New Image: NGC 5985 and the "Draco Trio"

[jthommes]

This grouping of galaxies is sometimes called the Draco Trio - from left to right is NGC 5985 , NGC 5982, NGC5981. Their distances (by redshift) are 118, 140, 118 million light years. The little galaxy above NGC 5982 is at a distance of 959 million light years.

This somewhat larger image field also captures NGC 5976 and UGC 9934 (also known as NGC 5976A) to the right side of the image. There are noticeable background galaxies seen on the full size image. There are multiple Quasars in this image (as seen on the annotated image) - the furthest of which has a redshift of 3.987 (light travel time or Lookback of 12.15 billion years).

The Pan and Zoom images can be accessed below but they can also be accessed from the main image webpage as well - or seen on astrobin (links below). The full resolution image has an image scale of about 0.58 arcsec/pixel.

• 
  NGC 5985 and Draco Trio

Full FOV image (Pan and Zoom):
NGC 5985 and Draco Trio (Full Size)

Annotated Image (Pan and Zoom):
NGC 5985 and Draco Trio Annotated

Images also available on astrobin -NGC 5985 and Draco Trio

Scope: Celestron 9.25 Edge HD 235 mm at f/7
Camera: ASI294MM (Baader LRGB Filters)
Location: DAA Observatory, Shelter Valley, CA

[StarHugger]

Another super nice image Jim, several Galaxies visible as well the Quasars!

Busy image...

Thanks Indeed!

[Bigzmey]

Looks great!

[AstroBee]

Very impressive, Jim! TSS APOD worthy.

[JayTee]

One of my favorite galaxy groups and they look awesome. Thanks for sharing.

[Juno16]

Fabulous image Jim!

Great detail in the galaxies and the background is a wonderful place to invest some time!

Lovely processing for this beautiful image!

[messier 111]

superb work , thx .

[Mac]

Wonderful capture Jim.

[Gordon]

Congratulations Jim on having your image selected as our TSS APOD!

app.php/article/1-29-2024-tss-astrophot ... of-the-day

[AstroBee]

Congrats on the TSS APOD, Jim!

[starfield]

Hey Jim,

Congrats on the APOD. Great image.

[jthommes]

Thanks for the comments folks! The APOD and congrats are much appreciated.

[jthommes]

Another super nice image Jim, several Galaxies visible as well the Quasars!

Busy image...

Thanks Indeed!

Thanks! I appreciate the comment.

I'll take this opportunity to make an observation. The quasars were somewhat interesting to me in this particular image. Here is what I have seen and my interpretation...
Our image sensors mostly do the visible spectrum (~ 380-750 nm wavelength). In this image, there is a quasar (upper left corner) with a Redshift of 3.987. Visible spectrum light originating from that quasar at, say, a blue 380 nm would come to us at (Z+1)*380 = 1895 nm - way into infra-red - our sensors don't see that far infra-red. So what do we see and why is it blue?

For us to "see" say 400 nm with our sensors and given the Redshift, it leaves the Quasar at 400/(z+1) = 80.2 nm - way into ultra-violet. Hydrogen emission has several different series depending on what the is energy transition level of the energized electron. The Balmer series is what we are all familiar with in our Ha images - Balmer series emissions are in the visible spectrum. But the Lyman series starts at 121 nm and goes down from there. Hydrogen is the most abundant element in the universe, therefore there is a lot of hydrogen emission radiation compared to other elements. Lyman-alpha emission line is 121 nm, but the series goes 121/103/97/95/94 nm (alpha, beta, gamma...). Lyman-alpha would come to us with that Redshift as as 603 nm (kinda orange) but the other emission lines are lower. If the weighted average was somewhere in the 96 nm average, it comes to us as 478 nm - well into cyan and blue.

Lower Redshifts would still be in the blue - catching Lyman-alpha as blue. At lower yet Redshifts, our sensors would capture the Balmer series as blue. In this image, most of the quasars are blue to white. However, in the upper center edge is a quasar (WISEA J153743.98+593607.9) that appears orange/red. - its Redshift is a measly 0.2. Most of the Balmer series would appear as orange red at that Redshift (0.2).

Sorry for the long winded observation, but I think that this is the first time I have seen a "red" quasar in one of my images.

[Thefatkitty]

That is just so good Jim, so much to see there! Thanks for the share and well-deserved APOD

All the best,

[StarHugger]

Another super nice image Jim, several Galaxies visible as well the Quasars!

Busy image...

Thanks Indeed!

Thanks! I appreciate the comment.

I'll take this opportunity to make an observation. The quasars were somewhat interesting to me in this particular image. Here is what I have seen and my interpretation...
Our image sensors mostly do the visible spectrum (~ 380-750 nm wavelength). In this image, there is a quasar (upper left corner) with a Redshift of 3.987. Visible spectrum light originating from that quasar at, say, a blue 380 nm would come to us at (Z+1)*380 = 1895 nm - way into infra-red - our sensors don't see that far infra-red. So what do we see and why is it blue?

For us to "see" say 400 nm with our sensors and given the Redshift, it leaves the Quasar at 400/(z+1) = 80.2 nm - way into ultra-violet. Hydrogen emission has several different series depending on what the is energy transition level of the energized electron. The Balmer series is what we are all familiar with in our Ha images - Balmer series emissions are in the visible spectrum. But the Lyman series starts at 121 nm and goes down from there. Hydrogen is the most abundant element in the universe, therefore there is a lot of hydrogen emission radiation compared to other elements. Lyman-alpha emission line is 121 nm, but the series goes 121/103/97/95/94 nm (alpha, beta, gamma...). Lyman-alpha would come to us with that Redshift as as 603 nm (kinda orange) but the other emission lines are lower. If the weighted average was somewhere in the 96 nm average, it comes to us as 478 nm - well into cyan and blue.

Lower Redshifts would still be in the blue - catching Lyman-alpha as blue. At lower yet Redshifts, our sensors would capture the Balmer series as blue. In this image, most of the quasars are blue to white. However, in the upper center edge is a quasar (WISEA J153743.98+593607.9) that appears orange/red. - its Redshift is a measly 0.2. Most of the Balmer series would appear as orange red at that Redshift (0.2).

Sorry for the long winded observation, but I think that this is the first time I have seen a "red" quasar in one of my images.

Interesting Jim,

No problem with the wind...Here

I know from building my Calcium H Solar filter you need a Ir Block verses an Ir Uv Cut to properly envelope the bandpass of 393 and 396, A Ir Uv Cut wont be useable below 400 as its cut off is there abouts, And it also blocks Uv so another issue...

An Ir Block takes you down to 350nm and modern cmos cameras start upward at about the same frequency...

I think its awesome though that your observing and imaging simotainiously, I dont know exactly what your imaging set up is but from listening to you so far you are in pretty deep.

Active Galactic Nuclei are a favorite and your doing a fantastic job with luring me in indeed.

[jthommes]

That is just so good Jim, so much to see there! Thanks for the share and well-deserved APOD

All the best,

Thanks for the kind word Mark! They are much appreciated.

[jthommes]

.....

Interesting Jim,

No problem with the wind...Here

I know from building my Calcium H Solar filter you need a Ir Block verses an Ir Uv Cut to properly envelope the bandpass of 393 and 396, A Ir Uv Cut wont be useable below 400 as its cut off is there abouts, And it also blocks Uv so another issue...

An Ir Block takes you down to 350nm and modern cmos cameras start upward at about the same frequency...

I think its awesome though that your observing and imaging simotainiously, I dont know exactly what your imaging set up is but from listening to you so far you are in pretty deep.

Active Galactic Nuclei are a favorite and your doing a fantastic job with luring me in indeed.

.
Thanks for the added info.

Yeah, your filter experience with another element (Calcium) is interesting. Of course all elements have spectral lines. The sun is mostly hydrogen and helium but the solar light intensity is so high that the calcium comes through strongly. Also, as you go up the periodic table from hydrogen, there are more electrons (not to mention atomic or molecular states) with different energy transitions and resulting wavelengths - the complexity of emission line identification grows. To assume that an astronomic light source consists of mostly hydrogen emission also sounds like a big leap. Clearly, my observation is pretty simplistic.

Isn't this Hobby fun!

[StarHugger]

.....

Interesting Jim,

No problem with the wind...Here

I know from building my Calcium H Solar filter you need a Ir Block verses an Ir Uv Cut to properly envelope the bandpass of 393 and 396, A Ir Uv Cut wont be useable below 400 as its cut off is there abouts, And it also blocks Uv so another issue...

An Ir Block takes you down to 350nm and modern cmos cameras start upward at about the same frequency...

I think its awesome though that your observing and imaging simotainiously, I dont know exactly what your imaging set up is but from listening to you so far you are in pretty deep.

Active Galactic Nuclei are a favorite and your doing a fantastic job with luring me in indeed.

.
Thanks for the added info.

Yeah, your filter experience with another element (Calcium) is interesting. Of course all elements have spectral lines. The sun is mostly hydrogen and helium but the solar light intensity is so high that the calcium comes through strongly. Also, as you go up the periodic table from hydrogen, there are more electrons (not to mention atomic or molecular states) with different energy transitions and resulting wavelengths - the complexity of emission line identification grows. To assume that an astronomic light source consists of mostly hydrogen emission also sounds like a big leap. Clearly, my observation is pretty simplistic.

Isn't this Hobby fun!

Indeed it is,

The interaction with those who image the skies at night and in colour remains a constant source of interest and information as I image Sol in colour wich of course is atypical with little information available...

I even design my filters specifically for use with colour cameras in mind and tune the input colours to match the filters colour characteristics.

It was actually my years of planetary observations with my dobs stacking mars and jupiter filter sets for better views that led me to apapting that ethic to creating my solar filters...

My disability initially led me to small scope solar and it seems I have been dragging my nite astro experience along behind me the whole way

And thank you too for all the detailed spectral information, you have retained likely more than I have yet to discover.

always learning...

[MariusD69]

Amazing image! Great work, Jim! Congrats for APOD!

[Greenman]

Wow, way to go Jim - a worthy APOD!