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View Full Version here: : Surprise, yes another M42


Robert_T
11-12-2020, 05:33 PM
a little over three hours of 90s and 30s subs over a couple of nights.

asi071mc pro, espirit100ed and L-extreme filter.

stacked in DSS and processed in PS with astronomy tool plugins.

i seem to be stuck with this more red/orange colouring with this Lextreme filter... at least with my processing.

C&C welcome

Startrek
11-12-2020, 06:06 PM
Robert
Nothing wrong your colour rendition of a fiery looking M42
Plenty of detail there and the trap nice and defined
Well done !!
I use Startools V1.6 to process which has a Compose module specifically designed for OSC Narrowband data
You can develop your own synthetic colour blends or just use the Ha, OIII , SII etc presets
Maybe give it a trial ?

Martin

RyanJones
11-12-2020, 07:19 PM
Nice effort Robert,

OSC cameras with dual band filters can be a bit tricky to colour balance until you get the hang of it. Ha is always going to be the dominant gas shown for two reasons. Number 1 is it is an emission gas meaning it creates its own light as opposed to O2 for example that reflects the blue light from another light source. And secondly O2 is at the same end of the spectrum as sky glow so it’s always harder to extract. With this in mind, be careful how much O2 end of the spectrum you’re chasing as the reality is it should be dimmer. All this said there is definitely a need to balance the colours. If you have already tried to balance the “ black background “ by picking a black area and making sure the values are the same for all three channels then you can also use selective colour in PS to change the tone of each channel. As I said before, the blue end of the spectrum is always going to need some teasing to get the contrast right due to the fact that your sensor simply isn’t going to recieve as much luminance down that end of the spectrum. You can try stretching the Blue and green channels slightly more than the red with curves early on in your processing too. It is a balancing act but it’s something you’ll get used to tackling as part of your work flow. Hope that helps a little. You’re off to a great start.

Cheers

Ryan

Robert_T
12-12-2020, 08:52 AM
thanks Ryan, I'm careful with black (and white) point balance recalibration as I go through each step of my processing, including between each of several stretch phases at the beginning. Great advice though on stretching the blue/green more as I think that will help... I notice my red humps are always broader.

Zuts
13-12-2020, 10:02 PM
I have the zwo duo band, I am thinking of adding another channel by getting an SII filter, rather than trying to compose a HOO image. Then theoretically I would have 3 distinct channels, HA, O3 from the duo band and SII from the other filter.

The trouble is it's an expensive experiment...but may reduce the red.