APOD: The Coma Cluster of Galaxies (2010 May 02)

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Expand view Topic review: APOD: The Coma Cluster of Galaxies (2010 May 02)

Re: APOD: The Coma Cluster of Galaxies (2010 May 02)

by DavidLeodis » Tue May 04, 2010 9:46 am

Thanks Dean. Your response is appreciated. :)

APOD images are regularly croppped, which can cause some confusion when reading the information about images that is brought up through links in explanations.

Re: APOD: The Coma Cluster of Galaxies (2010 May 02)

by Dean Rowe » Tue May 04, 2010 2:35 am

bystander wrote:
DavidLeodis wrote:I am confused (easily done I admit :) ) as to what is the size of the image used as the APOD. Does the "this shot" refer to the APOD or the larger FOV image from which the APOD is clearly derived or even the star chart? :? I would be grateful for any help. Thanks.
I probably shouldn't answer for Dean, but I'm fairly certain when he refers to "this shot" he is speaking of his original image, referred to in the APOD link pictured above (the larger FOV).
Yep - I didn't realize they cropped it on the APOD page until just now (the large version when you click the image is uncropped http://apod.nasa.gov/apod/image/1005/co ... we_big.jpg )
BTW: Welcome to The Asterisk*, Dean, and congratulations on your APOD. Great Pictures!
Thanks :D

Re: APOD: The Coma Cluster of Galaxies (2010 May 02)

by DavidLeodis » Mon May 03, 2010 7:34 pm

bystander wrote:
DavidLeodis wrote:I am confused (easily done I admit :) ) as to what is the size of the image used as the APOD. Does the "this shot" refer to the APOD or the larger FOV image from which the APOD is clearly derived or even the star chart? :? I would be grateful for any help. Thanks.
I probably shouldn't answer for Dean, but I'm fairly certain when he refers to "this shot" he is speaking of his original image, referred to in the APOD link pictured above (the larger FOV).

BTW: Welcome to The Asterisk*, Dean, and congratulations on your APOD. Great Pictures!
Thanks bystander. From that and by measuring the area covered by the APOD in the full FOV image I calculate that the APOD image covers approximately 48'x39' or about 1.4x1.1 full moons (give or take a bit and hoping not too much!). :)

Re: APOD: The Coma Cluster of Galaxies (2010 May 02)

by bystander » Mon May 03, 2010 5:16 pm

DavidLeodis wrote:I am confused (easily done I admit :) ) as to what is the size of the image used as the APOD. Does the "this shot" refer to the APOD or the larger FOV image from which the APOD is clearly derived or even the star chart? :? I would be grateful for any help. Thanks.
I probably shouldn't answer for Dean, but I'm fairly certain when he refers to "this shot" he is speaking of his original image, referred to in the APOD link pictured above (the larger FOV).

BTW: Welcome to The Asterisk*, Dean, and congratulations on your APOD. Great Pictures!

Re: APOD: The Coma Cluster of Galaxies (2010 May 02)

by DavidLeodis » Mon May 03, 2010 4:37 pm

Dean Rowe wrote:
alter-ego wrote:Pretty nice batch of galaxies. In the Coma cluster, I once counted at least 30 galaxies in the FOV of a 6" Newtonian. It was likely this same area. The field of view is ~35', just a little more than a full moon. Here is the star chart for the uncropped picture: http://www.jburnell.com/AGC1656CoreMap.jpg
The FOV of this shot is around 100'x70' or about 3x2 full moons.
I am confused (easily done I admit :) ) as to what is the size of the image used as the APOD. Does the "this shot" refer to the APOD or the larger FOV image from which the APOD is clearly derived or even the star chart? :? I would be grateful for any help. Thanks.

Re: APOD: The Coma Cluster of Galaxies (2010 May 02)

by supamario » Mon May 03, 2010 1:29 pm

Thanks Dean for the superimposed image and the likely explanation.
Cheers.
Mario

Re: APOD: The Coma Cluster of Galaxies (2010 May 02)

by DavidLeodis » Mon May 03, 2010 10:28 am

Almost every object in the photograph is a galaxy! I get mentally lost trying to envisage the sheer unimaginable (well at least to me) vastness of 'Space'. It's an amazing Universe out there and probably also whatever is beyond the Universe that we know of. It's time that Warp Drive was here to give me a chance to boldly go and seek out! :)

Re: APOD: The Coma Cluster of Galaxies (2010 May 02)

by alter-ego » Sun May 02, 2010 5:09 pm

Dean Rowe wrote:
alter-ego wrote:Pretty nice batch of galaxies. In the Coma cluster, I once counted at least 30 galaxies in the FOV of a 6" Newtonian. It was likely this same area. The field of view is ~35', just a little more than a full moon. Here is the star chart for the uncropped picture: http://www.jburnell.com/AGC1656CoreMap.jpg
The FOV of this shot is around 100'x70' or about 3x2 full moons.
You are correct about the original picture. My size estimate referred to the displayed APOD picture which is cropped to a smaller size from the original, whereas the star chart shows the original picture (as I stated). Often cropped / reoriented pictures are presented for aesthetics, focus on detail, aspect ratios, etc.

No matter how careful one is trying to be clear, there is always confusion.

Re: APOD: The Coma Cluster of Galaxies (2010 May 02)

by Dean Rowe » Sun May 02, 2010 3:31 pm

alter-ego wrote:Pretty nice batch of galaxies. In the Coma cluster, I once counted at least 30 galaxies in the FOV of a 6" Newtonian. It was likely this same area. The field of view is ~35', just a little more than a full moon. Here is the star chart for the uncropped picture: http://www.jburnell.com/AGC1656CoreMap.jpg
The FOV of this shot is around 100'x70' or about 3x2 full moons.

Re: APOD: The Coma Cluster of Galaxies (2010 May 02)

by Dean Rowe » Sun May 02, 2010 3:29 pm

supamario wrote:Excellent photo of an amazing region.
One object that particularly sticks out for me, is the "gray blob" at the very bottom, right of centre, in the APOD crop. It is a bit more pronounced in the full size image.
It is just as large as almost any other object in the image, but why is it so featureless and faint?
I think that's just and artifact, maybe a reflection from one of the stars or something? It doesn't show up in NED or some other images I looked at. I did find something similar on a DSS image, but in a different location - here's the DSS image superimposed on a crop of my shot.

Image

Re: APOD: The Coma Cluster of Galaxies (2010 May 02)

by Chris Peterson » Sun May 02, 2010 3:12 pm

rstevenson wrote:
gingerd wrote:Why "coma"or is that just the US spelling of comma? If it is comma then why, does it look like one?
Coma, not commma. This cluster is located in the constellation Coma Berenices. Perhaps that's why it is named as it is. Nothing to do with commas.
Hopefully this won't start a hairy debate!

Re: APOD: The Coma Cluster of Galaxies (2010 May 02)

by rstevenson » Sun May 02, 2010 2:37 pm

gingerd wrote:Why "coma"or is that just the US spelling of comma? If it is comma then why, does it look like one?
Coma, not commma. This cluster is located in the constellation Coma Berenices. Perhaps that's why it is named as it is. Nothing to do with commas.

Rob

Re: APOD: The Coma Cluster of Galaxies (2010 May 02)

by supamario » Sun May 02, 2010 2:15 pm

Orin, thanks for the link with the deeper exposure.. unfortunately, it just cuts off the object in question! :)

Re: APOD: The Coma Cluster of Galaxies (2010 May 02)

by orin stepanek » Sun May 02, 2010 12:47 pm

From an earlier discussion: http://asterisk.apod.com/vie ... f=9&t=1079

Re: APOD: The Coma Cluster of Galaxies (2010 May 02)

by gingerd » Sun May 02, 2010 11:58 am

Why "coma"or is that just the US spelling of comma? If it is comma then why, does it look like one?

Re: APOD: The Coma Cluster of Galaxies (2010 May 02)

by supamario » Sun May 02, 2010 9:52 am

owlice wrote:
supamario wrote:why is it so featureless and faint?
My guess would be because of distance (but this is just a guess).
My guess is, if it is at the same distance as the rest of the background galaxies, then it probably has a relatively lower star density (less mass) and therefore not as bright.
Otherwise, if it is distance related, then it would be a monster size galaxy if its apparent size still shows up as featureless.

Re: APOD: The Coma Cluster of Galaxies (2010 May 02)

by owlice » Sun May 02, 2010 8:55 am

alter-ego, nice chart; thank you for sharing it.

supamario,
why is it so featureless and faint?
My guess would be because of distance (but this is just a guess).

Re: APOD: The Coma Cluster of Galaxies (2010 May 02)

by supamario » Sun May 02, 2010 6:26 am

Excellent photo of an amazing region.
One object that particularly sticks out for me, is the "gray blob" at the very bottom, right of centre, in the APOD crop. It is a bit more pronounced in the full size image.
It is just as large as almost any other object in the image, but why is it so featureless and faint?

Re: APOD: The Coma Cluster of Galaxies (2010 May 02)

by alter-ego » Sun May 02, 2010 4:35 am

Pretty nice batch of galaxies. In the Coma cluster, I once counted at least 30 galaxies in the FOV of a 6" Newtonian. It was likely this same area. The field of view is ~35', just a little more than a full moon. Here is the star chart for the uncropped picture: http://www.jburnell.com/AGC1656CoreMap.jpg

Re: APOD: The Coma Cluster of Galaxies (2010 May 02)

by Astronut » Sun May 02, 2010 4:12 am

HHMMMMmmmm, what a strange part of space. All coma's. What do you think it's trying to tell us using only puncuation and no words?

APOD: The Coma Cluster of Galaxies (2010 May 02)

by APOD Robot » Sun May 02, 2010 3:52 am

Image The Coma Cluster of Galaxies

Explanation: Almost every object in the above photograph is a galaxy. The Coma Cluster of Galaxies pictured above is one of the densest clusters known - it contains thousands of galaxies. Each of these galaxies houses billions of stars - just as our own Milky Way Galaxy does. Although nearby when compared to most other clusters, light from the Coma Cluster still takes hundreds of millions of years to reach us. In fact, the Coma Cluster is so big it takes light millions of years just to go from one side to the other! Most galaxies in Coma and other clusters are ellipticals, while most galaxies outside of clusters are spirals. The nature of Coma's X-ray emission is still being investigated.

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