M31 Andromeda in RGBHaO

[cyan moon]

ASI533mc
SQA55
Star Adventurer GTI mount
SVBony SV165 40mm guide scope
ASI120mm guide cam
ASIAir plus
Astronomik l-3 uv/ir cut filter for broadband and SV220 for dual narrowband

8.5 hours of broadband data with 5 hours of dual narrowband data, stacked with drizzle at 6x, reregistered color channels and downsampled to 2x using custom in development Siril builds.

GraXpert background extraction 1 smoothing
Dev Siril SPCC using correction for exact camera and filters
BlurXterminator .4 stars/.8 nebulosity
GHST stretch
NoiseXterminator .8/2 reps
Redo black level for denoise
SCNR
Curves on Saturation
Tuning in GIMP

data shared here
#1408832186442059877 message

[tranquil sparrow]

Why on earth are you drizlling 6x

[cyan crypt]

Holy thats pretty

[golden pollen]

Me when drizzling x1243 doesn't give Hubble details: 😭

[cyan moon]

My setup is giving fwhm around 1.8px native res - if I register at 2x or 3x drizzle and just process that, blurx exaggerates artifacts from the registration process. At 6x and then downsampling back 3x, the artifacts are averaged away and blurx no longer exaggerates them

[tranquil sparrow]

your sampling is 2.965"/pixel native. So your FWHM is 1.8 * 2.965 = 5.33" FWHM. now with 6x drizzle your sampling bcomes almost 0.5". Your not helping the data, in factm your ruining it. The SNR hit from drizzling 6x is quite drastic. What are these artifacts you speak of?

With your setup i wouldnt be drizzling AT ALL, or mabye the occasional 2x

[cyan moon]

The SNR hit doesn't exist if you pixel area average back to 2x native

[tranquil sparrow]

Do you know how the drizzle alogrithm works?

[cyan moon]

Yup I'm working on Siril with it

[tranquil sparrow]

downsampling isnt the same as "un drizzling"

[cyan moon]

If you want I can post drizzle at 2x data in my data dump for your comparison

[tranquil sparrow]

I wanna know what these artifacts you speak off are lol

in the registration process?

[cyan moon]

Oh you might be thinking I'm doing .17 pixfrac no I'm doing 6x scale 1x pixfrac so at 6x drizzle the sampling is still 5.33 arcsec it's just 11 pix instead of 1.8

You can see what I'm talking about with artifacts at 32:00 here
https://youtu.be/fArpHNzUASg

[rough fossil]

Do you have pix or did someone do the blurx ?

The pix insights drizzle is so much better than sirils

[cyan moon]

I have pix but I'm using siril for drizzle because I'm helping develop it