M20 Lextreme and OSC StarTools

[gb44]

Hi all,
I have this one of M20 where I have used a QHY410c OSC camera and L-extreme filter with the Meade 12in.
I got 9x10min subs with SharpCap Pro and stacked in IP with calibration frames. I split the RGB file into R and G and under compose in StarTools
I put R and G where it seemed to ask for the files.
I'm not sure which file goes where....
Anyone got a good guide I can try?

GlennB

[Startrek]

Glenn,
As you using a OSC narrowband filter your capturing Ha and Oiii at 7nm bandwidth ( Not RGB broadband)

Also M20 Trifid is primarily a Broadband target so best to image it during the new moon period with just a luminance filter or UV/ IR cut filter , not an L Extreme filter

Here’s an “example only” of how I process Emission Nebula targets like M42, M8 , Carina , M16 , M17 and so ….with my OSC camera and L Extreme filter using Startools

Compose OSC Bi Colour Images for Emission , Reflection and Planetary Nebula using L Extreme filter

Open Startools and use “Compose” to load data set

Select Luminance Colour - L+Synthetic L from R (2xG ) B, R ( GB) (GB) ( Bi Colour from OSC DSLR )

Load your data set into
R / S11
Green / Ha
Blue /Oiii

Leave Luminance file None
Color Channel Interpolation On
Channel sliders are set to default or 1hr 3600sec ( no need to adjust )

When loaded press Keep , then choose Linear

Start your normal workflow in Synthetic Luminance or Mono until you hit the Colour module

Colour Module
Style Scientific ( Colour Constancy )
Saturation Amount 180% to 250%
Bright Saturation + 2.0 to taste
Dark Saturation + 2.0 to taste
LRGB Emulation Try both RGB Ratio CIELab Luminance Retention and Straight CIELab Luminance Retention
Bias Slider Mode - Sliders Reduce Color Bias
Red Bias 2.0 to 3.0
Green Bias 3.00 to 4.00
Blue Bias 1.20 to 1.60

The above settings are only a guide. Green bias must be reduced and Blue bias increased to obtain a good Bi Color image. Adjust as necessary.

The above should result in a good Bi Colour image when using the SHO Options in the Matrix at the bottom right

Generally for HOO , HHO, OOH options in the Matrix , reduce the Red bias, increase the Green bias and leave the Blue bias similar to SHO options.

For Interpolate and RGB options in the Matrix , again adjust the Red bias and Green bias to taste. Normally the Blue bias can remain between 1.20 to 1.60


You can still use your M20 L Extreme data set using the above procedures however the colours will be less than ideal

Maybe try M20 again during the dark period ( No L Extreme filter just a luminance or UV/IR cut filter and process with Startools just with Open and centre button OSC data Bayered and not white balanced ( not Compose ) I think you will find results to be far superior than this session

Hope the above helps in some way

Cheers
Martin

[gb44]

Thanks muchly Martin.
I've got M 8 and M 16 data too so plenty to go on with.
Cheers
GlennB

[RyanJones]

Hi Glenn,

Am I reading this right that you discarded the blue channel after splitting them ? I’m not sure why you would do that ? O3 shows up in both green and blue channels but more towards the blue. Conversely light pollution tends to show more prominently in the green channel. I generally use a HOO composition for that reason if I’m using just Ha and O3 data. You can, as Martin suggested, go for an SHO with a synthetic S2. M20, as Martin said, is much better imaged in broadband as the blue is a reflection nebula. That’s the data side of things. As for processing in startools, I know nothing so this is where my help must stop :rofl:

Cheers

Ryan

[gb44]

Hi Ryan,
Yep, I didn't use the blue channel in the pic. I've had no experience in using the NB software and I've taken little notice of the Oiii and Sii stuff. Just played around with DSLR achieving pretty pics. Now I'm seeing things from the other side - StarTools describes colour spaces as Scientifically correct and Artistically correct/detail aware. Cool. Pics telling the truth.

It'll be interesting to me to see what the B channel adds.

Cheers
GlennB

[gb44]

Thanks Martin,
The protocol worked easily and I think the result is much better.
Looking forward to doing my other data!

Pic attached with R/Sii G/Ha B/Oiii

GlennB

[Startrek]

Regarding Startools
When using an OSC you only have to use Compose for Narrowband data ( In Compose , select Luminance Colour - L+Synthetic L from R (2x G ) B, R (GB) (GB) Bi Colour from OSC DSLR )
For OSC Broadband just use Open then select Linear data OSC / DSLR Bayered and not white balance ( centre tab )
Startools does all the mapping behind the scenes in the Colour module

When using a Mono camera with either NB or LRGB filters you have many more options in Compose than a OSC

Cheers
Martin

[gb44]

Hi Martin
Thanks, I missed that part so I've done it again with Luminance, Colour set to
L+syntheticL from R(2G)B,R(GB)(GB)(Bi-colour from OSC.

The colour bias tweaks take a while but I saw the green/blue effect you suggested.

Attached the M 20

Cheers
GlennB

[Startrek]

Glenn
Yep that’s about as good as it gets with NB data on M20
Well done !
It’s primarily a reflection nebula ( not emission) so Narrowband filters don’t do this object justice

If you can just capture it again during new moon period ( dark ) without the L Extreme. Just use a UV/IR cut filter or a Luminance filter
The results will astound you, reds will be true reds and blues will be true blues

Cheers
Martin