Prom measure on scale

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MAURITS
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Prom measure on scale

Post by MAURITS »

How can I "measure to scale" the hight of a prominence on a solar picture?
I have seen this before but I can't figuring out how to get a scale value.
The picture below is not mine but this is what I mean ...
schaal zonnevlam.jpg
schaal zonnevlam.jpg (105.07 KiB) Viewed 1508 times


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Maurits

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banjo
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Re: Prom measure on scale

Post by banjo »

Hello,
one way to do this is to measure the diameter in pixels on your photo
example for me summer 6200pixels (see ephemeris sun)
1,392,684km / 6200 pixels = ~ 225 km / pixels
Prom diameter = 7000 pixels ---> (7000-6200) * 225 = ~ 180000km
Paul

https://www.webastro.net/noctua/astroph ... ires-r154/

https://pgj.pagesperso-orange.fr/position-planetes.htm


bresser/messier 150/1200 (or 200/1800 Istar ) Mod -D-Erf 160mm intern-glasspath 1.25-etalon Pst barlow X2 ASI174
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sorry for my English translators google :mrgreen:
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Re: Prom measure on scale

Post by Montana »

You need to use the solar ruler RegleSolaire
https://docs.google.com/viewer?a=v&pid= ... TI0ZmUyNTg

Download the PDF. Open your image in Photoshop. Open the PDF as a 'Smart object'. Copy and paste the ruler in as a layer in your image. Then free transform RegleSolaire so that the hatched lines fit your solar disc correctly. Remember to use the Shift key to keep the ruler perfectly round when you stretch or shrink to fit.

Alexandra


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Re: Prom measure on scale

Post by MAURITS »

Thanks Paul and Alexandra for the explanation.


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Maurits

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grimble_cornet
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Re: Prom measure on scale

Post by grimble_cornet »

Hi Maurits
As its my image you posted......... I can tell you exactly how it was done.
The scale Alexandra explained is what I used but it can be a bit frustrating as the numbered lines outside the disc are often in the wrong place. I edited the original overlay so that there are numbered layers at top, bottom, left and right - in that way there is always a set of numbers with the correct orientation close to the section of limb in your image.
Banjo's method of calculating can also be used to determine the size of the Earth - basically it is 1/109 the size of the sun. I downloaded a NASA image of the Earth from space and scaled it to match the solar diameters produced by my most commonly used scope/filter/camera combinations.
The white scale overlay has discs which represent the relative sizes of Earth and Jupiter so.............. an alternative method is to paste an image of Earth and then scale it to match the disc.

Best wishes,
Mike


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Mike Garbett

Selection of Solar and Deep Sky images on Flickr: https://www.flickr.com/photos/mikegarbett/
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Re: Prom measure on scale

Post by Ibbo »

Thanks Alexandra for the explanation.


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