Sunday, January 25, 2015

Entering the processing fray

The greatest advancement in astronomy is probably the computer, for amateurs and professionals alike. Stacking images is now routine procedure for images published by amateurs. I'm coming to this software angle rather late in the game. Here are my first attempts using Comet Lovejoy as my target and the free software Registax:

Single 3-minute image, no processing

Stack of 4 images

What a fabulous sinkhole for my time that has just opened up!

jg

Friday, January 9, 2015

Cold Fuzzies

The past two nights I was able to photograph Comet Lovejoy, despite the onsite of clouds and rain. The sky was more clear on Wedns. night, shown by the better color and contrast in the first photo.
However, I was surprised to see the last night, when photographing through clouds, the comet had a more noticeable tail. 


Also more noticeable is the slight drift or elongation of stars, caused by not having my camera mount accurately polar aligned. I couldn't see Polaris, so I had to guess at the alignment, and so the stars and comet show a little drift. I wonder if the drift motion, being at a right angle to the direction of the tail, helped enhance the tail.

jg


Thursday, January 8, 2015

What's that bright star in the south?

This time year people notice a bright star rising in the south in the early evening. While low, the star's light is scattered, creating a sparkling effect that's noticeable because of it's brightness. That star is the brightest star in our night sky, Sirius. (Pronounce in English as "serious"). Sirius is also the heart of Canis Major, the great dog:


Sirius is a binary star system: two stars orbiting a common center of gravity. Sirius A is the brighter star, and Sirius B is the dim but observable companion. Sirius B can be seen in a telescope, but it requires good optics and good viewing conditions. However, the orbit of Sirius B is taking it to it's farthest point in relation to Sirius A, making it easier to see apart from the glare of Sirius B:


When Sirius is at its highest point in the sky, viewers in the lower part of the United States, Southern California for me, can also see the second brightest star in the night sky, Canopus. It appears in the bush of the picture above, but the following picture shows Canopus a little brighter after moving out of the bush:


Look just to the right of the bush, the lower right, and you'll see Canopus just above the horizon.

jg





Tuesday, January 6, 2015

Lovejoy update


Comet Lovejoy on 6 Jan 2015. Tomorrow, the comet is predicted to be at its brightest, but tonight the sky was clear and clouds are in the forecast for tomorrow, so this may be as bright at it gets for me.





jg

Tuesday, December 30, 2014

Comet Lovejoy

On December 29 I observed comet Lovejoy using binoculars and a small telescope. It was very easy to see in a 9x50 finder scope, even with a bright moon. Here is a wide field view of the comet in relation to Orion. Lovejoy is in the crosshairs. Over the next week it will move approximately in the direction shown by the arrow.



Here is comet Lovejoy in a small telescope: 


The next best time to watch for this comet will be in the early evenings after January 7th, because the moon will be out of the way.

jg

Thursday, December 25, 2014

Iridescent clouds and crazy contrails

December 24 had some interesting clouds that produced great iridescence. My hand is blocking the sun in the picture below.


Iridescent clouds, 24 December 2014, ~12:00

The color in these photos matches that perceptible to the eye, though the sky is darker in my photos due to my camera's adapting to the brightness. Our eye can detect the colors of the sky and iridescence, but the camera, at least mine, has to choose one. If I had taken identical photos using different exposure times, I could combine the the images in Photoshop to reproduce the full range of color; but the iridescence was fleeting, leaving no time for tripod mounting or controlled exposures. My best results came from using the camera's automatic landscape settings.

Minutes after the above photos, a jet passed through the cloud, leaving a contrail up to the cloud but erasing the where it flew through. The erased parts are probably the hole-punch effect, where a plane or strong updraft punches holes in a cloud. This tells me that the cloud was very thin, perhaps a requirement for producing the iridescence. As the clouds thickened in the afternoon, the iridescence was gone.



Condensation trail with hole punch effect

jg


Tuesday, December 23, 2014

Ursid meteor splits 33 Capricornus

While looking for comet Finlay, which can be found next to Mars throughout this week, I bagged a meteor. Last night was the Ursid meteor shower, a light sprinkling offering 5-10 meteors per hour -- not the type of thing I stay out for on a cold night, but it was a clear night and good for star gazing.

Wide field:


Close-up:


Any meteor that crosses a star is suspect; that is, it could be a plane that blinks or a satellite that rotated its more reflective side toward Earth, but the star it passed through is listed in star charts as 33 Capricornus.

And of course, before after shots include the star:


I did find Comet Finlay, a feat that attests to my community's fairly dark sky. The following photo shows the faint green comet amid 9+ magnitude stars.


The 9th magnitude stars appear brighter than Finlay. Within the circle around Finlay, there's a 10th magnitude star and a few that are probably 11th magnitude (anything fainter is probably camera noise). Finlay is clearly brighter than 11th magnitude but very close in brightness (accounting for its being more diffuse) to the 10th magnitude star.

jg