Why have the tadpoles got no colour?

[blinky]

Ive added in a few hours of Sii to my tadpoles image so I now have around 3 hours in each narrowband.  I must be doing something wrong as I am getting no colour around the tadpoles and the star next to them - they are just grey, but in other images, they have a lovely colour to them....

Tadpoles-Added-Sii.xisf

[Sp@ce_d]

Not been on this target for years, funny enough I've just turned the Esprit 150 on it but only got Ha & OIII so far.  Is it SHO? Looks a bit HOO. They're strong in both Ha & SII, colour wise should match the opposite side which they do.. the OIII on the "noses" will lighten them. I tend to play with the latest version of SHO-AIP now, to get an idea. Looks like you're using PI by your attachment. Are you seeing a strong green with the Ha?

[blinky]

I linear fitted the Oiii and Ha to the Sii since it looked the weakest, this meant I didnt get too much green but not sure if thats the best way to do it?

[TerryMcK]

I suppose it depends on how much saturation and contrast is given to the background nebula. I've seen plenty of tadpole images that are similar but pop because of the contrast.

Very nice data though. You look as though you have sorted the problems you had with the F4. 

[Sp@ce_d]

Hmm.. so I've just gone back to some old data from my RC8. These are just the stacks thrown into SHO-AIP & stretched.. then the second one has had SNCR run. So I'd expect you to see a similar balance.

 

[blinky]

Had another play, this is a little better and maybe as much as I can get with the data I have?

[blinky]

29 minutes ago, TerryMcK said:

I suppose it depends on how much saturation and contrast is given to the background nebula. I've seen plenty of tadpole images that are similar but pop because of the contrast.

Very nice data though. You look as though you have sorted the problems you had with the F4. 

Yeah got the F4 sorted - borrowed a cocentre for the secondary then used a laser on the primary and did a wee tweak under the stars, a lot happier with it now.

[TerryMcK]

I managed to coax a bit more out of it by fiddling around with your xisf file. I used the Dark Structure Enhance script.

I also used Photometric Color Calibration based upon your camera pixel size and scope focal length, using CFA Harvard as the database server to plate solve after putting in the RA and Dec of the object. This has changed the star colours.

I think I have brought out the wispier outlying areas. However PI is such a complex program with many things that can be altered that sometimes one can go a little too far! I tried applying a MLTSharpen (Multiscale Linear Transform) to sharpen the stars but it looked a little too processed then so undid that.

 

Edited December 24, 2020 by TerryMcK

[blinky]

Ive never done colour calibration on narrowband images, thought it was not supposed to work but that looks a lot better. Star colours are definatly improved and there is more colour in the wispy areas, thanks

[blinky]

Final process - used Starnet then sharpened the nebula a little, did a correct stars on the star layer, messed about with the colour of the nebula then added them back together

 

Edited December 24, 2020 by blinky