A jól bevált helyen, Szelicsén partiztunk. Külön köszönetet érdemel Ilarie, akinek a 20 centis tubusával bolygóztam a 15 centisénél több fény reményében.
A csíkhúzós fotó Magic-Lantern-nel hajtott Canon 1100D-vel készült 97 képkockából egy „ha fényesebb” php-szkripttel.
*
We were at a star party on our well known spot near Sălicea.
Special thanks to Ilarie for letting me try his scope (20 cm) which is a bit larger than mine (15 cm) so I hoped for more light for planetary imaging with my webcam.
The star trails have been shot with a Canon 1100D powered by Magic Lantern. 97 frames were included, F/4 18 mm, ISO 800, 20 seconds each and then added with a „keep the lighter pixel” filter in a PHP script.
<?php
/*
Trivial code to create a startrails picture from individual frames depicting pointlike (or slightly elongated) stars by using a final_pixel[x,y] = max(input_image[0].pixel[x,y], ... input_image[input_image_count-1].pixel[x,y]) function. Progress is also saved.
*/
set_time_limit(6000);
$list = glob('input/*.*');
function pixel_to_luminance($i){
$r = $i >> 16;
$g = $i >> 8; $g = $g % 256;
$b = $i % 256;
$l = $r + $g*2 + $b;
return $l;
}
$output = imagecreatefromstring(file_get_contents($list[0]));
$c = 0;
for ($q=1; $q<min(500, count($list)); $q++){
$i = imagecreatefromstring(file_get_contents($list[$q]));
for ($y=0; $y<imagesy($i); $y++)
for ($x=0; $x<imagesx($i); $x++){
$pix_o = imagecolorat($output, $x, $y);
$pix_i = imagecolorat($i, $x, $y);
$l_o = pixel_to_luminance($pix_o);
$l_i = pixel_to_luminance($pix_i);
if ($l_o < $l_i)
imagesetpixel($output, $x, $y, $pix_i);
}
imagedestroy($i);
if ($q % 5 == 0){
$c++;
$c_ = $c;
if ($c < 10) $c_ = '0'.$c_;
if ($c < 100) $c_ = '0'.$c_;
imagejpeg($output, 'output_'.$c_.'.jpg', 90);
};
}
imagejpeg($output, 'output_final.jpg', 90);
imagedestroy($output);
?>




























