Author Topic: Beginner with a shooting star  (Read 3007 times)

Offline Blanconuclear

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Beginner with a shooting star
« on: 2020 February 23 13:14:38 »
First of all greets for everyone.
This is my first post in this forum, I am an absolute beginner and I apologize in advance if the question does not fit the required level.
Last night I took thirty pictures of the Rosetta Nebula and one of them shows the trace of a shooting star. I would like to show it in the final stacking result. Could anybody please explain how to do it?
Thank you and clear skies.

Offline ngc1535

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Re: Beginner with a shooting star
« Reply #1 on: 2020 February 23 22:53:33 »
Hi Blanco,

First... are you certain it is a "shooting star?" There are many things that *look like a "shooting star"* but actually are not.
Tumbling satellites (and their trails) can look like them. So can cosmic rays.
Ironically the entire idea of image integration is to generally reject these things so they do not show up in your image.

If the shooting star is actually very bright- there is a fancy way to do it- but it is likely that without some processing practice you will think it is a bit tedious in effort.
What you would do is integrate your images in the normal way and have this thing rejected and not appear. Then you subtract this integrated image from your single image that contains the "shooting star" (I will continue to be dubious...lol). This may require the application of Linear Fit before you do the subtraction.  You will then end up with an image that has just the "shooting star."
Finally you can blend/combine this image with your integrated result using a number of ways including using "maximum" or blend with "lighten."

This is the method I used to create the image below showing all the satellite trails running through my data (that were subsequently rejected).

You can also be a little more brute force with it an generate a mask (with a line of some kind)... but the above technique gets closer to keeping the "real" relationship of the values.


Offline Blanconuclear

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Re: Beginner with a shooting star
« Reply #2 on: 2020 February 24 11:51:25 »
Thank you very much, ngc.

Well, before posting the question I asked my "astro-friends" (who are guiding my first steps in this world of astrophotography) and they had no doubt that it is a shooting star. That's the reason why I dared to write my first post about it... but your image made me wonder if they are really right.
Anyway I'll put in practice your advices and will see...

Thanks again and clear skies.

Offline ngc1535

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Re: Beginner with a shooting star
« Reply #3 on: 2020 February 25 09:42:04 »
Just as a data point- I have been imaging the sky with CCD cameras (through telescopes) for over 25 years. In that time, I have captured 2 bonafide meteors in a picture. The most recent occurred just a few months ago and it (the meteor) was simultaneously captured on an all-sky camera image. (From that data, we were able to see the parallax and say something about the height of the meteor.) It is not impossible to capture this kind of event... but it is really quite rare with telescopic fields of view less than a few degrees in extent. There is a larger set of things (like satellites and cosmic rays) that look similar and are much much more common.
You did not post your image... so I cannot opine more in your particular case- but if I were betting... I know where I would put my money. :)

-adam

Offline Blanconuclear

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Re: Beginner with a shooting star
« Reply #4 on: 2020 March 01 11:55:40 »
Well, I wish I was a lucky beginner  :D
Here is the image.

Nebulosa Roseta y posible meteoro
by Corregidor, en Flickr

Clear skies.

Offline ngc1535

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Re: Beginner with a shooting star
« Reply #5 on: 2020 March 01 15:38:05 »
Well, I wish I was a lucky beginner  :D
Here is the image.

Nebulosa Roseta y posible meteoro
by Corregidor, en Flickr

Clear skies.

Yeah... Sorry, I am not convinced this is a meteor. It would be more persuasive if the trail was longer. Another possible thing that decrements the likelihood is that you will note the trail is roughly aligned E/W. This is exactly the direction you would expect to see satellites moving (or trailing) at this declination. But it isn't conclusively not a meteor traii... just not likely. As you saw in my picture above... there are some short trails that take this exact form. See below for an example of a meteor trail from a slightly larger field of view: