Starship Asterisk*

Orange Moon rising over Osborne Park industrial area, Western Australia, 4-July-2012

This image was taken on June 16,2012 from Anthem, AZ. Seeing conditions were 4/5. Imaged with Astro-Physics 152mm full aperture telescope with Daystar Quantum PE .5 Angstrom H-Alpha filter and Flea3 ccd video camera.

Uploaded with ImageShack.us

Mosaic composed of 42 images, taken with SCT8".

Full size: http://img403.imageshack.us/img403/3826 ... s72ppp.jpg

LBN 468, a reticular of dust
Copyright: Lorenzo Comolli

Data and description: http://www.astrosurf.com/comolli/d116.htm

The Sun 04-07-2012 AR1515
Panoramas from 12 pictures with 30%-40% overlap. Pseudocolor.
Telescope Coronado SolarMax II 90, camera Lumenera Lu070, barlow lens 5x.
Link to full picture: http://imglink.ru/pictures/05-07-12/46b ... d66981.jpg
Copyright: Andriy Avramenko, Ternopil, Ukraine

A Full Moon Rises
Copyright: Nino Schisano


my album on FLICKR: http://www.flickr.com/photos/nino_90/

Above the sea, through the mist...
Copyright: Nino Schisano

A black dot on the rising Sun
http://www.flickr.com/photos/nino_90/wi ... 7344590286
Copyright: Nino Schisano

Messier 94
http://www.emilivanov.com/CCD%20Images/M94_LRGB.htm
Copyright: Emil Ivanov bigger size can be found here

NGC4565: Needle Galaxy in Coma Berenice
http://www.astronomie-hoefferhof.de/de/galerie/175.html
Copyright: Richard Müller
[attachment=2]NGC4565_THELI_m.jpg[/attachment]

ISS Solar Transit
http://dl.dropbox.com/u/4852049/ISSSolarTransit.jpg
Copyright: Jim Chung
[attachment=1]ISSSolarTransit_Chung.jpg[/attachment]

IC 2944, HII Region in Centaurus
http://ryanhannahoe.nmskies.com/?p=546
http://www.robgendlerastropics.com/IC2944-Wide.html
Copyright: Ryan M. Hannahoe, data; Robert Gendler, processing Aurora over Halley 6, The Brunt Ice Shelf, Antarctica
Copyright: Sam Burrell
[attachment=0]HalleyAurora_Burrell.jpg[/attachment]

Sunset sun with sunspots and with Kelvin-Helmholtz instability clouds
URL of website, if any
Copyright:Mila Zinkova Mulch-colored sun with sunspots
URL of website, if any
Copyright:Mila Zinkova Sunset sun with sunspots and cormorants
URL of website, if any
Copyright:Mila Zinkova Sunset sun with sunspot mirage
URL of website, if any
Copyright:Mila Zinkova

https://www.facebook.com/photo.php?fbid ... =1&theater

Here is a photo I submitted to the Milky Way Scientists' Facebook page. It is a photo of the 2012 Solar Eclipse. Taken in Ennis, Texas, around 8:50pm.

M17

Copyright: Martin Matias Menrath
http://www.astronommmia.blogspot.com.ar/

http://upload.pbase.com/image/144578622

Galaxy NGC3521 18 hours 15 minutes. Taken from my home observatory in NSW Australia over several months and during some good seeing.

The extended star halo of this distorted galaxy is shown clearly as well as more of the spiral rings in the outer parts of the galaxy.

Equipment was a Planewave CDK17 telescope, FLI Proline 16803 camera, Paramount ME mount, SBIG STi guider and Lodestar guider.

Greg Bradley.

Mintaka, Alnilam, Alnitak (Orion)
http://www.flickr.com/photos/vegastarca ... hotostream
Copyright : VegaStar Carpentier

Okay, I have retired from commenting on this page, but VegaStar, I can't resist commenting on your lovely Orion's Belt image! How beautiful it is!!!

And while I'm at it: thank you, thank you, thank you, all of you brilliant astrophtographers who post wonderful images here.

Thank you so very much!

Ann

You may have retired Ann, but can I ask you to comment on one photo? (And the photographer too can comment, of course.) It's the third one up from this post, Galaxy NGC 3521 by Greg Bradley. On the provided link it says the image is in LRGB.

I have in my desktop collection the image below by Robert Pölzl, from the recent submissions thread of April 5th this year, which is also described as being in LRGB, but as you can see it presents a completely different colour of the galaxy. Any thoughts on these differences?

Rob

rstevenson wrote:You may have retired Ann, but can I ask you to comment on one photo? (And the photographer too can comment, of course.) It's the third one up from this post, Galaxy NGC 3521 by Greg Bradley. On the provided link it says the image is in LRGB.

I have in my desktop collection the image below by Robert Pölzl, from the recent submissions thread of April 5th this year, which is also described as being in LRGB, but as you can see it presents a completely different colour of the galaxy. Any thoughts on these differences?

Rob

NGC3521-LRGB-sm.jpg

Well, Rob, both images are handsome and beautiful. My impression is that Robert Pölzl's image provides a little more detail than Greg Parker's.

However, when it comes to color I think that Greg Bradley's image is a bit "truer".

The B-V index of NGC 3521 is +0.81. That is moderately, though not very, red. It is red enough that we should suspect that this galaxy definitely has a yellow bulge. In Greg Bradley's image the bulge (or inner disk) of NGC 3521 is golden-yellow, almost slightly reddish. In Robert Pölzl's image the bulge is faintly purplish.

A very interesting aspect of NGC 3521 is its diffuse and amorphous but "thick" stellar halo. In my opinion, we should expect a halo population with that kind of "texture" to be yellowish. If it was intrinsically blue, it ought to be slightly clumpy from the presence of clusters.

A stellar halo made mostly of old metal-poor stars will likely be white in color, similar to the integrated color of globulars. But in my opinion, the "thickness" of this halo, which makes it resemble "puffs of smoke", suggests to me that it might not be that old.

It is a known fact that metallicity generally increases as you move closer to the center of a large or moderately large galaxy. If the "thick and smoke-like" halo is comprised at least partly of old metal-rich stars that have been "stirred up" from the bulge, then the color of this halo ought to be yellowish. If I were to guess, Id' say that the color of the "thick" halo of NGC 3521 is likely yellowish. And it looks yellow in Greg Bradley's picture.

However, the very reddish color of the inner bulge of NGC 3521 looks slightly unlikely to me. On the other hand, the inner disk of NGC 3521 definitely contains a good number of emission nebulae, and it is possible that the color balance of the picture has been "weighted" towards the red in order to bring out as many emission nebulae as possible.

In Greg Bradley's image, the bright foreground star differs very markedly in color from the overall color of the galaxy. In Robert Pölzl's image, the color of the star and the color of the galaxy are rather similar. However, it is true that the star is much bluer than the galaxy. The spectral class of the star is F0(V), and its B-V index is +0.42. That is a very normal color for an F-type star. The galaxy, on the other hand, has a B-V index of +0.81. The galaxy is therefore much redder than the star, and it is to Greg Bradley's credit that he brings out this color difference.

However, the colors of galaxies are subtle. A color index of +0.81 is only very slightly yellower than Capella, whose color index is +0.79. You may want to check out this image of Capella, which in my opinion does a very good job of showing the true color of Capella. The integrated color of NGC 3521 ought to be similar.

Clearly the bulge (or inner disk) in Greg Bradley's image is much redder than this. On the other hand: the bulge of NGC 3521 is likely to be redder in color than the color which corresponds to a B-V index of +0.81. The outer disk of NGC 3521 is clearly bluer in the color than the hue which corresponds to a B-V index of +0.81, so in order to arrive at an integrated B-V index of +0.81, the inner disk has to be redder than +0.81 in order to "compensate" for the blue color of the outer disk. For all of that, I don't think that the bulge (or inner disk) is "truly" as red as it looks in Greg Bradley's image, even if we take into account the fact that there are many red emission nebulae in the inner disk of NGC 3521.

Arriving at "true color" is incredibly hard. I thank both Greg Bradley and Robert Pölzl for the fine job they have done portraying galaxy NGC 3521 in RGB!

Ann

Elliptical Venus Corona in the Hyades
http://www.astroarn.com
Copyright: Robert Arn
[attachment=3]Elliptic Corona in Taurus.jpg[/attachment]

Deep View of Messier 101
http://www.starpointing.com/ccd/m101.html
Copyright: Fabian Neyer Green Flash from Paris
https://www.facebook.com/media/set/?set ... d0c83ee692
Copyright: Bertrand Kulik
[attachment=2]r1.jpg[/attachment]

Morning Lineup: Pleiades, Jupiter, Venus and Aldebaran
Copyright: Yuri Beletsky
[attachment=1]venus_nolabels.jpg[/attachment]

NGC 3242: Planetary Nebula in Hydra
http://skycenter.arizona.edu/gallery/nebulae/ngc3242
Copyright: Adam Block/Mount Lemmon SkyCenter/University of Arizona Rho Ophiuchus Nebula
Copyright: Louie Atalasidis
[attachment=0]Rho-Ophiuchus-Region.jpg[/attachment]

Ann wrote:Arriving at "true color" is incredibly hard. I thank both Greg Parker and Robert Pölzl for the fine job they have done portraying galaxy NGC 3521 in RGB!

And thank you Ann for such a complete explanation.

I confess to retaining some confusion about how such dissimilar results could come from the same base image type (by which I mean LRGB.) I can well understand using different filters and achieving remarkably different results, for various purposes. But when you start with the same filter set, the resulting processing must be quite different to result in such dramatically different overall colour for the galaxy. Or perhaps another way to express the same confusion, if you point a spectrometer at each of these images (not at the galaxy itself), would you still get a B-V index of +0.81 out of both images?

I should add, I think both images are extraordinary and I too thank both photographers for submitting them.

Rob

Full Moon 04July 2012, Corfu, Greece

It gives you the feeling that the boat in the foreground looks something like a victory of human activity towards nature.
The Castle on the hill, it seems as if the efforts made ​​by man during its history.
Last the moon barely seen, As the presence of nature in our daily lives, which although crawling between existence and nonexistence, stood up erect and directly puts us one fundamental question., and directly puts us one fundamental question...
Man, how sure are you??

Canon eos 40D
ef 100-400 is usm
@400mm
f5.6
iso800
1sec


in High guality: http://www.astrovox.gr/forum/album_pic.php?pic_id=15138
Alternative: http://www.astrovox.gr/forum/album_pic. ... ser_id=685

M8 Lagoon Nebula
Copyright: Delio Tolivia Cadrecha Tagged M33
Copyright: Delio Tolivia Cadrecha & Kike Diez Alonso
Tags from: http://astronomy-mall.com/Adventures.In ... ouds.html)

IC 1805: Heart Nebula in Cassiopeia
http://www.robgendlerastropics.com/IC1805-RH-RG.html
http://ryanhannahoe.nmskies.com/?p=511
Copyright: Ryan Hannahoe, data; Robert Gendler, processing
[attachment=0]IC1805_Hannahoe_Gendler.jpg[/attachment]

M5: Globular Cluster in Serpens Caput
http://kerschhuber.astronomie.at//galer ... 05_a2.html
Copyright: Günter Kerschhuber
[attachment=2]20120517-M5-Ksth.jpg[/attachment]

Chameleon Cloud Complex
Copyright: Harel Boren
[attachment=1]Chameleon Cloud Complex 1500x1131 pixels.jpg[/attachment]