Image Analysis Tools in Pixinsight: Diagnose Problems in your Image Train
Do you ever have trouble with your imaging train and you just can't figure out what it is? You see weird stands and you can't help but wonder if it was guiding, collimation, wind, polar alignment or your mount and you beat your head against the wall trying to eliminate each factor.
Well, if you have PI there is a nice tool inside it that can help with your diagnosis. It can narrow things down to whether you might have tilt or not. We used it in my astrophotography group chat before looking for issues and I helped someone today with it too. Actually there are two things in the same spot to help!
First there is AberrationInspector found under Script >Image Analysis. It is the first one and it will take your image and cut 9 areas from it including the middle and the corners and allow you to compare them right next to each other. It allowed me to figure out that the WO Redcat isn't exactly suited for a full frame DSLR in the corners.
You can run it on an image that is either color or monochrome.
Next is FWHMEccentricity also found under Script > Image Analysis. I make a copy of the image I am looking at and then I convert it to grayscale since you can't do this on a color image.
Next you hit measure and let it run, then you hit support. That gives what amounts to a map of the image showing where the strangeness is, and it can tell you pretty quickly is you have tilt or not. If your dark gray is all the way to one side that's when you look for tilt.
It can save a bit of time if doing troubleshooting because it might point to something simply not tightened up. I don't know about you, but I've had that happen far too many times to admit. If you're trying for quick diagnosis in the field you can do it on a single sub as long as it has enough stars to work, so if doing that hit a nice rich star field. One more thing, if you do a meridian flip it may throw things off, so just stick to one side of the flip if you can.
So there you go. PI has a pretty neat tool to help diagnose tilt issues with your imaging train. Next time you're having trouble if nothing is obvious go ahead and run these and see if they can point you in a direction that may save you time and allow you to focus troubleshooting on one thing.
Well, since I know you're here for an image too, how about a the NGC 1316 area taken with CHI-2 on an advanced request? It turned out pretty cool in my opinion!
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