Docs for class on Astrophotography  

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(@b4silio)
Molecular Cloud Customer
Joined: 1 month  ago
Posts: 5
October 17, 2018 09:35  

Hi everyone,

In preparation for a class I'm giving soon on astrophotograhy I've prepared this:

as a support document that students will have at hand while trying things out on their own.

I'm looking for feedback on how to improve it, but also for ideas on how to structure the introduction of the class. Right now I feel I have 2 possibilities:

1 - Do things live with few images to not have too much waiting time during processing 
2 - Prepare the different steps beforehand and show them the results

Using few images might give results that are underwhelming compared to the WOW effect of seeing what can be extracted from really "bad" starting images. Showing end results only might rob people of the feeling that they can achieve something just as good themselves (which is the point of the class after all). A mix of both is (as often) probably the best solution, but I havent found a good trade off yet.

Any of you has had good experiences and has some pointers?


(@vincent-mod)
Neutron Star Moderator
Joined: 1 year  ago
Posts: 158
October 18, 2018 00:17  

I would have at least some of the results ready to show off, just in the case something goes wrong, but also to have a better overview of what is possible. And you could make a simple mosaic that shows of that capability while you are talking about it. If you do that without too many frames (noise isn't something to worry about in class) it should be fairly fast.

And congrats on that lesson btw, really nice! Big photo's, maybe having a bit less information per slide might help? Usually whole sentences and such don't work very well as people will focus on reading those instead of understanding the topic.

This post was modified 4 weeks  ago 2 times by Vincent Groenewold - Moderator

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(@vincent-mod)
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Joined: 1 year  ago
Posts: 158
October 18, 2018 00:22  

Oh and one other thing, you seem to be creating boxes with only background in the Light Pollution Tool. The great thing with APP is that you can just include stars! So I always create rather big boxes, like maybe 5-10 around the image and it works a treat.


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(@b4silio)
Molecular Cloud Customer
Joined: 1 month  ago
Posts: 5
October 18, 2018 17:28  

Hey @Vincent,

Thanks for the feedback!

- on the mosaic example, Yes! Definitely something to try out and it can give very good ideas of the breadth of features of APP

- on Light Pollution : (O_O) goodness gracious, that is awesome! I was wondering what the "tolerance" slider was supposed to do, I guess it's to threshold stars that are almost too dim? --> Gonna have to do some more tests but that's definitely a big change!

Question since I'm here: when integrating the results of multiple sessions, would it make sense to remove light pollution first and then stack or better to stack and then remove light pollution? Is LPR working BEFORE stretching (so that we could just reload the saved LPR file as Light) or is it stretching/neutralising BG first?


(@vincent-mod)
Neutron Star Moderator
Joined: 1 year  ago
Posts: 158
October 18, 2018 23:51  

Hi!

Yes, I like that feature as well. Gone are the days of finding that background yourself. 😉 The tolerance slider, although I'm not 100% sure, is a kind of cut-off for APP to consider something proper background (I am definitely not explaining it very well here). If you increase the tolerance you can see that some yellow boxes, suddenly turn green and are taken along in the background model. I normally don't use it, but it probably helps with certain data.

When you have stacks of previous sessions I would process them first by themselves, including LP correction etc. and then process them together again. In the case of having the raw data of all sessions (something I prefer), you just select "multiple sessions" in the Load-tab and go with that, the data is then normalized against each other. In general, all tools are best to use before stretching.


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