A not often seen galaxy (NGC4157)

[alan4908]

Well, I couldn't find another image of NGC4157 on SGL so it's obviously not that popular a target !  

The galaxy is located in Ursa Major about 56million light years from Earth and is approximately the same size as our own Milky Way. It is receding from us at 774 km/s.  From Earth you see it almost edge on, however, a little of the core detail is visible.  Three supernova explosions have been recorded in this galaxy.

Processing this galaxy was less than straightforward due to the fact that it has a low surface brightness but it is also surrounded by bright blue stars.  The LRGB image below represents 14.5 hours integration time and was taken with my Esprit 150. I've also attached an annotated version for the background galaxy fuzzy hunters.

I hope you like it !

Alan

LIGHTS: L:29, R:20, G:19, B:19 x 600s, DARKS:30. FLATS:40 all at -20C.

 

 

[tomato]

Wow, another great image, so much detail and colour in NGC 4517, it seems to me we don’t often see examples of imaged galaxies at this angle, a few degrees off edge on, and lots of distant galaxies in view. 

I know it is the accepted terminology, but I do think ‘faint fuzzies’ seems such an insignificant phrase to describe what these objects actually are, it’s like calling stars ‘tiny specks of light’.

[almcl]

What a cracking image, Alan!

And after just a moment or two I found at least another half dozen galaxies. 

I find these images of yours are very inspiring, please keep 'em coming!

[mdstuart]

http://images.mantrapskies.com/catalog/NGC/NGC4157/index.htm

Another pic of that awesome galaxy...plus some blurb..

[alan4908]

13 hours ago, tomato said:

Wow, another great image, so much detail and colour in NGC 4517, it seems to me we don’t often see examples of imaged galaxies at this angle, a few degrees off edge on, and lots of distant galaxies in view. 

I know it is the accepted terminology, but I do think ‘faint fuzzies’ seems such an insignificant phrase to describe what these objects actually are, it’s like calling stars ‘tiny specks of light’.

Thanks - yes, the galaxy is at somewhat an unusual angle which you don't often see. The faint fuzzies terminology - Hmmmm, well I guess it does seem quite an insignificant phrase if you pause to consider what these faint objects actually are. 

11 hours ago, almcl said:

What a cracking image, Alan!

And after just a moment or two I found at least another half dozen galaxies. 

I find these images of yours are very inspiring, please keep 'em coming!

Thanks !  Yes, there are quite a few faint background objects that the Pixinsight annotation routine didn't pick up.

11 hours ago, mdstuart said:

http://images.mantrapskies.com/catalog/NGC/NGC4157/index.htm

Another pic of that awesome galaxy...plus some blurb..

Thanks Mark - I hadn't come across that resource before - it looks very interesting.

Alan 

[ollypenrice]

I dare say this will become a more popular target when people see this! Lovely image. The galaxy seems to have one extending spiral arm to the right.

Olly

[Paul73]

A cracker of an image! 

Loads in the background too. I’ll have to give it a go visually next time I’m out.

Paul

[gorann]

Yes, magnificent image - you found an unknown juvel up there! Unknown to me at least but it is now on my list.

[alan4908]

On 09/03/2019 at 08:25, ollypenrice said:

I dare say this will become a more popular target when people see this! Lovely image. The galaxy seems to have one extending spiral arm to the right.

Olly

Thanks Olly. Yes, it does seem a little asymmetrical in the spiral arms. Hopefully, a few more images should be able to confirm this.

 

On 09/03/2019 at 09:07, Paul73 said:

A cracker of an image! 

Loads in the background too. I’ll have to give it a go visually next time I’m out.

Paul

Thanks Paul - yes, there does appear to be a lot of distant objects in the background. However, apart from the confirmed galaxies identified by the Pixinsight annotation script, I have no idea what these are....

18 hours ago, gorann said:

Yes, magnificent image - you found an unknown juvel up there! Unknown to me at least but it is now on my list.

Thank you Gorann. I shall look forward to seeing your rendition !

Alan

 

[Barry-Wilson]

Well researched galaxy image - one for the to do list. Good work Alan.

[alan4908]

15 hours ago, Barry-Wilson said:

Well researched galaxy image - one for the to do list. Good work Alan.

Many thanks Barry 

Alan

[wimvb]

Excellent!

Close examination of your image and the image in the link that @mdstuart provided, indicates that this galaxy may have Ha or dust filaments that extend almost perpendicular to the disk, similar to those of M 106. Do you have the possibility to collect Ha?

There's science here.

Edit:

A bit of research (aka googling) doesn't turn up any other image that supports this hypothesis, not even Adam Block's version. So probably a fluke.

[alan4908]

On 12/03/2019 at 12:50, wimvb said:

Excellent!

Close examination of your image and the image in the link that @mdstuart provided, indicates that this galaxy may have Ha or dust filaments that extend almost perpendicular to the disk, similar to those of M 106. Do you have the possibility to collect Ha?

There's science here.

Edit:

A bit of research (aka googling) doesn't turn up any other image that supports this hypothesis, not even Adam Block's version. So probably a fluke.

Thanks for the comment wimvb. 

I did not detect any Ha or dust filaments during the processing of the image, so I decided on a strategy of not incorporating any additional Ha.

Alan