Barnard's Galaxy NGC 6822

[sjastro]

Poor seeing conditions.

LRGB image 4 hr L, 1 hr R, 1 hr G, 1 hr B, ST-10XME.
Scope BRC-250.

http://users.westconnect.com.au/~sjastro/ngc6822nc.html

Clear skies

Steven

[rogerg (Roger)]

That's a tough one to image and make look good. Your results aren't bad considering. 4 hours L is a decent time.

[madbadgalaxyman (Robert)]

Thank you, Steven, for an interesting image of NGC 6822.

According to Sidney van den Bergh in his encyclopedic book "The Galaxies of the Local Group" (Cambridge University Press), N6822 is over two mags less luminous than the LMC. (measured in the V-band)

Yet it still looks complex and interesting, as we are very fortunate to be located in the same galaxy group.

NGC 6822 is a more typical dwarf irregular galaxy than the LMC, in that it is low surface brightness and its overall rate of star formation is very low.
Barnard's Galaxy is not particularly blue either, in the optical regime, with an optical color of B-V equals 0.79
(the LMC is much more blue, at B-V = 0.52)

Some impressive Large Telescope images of N6822 and other members of the Local Group can be found at the website of the Local Group Survey:

http://www.lowell.edu/users/massey/lgsurvey

One of the more interesting multi-wavelength observations of NGC 6822 concerns the relationship of the optical image to the vast and distended cloud of HI (neutral atomic hydrogen) in which the galaxy is embedded:

Here is an image which overlays DSS (optical) with the borders of this disk of cold atomic gas:



The gaseous part of N6822 is a completely different shape and size compared to the optical part! Also, the vast gaseous disk has only formed stars in its very central part......

cheers,
the bad galaxy man

[gregbradley]

Very good Steven.

Not too often imaged. 7 hours at F5 and an ST10 shows how dim this one is.

Greg.

[atalas]

Nice work Steven.

[Alchemy (Clive)]

Faint little beast to pull out, had a go at this a while back but can't say I was impressed with my results.

Re the seeing, I'm assuming you didn't do this monday or Tuesday as the seeing was pretty good at my place, particularly tuesday.

Didn't bother last night as when I got home at 10 pm there was some very thin haze around.

Its been nice to have some clear skies, they have been few and far between for a long time now. Imagers from south of the divide have not put up much work.

Always enjoy looking at your work Steven as you do like the different and diverse.

[sjastro]

Originally Posted by Alchemy

Faint little beast to pull out, had a go at this a while back but can't say I was impressed with my results.

Re the seeing, I'm assuming you didn't do this monday or Tuesday as the seeing was pretty good at my place, particularly tuesday.

Didn't bother last night as when I got home at 10 pm there was some very thin haze around.

Its been nice to have some clear skies, they have been few and far between for a long time now. Imagers from south of the divide have not put up much work.

Always enjoy looking at your work Steven as you do like the different and diverse.

Hello Clive. I took the L images on Tuesday. Seeing was average. The colour images were taken last night and I to deal with high level clouds.
I've boosted the red channel in the H-Alpha regions as a result to bring out the detail.

Originally Posted by atalas

Nice work Steven.

Thanks for the comment Louie.

Originally Posted by gregbradley

Very good Steven.

Not too often imaged. 7 hours at F5 and an ST10 shows how dim this one is.

Greg.

Hi Greg. Actually my original target was going to be SagDig which makes Barnard's Dwarf superluminous by comparison.

Originally Posted by madbadgalaxyman

Thank you, Steven, for an interesting image of NGC 6822.

According to Sidney van den Bergh in his encyclopedic book "The Galaxies of the Local Group" (Cambridge University Press), N6822 is over two mags less luminous than the LMC. (measured in the V-band)

Yet it still looks complex and interesting, as we are very fortunate to be located in the same galaxy group.

NGC 6822 is a more typical dwarf irregular galaxy than the LMC, in that it is low surface brightness and its overall rate of star formation is very low.
Barnard's Galaxy is not particularly blue either, in the optical regime, with an optical color of B-V equals 0.79
(the LMC is much more blue, at B-V = 0.52)

Some impressive Large Telescope images of N6822 and other members of the Local Group can be found at the website of the Local Group Survey:

http://www.lowell.edu/users/massey/lgsurvey

One of the more interesting multi-wavelength observations of NGC 6822 concerns the relationship of the optical image to the vast and distended cloud of HI (neutral atomic hydrogen) in which the galaxy is embedded:

Here is an image which overlays DSS (optical) with the borders of this disk of cold atomic gas:

Attachment 99582

The gaseous part of N6822 is a completely different shape and size compared to the optical part! Also, the vast gaseous disk has only formed stars in its very central part......

cheers,
the bad galaxy man

It's good to provide a technical description along with an image. I should perhaps do more of that. Thanks for providing the detail Robert.

Originally Posted by rogerg

That's a tough one to image and make look good. Your results aren't bad considering. 4 hours L is a decent time.

Thanks Roger.

[Stevec35 (Steve)]

I think that's a pretty good effort Steven. I don't know if you considered blending in some Ha. That might really make the nebulosity pop out.

Cheers

Steve

[jase (Jason)]

Marvellous Steven. This is a tough target at the best of times. May have to give something similar a go myself. I think to appreciate this work that you have portrayed, one must appreciate your imaging style. From recollection, you prefer to keep processing to a minimum to present an object in its natural form. This target is no exception. Thoroughly enjoyed it. I hope to see more of your work.

[sjastro]

Originally Posted by jase

Marvellous Steven. This is a tough target at the best of times. May have to give something similar a go myself. I think to appreciate this work that you have portrayed, one must appreciate your imaging style. From recollection, you prefer to keep processing to a minimum to present an object in its natural form. This target is no exception. Thoroughly enjoyed it. I hope to see more of your work.

Thanks Jase. Going against the minimum processing attitude, I did a form of "pseudo Ha imaging via processing" to bring out detail in the nebulae.

Originally Posted by Stevec35

I think that's a pretty good effort Steven. I don't know if you considered blending in some Ha. That might really make the nebulosity pop out.

Cheers

Steve

Unfortunately Steve I don't have the facility for Ha imaging. Guiding through the ST-10XME makes the acquisition of guide stars with a Ha filter near impossible.

[strongmanmike (Michael)]

Yeh nice result Steve

Mike

[sjastro]

Originally Posted by strongmanmike

Yeh nice result Steve

Mike

Thanks Mike.

Regards

Steven

[Star Catcher (Ted Dobosz)]

Yep, I think this came up well Steven.

[Ross G]

A great capture Steven.

Thanks.

Ross.

[sjastro]

Thanks Star Catcher and Ross.

Clear skies

Steven

[multiweb (Marc)]

Great shot. Very detailled.

[sjastro]

Thanks Marc.

Regards

Steven

[seeker372011 (Narayan)]

Didn't realize this could turn out to be so interesting through a backyard scope..always enjoyblooking at your work which has so often been a source of inspiration for potential targets

[bartman (Bart)]

Hi Steven,
Great pic!
I just have to ask ...for my own curiosity, what are the the very small black lines ? And what is the large-ish white line to the right of the galaxy?
Thanks
Bartman

[sjastro]

Originally Posted by bartman

Hi Steven,
Great pic!
I just have to ask ...for my own curiosity, what are the the very small black lines ? And what is the large-ish white line to the right of the galaxy?
Thanks
Bartman

Hi Bart,

The black lines are a result of dead or cold pixels.The stacking procedure of each individual image was summed rather than averaged or median combined which means that any pixel defect will end up in the stacked image. Since the images are registered using stars whose positions vary on the chip, the fixed pixel defects are not registered and will "line up" in the combined image.

The bright line is a meteor streak.

Originally Posted by seeker372011

Didn't realize this could turn out to be so interesting through a backyard scope..always enjoyblooking at your work which has so often been a source of inspiration for potential targets

Thanks for your comments Narayan.

Clear skies

Steven