Beginner Needs Help /:o

[Didge]

Hello ...

I'm a newcomer to astrophotography, and on a steep learning curve to understand post-processing,
I'm hoping someone on the forum can offer some guidance to help me get started with StarTools.

I've managed to capture what I think are good data sets using an OSC camera.
I stacked these using Affinity Photo, and then produced some nice images after many hours of manual processing. It took a very long time, and I'm pretty sure a lot of fine detail in those images is being lost in the process.

In searching for a better way, I found StarTools through some links in online image-processing tutorials - It seems to be just what I need

I spent the weekend going through all the learning materials on the StarTools website, and a lot of other YouTube videos. I think I understand the workflow, and the processes involved.

I re-stacked the images after disabling all image correction, and imported the stacks into StarTools - but haven't been able to generate an image as good as the ones I processed manually.

I'm sure I'm doing something wrong, or perhaps I'm making some mistakes in preparing the stacks.

I'd greatly appreciate any help - if someone can set me on the right track ?

Here are the stacks (as PNG) on DropBox - along with JPGs of my manually processed images that show what detail is in there - if anyone can offer any advice I'd be very grateful

https://www.dropbox.com/sh/oz04aauz3cez ... xyI3a?dl=0

Best regards,

Gary

[Mike in Rancho]

Hi Gary, and welcome!

First off, do not be overwhelmed! Easier said than done as a beginner, but do keep that in mind. Just pick up things bit by bit, learn, and improve. You'll totally get there.

I took a very quick stab at your Helix png. I admit I didn't even know ST could open a png as a stack, though I suppose maybe I have heard of that output before. Sharpcap perhaps?

In any event, we'll have to ask Ivo if that is all good to go that way for linear stacking output. The typical recommendation is FITS, though TIFF can do also. My only concern after looking at the EXIF data, is that this stack is in 16-bit depth. Now, I don't know much about Affinity other than a good number of folks seem to like it, and that it's a general photo program like PS or Gimp, but also has some special astro/stacking features.

If possible, see if you can generate a 32-bit output as the result of your stacking. Note, not a conversion afterwards, but the actual stacked output. I don't know what the source camera or acquisition program was here, but frequently the individual subs are something like 14 to 16 bit. The stacker can take advantage of the stacking process and produce an output in 32-bit depth. DSS, Siril, ASTAP, PI, will all produce 32-bit stacks, so you for sure want that extra detail if Affinity can do it also.

What are the particulars behind the data here - basically meaning camera, scope, filter if any, number of lights and exposure time, darks, flats (if any), dark flats...?

I noticed vignetting right off the bat, and while ST's Wipe module handily took care of that, you'll for sure want to try out calibrating with flats so that ST doesn't have to. The cores of many stars seem saturated, so you could be a bit overexposed on the sub length here (or perhaps too much ISO/gain). And in fact in your sample image the stars are all pure max white, perhaps with a little ring of color.

I've never tried this target myself, and it's a bit on the low DEC side for me, but I would imagine there's a very pretty star field surrounding the Helix. You'll want to capture that and let ST show it off.

Your colors are quite bold, but perhaps a bit to the blue/purple side of things, and maybe overstretched? I used ST's color sampling on a star mask. How correct that was, if too many stars are oversaturated, I'm not sure, but the result seemed moderately close to broadband Helix images on the net. I may have boosted the color saturation a bit.

Here's what I came up with, and a log with some very brief annotations in case you want to follow along and see what happens on the screen as you go through the steps. The unofficial ST manual is also very handy to download and have open while you work. It's full of tips and explanations.

Didge Helix ST8 1A.jpg (517.8 KiB) Viewed 2547 times

Code: Select all

-----------------------------------------------------------
StarTools 1.8.527MR2
Sun Jul 31 22:25:00 2022
-----------------------------------------------------------
File loaded [G:\ASTRO\2-ST FOLDER\didge\StarTools\2021 09 11 - 20 58 06 = NGC7293 - Helix Nebula = Lights Only\• Stacked - Affinity - Unadjusted.png].
Image size is 4944 x 3284
--- 
Type of Data: Linear and was Bayered, but not whitebalanced

[*AUTODEV 1, CHECK TO SEE WHAT'S HERE!*]

--- Auto Develop
Parameter [Ignore Fine Detail <] set to [Off]
Parameter [Outside RoI Influence] set to [15 %]
Parameter [RoI X1] set to [0 pixels]
Parameter [RoI Y1] set to [0 pixels]
Parameter [RoI X2] set to [4944 pixels (-0)]
Parameter [RoI Y2] set to [3284 pixels (-0)]
Parameter [Detector Gamma] set to [1.00]
Parameter [Shadow Linearity] set to [50 %]

[*REMOVE THE STACKING ARTIFACTS*]

--- Crop
Parameter [X1] set to [49 pixels]
Parameter [Y1] set to [32 pixels]
Parameter [X2] set to [4895 pixels (-49)]
Parameter [Y2] set to [3252 pixels (-32)]
Image size is 4846 x 3220

[*REDUCE PROCESSING SIZE, INCREASE SOME SNR*]

--- Bin
Parameter [Scale] set to [scale 50.00% / +2.00 bits / +1.00x SNR improvement]
Image size is 2423 x 1610

[*REMOVE GRADIENTS AND VIGNETTING, USE VIGNETTING PRESET*]

--- Wipe
Parameter [Synthetic Dark/Bias] set to [Off]
Parameter [Gradient Edge Behavior] set to [Absorb 50%]
Parameter [Synthetic Flats] set to [Vignetting]
Parameter [Sampling Precision] set to [256 x 256 pixels]
Parameter [Dark Anomaly Filter] set to [5 pixels]
Parameter [Gradient Falloff] set to [75 %]
Parameter [Synth. Bias Edge Area] set to [100 %]
Parameter [Gradient Aggressiveness] set to [95 %]
Parameter [Correlation Filtering] set to [Off]

[*SET FINAL STRETCH ON WIPED DATASET*]

Redoing stretch of linear data
--- Auto Develop
Parameter [Ignore Fine Detail <] set to [3.4 pixels]
Parameter [Outside RoI Influence] set to [15 %]
Parameter [RoI X1] set to [1103 pixels]
Parameter [RoI Y1] set to [688 pixels]
Parameter [RoI X2] set to [1316 pixels (-1107)]
Parameter [RoI Y2] set to [903 pixels (-707)]
Parameter [Detector Gamma] set to [1.00]
Parameter [Shadow Linearity] set to [50 %]

[*LARGER SCALE DETAILS, COMPRESS SHADOWS (NOISY)*]

--- Contrast
Parameter [Expose Dark Areas] set to [Yes]
Parameter [Brightness Retention] set to [Off]
Parameter [Precision] set to [256 x 256 pixels]
Parameter [Shadow Detail Size] set to [10 pixels]
Parameter [Locality] set to [50 %]
Parameter [Shadow Dyn Range Alloc] set to [25 %]

[*SMALLER SCALE DETAILS*]

--- HDR
Parameter [Signal Flow] set to [Tracked]
Parameter [Quality] set to [Low]
Parameter [Gamma Shadow (Lift)] set to [1.00]
Parameter [Gamma Highlight (Tame)] set to [1.25]
Parameter [Gamma Smoothen] set to [20.0 pixels]
Parameter [Context Size] set to [15x15 pixels (0.62% image W, 0.93% image H)]
Parameter [Shadows Detail Boost] set to [50 %]
Parameter [Highlights Detail Boost] set to [30 %]

[*SVD: AUTO APOD MASK USED + MANUAL CORRECTIONS TO 2 BRIGHTEST STARS*]

Mask used (BASE64 PNG encoded)

[*CHOOSE SAMPLE STARS ACROSS IMAGE, INCREASE PSF AREA TO 19*]

PSF samples used (11 PSF sample locations, BASE64 encoded)

VFMAAAsAdwlKBl0FygUXARUFaQSFBMMHpwShCFgDCgIhA3kDBAL1COMB1AahACADeABEAIAA

--- Spatially Variant PSF Deconvolution
Parameter [PSF Resampling] set to [None]
Parameter [Synthetic PSF Model] set to [Circle of Confusion (Optics Only)]
Parameter [Sampled PSF Area] set to [19x19]
Parameter [Synthetic PSF Radius] set to [1.5 pixels]
Parameter [Synthetic Iterations] set to [Off]
Parameter [Spatial Error] set to [1.00]
Parameter [Deringing Fuzz] set to [25.0 pixels]
Parameter [Deringing Detect] set to [75 %]
Parameter [Dyn. Range Extension] set to [1.00]
Parameter [Linearity Cutoff] set to [85 %]
Parameter [Sampled Iterations] set to [10x]
Parameter [Deringing Amount] set to [0.90]

[*KEEP MASK THAT WAS USED FOR SVD*]

Mask used (BASE64 PNG encoded)

[*HIT SAMPLE BUTTON, THEN - MASK, CLEAR, INVERT, KEEP*]

--- Color
Parameter [Bias Slider Mode] set to [Sliders Reduce Color Bias]
Parameter [Style] set to [Scientific (Color Constancy)]
Parameter [LRGB Method Emulation] set to [Straight CIELab Luminance Retention]
Parameter [Matrix] set to [Identity (OFF)]
Parameter [Dark Saturation] set to [2.0]
Parameter [Bright Saturation] set to [Full]
Parameter [Saturation Amount] set to [312 %]
Parameter [Blue Bias Reduce] set to [1.00]
Parameter [Green Bias Reduce] set to [1.33]
Parameter [Red Bias Reduce] set to [2.23]
Parameter [Mask Fuzz] set to [1.0 pixels]
Parameter [Cap Green] set to [100 %]
Parameter [Highlight Repair] set to [3 pixels]

[*ISOLATE TARGET*]

--- Super Structure
Parameter [Detail Preservation] set to [Linear Brightness Mask]
Parameter [Compositing Algorithm] set to [Multiply, Gamma Correct]
Parameter [Brightness, Color] set to [Process Both]
Parameter [Brightness Retention] set to [Off]
Parameter [Mask Fuzz] set to [1.0 pixels]
Parameter [Airy Disk Radius] set to [50 %]
Parameter [Gamma] set to [0.60]
Parameter [Detail Preservation Radius] set to [20.0 pixels]
Parameter [Saturation] set to [100 %]
Parameter [Strength] set to [100 %]

[*FINISH TRACKING, APPLY NOISE REDUCTION*]

--- Unified De-Noise
Parameter [Grain Size] set to [6.0 pixels]
Parameter [Walking Noise Size] set to [1.0 pixels]
Parameter [Walking Noise Angle] set to [0]
--- Unified De-Noise
Parameter [Scale 1] set to [99 %]
Parameter [Scale 2] set to [95 %]
Parameter [Scale 3] set to [95 %]
Parameter [Scale 4] set to [95 %]
Parameter [Scale 5] set to [50 %]
Parameter [Equalized Grain] set to [0 %]
Parameter [Scale Correlation] set to [25 %]
Parameter [Color Detail Loss] set to [50 %]
Parameter [Brightness Detail Loss] set to [50 %]
Parameter [Grain Dispersion] set to [6.0 pixels]

File saved [G:\ASTRO\2-ST FOLDER\didge\Didge Helix ST8 1A.tiff].

Hope this helps! I know others will chime in here shortly, and may have better beginner tips than I can think of right now.

[admin]

Gary and myself have been corresponding through email, and a number of issues with the dataset(s) appear to stem from stacking with Affinity and, as @Mike in Rancho mentioned, the lack of calibration frames.

If anyone has a guide on how to get Affinity to produce better stacks (e.g. turn off white balancing, use a more conservative debayering algorithm, etc.) then that would be great!

[Mike in Rancho]

No Affinity gurus here? Well, maybe not surprising. I think it might be a little more popular on CN, and since it is also a processing alternative of sorts, like PS or Gimp, probably isn't going to get a lot of ST traction.

But for use as just a stacker, all I really found was this help manual: https://affinity.help/photo/en-US.lproj/index.html

On the side you can open the AP stacking menu. Bilinear debayering seems to be an option in the RAW settings. Background calibration appears to be a checkbox in the stacking settings.

White balance may be more difficult. As I read it, there are only three options. The best may be "camera," if the camera's WB settings had been set to some sort of neutral/no-balance option.

I think we still have no info here on the camera used, so how to go about that will depend on what it is, and on what program the files were acquired through. For some OSC astrocams, both a native driver and ASCOM driver may be available, and could have very different WB settings if not changed from defaults. A DSLR situation I would be unsure about, since that would not be FITS and you'd have to find out how Affinity reads the files. Of course some DSLR's also precondition their "RAW" files anyway with some scaling of red and blue, and I don't think any stacker can do a thing about that, other than to try to be otherwise neutral.

All I got.