A few degrees in Virgo

[Martin Meredith]

My current mode of EAA involves searching for an interesting-looking region using deep charts and spending the entire session hopping around within that small area, with little or no prior knowledge of the field or what I might find. On Sunday I chose the patch of sky where Virgo, Bootes and Coma Berenices meet. The night was moonless but not pristine due to nearby street lighting, with an SQM reading of 19.4.

The first stop was Shakhbazian 356, a compact group of 5 galaxies with mags from 17.4 to 18.2, at a distance of 1.3 BLY, 4 of them forming a graceful curve. 

Next, a short star-galaxy hop over to a river of galaxies centred on NGC 5171, flowing past a pair of blazing 8th magnitude stars. I don't want to ruin the image by labelling all the galaxies visible in this shot. The brighter members form a group at around 370 MLY distance, while the fainter intermingled galaxies are at around 1.25 BLYs. Part of the galaxy cluster is known as Vorontsov-Velyaminov 1625. Galaxies down to nearly mag 20 are visible in the shot. I imagine this would be an interesting group at the eyepiece for large dobs and also for `real' imagers…

Two degrees to the north we find a constrasting group of galaxies at a distance of 330 MLY, the face-on spiral NGC 5230,  elliptical NGC 5222 and oriented spiral NGC 5221, all three at mag 13.1 or so. Perhaps visually less attractive than the previous group, but each member is intriguing nonetheless. 

The face on spiral has very irregular/asymmetric arms with a large gap in the ESE region. The elliptical may be interacting with the smaller spiral PGC 93122 to its W. But perhaps most interesting of all is the Saturn-like NGC 5221. While observing, I noted that this galaxy seems to be surrounded by an odd reflection, and I wondered about an artefact. Checking the next day on Aladin it turns out to be genuine. In fact, the nearer arm seems to be being pulled downwards, while at the same time there is a very extensive (though faint) pull in the upper arm towards the NE. The attached image from the SDSS via Aladin shows these features more clearly. How they arose is not obvious, but Arp groups this galaxy with NGC 5222 as the possibly interacting pair Arp 288, classified as "double galaxies with wind effects".

Then on to an anonymous grouping of faint galaxies I spotted 3' away forming a lambda-shaped asterism. I say anonymous because while these are listed individually (the principal member being mag 16.5 PGC 1434880), they don't seem to be in any of the main compact galaxy group listings, yet most are assigned a similar distance at around 1.2 BLY. By the way, like many of my images these are best viewed in a darkened room to simulate my near-live view  .  If you do so, you may be able to spot the edge-on galaxies at the tips of the lambda that give this group the look of a meteor shower, with the radiant at the principal galaxy. I'm also showing the SDSS coloured image of what I think is a rather attractive cluster.

Nearby I noted a mag 20.2b, 19.96v quasar (SDSS J13309+1328) with redshift of 3.14, placing it at a light travel time of 11.7 BLY i.e. 85% of the estimated age of the universe. My identification of it on the plot is rather tentative -- a longer stack would have been preferable. But that's probably the most distant object I've knowingly observed.

Finally, 3' away via NGC 5185 in this single 30s shot is the 45-strong 2.2 BLY distant galaxy group Abell 1742. I only include this to juxtapose its distance with the proximity to the multiple (5) star system O Struve 579, which is 40 million times closer at 59 light years, and is known to possess at least one exoplanet.  

Perhaps not all 3-degree regions are as action-packed as this, though many are, and its a sobering thought that at this scale I'd have to observe every night for the next 20 years before running out of sky. I'm not sure even my long-suffering family would accept that.

Bad weather is predicted here for the foreseeable (typical when there's a new moon!) so that's probably the last from me for a while (sighs of relief all round). 

Thanks for looking

Martin

[Paul73]

Martin

Great images and informative write up as always.

I'll come back to this one on a bigger screen later.

Paul

[Macavity]

Great stuff. Really like the originality / background research.

Just the sort of stuff (we) EAA'ers(!) should be doing?

[Paul73]

Ok. I'll bite.

EAA???

Paul

[Macavity]

Ok. I'll bite.

EAA???

Paul

Hey, I'm as new as you (anyone) to this, but

"Electronically Assisted Astronomy"? lol.

And <thinks> rather   maybe...

[shirva]

[Paul73]

That makes more sense than any of the options that I came up with!!!

[mdstuart]

Makes me want to get the dob out!

[Martin Meredith]

Thanks everyone. Yes, sorry about the un-expanded EAA. I've been spending too much time on the 'sister' site across the Atlantic. I prefer EAA to Video Astronomy though as a title, at least to describe what I do. But I don't want to start a parallel debate on name changes! Surely what matters is that we get the kit out as often as possible and enjoy what we do, being fortunate enough to live in a time when the hardware/software and community makes observing such a lot of fun.

Martin

[HiloDon]

Great images and presentation, Martin! As always. I have learned so much from you about our universe and EAA. Thanks for all of your efforts and sharing them with us.

Don