation with the layers tool, but at what point in the process? And how to keep from introducing noise in the DSO?

Thank you!

[admin]

I had a quick question, which is probably trivial for the more experienced people. My main problem is that I did not come to Startools with any other software under my belt.

Using the layers and/or the LRGB tools I can do just about any palette I want with emission-line data.

Say, for example, I am doing plain old Hubble palette. Also assume that I have a very small amount of RGB data (short exposures) to capture star colors only. SNR in the DSO will be non-existent. What is the best way to combine that star data with my Hubble palette narrowband data?

I imagine some operation with the layers tool, but at what point in the process? And how to keep from introducing noise in the DSO?

Thank you!

Hi, you're definitely thinking in the right direction! The Layer module will indeed be most suited for this.

I've never done this myself, but here's how it would work in StarTools;

Process your RGB image to your liking as normal, so that it brings out star color. Create a star mask and save the mask. Also save your RGB image.
Next, load up your HST image and launch the Layer module. Load ('open') up your RGB image in the foreground. In the mask editor, load the mask you created previously. Back in the Layer module, set Blend mode to 'Color of fg' (foreground). Use mask fuzz to make a smooth blend between background and foreground. If you find it is not picking up enough color from the stars, grow your mask little.

Let me know how you go!

Cheers,

[hoa101]

I was messing with some data and had an additional question if you do not mind. How does Startools react when you load the SII-Ha-OIII straight away and start stretching? Most people want to stretch OIII and SII more such that Ha does not dominate the image.

I tried to stretch and process them independently similar to your "synthetic" luminence tutorial initially. However, it is really hard to get the same amount of stretching, which results in an unbalanced final RGB image.

For example this photoshop method here: http://bf-astro.com/hubbleP.htm

I have tried to reproduce this type of image in Startools but just cannot quite figure it out.

Any thoughts? Maybe a narrowband tutorial is in order at some point.

[admin]

Apologies for the tardy reply - moving house... (fun, fun, fun)

How does Startools react when you load the SII-Ha-OIII straight away and start stretching? Most people want to stretch OIII and SII more such that Ha does not dominate the image.

That should work just fine - just use the Color module right before switching off tracking to modify the prevalence of S2, Ha or OII - just bump up OIII's and S2's ratio. You could even decide to process color and luminance seperately and recombine them at a later stage.
StarTools does not support hue changes or color range selections during color calibration, as they are deemed as 'tampering' with the true representation of gas distribution. You should be able to achieve pleasing hubble-esque images without cheating though (the reason why hue changes are deemed cheating, is that you are destroying the true meaning of the color blends instead of merely modfying which gasses 'poke through' more *globally* - in essence changing hues is just abritrarily changing those gas levels *locally* to make a pretty color...). That said, if you really want to change the colors, you could do it in a free program like the GIMP.

Hope this helps!