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.

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.

Decided that I might try processing the RGBHa data I collected for M31 a while back so I'm capturing bias and dark frames to match. I may capture M31 later with the 200mm f4 lens but I have a feeling that I shall be wanting to capture other DSOs in NB. No clear sky tonight so gabbing any half useful bias and dark frames is worthwhile.

I think I can work out the general process. Take the all calibrated lights and register them against a reference from one colour or register the master lights - don't know which is best. As I recall from two and a half years ago I used registration software to align the separate colours to one of them as reference then took them into Photoshop as layers ... hmmm... maybe something to look into tomorrow when I'm fresher... Meanwhile, I could calibrate more data, register and integrate into mono images. Or do something else entirely!

Been scanning the book - and... OMG!! "ma bwain hurts Bwian!!! First of all the techno-speak needs translating into English

Nor me It means either I have to try and remember how I did it in Photoshop over two years ago or get reading about PixInsight. I think I would prefer the latter as that's the way I want to go in future. My main machine is now my Linux Mint desktop which is running PixInsight whilst the Win 7 machine has been relegated to the background as a server just for things that won't run in Linux - accessed via TeamViewer. My aim is to move away from Windows.

Here's the OIII processed in the same way. 64 120s subs selected in Blink with BPP and Photoshop processing with this result.

I've been processing some data from way back in the beginning of October, of the Cygnus area widefield taken with the 28mm f3.5 lens. So far in Ha (but there's also OIII) - 160 original frames reduced to 100 by inspection in Blink. So that's 100 Ha subs of 120s with gain of 500 and temperature around -30C. There were also 25 matching darks from the time with one duff leaving 24 which I've integrated for calibration. Already had matching master bias and flat so processed in BPP saved in TIFF format and post processed in Photoshop via TeamViewer in Win 7 desktop. I'm currently capturing more 120s darks to add to the previous 24 but not sure they're needed.

This image crop gives about the same FOV as I would get with a 200mm lens and I was going to set that up for this sort of image size but with the 200mm lens being more than a stop slower I'm wondering if the 200mm lens would be such a good idea - I would need twice as much imaging time to get the same amount of data and although better resolution, do I really need such high resolution. I'm thinking deeper data might be better than higher resolution given limited imaging time.