Ha Mono to color conversion in Maxum Dl

[carl20171]

I have 11 nice 180 sec. pictures of the Bubble Nebula. They are with a mono camera. I used a manual filter wheel selection and set it to Ha. so the fits header does say Ha.  I go to Maxum DL and load my calibration frames then

1) load the images in the stack window

2) select auto calibrate and classify by filter and select Ha in the red channel and leave the other filters blank

3) Alignment by auto star matching

4) For some reason the color tab is greyed out and I cant make any selections.

5) Combine tab is median and 16 bit selected. 

6) I hit go and get a pretty nice image in mono. 

Where's the color ??   

I then tried going to the convert to color selection but I think that is only for color cameras and I have a mono. It changes a tiny bit but mainly stays mono. 

I tried color stack and color combine with no luck there either. 

I though if I used Ha I would at least be able to convert to red. I cant remember what I pressed but one time I did get things to turn red but it made the whole picture red even all the stars. 

Can anyone direct me on the proper procedure. Maybe copy and paste my steps in a reply and correct them?

Thanks Carl

[ollypenrice]

Most people with an image in 'H alpha only' present it in greyscale (casually known as black and white) because this will give the highest contrasts. You can, if you wish, present it in monochrome red though this would be unusual. One simple way to do it would be to open the image in Photoshop, change the mode from greyscale to RGB and then delete the green and blue channels.

Be aware, though, that this is an artificial red even though the light you captured was genuinely red light. This is because an Ha filter passes almost monochromatic red light, meaning it has almost no variation in tone. It is also close to the edge of human visual perception. 

Olly

[carl20171]

Thanks for the reply. So to get the color images I see on the web  I need to capture in Ha SII and OIII, is that correct?

[lensman57]

Thanks for the reply. So to get the color images I see on the web  I need to capture in Ha SII and OIII, is that correct?

You can try a bi colour with Ha and Oiii mapped to RGB.

A.G

[ollypenrice]

Yes. There are two kinds of colour imaging in astronomy, natural colour and colour mapping. In natural colour imaging the flters used are red green and blue - which allow pictures to resemble nature. In colour mapping the light from a particular excited gas (hydrogen, oxygen, sulphur etc) can be arbitrarily ascribed to the colour channels available in graphics programmes. These resemble geology maps, for instance, in which different rocks can be given different colours.

Careful combining of Ha O111 O111 can give a result similar to natural colour.

Olly

(Oh, and sometimes narrowband data is blended with natural colour to enhance signal and structural detail without dramatically altering the colours.)

[r3i]

Here's a couple of walk-through tutorials I've used recently to process narrowband images.  Olly may be able to suggest better procedures but hopefully they give you a starting point:

Ha-OIII bi-colour: http://www.starrywonders.com/bicolortechniquenew.html

SII-Ha-OIII Hubble Palette: http://bf-astro.com/hubblep.htm

[carl20171]

Thanks for the tutorial links. They really help. If I could ask another question.

1) I have photoshop but have not used it yet. Is it even possible to combine Bi color and get a color photo in Maxum Dl with Narrowband filters? Or should I go right to photoshop after stacking separate RGB channels.

In the long run due to light pollution I will have to become a NB expert.

[r3i]

I don't use Maxim DL so can't help you directly (hopefully someone with experience of that application will chime in).  

I use Nebulosity for aligning the 3 NB images and I save the result as 3 separate images which will now be aligned with each other. These are then taken into PS and merged into an RGB image using the Channels - Merge operation.

[carl20171]

1) So the 3 RGB images still look mono to the eye until they are combined in Photoshop? They wont look Red Green and Blue yet?

2) If you bring 3 RGB into photoshop does photoshop do the star alignment of the 3 images as well as merge the color?

3) Once you merge the color that is when you can actually see color on the screen?

Thanks Carl

[Davey-T]

I've done false colour narrow band in Maxim, just right click the HA  files and tick the red option to assign them to red, same with O111, blue and S11,green or whatever colour you like.

Dave

[r3i]

1) So the 3 RGB images still look mono to the eye until they are combined in Photoshop? They wont look Red Green and Blue yet?

2) If you bring 3 RGB into photoshop does photoshop do the star alignment of the 3 images as well as merge the color?

3) Once you merge the color that is when you can actually see color on the screen?

Thanks Carl

1. Yes the 3 images will appear mono in PS, in fact they come into PS as greyscale images not as RGB images.

2. Not sure if PS provides an automatic alignment operation, I think you would have to do it manually. You'd be better off doing the alignment in Maxim I would have thought.

3. Yes, the merge channels in PS combines the 3 greyscale images into a single RGB image and it is then that you will see a colour image.