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Sirius A and Sirius B, 


             Astroavani - Avani Soares

Sirius A and Sirius B

Acquisition details

Basic astrometry details job: 877676

Resolution: 480x480

File size: 34.0 KB

Locations: Observatório Parsec, Canoas, Rio Grande do Sul, Brazil


After everything I've read and researched so I believe this was a good catch. I was estimating the image size in arcseconds and have no doubt that Sirius B was recorded.

The Sirius was extremely large but this can be easily explained:

The first part of the problem is that Sirius A is many magnitudes brighter than Sirius B. The second part concerns the spreading that the starlight naturally suffers when passing through the atmosphere. This scattering has a Gaussian profile: bright in the center and increasingly weak away from the center. The last part is the digital light sensor has an upper limit that does not change value when reached.

Cómo Sirius A is much brighter than B, even to the far side and his weak picture is even brighter than the center of B. What has happened is that the very bright Sirius edges of the image (and the center also) have done the pixels of the sensor reach the brightness threshold while for Sirius B this may not have happened to the image center.

As the size of the illuminated disk in order to have an idea Gaussian scattering has a minimum approximate size typical of one arc second. We can compare with the angular distance between the two stars.

The only way I imagine it possible for the two stars look like dots would reduce the exposure time to the Sirius Point A look like a point and make other equal exposure so that the exposure time of all added up equal to the image above. Then we'll have to align them get the average and use some HDR technique to increase the brightness of Siruis B (which will appear to be invisible) without increasing the A. Usually this is done using masks in photoshop or gimp or similar. Wearing masks also gives to do with only two exhibitions: at what we have and once that Sirius A appears as a point, regardless of how B appears.



Sirius A and Sirius B, 


             Astroavani - Avani Soares