SNR IC 443 in green and red

[Bertrand Laville]

Hi All,

Some weeks ago, I took the opportunity of three very good nights in southern Alps to catch a glimpse at half a dozen of strong targets, through my 25" Obsession. Among them was IC 443, a supernova remnant in Gemini, probably one of the best SNR in the eyepiece, after Veil of course.

If the green color was imediately obvious, I was suprised to perceive the red H alpha after about half an hour of observation. Since that moment, the different parts of the nebula where clearly seen, some in green, some in red, some in both green and red.
Here is my drawing:

2817

More details here: http://www.deepsky-drawings.com/ic-0443-t635/dsdlang/en

Clear skies
Bertrand
http://www.deepsky-drawings.com/

[Bertrand Laville]

Apologies for the hereabove poor drawing.
Here is a better one (at least I hope...!)

2818

[Bertrand Laville]

Second try partly missed !
Sorry, I do not try again !

[Norman]

Hello Bertrand,

interesting object and good abservation. But are you sure about the origin of the color? At least my OIII filter (Astronomik) shows stars green. I read your post as if red parts itself have been weak - so these weak parts in color... is a bit contradictory to what i learnt and experienced so far...

CS
Norman

[Bertrand Laville]

Hi Norman,

Your OIII filter is an Astronmik, mine, in this observation, is a Lumicon of the 90's. Yourse cuts all wavelenths except 500 A°, mine let the red going through. This is obvious in such observations as "my" stars" are red and not green.

The red color of H alpha is usual in this filter, since the luminosity of the target is enough strong.
Please, have a look, for instance at: http://www.deepsky-drawings.com/m-42-centre-t635/dsdlang/en, or also http://www.deepsky-drawings.com/ngc-6992-6995-ic-1340-t635-2/dsdlang/fr

Of course, if I use an Astronomik OIII, or an Astrodon OIII, both filters that also I have, stars are green, and I can't see any red color.

Clear skies
Bertrand
http://www.deepsky-drawings.com/

[Norman]

Hi Bertrand,

ah, okay - when luminosity was strong enough - okay. In your first post i understood you that way that the red part of the object (not the color) was very weak and only visible after quite a while. Interesting with the different wavelengths - i see.

Anyway - very interesting object of the season i will try soon as far as clouds allow. By the way - very nice ressource of sketches Bertrand.

Clear Skies
Norman