Thursday, October 29, 2015

Venus, Jupiter and Mars before dawn 2

This morning was clear after many cloudy days...

So, here are Venus, Jupiter and Mars among stars at about 6 a.m. EET 2015 Oct 29. Kyiv, Osokorky district.

Canon EOS 600D on tripod + EF-S 18-55 kit lens (the first picture); EF-S 55-250mm f/4-5.6 IS II (the second one).

Jovian moons (Callisto and Europa) are visible in the second picture.




Monday, October 19, 2015

Venus, Jupiter and Mars before dawn

Venus, Jupiter and Mars before dawn (2015 Oct 17). Kyiv, Osokorky district.

6:20 EEST; Canon EOS 600D on tripod + EFS 18-55 kit lens.



6:00 EEST; Canon EOS 600D on tripod + EF 50mm f/1.8 II lens.

Zoomed part of the picture: Callisto, Ganymede, Europa are clearly seen on the one side and Io is hardly seen on the other. Mars is above Jupiter.

Wednesday, September 9, 2015

Double Supernumerary Rainbow

Double rainbow at sunset (Osokorky district, Kyiv). This is a panoramic image made from three pics taken using Canon IXUS 132 [08 SEP 2015 ~18:06 EEST]

Note that colors of the fainter secondary rainbow are in reverse order (because of double reflection of sunlight inside the raindrops -- see graphical explanation at the end).



The bright primary rainbow is supernumerary: you can see additional narrow faint rainbow(s) on the inner side of the primary one; this effect is better seen in the picture with enhanced contrast:


An appearance of the supernumerary rainbow is explained by interference of sunrays:
It is not possible to explain their existence using classical geometric optics. The alternating faint rainbows are caused by interference between rays of light following slightly different paths with slightly varying lengths within the raindrops. Some rays are in phase, reinforcing each other through constructive interference, creating a bright band; others are out of phase by up to half a wavelength, cancelling each other out through destructive interference, and creating a gap. Given the different angles of refraction for rays of different colours, the patterns of interference are slightly different for rays of different colours, so each bright band is differentiated in colour, creating a miniature rainbow. Supernumerary rainbows are clearest when raindrops are small and of uniform size. [https://en.wikipedia.org/wiki/Rainbow]
Here is an explanation how primary and secondary rainbows appear.
In the figure beneath paths of rays, which form primary and secondary rainbows are shown (from Wikipedia):
(7) primary rainbow; (8) secondary rainbow

The next figure is René Descartes' sketch of how primary and secondary rainbows are formed (from Wikipedia):


Wednesday, August 19, 2015

Milky Way in Cygnus

Dark dust clouds divide band of Milky Way in constellation of Cygnus (Northern Cross).
Below and slightly to the left to the brightest star of the constellation -- Deneb -- one can see an emission nebula “North America”, the shape of it closely resembles that of Earth continent.


An image is an average of 72 frames (12s each) taken by Canon EOS 600D (on tripod) with EF-S 18-55 mm f/3.5-5.6 IS II lens.
I emphasised bright stars of the constellation (they were processed separately and overlayed on the main image):



Processing: DeepSkyStacker, FITStacker, RawTherapee, GIMP.

The pictures above were captured from a bank of Nebrezh lake (Osokorky district, Kyiv):

**** UPDATED 27-08-2015 ****
The same picture, other treatment. This image is not cropped, you can see big distortions at the angles (probably because of a "field rotation"). Nevertheless Milky Way's dark nebulas are better seen in this image:

By nova.astrometry.net (size 65.6 x 40.7 deg):

Wednesday, August 12, 2015

A Meteor of Perseid Shower

It seems that weather tonight will be not favourable for observations because of clouds...
A pic beneath was captured in the night from 8th to 9th of August (Kyïv, Osokorky)
08-Aug-2015 ~23:28 EEST (UT+3)
Canon EOS 600D + EF-S 18-55mm f/3.5-5.6 IS II; Exposure 20s; F=18mm; f/3.5; ISO 1600

****UPDATED****
Another treatment option

Sunday, August 9, 2015

Cluster Chi-H Persei

Night from 8th to 9th of August 2015
Canon EOS 600D on tripod (no tracking) + EF 50mm F/1.8; 60x5s; ISO 3200; F/2.5

Stars, Satellites and Meteors above a Tree

Night from 8th to 9th of August 2015
https://youtu.be/cP-6MXpR3mw

Here is a frame from the video (meteor from Perseid shower):