Between July 22nd and September 3th, the Royal Palace in Brussels will host the exposition "Science and Culture" with the theme "Hemel - Ciel - Sky". See also this link.
Have fun !
Sunday, July 23, 2017
Hemel - Ciel - Sky
Between July 22nd and September 3th, the Royal Palace in Brussels will host the exposition "Science and Culture" with the theme "Hemel - Ciel - Sky". See also this link.
Have fun !
Saturday, July 22, 2017
Venus - Moon Conjunction July 20
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| Composition made by Guido Gubbels |
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| Moon 11% illuminated - Venus bright NE of the Moon a couple of minutes after conjunction |
Friday, July 21, 2017
My picture published in newspaper
Thursday, July 20, 2017
Venus in Conjunction with Moon
In total 6 members of Astronomy club Helios gathered together to observe the conjunction between Venus and the Moon. Around 12h UT the moon was about 11% illuminated and Venus was 3° NE of the Moon.
Wednesday, July 19, 2017
Heliographic Coordinates
In order to define anything on the photosphere of the Sun we need to measure this in terms of heliographic latitude and longitude. This changes by time due to :
1) the fact Earth - Sun distance changes
2) the rotation of the Sun
3) the rotation axis of the Earth being inclined by 23.4° to the ecliptic
4) the rotation axis of the Sun being inclined by 7.25° to the ecliptic
This can be calculated once we have
1) the apparent diameter of the Sun
2) the heliographic latitude B0 of the centre of the Sundisk
3) the heliographic longitude L0 of the centre of the Sundisk
4) the position angle P of the north end of the axis of rotation, when positive it is east of the north point
In a later blog I will post more details about this calculation. Below is the Sun (with Sunspot) including the position angle. The software used was HelioViewer from Peter Meadows.
North is defined by taking two pictures with tracking modus off when using an equatorial set up. By drawing a line between the two sunspots and turning this horinzontal, we find north - south of the Sun.
The "north" positioned Sun (BMP format) is uploaded within HelioViewer. Once your settings (position, time) are entered, the software calculates all coordinates and makes a final drawing of the Sun with Heliographic coordinates.
1) the fact Earth - Sun distance changes
2) the rotation of the Sun
3) the rotation axis of the Earth being inclined by 23.4° to the ecliptic
4) the rotation axis of the Sun being inclined by 7.25° to the ecliptic
This can be calculated once we have
1) the apparent diameter of the Sun
2) the heliographic latitude B0 of the centre of the Sundisk
3) the heliographic longitude L0 of the centre of the Sundisk
4) the position angle P of the north end of the axis of rotation, when positive it is east of the north point
In a later blog I will post more details about this calculation. Below is the Sun (with Sunspot) including the position angle. The software used was HelioViewer from Peter Meadows.
North is defined by taking two pictures with tracking modus off when using an equatorial set up. By drawing a line between the two sunspots and turning this horinzontal, we find north - south of the Sun.
The "north" positioned Sun (BMP format) is uploaded within HelioViewer. Once your settings (position, time) are entered, the software calculates all coordinates and makes a final drawing of the Sun with Heliographic coordinates.
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