revisiting the expanding crab

here's my biennial addition to the crab nebula expansion from 2006 to 2014(15)
it appears as though the pulsar wind is outstripping the filaments, especially mid lower left:

RGB only as my earlier images were limited.
a wider version shows a high proper motion star lower left.
Here’s is a composite of LRGB plus a touch of OIII luminance for the outer shell and faint jet up top as well as a 540x50nm filter for the pulsar wind (I finally switched to north up):

In year’s past, the pulsar wind appeared bluish, but this was using an LPR fliter which knocks out a chunk of the spectrum in green including the pulsar wind.
This year I used astrodon RGB filters without an LPR filter and excalibrator for color balance, so I think this is more “accurate”.
Yes, this is actually my first LRGB CCD image with RGB from a mono camera
what's the pulsar wind?
this:


I used a “green continuum” filter with a bandwidth of 50 nm centered at 540 nm which avoids the major emission lines of the crab nebula,
isolating the glowing pulsar wind caused by electrons accelerating in the rapidly rotating magnetic field of the spinning neutron star/pulsar.
the pulsar wind glow, rather than the central star, excites the gas filaments
which in turn give off the emission line signal.

Here’s the OIII:

Which gives a nicely defined outer shell, and a hint of the “jet” on top
Note that the upper right corner is a bit weak in OIII, the crab is stronger in broad band emissions there, not sure why.

And lastly here it is in red white and blue in honor of the date of the crab nebula supernova on July 4th:

Red is mapped to, um red, the continuum filter to white, and OIII to blue with an emphasis on the pulsar wind.
Maybe I can talk the APOD folks into posting it for July 4th

I captured the pulsar wind 2 years ago with a filter that had a narrower bandwidth and lower transmission, but failed to demonstrate any short term motion associated with the pulsar wind, which I caught with luminance in 2010.
Unfortunately, it was a bit of a fail as I was able to demonstrate very little if any motion with the new broader higher transmission continuum filter:

note slight expansion in the clear area around the central neutron star
The motion was a bit more evident on L/RGB than the continuum filter

(comparing 4 nights 2 luminance and 2 RGB pseudoluminance)
An analysis of the two RGB nights seemed to indicate the motion was better in the red channel, (subtle difference due to seeing/refraction?)
Not sure if that means it’s Ha/NII or red continuum…


Speaking of moving things I caught minor planet 541 Deborah (discovered by Max Wolf on August 4, 1904) on color images.  The seeing was so bad (FWHM>7) that I actually threw the subs out.



found another moving object, very slow satellite or fast minor planet trailing in 10 minute subs at .8”/px:

at
05 34 32
22 01 00
on 2014 11 28 8:25:35 UT
MP checker indicates this is (2945) Zanstra    
05 34 31.8 +22 01 00  16.4   0.0W   0.0S    33-     0+
a main-belt asteroid discovered on September 28, 1935 by H. van Gent

also see older posts:
http://astrowhw.blogspot.com/2013/07/4th-of-july-supernova-revisited-crab.html
http://astrowhw.blogspot.com/2013/07/crab-nebula-expansion.html

and this animation

2015
11/26/14-3/9/15
8" LX200R, SX Trius 694 and QSI 660 binned x2 to 0.8"/px, ASA DDM60
astrodon LRGB E SERIES GEN-II, OIII 5 nm, chroma 540x50 nm filter (greenish continuum)
L 346 x 1 min
red 33 x 4 min, green 22 x 4 min, blue 22 x 4 min (included as pseudoluminance)
OIII 24 x 20min
540x50 53 x 5min, 56 x 10min

2013
1/12/2013-3/4/2013
8" LX200R @ 0.6"/px, SX AO, Astrodon OIII 5nm, IDAS LPR filters SX H9/H9C
RGB(IDAS) 14x20 min, luminance 35x5 min with idas, 35x5 min unfiltered, plus RGB pseudoluminance
OIII 19x20 min

2010
12/6/2010-2/6/2011
8" LX200R, SX AO, Astrodon OIII 5nm IDAS LPR, SX H9/H9C
RGB 31x20 min, luminance 205x5 min plus RGB pseudoluminance, OIII 47x10 min binnned x2

2008
forgot the details there was too much star trailing for me to complete the initial processing.
aborted HaRGB

2006
1/2,3,5/06
nexstar 8 GPS, IDAS LPR filter, f/6.3 FR, SXV H9C
120x1 min, 240x30 sec (unguided)

planetary conjunctions: moon, venus, and late jupiter...saturn

After sunset on 6/21/15 there was a scenic arrangement of the crescent moon, venus, and jupiter--and it was clear (which has been problem here in June).  Though too wide to be captured in a telescope, I decided to turn my new mono planetary camera on the subjects. 


venus gave her usual inscrutable crescent:

Though very low in the sky I was able to get some detail on jupiter and lucky enough to catch the great red spot:

and the moon...well it's really big.  the widest field my planetary rig could manage was just a small section of the terminator:

a bit later i took crack at saturn:

while the moon has now wandered off, jupiter and venus will continue to close until tues 6/30/15 when they will be .3 degrees apart, and can be caught together in a medium power telescope field. 

Processing notes:

One of the problems with imaging jupiter with a mono camera is that it rotates so rapidly that the surface details move between red, green and blue filter images.  Here are the rotating originals:

I used a software program called WinJupos to "derotate" the images for the RGB combine:

nexstar 8 GPS (8" SCT on alt azm mount)
ZWO ASI120MM-S
zwo RGB filters stacked in autostakkert, Drizzle 3x
wavelets in registax6 derotated and compbined in winJupos

red channel only was used for venus and the moon as it's less subject to atmospheric distortion due to poor seeing

RL deconvolution in maxim DL and finally reduced to 2x scale
except moon drizzle to 1.5x.

Saturn's out

prime viewing time for saturn
unfortunately i've been clouded out almost every night since Saturn's transit.

Here it is on the evening of 6/1

If you look closely you can see faint moons Tethys above and Dione below.

Also, if you look west after sunset later this week you should see a nice you should see a nice pairing of bright Venus and Jupiter along with the crescent moon.

http://www.skyandtelescope.com/observing/this-weeks-sky-at-a-glance-june-12-20/

interestingly, a year to the day from the first saturn of last season.

Imaging details:
nexstar 8 GPS (8" SCT on alt azm mount)
ZWO ASI120MM-S Camera
captured with firecapture @ 76 fps (exposure limited at 40% histogram with gain 82)
1 minute exposure for each color, zwo RGB filters
stacked in autostakkert, Drizzle 3x
sharpened in registax 6
RGB combine in maxim DL then RL deconvolution
downsized to 2x
6/2/15 fair seeing

~ (UT)=080100 (1 AM local 50 minutes past transit)

M76 in Nitrogen II Oxygen III and Helium II a rainbow in space

what's black and white and red all over?
...an image using an Ha filter. 

due to the abundance of hydrogen, you'll get some signal all the way from the highest energy to the lowest energy regions in a nebula right up to the ionization front, with rare exceptions.  thus hubble pallet images using SII, Ha, and OIII are typically teal and gold rather than red green and blue.

I chose a M76, a relatively bright planetary nebula with some detail, for the first image with my new narrower Helium II filter (4nm from chroma).

a quick blink of the mono channels for this one showed me that the brightest signal areas were not quite completely separated

which means a scientifically assigned color pallet will give the full spectrum...

a rainbow in space:

Helium II blue, (so faint it's stretched), Oxygen III linear green, Nitrogen II linear red

here's the color image with a log stretch which works quite well for bright planetaries with faint shells:

a healthy does of NII was applied as luminance

here's another variant with OIII assigned to teal rather than green:


mono NII


mono OIII


Helium II as blue with a green continuum filter as red and green (both new filters):


stretched blink


still looking for the pot of gold

8" LX200R, SX Trius 694 and QSI 660 binnedx2 to 0.8"/px
astrodon 3nm NII, 3nm OIII, chroma 4nm Helium II filters
ASA DDM60
NII 35x20min OIII 17x20min HeII 27x20 min
11/2014-2/2015
never enough exposure time...

planetary nebula IC 418: a blue gem in a red cocoon

here's my first light with a new ccd camera: starlight xpress trius 694
believe it or not i've never used a filter wheel before
just manually screwed one filter on, imaged for a few nights, then went on to the next
not a big deal for super long narrow band imaging, but inconvenient for quick bright planetaries
so the filter wheel that came with the camera is more of a novelty to me
than the larger, more sensitive chip
thus a quick shot of a bright planetary as first light.

after seeing IC 418 listed as one of winter's best planataries in feb S&T
i decided to revisit the red planetary with narrow band filters
as my prior rgb effort yielded nothing but a red disk with a brighter spot in the center

so here it is in NII/OIII/OIII:

it's difficult to make out the central structure at native image scale
so i upsampled x2
for a final resolution of (EDIT: 0.2"/px)  (makes a difference to my eye)
straight linear stretch with a bit of RL deconvolution

in OIII there is a disk with a subtle central brightening:

here's the NII which shows a central star with an outer shell:

blink

difficult to say whether the mottling is noise or a hint of the spirograph pattern detected in the hubble image

interestingly combining the NII and OIII in a color image
seems to create an unsharp mask like effect
making the central OIII brightening (gem) more evident


prior effort (RGB 2007):

i also shot HeII subs but found only a very faint ring around the central star
seemed matched continuum filter images with equivalent exposure (accounting for bandwidth)
meaning it's either broadband glow or artifact such as reflections, corrector plate dust etc.

of course after imaging it i came across this on Jim Kaler's web site
indicating there are no HeII emissions:

http://stars.astro.illinois.edu/sow/ic418.html
"The low excitation nebula, with its relatively cool central star, does not exhibit He II emission lines (those of ionized helium), just those of He I (neutral helium)"
i believe this is taken from a 50 year old reference:
From L.H. Aller and J.B. Kaler, Astrophysical Journal vol. 140, p. 936, 1964.
so i'm a bit behind the times...

i also shot a 20 minute sub binned x2 in NII and OIII
and found no evidence of any other outer shell (didn't check Ha)


8" LX200R, SX Trius 694  0.4"/px
astrodon 3nm NII, 3nm OIII filters
NII 22x30s, OIII 20x30s
ASA DDM60
no AO no guiding
1/2/15

Comet Lovejoy C/2014 Q2

caught a bright comet with an impressive tail in January:

The image frame is approximately 2 degrees wide, making this the longest comet tail I've captured as it clearly departs the frame.  Some images from dark skies show a tail spanning 19 degrees.  

This was shot through heavy light pollution and passing clouds (explaining the gaps in the star trails).  Nevertheless, the bright, twin tail structure is still visible.  

The comet was easily visible in binoculars, brighter than the andromeda galaxy, though i could not detect the tail.  

Here's a video of the individual frames complete with clouds and airplanes:

Lovejoy animation (warning large file)

Note the comet tail follows the direction of the solar wind rather than the comet motion in this instance.   

Though fading a bit from peak brightness

It should still be visible early evening  in Andromeda this weekend with the new moon approaching

finder chart

FS60C@ f/42. with SX H9C color camera and chroma light pollution filter.  60x2 minute exposures with mount tracking on comet (ASA DDM 60).  

speaking of gas giants...Uranus

Uranus, seventh planet from the Sun. It has the third-largest radius and fourth-largest mass in the Solar System. Uranus is similar in composition to Neptune.  Along with Neptune, sometimes called an "ice giant" (prior post).  It has the coldest planetary atmosphere in the Solar System, with a minimum temperature −224 °C.  It has a complex, layered cloud structure, with water thought to make up the lowest clouds, and methane the uppermost layer of clouds.  At 20 a.u. it has an 84 year orbit.  Like other gas giants it spins rapidly, making one revolution in 17 hours.
Uranus has an axial tilt of 98°, so its axis of rotation is approximately parallel with the plane of the Solar System. This gives it bizarre seasonal changes. Combine this extreme tilt with it's 84 year orbit and you get a 21 year "night" at the pole during winter, compared to a 17 hour day at the equator during equinox.  
Like Neptune, there's not much to see visually.  Unlike Neptune, it can be seen with the unaided eye in dark locations.  At high power it can be seen as a small disk rather than a dot.  A slightly more green than Neptune.  A monster telescope or camera might detect several moons (see below), and possibly faint cloud formations.

Uranus and moons 10/19/06 05:32 UTC

The Hubble or flyby space craft can detect faint rings.

Neptune overview

Neptune--eighth and farthest planet from the Sun (after Pluto’s demotion).  Along with Jupiter, Saturn and Uranus, a gas giant.  Smaller, but slightly more massive than its near-twin Uranus.  Uranus and Neptune are sometimes referred to as "ice giants" as they contain a higher proportion of "ices" such as water, ammonia, and methane.   Traces of methane in the outer atmosphere account for the planet's blue appearance.  At 30 au its orbit around the sun takes 165 years, so it’s not moving much in the sky from year to year. 

Discovered in 1846, Neptune was the first planet found by mathematical prediction rather than by empirical observation. Unexpected changes in the orbit of Uranus suggested gravitational perturbation by another planet. There’s been controversy over credit for the discovery:

http://en.wikipedia.org/wiki/Neptune#Discovery

Interestingly, Galileo made the first recorded observation of Neptune, but apparently did not recognize it as a planet, though some have suggested that he was aware that it had moved relative to fixed stars. 

For visual astronomers, there’s not much to see except for the fact that at high power it can be seen as a small bluish disk rather than a dot.  It generally cannot be seen with the unaided eye.  Due to its distance, its apparent size is the smallest of the planets.  With dark skies or a camera you may be able to pick up a few moons.

Here’s an image of Neptune, the white spot to the right is its large moon triton:

With the Hubble or flyby space craft, surface storms and very faint rings have been detected.  

wiffed on einstein's cross: happy solstice

Gravitational lensing is a phenomenon predicted by einstein's general theory of relativity wherein the warp in space due to the gravitational field of a large galaxy or group of galaxies causes a magnification or lensing effect upon light from a galaxy that is more distant.  

einstein's cross a/k/a cgcg378-15 is a galaxy who's lensing effect splits the image of a distant background quasar into four separate images.  

i've been trying to image this elusive structure for years.  failing time and time again to even find it.  last year, i thought i'd caught it, but entered the incorrect catalog number, imaging the wrong galaxy (cgcg 378-14 instead of cgcg 378-15):

this year i'm sure i actually caught the right galaxy:

though the core doesn't look quite round, i certainly can't claim to have resolved the cross.  There do appear to be interesting reddish Ha emissions in the spiral arms.  

this one stays on the list for next year.

PS what i should see is 4 dots in the center instead of one. the dots represent the single distant quasar viewed through the distorted lens of the galaxy's gravitational field.
Here's a shot from a professional observatory with a an aperture measured in meters:

here's the Hubble super close up of the core only

with a little imagination, a close look at the core suggests it's not quite round, but not convincing enough to say i'm seeing the lensing effect.

happy solstice xmas and hanukka

details:

8" LX200R, SX AO, SX H9/H9C, .6"/px
IDAS LPR filter
lum 113x5 min, RGB 13x20 min
9/2014
Newport Beach, CA

North America and Pelican Nebulae

North America and Pelican Nebulae

The North America Nebula is a huge emission nebula in Cygnus close to the bright star Deneb.
It took me years to see it through a telescope, even from dark skies.  At 4 times the size of the full moon, i was staring right at the middle of it with my long focal length telescope.  Finally i used a filter in the small low power finder scope on top and caught it.
This image is a two frame mosaic with my shortest focal length telescope, showing the North American nebula to the left, and the pelican nebula to the right of a central patch of dust.
This image uses the "hubble pallet" with high energy oxygen as blue, low energy sulfur as red, and hydrogen as green.

not entirely happy with the framing as i've clipped the west coast in order to include the pelican :(
might try again next year

Here it is with an alternative pallet using only high energy oxygen as blue and low energy sulfur as red (hydrogen was used in part as luminance):

Here's an older close up of the "cygnus wall" aka "gulf of mexico"

and the Pelican

Takahashi FS60c @255mm CS 8.6nm Ha, AD 3nm OIII, AD 3nm SII, SX H9
2 frame mosaic total time Ha 49x5 min, OIII 74x10 min, SII 92x10 min
Newport Beach, CA 10/2014

Photographic Light Pollution Filter Comparison: Hutech IDAS LPS-P2 vs Chroma Loglow

Having recently moved I've noticed some improvement in my skies from bortle white to bortle "off white".  At zenith on a good night, my sky quality meter reads 18.12 mag/arcsec^2.  There is a red glow to the north up to an altitude of 40 degrees and a grey glow above that to 70 degrees.  The sky is darker above and to the south.   The milky way is impossible naked eye.
I do all my imaging from these skies with an LPS filter, narrow band filter, a combination of both.  Emission nebulae are great, galaxies are difficult, but can be very rewarding (especially if there are HII regions),  reflection nebulae are very difficult and dust is impossible.
As a testament to the fact that I purchase too many filters, I was given a Chroma Loglow filter to test.  So I've compared it the the Hutech IDAS LPS-P2 filter which many (including me) consider the gold standard light pollution filter.  A quick visual inspection showed more light passing through the Chroma than the IDAS.  I initially thought the Chroma had more of a reddish cast, but realized this was on a fluorescent bulb.  Searching around for an incandescent bulb yielded similar, more neutral color balance for each with perhaps a slight blue cast to the IDAS.

Iris Nebula, a reflection nebula surrounded by dust shot through heavy light pollution:

Reflection nebulae are usually blue because the scattering is more efficient for blue light than red (this is the same scattering process that gives us blue skies and red sunsets) (Wikipedia).
The black void above, below, right, and left of the nebula is caused by intervening dust.  darker skies allow the glowing dust to be imaged.

Dumbbell Nebula, an emission (planetary) nebula, at maximum elevation with minimal gradients due to light pollution:

Here are the details of the filter test:
It should be noted that the filters were used on different nights, though the conditions were similar.  My first target was M24, low in the south, but in the direction with least light pollution, using an FS 60C at F 4.2 and a Starlight Xpress H9C camera.  The star and background signal was much higher with the Loglow, though I did not note any difference in depth or gradients in this dense star field (comparison images not shown).  The seeing was slightly better when the IDAS was used.  The combined image can be seen here in a prior post.

Dumbbell Nebula
Next up was M27, an excellent target, as it has strong OIII and Ha emissions transiting at zenith in an area where gradients and light pollution are minimized.  Using an FS 102 at F 6, I compared a Baader IR/UV filter to the IDAS and the Loglow.  There were no appreciable light pollution gradients.  The nebular emission signal was enhanced relative to the stars with both the IDAS and the Loglow.  I could not appreciate any significant difference between the IDAS and the Loglow.  I've attempted to minimize processing to color balance and matching digital development:
IR/UV

IDAS

Loglow

blink:

stack of 9x120 sec exposures, color balanced by eye followed by digital development in maxim.

Iris Nebula

Last was the Iris nebula, a reflection nebula surrounded by dust in the dreaded northern muck, again with the FS 102 at F6.  As there appeared to be a significant color difference in the reflection component, the images were color balanced with x-calibrator.  The reflection component appeared significantly more blue with the IDAS and Loglow compared to the IR/UV filter.  I am not certain whether this is the result of grey light pollution contaminating the IR/UV images or enhanced color by the IDAS and Loglow due to rejection of signal in the middle of the color spectrum.  In any event, I found the effect aesthetically pleasing.

IR/UV

IDAS:

Loglow:

stack of 19x5 minutes color balanced with x-calibrator, ddp in maxim.

An aggressive histogram stretch in maxim showed the worst gradient with the IR/UV and best with Loglow, though the IDAS was close.

IR/UV

IDAS

Loglow

I did shoot some luminance with the two filters, but the background signal was so high with 2 minute subs, that it reached the non-linear region of my camera, making flats ineffective.  Between hot spots and dust specks it was difficult to make any comparisons.

Signal:

I compared the stellar, nebular, and background signal for a representative section of the M27 stacks and found the following:

For all of the quantities, the Lowglow had higher signal than the IDAS; the IR/UV the highest signal of all. 

However, for the ratio of stellar signal to background and nebular signal to background, the IDAS had the highest ratio, followed by the Loglow, and then the IR/UV filter.

	idas	loglow	ir/uv
M27 background	1,280	2,230	2,890
star	27,777	27,928	30,110
fwhm	2.03	1.74	1.75
nebula (color balanced)	1779	2733	3388
nebula (unbalanced)	1672	2745	3400
star/background	21.70	12.52	10.42
nebula/background	1.39	1.23	1.17
nebula(unbalanced)/background	1.31	1.23	1.18
iris background	3,500	5,376	7,257
iris star	19,000	21,000	28,000
fwhm	1.68	1.98	1.76
excalibrator green	0.93	0.99	1.03
excalibrator blue	0.76	0.81	1.16
star/background	5.43	3.91	3.86

Takahashi Fs 102 @619 mm Hutech IDAS LPS-P2/Choroma LoGlow, Starlight Xpress H9C/H9

M 27 34x2 minutes RGB, IRIS ~100 x 2 min luminance, 84x5 min RGB

9/15-9/24/14 Neport Beach, CA

Bottom Line

The two filters were comparable in terms of reducing light pollution gradients and enhancing nebular emissions.

The LoGlow seemed to be slightly better than the IDAS-P2 in terms of light pollution gradient reduction.

The LoGlow also passed more signal while the IDAS-P2 had a higher signal to background ratio. 

clear skies

10/23/14 partial eclipse animation

finally finished the animation of the partial eclipse in hydrogen alpha.

imaged over about two hours.

a "usb fault" caused me to miss the very beginning while trees interfered with the end.

here's the full disk animation (large file) over 2 hours:

full disk eclipse animation

though the sun spots were dramatic in white light, they were less prominent in hydrogen alpha at this scale.

other than the moon passing by, there was not a whole lot happening during the time period of the animation at large scale.

Here's the sunspot, AR 2192 in hydrogen alpha:

Here are 150% enlargements of two small sections that showed some activity:

solar active region AR 12192: the monster revisited

here's a wider view of the monster sunspot grouping i caught just before the recent partial eclipse.
according to one source, this grouping, known as AR 12192 is one of the largest sunspot groupings in recorded history

fortunately, it arrived at a time when i was working on my sunspot technique and had made great strides, imaging structures i'd never been able to catch before.  specifically, the honeycomb-like granular structure on the bright surface and the and the "penumbral filaments" at the edge of the dark spot (best seen around the large spot to the right). 

"Granules on the photosphere of the Sun are caused by convection currents (thermal columns, Bénard cells) of plasma within the Sun's convective zone. The rising part of the granules is located in the center where the plasma is hotter. The outer edge of the granules is darker due to the cooler descending plasma." (Wikipedia)
These convection currents contribute to the sun's magnetic field.

the penumbral filaments at the edge of the dark spot aren't that well understood (at least by me).  they seem to involve an interaction between magnetic fields of different orientations and convective flow.
magneto-convective cell reference

the sun rotates once every 27 days or so
will be interesting to see if this grouping comes back around.  

the key to the improved image was taking a huge number of frames over a short period and discarding all but the very best.  to do this i had to use a different camera with a smaller field of view and faster frame rate.  unfortunately, the field of view was smaller than this large grouping.

compare the detail (especially the fine filaments) on this small high frame-rate field to the right side above:

i tried a mosaic in an attempt to get a wider field and high frame rate, but it came out to too patchy

for reference here's a prior image at the same scale:

IMAGE improvement DETAILS
the following measures gave improved images:
1. switched cameras from DMK 51 to zwo ASI120MC which allows a much higher frame rate.
-DMK is great for wide full disk animations, but limited to 12 fps-i'd misread the framerate as 60 fps-that's the output avi :(
using a partial frame with the zwo got me to an average of 54 fps which overcame the handicap of the color camera
2. much smaller stack: took only the best 20 or so images at the upward curve to the left of registax stackgraph quality indicator.
3. kept the imaging time very short--20 seconds
4. put the solar filter (baader film) on the scope inside and immediately pointed it at the sun when i brought it outside.
-the charcoal black carbon fiber tube heats up very quickly with direct sunlight. rather than insulate, i figured the film would reflect the energy immediately, keeping the tube out of direct light. 

i think the biggest factor was limiting the stack size
which means i can reprocess some of my older images :)

did not recollimate
tried an off-axis mask prior to these changes with no improvement
no change in focus technique