OIII is green and not blue?

[pipnina]

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

[tingting44]

i all ways thought green was not a true colour in space, but if its good enough for NASA..... lol

https://www.nasa.gov/multimedia/imagegallery/iotd.html?id=370879

good luck with 1st light with your new filter

[seo]

Here is  the wavelength spectrum...

[John]

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

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

[Mrbloke]

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.

[Pluto the Snowman]

I actually thought OP misspelled oil lol! Have no idea what all that is about.

[Dom1961]

If you're not happy with the colour just tilt it

[John]

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 !

[Paul73]

Pip

You often find that OIII filters have a spike in transmission in the red as well. I have Lumicon 1.25" and 2" OIII. One shows a pleasing green colour. The other has hints of red!

Good luck with the Veil.

Paul

[laser_jock99]

In the Imaging Section we had already decided OIII was turquoise

http://stargazerslounge.com/topic/244610-m27-lets-see-your-pictures/page-2?hl=dumbbell

anything other colour might be in the imagination of the image processor! 

[MarsG76]

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.

[seo]

+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.