Jump to content

1912116577_Solarchallenge2022banner.jpg.913a200cf105ddeae9f37765cb1d0c73.jpg

OIII is green and not blue?


pipnina
 Share

Recommended Posts

I got my OIII filter the other week, and so you can imagine the first thing I did was hold it up to my eye to see what things were like through it. I was more surprised than anything that I was seeing such a strong green instead of bluish green like I had expected.

Perhaps fooled by astroimages (which seem to represent OIII on the blue channel, perhaps due to their apparent hate of the colour green?[citation needed]) I wasn't expecting that. It makes me wonder what nebulae like M42 or the veil would look like in an image comprised of Ha + S-II on red, O-III on green and He-II and Hb on blue.

I've often thought before that the universe is missing out (nebulae usually being represented as red/blue/yellow/brown)... green is my favourite colour after all, but I guess it was full of it all along!

Alas, my filter hasn't seen astronomical use yet... When I went to use it on saturday last week the clouds came in just as I was pointing it at the veil with my RDF. Disappointing!

    ~pip

Link to comment
Share on other sites

My Lumicon O-III filter tints things green in daylight too. It has a spectacular effect on objects such as the Veil though, and thats not green at all :smiley:

Imaging is so different to what we experience visually that trying to draw any parallels is invariably misleading.

Link to comment
Share on other sites

John, are you saying that the Veil is NOT green for the Lumicon?  What colour (if any) is it then?

The veil is most definitely green with the Explore Scientific OIII in place.  You can also get some purple tinges if you put things on the outer field of view.

Link to comment
Share on other sites

John, are you saying that the Veil is NOT green for the Lumicon?  What colour (if any) is it then?

The veil is most definitely green with the Explore Scientific OIII in place.  You can also get some purple tinges if you put things on the outer field of view.

It's shades of grey to me as are the majority of deep sky objects. I can see a faint tints of green in M42 and possibly in M57 and objects like the Blue Snowball planetary nebula have a hue (not filter added).

I've viewed the Veil recently with a 20" dob under a darkish sky and the same Lumicon filter and again my eyes saw shades of grey. There was somewhat more detail than my 12" shows of course.

Peoples eyes can vary with colour perception. Young people seem to see colour tints in DSO's more readily than oldies like me I think !

Link to comment
Share on other sites

I use Baader CCD narrowband filters and when exposing using a modded Canon 40D through the OIII filter, I find that I have most of the signal in green but still a substantial amount in blue channels... nothing but noise in the red channel.

I'd say that OIII is 3/4 in green and 1/4 blue (roughly.. very roughly) and seeing that also our eyes are more sensitive to green, the view through the filter looks green.

Theres still enough blue data captured that when I exposed the Helix Nebula through Ha, (that had a little bit of signal in blue also), and OIII, I was able to get nice color by using red from Ha, Green from OIII, and Blue by adding the signals from Ha just blue channel exposures and only blue channel signal in OIII exposures.

Link to comment
Share on other sites

+1 to laser_jock99.

OIII is clearly in between blue-green section which is turquoise. Different sensors don't react in the same way as of course the pallets used and the different computers-screens combinations used.

post-47040-0-48456800-1443212922.jpg

  • Like 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.