Draco Dwarf. An incredible invisible galaxy.

[Datalord]

Shot over two nights with just 33*600s bin2 in RGB on my RC12. Pardon the heavy processing, but this is a shy galaxy to tease out.

The Draco Dwarf was not discovered until 1954 from photographic plates, despite being very close to us at 260,000 light years. It is an ancient, small galaxy, virtually dust-less and with primarily red stars formed over 10 billion light years ago. As you can see, there is nothing discernible structure or way to make it out if you don't know it is there. The Andromeda galaxy is estimated to be 100,000 times more luminous.

All of these properties has made it a target for lots of studies, because it seems to be the heaviest known object in the universe in terms of dark matter. And it's on our doorstep.

Interesting thing. The universe never fails to surprise.

[Knight of Clear Skies]

Nice capture, I always like to see objects of interest as well as the most photogenic objects. I had a feeble go at capturing it a while ago with a 200mm lens, thinking at the short focal length I might get a slightly nebulous appearance, but all I got was a small and faint star cluster. There is also a Quasar at 8 billion ly distance around there, not sure if it's in your field of view.

If you're interested I put a few links about the Draco Dwarf and its discovery in this thread, including the original discovery plate. You've captured the RR Lyrae variable stars that were used to identify it as a separate galaxy.

Edited May 6, 2020 by Knight of Clear Skies

[wimvb]

Great catch. These dwarfs are really difficult, I tried the Ursa Major dwarf a while ago. You've done very well.

[Datalord]

1 hour ago, wimvb said:

Great catch. These dwarfs are really difficult, I tried the Ursa Major dwarf a while ago. You've done very well.

Thanks! Just to add to the fun, it was done at 90% moon with high clouds. Because why make it easy? 😅

[dannybgoode]

Apologies if I am being thick but is the galaxy the small smudge at around 8 o’clock in the centre-ish?

If so that’s extremely impressive. If not then it really is invisible to me!!

[Knight of Clear Skies]

12 minutes ago, dannybgoode said:

Apologies if I am being thick but is the galaxy the small smudge at around 8 o’clock in the centre-ish?

It's not obvious, that's a background galaxy. The Draco Dwarf itself has the appearance of a star cluster in centre frame, it's close enough to resolve the brighter individual stars. It has a large angular size, being about Moon sized, but the total luminosity of all its stars is less than that of some of the brightest stars in the Milky Way.

[dannybgoode]

13 minutes ago, Knight of Clear Skies said:

It's not obvious, that's a background galaxy. The Draco Dwarf itself has the appearance of a star cluster in centre frame, it's close enough to resolve the brighter individual stars. It has a large angular size, being about Moon sized, but the total luminosity of all its stars is less than that of some of the brightest stars in the Milky Way.

Thank you - that was what I was also looking at as I saw the obvious cluster.  Bet that was a bit of a faff to process - extremely well done though.

[Datalord]

52 minutes ago, dannybgoode said:

Bet that was a bit of a faff to process

That would be an understatement. I had no concept of what it would mean when I started it. Honestly, I saw a blob on cartes du ciel and sent the telescope over there to image before I knew what this would mean.

53 minutes ago, dannybgoode said:

extremely well done though

Thanks!

[wimvb]

1 hour ago, dannybgoode said:

Apologies if I am being thick but is the galaxy the small smudge at around 8 o’clock in the centre-ish?

If so that’s extremely impressive. If not then it really is invisible to me!!

 

1 hour ago, Knight of Clear Skies said:

It's not obvious, that's a background galaxy. The Draco Dwarf itself has the appearance of a star cluster in centre frame, it's close enough to resolve the brighter individual stars. It has a large angular size, being about Moon sized, but the total luminosity of all its stars is less than that of some of the brightest stars in the Milky Way.

That "smudge" is a galaxy some 380 Mly distant. The dwarf galaxy is slowly being ripped apart by our own Milky way. According to (one) theory, galaxies form by accumulating matter and stars from dwarf galaxies. So, what we're seeing here as a cluster of stars, are the remains of an ancient galaxy.

[Datalord]

1 minute ago, wimvb said:

That "smudge" is a galaxy some 380 Mly distant.

Haha, nice one, Wim. I forgot to pick up on that thing.

Danny, if you're interested in better images of "smudges" like that, have a look at my Abell 2199: 

 

[wimvb]

This image makes me even more determined to add colour and more luminance to my UMaI image. I like projects like these, with physics in action on a grand scale.

[Knight of Clear Skies]

8 hours ago, wimvb said:

This image makes me even more determined to add colour and more luminance to my UMaI image.

Which image is that please?

[wimvb]

5 hours ago, Knight of Clear Skies said:

Which image is that please?

Not even close to yours @Datalord's but otoh only 1 hour of data. If I add 5 hours of L, and a decent amount of rgb ...

There's a reason this galaxy wasn't discovered until 2005. 😋

Edited May 9, 2020 by wimvb

[Knight of Clear Skies]

1 hour ago, wimvb said:

Not even close to yours

Nice catch, I've never seen that target before, but the Draco Dwarf isn't my image.

Edited May 9, 2020 by Knight of Clear Skies

[ollypenrice]

Nice one. It is indeed a very curious object.  There is a great deal of IFN in the area as well, certainly in a slightly wider field. It's quite hard to believe that this is a galaxy since it so closely resembles an open cluster but a galaxy is it is, even if dwarfish.  It would be worth a longer and less moon-infested visit, methinks.

Olly

[wimvb]

4 hours ago, Knight of Clear Skies said:

but the Draco Dwarf isn't my image

Duly noted and corrected.

[Datalord]

5 hours ago, wimvb said:

Not even close to yours @Datalord's but otoh only 1 hour of data. If I add 5 hours of L, and a decent amount of rgb ...

There's a reason this galaxy wasn't discovered until 2005. 😋

Excellent post there. It's interesting to think that there is so much hidden right in front of us. 400kly is nothing compared to our other galaxy targets. 

[Datalord]

Decided to send it through annotation to see if there was anything else interesting that popped up. The only thing I could find was PGC140771 (otherwise known as "The Smudge"😆) which had a supernova discovered in 2017. A google search on PGC2571076 didn't give me anything.

 

[ollypenrice]

😆 When astronomers call something 'The smudge' we need to be on our guard!!! 🤣

Olly

[wimvb]

6 hours ago, Datalord said:

A google search on PGC2571076 didn't give me anything.

http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Leda+2571076&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id

[Datalord]

1 hour ago, wimvb said:

http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Leda+2571076&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id

Ah, that's a simbad number. Never made that connection. 700 million light years is a decent distance to pick up a recognizable galaxy.

Odd it didn't pick up these.

[Shibby]

What a fascinating object! Thanks for imaging and posting it.