Masking, I Really Need Help to Understand it

[astronomynut]

I downloaded Star Tools in the hope I can learn how to use this software. I am not a very techy type, and one of the big problems I have had is understanding "Masking". Yes, I've read about it, but for some reason, just like most things that are usually obvious with most people, I just do not get it.

I really need someone to walk me through the process, or various ways of doing a mask, and why it is done a certain way. I've not been able to perform any of the processes that require this step, as all I get is either a flashing screen of green, or flashing pixels. And usually I end up with the program going in a loop, telling me that something isn't right, and me not understanding what it is saying. I can just hear some of you, "Must be a dumb blonde", and yes I am.

I hope someone has the patience to walk me through the process. My purchase of the license key is really dependent on my understanding how this software works. If it is too difficult for me, then I probably will not bother spending money on something I cannot use. Caley

[Cheman]

Hi A-nut!!
the flashing green you see tells you that a mask is set. Everything that is covered by the green is in the mask, meaning it will be affected by processing. Things out of the mask will not. You can set a mask before opening a processing module by selecting the Mask button along the top. You can also set a mask from within many(most?)processing modules. Some modules require or work better with a mask and will prompt you to set or modify a mask. When you open a file, a full mask will be in effect. (the whole image is covered by green) The most useful and also the most automatic is the star mask. Select auto>stars>do. Leave the default settings for now. Startools will do its thing and will select the stars. You can keep this, or clear it or adjust the mask (shrink, grow). You can also invert the mask, it will then select everyting EXCEPT the stars that were previously selected. The mask will not remain unless you KEEP the mask, then you can continue with processing. There are many other options at the bottom of the mask screen, to select things to be masked, but for now, just try the auto star do. Once you see how that works, the rest will make more sense. Dont be affraid to play with it, you cant hurt anything!!
Were all here to help each other, keep asking questions and soon you'll get the hang of it
Hope this helps
Che

[astronomynut]

Che, Thanks, Believe it or not, I just could not figure that out. I have been trying to process one photo that has many faint galaxies in it. The problem is that with Star Tools, I cannot see those, like when I preprocessed things with DSS, and then went to either WLPG or GIMP. Star Tools seems to bury the data so that it isn't visible. I am wondering if it might not be better to pre process in DSS to bring out those little objects, then transfer to Star Tools, that is, if Star Tools will accept the data from DSS that is somewhat pre processed.

Or maybe Star Tools has a way to enhance the galaxies, and not eliminate them during this masking thing. The problem is not knowing where those galaxies are until they are brought out with some form of processing, like what DSS or GIMP have. Maybe Star Tools calls things a different name.

I get the feeling that depending on what type of object you wish to process, there is a different routine that needs to be used, in order for you not to eliminate the data that general work flow routines suggest. I tried M42/42, and lost 3/4 of the nebulosity using Star Tools, as compared to my just using DSS. Very strange.

Caley

[Cheman]

Hi Caley
If you'd like, post a link to your stacked file, dropbox or google drive, etc. I, or Ivo or another, will be glad to take a look at it and process it and give you our processing log. I've had some trouble in the past downloading realllllyyyy big files, but I'll give it a go if I can. That might help you get a good start with Startools. It is different from any other processing program I've used, so it takes getting used to. By far it has been the best money I've spent for astrophotos.
Che
EDIT: And BTW, do not do any processing in DSS other than stacking. Let Startools have the most virgin data you can.

[Amaranthus]

Just to clarify what Cheman said, in some instances (e.g. sharpen, decon etc.) only the part of the image covered by the mask (in green) will be modified. In others (e.g. wipe) the whole image will still be affected but only samples used to ascertain the 'background/gradient' will be drawn from the masked area -- then wipe is still applied to all pixels.

[astronomynut]

Most of these files are over 200mB, so they are just too big to upload and then have someone download.

When I can get some time, I will try the masking again, and somehow, try to keep from losing the main objects in the photo, the galaxies or nebulosity. Caley

[Cheman]

Caley
you could bin the file in StarTools, then save it, then put it in dropbox, if you want
Che

[admin]

Hi Caley,

Some great help here already. Somehow getting a data set to us would be extremely helpful; 200Mb is typically doable with even modest broadband connections. Something like Dropbox will just keep uploading in the background while your computer is switched on - once it's been uploaded to Dropbox' servers others can use the file. It may take a while, but we have all the time in the world!

One other hint that may help is to revisit the AutoDev or (manual 'Develop') module after applying Wipe. Wipe will typically have removed a lot of 'useless' signal (such as light pollution, gradients, etc.) after which applying AutoDev (or Develop) *again* will allow you to bring out much more detail, now that the 'useless' stuff has been removed.

[astronomynut]

I can't Bin and save, as I still have yet to purchase the license. I am waiting to do that for one reason, and that is I need to know that I can actually use this software. I've purchased software that I never could figure out how to use, and I kind of dislike spending money on something that is only going to gather dust.

Admin, On one of my photos I used AutoDev, and got some horrendous colours. I tried to work with those, and never could get anything other than those terribly sickening colours. I then used the other way, which I guess is the manual method, and saw absolutely no change in the data. I proceeded to try all the recommended procedures, and eventually lost so much of the objects, that I basically had nothing. Apparently I am missing something. Maybe it is going back after the I use the WIPE functions, and redoing the Manual part. I actually think I did that once, and still got nothing. I guess I will eventually figure things out. Right now, what I thought was a difficult program, GIMP, seems easy compared to Star Tools. Caley

[Cheman]

I can't Bin and save, as I still have yet to purchase the license.

Oh yeah, forgot that part