R(G)B imaging???

[northcanadian]

Hi folks:

I read an article recently where imaging can be done with just the red and blue filters...then combining the two to create the green..  I'm just wondering if any members do their imaging this way?

Thank you

Cheers

Roger

[johnrt]

I have experimented with this in the past and have got decent enough results, but the colours are not the same as when I use all three RGB, so I stick to using all three filters.

[swag72]

Yes I have cut the corners in R(G)B on a number of ocassions. I regularly do with with narrowband imaging as well, creating a Hubble palette image from only 2 filters and synthesizing the green channel.

[Gina]

Yes I have cut the corners in R(G)B on a number of ocassions. I regularly do with with narrowband imaging as well, creating a Hubble palette image from only 2 filters and synthesizing the green channel.

That's very interesting Sarah   Or did you not mean Hubble on NB images?

EDIT Ummm - you don't have a green channel in NB   Do you do Hubble palette in RGB then?

[johnrt]

I also use only 2 narrowband filters and synthesise a green channel from a mix of Ha & OIII, this is quite different to RGB I find though.

[Pete Presland]

not sure whether you are refering to DSO's or planets.

for planetary imaging i know you can, but i certainly would not unless i had no choice. the channels reveal different detail so i would always want to do all 3. i do remember reading that Damien Peach saying that doing R,G,B,G,R, then using the "B" channel twice in each R,G,B image.

[ollypenrice]

That's very interesting Sarah   Or did you not mean Hubble on NB images?

EDIT Ummm - you don't have a green channel in NB   Do you do Hubble palette in RGB then?

' The channel formerly known as green...'

lly

Back on topic, don't do it! Do it properly!!

[Pete Presland]

' The channel formerly known as green...'

lly

Back on topic, don't do it! Do it properly!!

so is the reason for doing RGB to reveal different data for each channel or just to use a more sensitive camera?

[steppenwolf]

I have experimented with this and it can produce fair results in broadband images but not as good as true RGB images where you have captured all three channels. There is some great red and blue data available from the Deep Sky Survey on NASA's website and this produces some very worthwhile images if you want to give it a try.

However, two-colour imaging using narrowband data (Ha and OIII) can be very much more successful, giving you a wide range of palettes to experiment with - if you are working from false colours to start with, you may as well let your mind have free rein!

[Gina]

However, two-colour imaging using narrowband data (Ha and OIII) can be very much more successful, giving you a wide range of palettes to experiment with - if you are working from false colours to start with, you may as well let your mind have free rein!

Surely you can't get the tremendous colours of the Hubble palette with Ha, OIII and SII without the SII?

[carastro]

Gina, there are some narrowband objects which have hardly any Sii data and therefore it is a lot of effort for hardly any result.  Consequently many imagers don't bother with the Sii unless they know it has a good signal and just do bicolour images using either the Oiii in two of the channels, or making a false channel for where the Sii would normally be.  I have done this myself a few times.

Carole 

[swag72]

Surely you can't get the tremendous colours of the Hubble palette with Ha, OIII and SII without the SII?

I think that you can .... yes.

[steppenwolf]

Surely you can't get the tremendous colours of the Hubble palette with Ha, OIII and SII without the SII?

I think you can at least get close but remember that SII is often very weak anyway so its contribution is sometimes fairly insignificant. Although I wasn't aiming for a 'Hubble Palette' lookalike here, the following image is typical of the narrowband bi-colour images that I am currently playing with. Ha mapped to red, OIII mapped to both green and blue channels.