Moon Rotation How to Do with 2 Circle Images

I am trying to add moon position on the watch face first time. I have added rotation to the dark circle inside and white is part of background ,please see screenshot

but I am unable to figure out how to rotate and what should be the pivot point so the dark sphere rotates on the white one in correct way

I need some help please , what am i doing wrong, please see the wfs attached will really appreciate that. I want to move the sky blue circle on the white one to show moon present position as shown in ref image as well attached

moon (1.9 MB)

Hello, I think problem will be with the concept.
The blue circle can not simulate the projection of the lit part of moon sphere how we observe it from earth, because the shape of this projection changes and is in from of circle only in full moon phase.
The blue circle would form the uncovered part of white circle into a kind of arc, even when half circle should be seen (phases on 8th and 21st on your second image). It will match natural view of moon only in full moon and shortly before and after new moon phases.
If you do not mind that, then you could put the blue circle in a side of a transparent image and put its pivot point above or below your white moon circle. Something like this:

1 Like

Okay thanks peter.

i am thinking instead of this

i have 26 png images of moon. whcih includes a full black .First 2 i think will be black. then others 26 pngs to appear in circle

i see 28 postions of rotation for phases in wfs.

should i add pngs wih tag expression and transpernecy for each to appear on 28 days.
or use rotation in wfs. im confused about this.

i want to change each image on each rotation which are 28 rotations in wfs . should i use rotation or transparency tag

Hello again,
yes, you can insert 28 images as separate layers, and let them show on certain day with tag expression in opacity like this:
[MOON_PO]==7?100:0 it means, if its the day 7, use opacity 100 (show the image), else opacity 0 (hide)
check also this guide and the moon phase tags:

1 Like

Thanks Peter

i will try the tag expressions to show images on each day that should work fine. I appreciate your help .:+1:

Sorry, I did not notice it right away, but the [MOON_PO] could be a decimal number. Then the formula for each image would be little more complicated, to cover times from-to or to round/floor the number.

1 Like

With ref to this article for Samsung Galaxy Studio Tizen :-

I tried to make a tag but does not seem to work for me, For the new moon Quarter.besides its not what i m looking for . i want to show 28 images not 4 images for four Quarters.

Tag Expression for the New Moon symbol from 27.5 to 6.5

([MOON_PO]>=27.5)+([MOON_PO]<=6.5)? (([HOUR]>=6)*([HOUR]<=18)?100:0) : 0

([MOON_TY]== 0)? +100:0 31 May 2022 NEW MOON
([MOON_TY]== 1)? +100:0 1 to 7 Jun Evening Cresent
([MOON_TY]== 2)? +100:0 8 Jun First Quarter
([MOON_TY]== 3)? +100:0 9 to 14 Jun Waxing Gibbious
([MOON_TY]== 4)? +100:0 15 Jun Full Moon
([MOON_TY]== 5)? +100:0 16 to 20 Jun Waning Gibbous
([MOON_TY]== 6)? +100:0 21 Jun Last Quarter
([MOON_TY]== 7)? +100:0 22 Jun to 28 Jun Morning Crescent

Dont know how to formulate using from-to or to round/floor and round decimal numbers yet my knowledge is limited about these functions.

Analog basic 6_1654270086251
Analog basic 6_1654270096233
Analog basic 6_1654270101008
Analog basic 6_1654270108710

This is how i have it and it looks like now with 7 ximages for moon phases few examples. Maybe for a while i should stick to showing 7 Types OF Moon Phases
and use this .

Till i learn how to round off decimal value :slight_smile:

Training for
Moon phase tag expressions is HERE
Math Functions for rounding off is HERE

Functions Definition Expression example Output example
round(num) Returns the closest integer to num. round(1.6) 2

Hope that helps,

Samsung Developer Relations