Datalord

Wow, I think I saw his work on astrobin earlier. I was wondering if he would make a PI implementation. This is insanely cool.

How do you get that?

Nope, not at long FL. The amount of issues I've had with that mount and the performance compared to the ASA is miles apart. You do not expect a linear correlation between performance and cost, but the ASA literally gives me 3 times better RMS than the CGX all other things being equal.

+1. It gave me almost the same problems until I bought a lodestar. It is horrible, flimsy and I pray every day nothing will accidentally bump it on my setup, because it can only be focused with extreme care and on a clear night. Apart from that, I always have guide stars with SNR above 50

Haha, thanks. Actually that name is from my past working with large databases, but it is oddly fitting here as well. I used to do the same with my RASA, but then one time some demon took a hold of me. When you see the one I posted with 4h of data compared to the one with 17h, I find it well worth it.

And I was letting you know that there is an easier and more precise way of doing the blending of stars in PI, once you get the process and intent of the math. What you told me about NB pixelmath is what I did, because that's what you do to make an NB image. After that I asked if anyone else has an opinion.

Platesolving is amazing when it works. The software that comes with my ASA mount is completely useless if platesolving doesn't work, so I was in a world of agony until I finally got my PA good enough. It wouldn't solve the plate if I was more than 40 arcmin off the target. 🤬

There's a different way of doing it: http://pixinsight.com/tutorials/NGC7023-HDR/index.html#High_Contrast_Small_Scale_Structures Anyone else with an opinion on the image?

PI is incredibly effective at so many tasks. The learning curve is to figure out which process to use when and, more important, which mask to create for what purpose. 80% of success comes down to masks, but once you get a grip on that, you can do some crazy things with it.

This one has been a really hard process. I have 15 hours of 20 min OIII, 21 hours of 20 min Ha and something like 20 hours of mixed LRGB. I used the HaOIIIRGB for this by combining the NB in HOO and using the RGB for starfield blend in. It's a very red image. I tried downplaying the Ha and bringing out the blue, but I had so much problems finding a way to make it pop out.

Totally agree. Keep the stars. They are small and pinpoint and part of the picture. The alternative is to make a completely starless version, but I don't know how to help you with that.

Any chance you can share the image before morph?

Nope, I agree that I see it as artifacts of processing and I'm trying to figure out a way to help.

second. I know it is tiny stars, but I think they might become too small. That's why I would like to see how big they are before you morph.

Colours are way better, but I think I agree with @Xplode about the artifacts. You say they come morphological transform. Can I ask you to upload the image (possibly STF'ed) before you do the morph?

This is so interesting. I'm currently processing NGC6888 and have a thread on the selection on subs here: I came to the exact opposite conclusion. Difference is that I don't have the final image to show for... yet. 🙂 And btw, fantastic image. Well done!

More followup to some of @vlaiv comments about PSF. I started digging into the processing of the "junk" stack I drizzled(2) and before deconvolving I have to create this PSF from the image. I'm honestly shocked at how round it is. Remember, this includes all those hours of "bad" images; I believe I have 12 hours of "good" Ha and 11 hours of "bad" that went into this stack.

Congrats on making the choice. One pet peeve of mine: could you respond to the other posts you made about deciding which mount to buy? Think of the person googling for the same question and then wondering which conclusion you came to and why.

I think my experiment above shows you should actually keep them and use an aggressive weight formula in the SubframeSelector. I'm quite pleased with the results I got.

Got around to stacking the "Good" images. 37 of them, clipping off the worst eccentricity and FWHM. Then I normalized, stacked and nuked it with the exact same ScreenTransferFunction as I did with the full junk stack. Left is "junk", right is "good". I can't see much difference. If anything, there is a bit better control over the noise in the "junk" stack.

Ok, started with a full integration of all Ha frames I had. 64 frames of 20 min. Used PI Subframeselector to give weights to the images with a weight formula heavily, heavily focusing on eccentricity and FWHM: (20*(1-(FWHM-FWHMMin)/(FWHMMax-FWHMMin)) + 80*(1-(Eccentricity-EccentricityMin)/(EccentricityMax-EccentricityMin)) + 1*(SNRWeight-SNRWeightMin)/(SNRWeightMax-SNRWeightMin))+50 I threw away 0 frames in this "junk" run. Then I normalized and stacked and it gave me this: That's so good I was very pleasantly surprised. I looked closer and not only were the stars tight, they were even kinda blocky, so I tried to drizzle2. You can see the normal stack left and the drizzled on the right. Not much difference at this scale, but closing in on the pixels the drizzled stars becomes more round in their white profile. I haven't stacked the "good" stack alone, but that is the next task. It will have to be pretty amazing to convince me not to keep this one, though.

Yes. And completely removing the stars from the bad is a tactic I'll try along with Vlaivs.

No, it's 27 good hours and 28 "bad". 55 in total.

No, the mount is working like a charm now that I just use normal guiding and the occasional MLTP sent to the mount. Agree, but... Determining that point is exactly what this post is about. The above bad sub looks quite fine in the nebula on the zoomed out version, which is why I'm even contemplating getting this data in. Do you consider the above image "slight" or worse?

I'll give it a go. Not much work to make an extra stack.