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.

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.

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

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.

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

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

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.

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.

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

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

Here are the results of LinearFit.

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.

Next step is Matching the Images with LinearFit

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

DynamicCrop completed Yes, good tutorial

Now onto DynamicCrop...

That's better - that worked Now have Ha_r.xisf and OIII_r.xisf in my Cygnus WF directory.

First "trap" was that the XISF master files resulting from BPP contains three images - the result plus rejection low and rejection high. So I need to bring these up and save the image file on it's own.

Anyway, while that lot is downloading I'm looking into combining data into a colour image. Googling took me to a LightVortex Tutorial and onto another tutorial for StarAlignment. These look more readable than the book At least for an oldie like me

32MByte with a protocol of 10 bits per data byte would be 320Mbits. So we have 320Mbits in 20s ie. 16Mbits in 1s a data rate of 16MB/s. I think that's right now...

It used to take a couple of seconds per 32MB file but now I've timed it at 20s - ten times as long so it looks like the line has gone from gigabit to 100Mb/s. The Ethernet switch is showing gigabit though on its LEDs. 20s for 32MB means 20s for 256Mb though I think there are a couple of extra bits in the protocol. That works out at 8Mb/s so it looks like I'm getting 10Mb/s which would be right for 10bit per data byte protocol. EDIT>>> No that's not right - I'm not awake yet

Not that I know of.

Reconnected with the Ethernet link which is working, though slowly - taking an hour and a half for 250 files rather than the usual 15-30m.

Oh!!! Just checked and the WiFi download has stopped dead! Getting another problem too - it keeps saying "Access Denied" at times.

Captured all those - no problem. Downloaded the darks and now downloading the bias frames but something has gone wrong with the gigabit Ethernet on my obsy laptop - the data rate has dropped vastly to little more than I get with WiFi. I have tried rebooting but no better Checked connections and they seem fine. Very puzzling. I guess that laptop is pretty "long in the tooth" now or maybe it's finally succumbed to the cold and damp. I really need to sort out an alternative. I've been dithering too long now to return the mini PC box to Amazon for no specific reason so maybe I should have another go at getting it working. Or I guess I could try returning it as no good for what I want. TBH I don't really want to mess about trying to return it and I don't know what else to get. I ought to be able to get it working - replace Win10 with Linux for instance or dual boot. Clear night skies should be returning soon - maybe tomorrow night - so I need to sort things out. The laptop is still working for capturing images and so is the relatively slow WiFi file transfer but the loss of Ethernet speed worries me.