Sunday, August 30, 2015

still more summer sun: filaments, proms and spots

used a variety of cameras telescopes and filters to capture a range of solar activity last Sunday 8/23/15.

sunspot grouping AR 2403 in hydrogen alpha compared to broad spectrum (white light):




Ha single stacked, large chip camera full disk:



the prominences projecting off the edge out into space are much more faint, so i created a composite of this and a longer exposure which burns out the center (color version):


double stacked Ha for better contrast, capturing  the filaments and prominences smaller chip camera which has a faster capture rate:




closer view of filaments and prominences upper right:

negative:


prominence only with over-saturated pixels blacked out:


Hydrogen alpha activity around sunspot grouping AR 2403:


close up version in white light showing the sun spots


Imaging details/discussion:
full disk Lunt 60 PT single stacked, on grab & go alt-azm mount, DMK 51

i switched to 60/50 double stacked as i thought higher contrast would make it easier to capture the prominence/filament juxtaposition upper right.  The single stacked Ha band width is .7 anstroms, double stacked narrows it to less than .5 angstroms.  this makes the surface filaments stand out more.  since the double stack leaves a bit of a gradient with full disk anyway, i switched to my new planetary camera ASI 120 MM-S which isn't big enough for full disk, but it has a much higher frame rate--10x faster than the DMK when cropped.

the white light capture was done with an 8" SCT, baader photographic film an IR/UV cut filter and a 550x10nm filter with the faster ASI 120 MM-S camera.  i tried 4 different filters: 540x10nm, 550x10nm, 8.5 nm OIII, 10 nm Helium.   On quick switching with a filter wheel the 550x10 seemed slightly better than the 540x10.  i then took a series of 6 20 second captures separated by a minute with the 550x10 filter hoping to capture some sort of motion.  what i found was huge variation in seeing with 4 of the 6 captures showing mush and two showing some detail, making it difficult to really conclude whether one filter was better than the other.



Monday, August 10, 2015

Sunny Sun Day

Sun showed a lot of activity on Sunday so I took a quick full disk shot with the lunt 60 on my grab and go alt-azm mount.

Hydrogen alpha
sun-ha-800.jpg

composite:
sun-ha-composite-800.jpg

exclusion:
sun-ha-exclusion-800.jpg
the exclusion seems to bring out the very long serpentine filament mid/upper left

colorized:
sun-ha-composite-color-800.jpg

Lastly here's a close up of the prominence to the right:


Lunt 60 PT single stacked, DMK 51


tried the sun spot grouping in WL, but failed miserably on saturday

Monday, July 13, 2015

Pluto

Pluto is getting a huge amount of press from NASA
due to the new Horizons probe's closest approach to pluto tomorrow. 
latest images can be seen here

Here's pluto back when it was still a planet in July 2006:



because of it's great distance, 
both visually, and photographically from earth, 
pluto is just another white dot in a field of stars
which can be distinguished only by the fact that it moves across the stars (in this case the images were taken over several different nights).  

here's a recent image by fellow OCastronomers member Tom Munnecke

pluto has 5 known moons, perhaps more to come.  it's largest, charon has half the diameter of pluto.  As a result, the center of mass of the system (and their combined orbit) lies outside of pluto; they orbit eachother (one of the less valid reasons for demoting pluto)

The book
How I Killed Pluto and Why It Had It Coming by Mike Brown
gives an interesting account of why pluto should not be a planet (eccentric orbit, small size, etc), pointing out the fact that there were a number of asteroids (ceres etc) that had been planets, but were later demoted.  credit is due to the astronomical societies for waiting 5 years after the death of Clyde Tombaugh, it's discoverer, before demoting it.  credit is also due to Mike Brown who helped demote it, having discovered (with his team) 2 more "transneptunian objects".  Had he made the case for pluto's planet-hood, he would have made the case for his discoveries, becoming the only living planet discoverer, and the only one to have discovered more than one.  
It also gives a remarkably restrained account of one of the slimier moves in the astronomy world: a group from Spain saw an abstract title for an upcoming meeting,  peeked at the server logs, determining the location of the object mike brown was studying, then claimed the discovery as their own, without so much as a reference to the US group.  
The book is actually a good read, thanks chris


Here's one of his discoveries:

Transneptunian object 2005 FY9 a/k/a Easter bunny passing egg shaped galaxy ngc 4314 2/22/2006.  
This dwarf planet is now named Makemake (god of fertility in the mythology of the Rapa Nui people of Easter Island).  discovered around easter when his wife was pregnant...