| Convert visual mags/arcsecond² to cd/m² |
|
| Using the formula: |
| [value in cd/m2] |
= |
10.8×104 × 10(-0.4*[value in mag/arcsec2]) |
|
| OpenOffice formula: |
=108000*POWER(10;(-0.4*mags)) |
| MS-Excel formula: |
=108000*POWER(10,(-0.4*mags)) |
| |
Where mags is the cellname that contains the mag/arcsec2 reading. |
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|
| Convert cd/m² to visual mags/arcsecond² |
|
| Using the formula: |
| [value in mag/arcsec2] |
= |
Log10([value in cd/m2]/108000)/-0.4 |
|
| OpenOffice formula: |
=(LOG(cdm2/108000))/-0.4)) |
| |
Where cdm2 is the cellname that contains the cd/m2 reading. |
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| |
This formula was derived from conversations on the Yahoo-groups darksky-list
Topic: [DSLF] Conversion from mg/arcsec^2 to cd/m^2
Date range: Fri, 1 Jul 2005 17:36:41 +0900 to Fri, 15 Jul 2005 08:17:52 -0400
PDF summary of conversation.
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| Percentages to mpsas to percentages |
| |
The direction of darkening/lightening is included the calculation. For example:
an increase of 0.5mpsas is 36.90% darker.
a decrease of 0.5mpsas is 58% brighter.
You can use the following formulas:
Percent to mpsas:
mpsas =-2.5*LOG(1 + pct)
Ex. for darkening of 36.9%:
mpsas = -2.5*log(1 - 0.369)
= .5 mpsas
mpsas to percent:
10^(mpsas/-2.5)-1
(Open office formula) POWER(10,(mpsas/-2.5))-1
Ex. for darkening of 0.5mpsas:
pct = 10^(0.5/-2.5)-1
= 10^(-0.2)-1
= 0.631 -1
= -36.9%
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