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Tuesday, March 24, 2015

The blue dot and rings in Sh2-232



This is a followup to my previous blog post. When I was processing the data, I noticed a small nebula in center of the large complex of Sharpless 232. It seems to be the only O-III emission source in this large emission nebula. My O-III exposure was relatively short though, only 2h. The origin of this small ionization zone puzzles me. I made a small animation from integrated emission channels. No other processing, than calibration and simple un linear stretching has been done to the images.

EDIT

One mystery solved with a help from another astroguy. "Saloja" from a Finnish astro group used the Megastar database and found out, that this blue dot is a known planetary nebula, PN G173.5+03.2.  Thank you Saloja!


Narrowband image of Sh2-232 in mapped colors

Note the blue dot at middle of the photo, it's not a star but a small area of nebula emitting the O-III light.

An animation of emission channels

This animated GIF shows all three emission channels imaged for this photo, O-III, S-II and H-alpha. 
The small nebula is visible in both, H-a and O-III, S-II doesn't show it. It could be nice to understand the mechanism behind this small object. 
Is it part of the large nebula and what is the energy source for the ionization? It might even be a planetary nebula, part of the large Sh2-232 complex or a separate object front or behind it. 
Has anyone else noticed this object? Let me know, if you have some info about it.



Another interesting feature of  Sh2-232
A ring like formation

I have animated to this starless version of Sh2-232 photo, what I'm seeing in lower part of the nebula. There is a ring like formation and I'm seeing some hints of the concentric structure too.






Monday, March 23, 2015

Sharpless 232 (Sh2-232) and companions in Auriga



This was one of the most difficult targets I have shot lately, very diffused and dim. Now when the season is about to end, up here 65N, we have had clear skies one after another and I have collected exposures to unveil this target. Total exposure time is now about 24h hours. Image is a two frame mosaic.

There seems to be some interesting looking structures in this emission nebula. One of them can be seen at bottom right, just under the larger nebula. It looks like some kind of circular formation with several dim concentric layers. An other one is a very small area emitting light from an ionized oxygen (O-III) at center of the Sh2-232 at right.

Sharpless objects 232, 231, 233 and 235
Image is a two frame mosaic, click for a large image

Image is in mapped colors from an emission of  the ionized elements. Golden areas are from emission of sulfur and hydrogen. There is a very little an ionized oxygen, O-III, in there.

An experimental starless version

This starless image shows better the details of the actual nebula complex. (The blue dot is not a star)


A single frame closeup of Sharpless 232

Note the blue dot at middle of the photo, it's not a star but a small area of nebula emitting the O-III light.


A closeup of the blue dot at the middle

There is a small area of an ionized Oxygen (O-III) it can be seen as a blue dot at the center.

An animation

This animated GIF shows all three emission channels imaged for this photo, O-III, S-II and H-alpha. 
The small nebula is visible in both, H-a and O-III, S-II doesn't show it. It could be nice to understand the mechanism behind this small object. Is it part of the large nebula and what is the energy source for the ionization? Has anyone else noticed this object? Let me know, if you have some info about it.
EDIT

One mystery solved with a help from another astroguy. "Saloja" from a Finnish astro group used the Megastar database and found out, that this blue dot is a known planetary nebula, PN G173.5+03.2. Thank you Saloja!
INFO

Sharpless 232 (Sh2-232) large and very faint member of coplex of diffused nebulae in Auriga. One frame photo covers about a square degrees of sky. Panorama spans about 1,5 degrees horizontally. There are generally very little information about this group of nebulae.


Photo in visual colors
Click for a large image

Natural color composition from the emission of ionized elements, R=80%Hydrogen+20%Sulfur, G=100%Oxygen and B=85%Oxygen+15%Hydrogen to compensate otherwise missing H-beta emission. This composition is very close to a visual spectrum and it has a very red appearance due to domination of hydrogen emission, H-alpha.


The Sh2-232 in visual colors



Orientation in wide field mosaic of the Auriga

The are of interest is marked as a white rectangle. More info about this wide field photo can be found HERE


Technical details

Processing work flow

Image acquisition, MaxiDL v5.07.
Stacked and calibrated in CCDStack2.
Deconvolution with a CCDStack2 Positive Constraint, 33 iterations, added at 50% weight
Color combine in PS CS3
Levels and curves in PS CS3.

Imaging optics
Celestron Edge HD 1100 @ f7 with 0,7 focal reducer for Edge HD 1100 telescope

Cameras and filters
Imaging camera Apogee Alta U16 and Apogee seven slot filter wheel
Guider camera, Lodestar x2

Astrodon filter, 5nm H-alpha
Astrodon filter, 3nm O-III
Astrodon filter, 3nm S-II

Exposure times
H-alpha, 60 x 1200s = 20h
O-III, 6 x 1200s = 2h min.
S-II, 6x1200s = 2h min.
Total 24h

A single un cropped, calibrated and stretched 20 min. H-alpha frame as it comes from the camera




Another interesting feature of  Sh2-232
A ring like formation

I have animated to this starless version of Sh2-232 photo, what I'm seeing in lower part of the nebula. There is a ring like formation and I'm seeing some hints of the concentric structure too.


Sunday, March 22, 2015

Messier 13, the Great Globular Cluster in Hercules



The season is about to end up here 65N for about six months. We have had clear skies for a couple of weeks now and I have lots of new material to publish in near future.

Messier 13 is a kind of fast project shot between dimmer targets. My location is not ideal for a broadband targets, like galaxies and clusters, due to massive light pollution. How ever, this is my try with a M13.


Messier 13
Click for a much large image

LRGB photo of the Great Globular Cluster in Hercules. Note. galaxy NGC 6207 at a lower left corner. 


INFO

M13 locates in constellation Hercules at a distance of 25000 light years. The Great Globular Cluster in Hercules is one of the most brightest globular star clusters in northern sky. Stars are backed to a spherical formation with a diameter of about 150 light years.


Technical details

Processing work flow

Image acquisition, MaxiDL v5.07.
Stacked and calibrated in CCDStack2.
Deconvolution with a CCDStack2 Positive Constraint, 33 iterations, added at 50% weight
Color combine in PS CS3
Levels and curves in PS CS3.

Imaging optics
Celestron Edge HD 1100 @ f7 with 0,7 focal reducer for Edge HD 1100 telescope

Cameras and filters
Imaging camera Apogee Alta U16 and Apogee seven slot filter wheel
Guider camera, Lodestar x2

Custom Scientific LRGB 50mm Square Filters 

Exposure times
Luminance, 14 x 600s = 2h 20min
Red, 6 x 200s binned 2x2 = 20 min.
Green, 6 x 200s binned 2x2= 20 min.
Blue, 6 x 200s  binned 2x2 = 20 min
Total 3h 20min




Thursday, March 19, 2015

NGC 2174, the Monkey Head Nebula, project finalized



This photo shows more about this nebula, than I have used to see in any images taken with the same detail level. I haven't been aware of the curved dimmer areas at lower part of my photo.


NGC 2175
Click for a large image

Image is in mapped colors from an emission of  the ionized elements. Golden areas 
are from emission of sulfur and hydrogen, bluish hues are from ionized oxygen.


A closeup





Fancy a burger?

I had an urgent desire for a hamburger after seeing this detail...


NGC 2174 in visual colors

Natural color composition from the emission of ionized elements, R=80%Hydrogen+20%Sulfur, G=100%Oxygen and B=85%Oxygen+15%Hydrogen to compensate otherwise missing H-beta emission. This composition is very close to a visual spectrum.



INFO

NGC 2174, also known as a Monkey Head Nebula, locates at constellation Orion at distance of about 6400 light years. My photo shows about one square degrees of sky (The apparent size of the Moon is 0,5 degrees) The lower part of the photo shows a rarely imaged dimmer parts of the gas formation.


Image in H-alpha emission alone



Technical details

Processing work flow

Image acquisition, MaxiDL v5.07.
Stacked and calibrated in CCDStack2.
Deconvolution with a CCDStack2 Positive Constraint, 33 iterations, added at 50% weight
Color combine in PS CS3
Levels and curves in PS CS3.

Imaging optics
Celestron Edge HD 1100 @ f7 with 0,7 focal reducer for Edge HD 1100 telescope

Cameras and filters
Imaging camera Apogee Alta U16 and Apogee seven slot filter wheel
Guider camera, Lodestar x2

Astrodon filter, 5nm H-alpha
Astrodon filter, 3nm O-III
Astrodon filter, 3nm S-II

Exposure times
H-alpha, 16 x 1200s = 5h
O-III, 6 x 1200s = 2h min.
S-II, 6x1200s = 2h min.
Total 9h

A single un cropped, calibrated and stretched 20 min. H-alpha frame as it comes from the camera