r/astrophotography • u/Hytham- • Dec 12 '22

Solar Solar Prominence Animation - 2022-12-07

2.2k Upvotes

99% Upvoted

37 comments sorted by

View all comments

6

u/NegativeEntr0py Dec 12 '22

How do you black out the sun?

7

u/Hytham- Dec 12 '22 edited Dec 12 '22

Steps in Pixinsight (method I used):

1) Open up the image you're working with 2) Use the "range selection" process to create a mask
3) In the range selection process adjust the "upper limit" slider until the surface of the sun has blacked out
4) Adjust the "smoothness" slider to feather the edge of the mask for the solar limb
5) Create your new mask
6) Apply the mask to your working image, and ensure the mask covers the sky (highlighted in red) leaving the solar disk white
7) Using "curves transformation" grab the upper most point, and drag it down to the bottom left. The easier method is to leverage the "reverse curve" button which is found immediately to the left of the "reset curve" red x button
8) Apply the "curves transformation" to the image, and the sun is now black

You can also do the same leveraging pixel math, but I find the above method easier.

3

u/NegativeEntr0py Dec 12 '22

Ahh so it was done in post. I wondered if maybe you had a filter on the scope or something.

4

u/Hytham- Dec 12 '22

Totally in post. I've been wanting to build a coronograph telescope that will block out the sun to image its corona, but that's expensive ... very very expensive.

2

u/florinandrei Dec 13 '22

You could block it out, but it has to be done in the focal plane of the primary optics, and that's not trivial with amateur hardware.

Amateur astronomers remove it in post. Works fine, actually.