Thoughts on which imaging rigs to concentrate on

[Gina]

DynamicCrop completed   Yes, good tutorial

Edited November 27, 2016 by Gina

[Gina]

DynamicBackgroundExtraction up next and completed   Seems to work well.  Here are some pics.  See the image titles for identification.  I used Generate then added a few more points of my own round the margins and on a few clear areas.  There's certainly quite a variation in the background so this process seems well worthwhile

[Gina]

Next step is Matching the Images with LinearFit

[Filroden]

DBE seems to be removing more than background. I'd expect a much simpler background. You should probably delete any of the marks which sit over or near the nebulosity. You may have to limit yourself to marks around the periphery on the Ha image.

[Gina]

Oh - I see.  I can always go back and re-do things.  I've saved the files at each stage and fortunately this only a two colour capture.  I was very careful to avoid the areas of nebulosity though so I think I'll go ahead and see what result I get and redo DBE if it seems warranted.

Edited November 27, 2016 by Gina

[Gina]

Here are the results of LinearFit.

Edited November 27, 2016 by Gina

[Gina]

I am now moving on to the next step - Colour-Combining with ChannelCombination

[Filroden]

One thing I like about PixInsight is that its history is stored with the image so you don't have to create multiple saves. However, I think this has to be linked to saving a project as that preserves settings such as masks used, etc. It means at any stage you can go back steps and redo anything.

[Gina]

Thanks Ken   Yes, I saw Projects mentioned in the book and I shall be looking at that later.  ATM I want to see what I can get with a colour combination ASAP with minimal fiddling

[Gina]

ChannelCombination is too crude for an HOO colour combination as the OIII dominates far too much so I'll try PixelMath next as that has much more control.

[Filroden]

Now that result surprises me as there is far more visible data in the Ha. I thought your red channel was going to dominate!

[Gina]

Undoubtedly PixelMath gives the control needed for NB imaging but I think my OIII capture is a bit duff   There's far too much "stuff" whether stars or noise in the background.  I've used the formulae mentioned in the tutorial for NB HOO and tried all sorts of other variations but came back to the original - other ratios gave too much red or too much green and unbalanced the background.  I think maybe a bit of non-linear processing would help.

I recall that when I was using Photoshop I adjusted curves in the various colours to create the final image, matching histograms before applying Hubble Palette for tri-colour NB or not for HOO.

I know the OIII data is not the best for this job but I'm not sure what to do to it.  Maybe I should try colour on some of my other data.

[Gina]

Re-done as straight HOO - looks the same as having (0.2*Ha)+(0.8*OIII) for the green channel to me

[Filroden]

I'm not seeing any Ha come through into the Veil. I wonder if you've stretched the OIII much more than the Ha so it's now contributing too much. Maybe only put 30% of the OIII into blue/green as a quick way to dial it back?

[Gina]

Neither image was stretched before combination.  Just auto-stretch applied to the result.  Before that all was linear.

[Gina]

I've saved the PixelMath image as TIFF and transferred it into Photoshop where I've matched up the histograms using curves as I used to do before.  The starting histograms for the three colours were very different and after matching as well as I could the image is very different.  I've saved the Photoshop image in PNG format and transferred it back to here (Linux Mint desktop) for upload.

Here's the edited image and the new histogram.

[Gina]

Applied noise reduction and "Enhance DSO and reduce stars" in Photoshop plus a touch of curves.

[Filroden]

That's definitely better balanced.

[RichLD]

Getting better all the time Gina!

[Gina]

Now working on the Cygnus Loop in bi-colour.  I examined the SII and though there's a bit of image there I decided not to use it at this time - maybe later when I get on to tri-colour and maybe Hubble Palette.

As before, the result from PixelMath needed more post processing which I have done in Photoshop.  I'll look into using PixInsight later.

[Gina]

Going for RGBHa on M31 now.  Using master bias and dark which I processed yesterday and flat frames taken around the same time.  Currently processing 193 red frames in BPP.

Edited November 28, 2016 by Gina

[Gina]

Filled up the 500GB SSD so PI shut down - had to clear some space.  Had a couple of abortive attempts at the Cygnus Loop I could delete giving nearly 100GB free space   Anything not needed in the near future but may be later when I refine my use of PI, can be backed up to my new USB3 2TB drive.  But I'm almost immediately deleting unwanted data and being much more strict with myself in view of the "explosion" of data from the ASI1600MM-Cool as compared with the Atik 460EX (far fewer pixels and longer/fewer subs).

[Gina]

Processing 193 x 32MB = 6GB of source data that expands to 12GB in PI several times over for calibration, registration and integration, is taking quite a long time in spite of having a fast machine.  The main limitation according to the System Monitor is the CPU with all 4 cores running 100% most of the time.  I'm wondering if the CPU is being throttled back as the cooling system is rather crude.  If it is I could convert to water cooling - I have the kit but it's not being used ATM.

[Gina]

Done a "Google" and run cpufreq-info which shows the CPU core speeds - here's the result :-

gina@gina-mint-PI ~ $ cpufreq-info
cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009
Report errors and bugs to cpufreq@vger.kernel.org, please.
analyzing CPU 0:
  driver: acpi-cpufreq
  CPUs which run at the same hardware frequency: 0
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency: 4.0 us.
  hardware limits: 1.90 GHz - 4.20 GHz
  available frequency steps: 4.20 GHz, 3.10 GHz, 2.80 GHz, 2.40 GHz, 1.90 GHz
  available cpufreq governors: conservative, ondemand, userspace, powersave, performance
  current policy: frequency should be within 1.90 GHz and 4.20 GHz.
                  The governor "ondemand" may decide which speed to use
                  within this range.
  current CPU frequency is 2.80 GHz.
  cpufreq stats: 4.20 GHz:40.94%, 3.10 GHz:1.74%, 2.80 GHz:1.67%, 2.40 GHz:6.02%, 1.90 GHz:49.63%  (41142)
analyzing CPU 1:
  driver: acpi-cpufreq
  CPUs which run at the same hardware frequency: 1
  CPUs which need to have their frequency coordinated by software: 1
  maximum transition latency: 4.0 us.
  hardware limits: 1.90 GHz - 4.20 GHz
  available frequency steps: 4.20 GHz, 3.10 GHz, 2.80 GHz, 2.40 GHz, 1.90 GHz
  available cpufreq governors: conservative, ondemand, userspace, powersave, performance
  current policy: frequency should be within 1.90 GHz and 4.20 GHz.
                  The governor "ondemand" may decide which speed to use
                  within this range.
  current CPU frequency is 2.40 GHz.
  cpufreq stats: 4.20 GHz:43.18%, 3.10 GHz:2.12%, 2.80 GHz:2.05%, 2.40 GHz:8.28%, 1.90 GHz:44.36%  (38883)
analyzing CPU 2:
  driver: acpi-cpufreq
  CPUs which run at the same hardware frequency: 2
  CPUs which need to have their frequency coordinated by software: 2
  maximum transition latency: 4.0 us.
  hardware limits: 1.90 GHz - 4.20 GHz
  available frequency steps: 4.20 GHz, 3.10 GHz, 2.80 GHz, 2.40 GHz, 1.90 GHz
  available cpufreq governors: conservative, ondemand, userspace, powersave, performance
  current policy: frequency should be within 1.90 GHz and 4.20 GHz.
                  The governor "ondemand" may decide which speed to use
                  within this range.
  current CPU frequency is 1.90 GHz.
  cpufreq stats: 4.20 GHz:40.69%, 3.10 GHz:1.84%, 2.80 GHz:1.86%, 2.40 GHz:7.87%, 1.90 GHz:47.73%  (47445)
analyzing CPU 3:
  driver: acpi-cpufreq
  CPUs which run at the same hardware frequency: 3
  CPUs which need to have their frequency coordinated by software: 3
  maximum transition latency: 4.0 us.
  hardware limits: 1.90 GHz - 4.20 GHz
  available frequency steps: 4.20 GHz, 3.10 GHz, 2.80 GHz, 2.40 GHz, 1.90 GHz
  available cpufreq governors: conservative, ondemand, userspace, powersave, performance
  current policy: frequency should be within 1.90 GHz and 4.20 GHz.
                  The governor "ondemand" may decide which speed to use
                  within this range.
  current CPU frequency is 4.20 GHz.
  cpufreq stats: 4.20 GHz:42.52%, 3.10 GHz:2.06%, 2.80 GHz:3.33%, 2.40 GHz:6.18%, 1.90 GHz:45.91%  (39898)
gina@gina-mint-PI ~ $ 

 

[Gina]

Another check :-

gina@gina-mint-PI ~ $ cpufreq-info
cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009
Report errors and bugs to cpufreq@vger.kernel.org, please.
analyzing CPU 0:
  driver: acpi-cpufreq
  CPUs which run at the same hardware frequency: 0
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency: 4.0 us.
  hardware limits: 1.90 GHz - 4.20 GHz
  available frequency steps: 4.20 GHz, 3.10 GHz, 2.80 GHz, 2.40 GHz, 1.90 GHz
  available cpufreq governors: conservative, ondemand, userspace, powersave, performance
  current policy: frequency should be within 1.90 GHz and 4.20 GHz.
                  The governor "ondemand" may decide which speed to use
                  within this range.
  current CPU frequency is 4.20 GHz.
  cpufreq stats: 4.20 GHz:39.94%, 3.10 GHz:1.93%, 2.80 GHz:2.03%, 2.40 GHz:8.12%, 1.90 GHz:47.97%  (74538)
analyzing CPU 1:
  driver: acpi-cpufreq
  CPUs which run at the same hardware frequency: 1
  CPUs which need to have their frequency coordinated by software: 1
  maximum transition latency: 4.0 us.
  hardware limits: 1.90 GHz - 4.20 GHz
  available frequency steps: 4.20 GHz, 3.10 GHz, 2.80 GHz, 2.40 GHz, 1.90 GHz
  available cpufreq governors: conservative, ondemand, userspace, powersave, performance
  current policy: frequency should be within 1.90 GHz and 4.20 GHz.
                  The governor "ondemand" may decide which speed to use
                  within this range.
  current CPU frequency is 4.20 GHz.
  cpufreq stats: 4.20 GHz:42.39%, 3.10 GHz:2.49%, 2.80 GHz:2.55%, 2.40 GHz:9.91%, 1.90 GHz:42.66%  (67654)
analyzing CPU 2:
  driver: acpi-cpufreq
  CPUs which run at the same hardware frequency: 2
  CPUs which need to have their frequency coordinated by software: 2
  maximum transition latency: 4.0 us.
  hardware limits: 1.90 GHz - 4.20 GHz
  available frequency steps: 4.20 GHz, 3.10 GHz, 2.80 GHz, 2.40 GHz, 1.90 GHz
  available cpufreq governors: conservative, ondemand, userspace, powersave, performance
  current policy: frequency should be within 1.90 GHz and 4.20 GHz.
                  The governor "ondemand" may decide which speed to use
                  within this range.
  current CPU frequency is 1.90 GHz.
  cpufreq stats: 4.20 GHz:41.70%, 3.10 GHz:1.99%, 2.80 GHz:1.95%, 2.40 GHz:8.09%, 1.90 GHz:46.28%  (63742)
analyzing CPU 3:
  driver: acpi-cpufreq
  CPUs which run at the same hardware frequency: 3
  CPUs which need to have their frequency coordinated by software: 3
  maximum transition latency: 4.0 us.
  hardware limits: 1.90 GHz - 4.20 GHz
  available frequency steps: 4.20 GHz, 3.10 GHz, 2.80 GHz, 2.40 GHz, 1.90 GHz
  available cpufreq governors: conservative, ondemand, userspace, powersave, performance
  current policy: frequency should be within 1.90 GHz and 4.20 GHz.
                  The governor "ondemand" may decide which speed to use
                  within this range.
  current CPU frequency is 4.20 GHz.
  cpufreq stats: 4.20 GHz:46.11%, 3.10 GHz:2.16%, 2.80 GHz:3.15%, 2.40 GHz:6.17%, 1.90 GHz:42.41%  (53073)
gina@gina-mint-PI ~ $