Sun to Earth scale for pictures: Is this right?

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Thefatkitty Canada
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Sun to Earth scale for pictures: Is this right?

#1

Post by Thefatkitty »


Earlier today I took some shots of le Soleil, and got to thinking about how I've seen others on here scale the Earth to their Sun pictures.

I'm not even to sure what to search for on that, so I tried something. I don't know if this is right, so that's why I ask.

First I brought up my pics of the Sun. I then overlaid a grid on the pic, and measured with the select tool how many pixels it was across the exact center from one edge of the disc to the other. I had to check that a few times, as the result in pixels was the exact same as my year of birth, 1965. Odd that, but easy to remember :lol:

I did a search on converting pixels to inches, and came across this site, Ninjaunits.com. Neat. It needed the DPI of my monitor (obviously) which was 75. I then put in the pixels, and the result in inches was 26.2.

I then did a search on sun scaled diameter, and ended up on this site, Exploratorium.edu. Fun site, actually. You can put in the dimensions for making a scale solar system, so I put in 26.2 inches for the Sun, and in comparison the Earth was 0.2398 inches.

Back to Ninjaunits, where I was informed that 0.24 inches was 18 pixels. Ok, so I'm off by 0.0002 inches...

I then drew a circle in my image 18 pixels across, and colored it pale blue :lol:

So that's my question here; is my logic on this right or am I off base on this?

This is the image I ended up with, my "earth" is to the bottom right. I'd appreciate any and all advice :D
Sun_Earth_s.jpg
Thanks again and all the best,
Mark

"The Hankmeister" Celestron 8SE, orange tube Vixen made C80, CG4 & AZ-EQ5 mounts.
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Re: Sun to Earth scale for pictures: Is this right?

#2

Post by notFritzArgelander »


Your logic is fine. But there is an easier way. The Sun's radius is about 109 times Earth's. So the number of pixels in the Sun diameter, 1965/109=18 the number of pixels in Earth's diameter.
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: AWB 130mm, f5, Z12 f5; Cats: VMC110L, Intes MK66,VMC200L f9.75 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binoculars: Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker IV, Vixen Porta II, Celestron CG5
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Re: Sun to Earth scale for pictures: Is this right?

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Post by MistrBadgr »


That is an excellent demo picture, showing the relative sizes and a sunspot that is about the same size as the Earth, even without the extra frills to the left of the dark dot! :)
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Re: Sun to Earth scale for pictures: Is this right?

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Post by Thefatkitty »


notFritzArgelander wrote: Thu May 13, 2021 2:02 am Your logic is fine. But there is an easier way. The Sun's radius is about 109 times Earth's. So the number of pixels in the Sun diameter, 1965/109=18 the number of pixels in Earth's diameter.
Leave it to me to overthink this one... Whenever it comes to math I always seem to take the hard route to my answer. Could've saved myself a lot of typing too :lol:

Thanks for the verification nFA!

All the best,
Mark

"The Hankmeister" Celestron 8SE, orange tube Vixen made C80, CG4 & AZ-EQ5 mounts.
Too much Towa glass/mirrors.

H/A - PST stage 2 mod with a Baader 90mm ERF on a Celestron XLT 102 (thanks Mike!)
Ca-K - W/O 61mm, Antares 1.6 barlow, Baader 3.8 OD and Ca-K filters with a ZWO ASI174mm.
W/L - C80-HD with Baader 5.0 & 3.8 Solar film, Solar Continuum 7.5nm and UV/IR filters with a Canon EOS 550D.

Oh yeah, and Solar Cycle 25 :D
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Re: Sun to Earth scale for pictures: Is this right?

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Post by AstroBee »


I've successfully used the "Solar Ruler" in the past.

https://thesolarexplorer.net/index.php/ ... olar-ruler

Look about half-way down this link for the "La Règle Solaire (pdf 88 Ko)" link.
https://sites.google.com/site/astroblue ... ico-utiles

You can convert the PDF into a PNG and bring it in as a layer over your image. Resize to fit, voila!

It's really great because it gives you an idea of the height of the prominences too.
Greg M.~ "Ad Astra per Aspera"
Scopes: Celestron EdgeHD14", Explore Scientific ED152CF & ED127 APO's, StellarVue SV70T, Classic Orange-Tube C-8, Lunt 80mm Ha double-stack solar scope.
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Re: Sun to Earth scale for pictures: Is this right?

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Post by messier 111 »


fine work , thx .
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Re: Sun to Earth scale for pictures: Is this right?

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Post by Ben Cartwright SASS »


I found an easy way, I downloaded GIMP and then take any of my solar images with the limb, I then draw a circle using the Elipse select keeping at 1-1 and fixed and then match the circle to the limb and see what the diameter is in pixels, I have found my Lunt 102 is about 5200 pixels making the sun 5000/109= ~46 pixels

I then downloaded a tif of the earth and resize it to 26 pixels and drag and drop
20200601 Prom color w EARTH.jpg
11_07_41_AS_F50_lapl4_ap7783 REG6 COMBINED w EARTH.jpg
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Re: Sun to Earth scale for pictures: Is this right?

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Post by AstroBee »


Looks about right.
Another way is to search for "Solar Ruler" and you'll find a website that has a scaled solar image with the earth and I believe Jupiter to scale. You can layer that over your image and adjust the size.

Edit: I didn't realize this was from a post where I already mentioned that.
Greg M.~ "Ad Astra per Aspera"
Scopes: Celestron EdgeHD14", Explore Scientific ED152CF & ED127 APO's, StellarVue SV70T, Classic Orange-Tube C-8, Lunt 80mm Ha double-stack solar scope.
Mounts: Astro-Physics Mach One, iOptron CEM70EC Mount, iOptron ZEQ25 Mount.
Cameras: ZWO ASI2600mm Pro, ZWO 2600MC Pro, ZWO ASI1600mm
Filters: 36mm Chroma LRGB & 3nm Ha, OIII, SII, L-Pro, L-eXtreme
Eyepieces: 27mm TeleVue Panoptic, 4mm TeleVue Radian, Explore Scientific 82° 30mm, 6.7mm , Baader 13mm Hyperion, Explore Scientific 70° 10mm, 15mm, 20mm, Meade 8.8mm UWA
Software: N.I.N.A., SharpCapPro, PixInsight, PhotoShop CC, Phd2, Stellarium
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Re: Sun to Earth scale for pictures: Is this right?

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Post by Ben Cartwright SASS »


AstroBee wrote: Sun Sep 26, 2021 11:05 pm Looks about right.
Another way is to search for "Solar Ruler" and you'll find a website that has a scaled solar image with the earth and I believe Jupiter to scale. You can layer that over your image and adjust the size.

Edit: I didn't realize this was from a post where I already mentioned that.
:dance: Yes I resurrected an older thread
I might not always be right but I am never wrong, once I thought I was wrong, but I was mistaken...

Ferengi Rule of Acquisition #59
Free advice is seldom cheap

"Sometimes having is not so pleasing as wanting, it's not logical but it is true"
Commander Spock

Canon DSLR's R7, R6II, 5D, 7D2, 90D 21 lenses incl. 100-400L mk ii, 70-200L mk iii f/2.8, RF600/11
Lunt LS50 DS, LS80 DS, Lunt 102ED, Stellarvue SV80 APO, Orion ST80, 127 MAK, Skywatcher Evostar 120ED, 102 MAK, Celestron 8" Edge HD, 102AZ
Skywatcher EQ6-R Pro
ZWO ASI071MC-cool, ASI174mm, ASI174mm-cool, ASI178MC-cool, ASI290 mini, ASI120MM-S, ASI120MC Revolution Player One mm (178 chip)
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