A different view of the Tarantula

[sjastro]

The image is a combined visible light and long wave UV of the Tarantula Nebula.

The aim was to highlight the intensities of H-Epsilon, H-Zeta and H-Eta long wave UV emissions in an image that contains the familiar H-Alpha, H-Beta and O-III emissions found in visible light images. Since these UV emissions have no "colour" they were mapped to the blue channel and appear as yellow in the final image.

The more yellow the greater the uv intensity in the image.

Imaging details.

UV image (340nm-400nm) LRGB image
6 hrs UV pass, 1 hr R, 1 hr G, B=UV pass.

Visible light image. LRGB image.

1 hr L=R filter, 1 hr R, 1 hr G, 1 hr B

Telescope BRC-250, ST-X10ME,
Each image was merged at 50% opacity in Photoshop.

Higher resolution merged image can be found here.
http://members.iinet.net.au/~sjastro/tar_light_UV.jpg

A higher resolution comparison of the uv and visible light luminance can be found here.

http://members.iinet.net.au/~sjastro...n_uv_light.jpg

Clear skies

Steven

[Larryp (Laurie)]

Great image, Steven!

[strongmanmike (Michael)]

Interesting exercise Steve, the colours are different but quite pleasing The comparison between the UV and R is quite revealing. The Tarantula is certainly a complex region.

Mike

[RickS (Rick)]

Interesting to see a novel take on the Tarantula, Steven!

[seeker372011 (Narayan)]

It is certainly different.very interesting

[LightningNZ (Cam)]

A blue-red bi-colour of these two might look pretty cool? Fascinating stuff, thanks for posting.
-Cam

[alpal]

Hi Stephen,
Wow - that's got a nice low noise smoothness to it.
Could we see a 1920×1080 version of all of them please?

cheers
Allan

[dvj (John)]

Bravo! I love the concept and the UV image by itself it quite interesting.

j

[Merlin66 (Ken)]

Another excellent cutting edge image!
I think you are succeeding in lifting everyone's awareness of what UV imaging can add to our appreciation of DSO's
Well done!

[sjastro]

Thanks for the comments.

There are some caveats to UV imaging. The extinction factor is large.
I tried using the filter as a pseudo Calcium K line filter on the Sun and found I needed to increase the exposure time by about 4-5X when shooting at 45 degrees above the horizon as compared to imaging near the zenith.
I suppose this is not that surprising given it is very difficult to get a Sun tan in the morning or late afternoon.
Pollutants such as smoke haze make UV imaging very difficult.
Once again this is not surprising as UV block filters cut through haze, UV pass filters on the other hand have quite the opposite effect.

Originally Posted by alpal

Hi Stephen,
Wow - that's got a nice low noise smoothness to it.
Could we see a 1920×1080 version of all of them please?

cheers
Allan

Allan,

The direct links are to images at 80% of full resolution. The colour data was taken nearly two years old and due to the image rotation using a helical focuser much of the combined image has been cropped out.

Regards

Steven

[Ross G]

Interesting capture Steven.

Ross.

[David Fitz-Henr]

Interesting images Steven, and the colour looks great - fascinating to see a familiar image in a "new light"

[sjastro]

Thanks David and Ross.

I generally avoid imaging well known objects like the Tarantula or M42, they are done much better by others in the visual range of the spectrum.

So all I am left with is to pick up the scraps in the long wave UV range.

Clear skies

Steven