Interacting galaxies
Canes Venatici
RA 12h 30m 36s
DEC +41° 38′

Arp269_DSS.JPG

My one observation of these interacting galaxies was in 2010 and was initially a case of mistaken identity. I was looking for Arp 23 and came across these galaxies first – and once I saw they weren't Arp 23 I thought they weren’t an Arp at all. Despite these two mistakes the view of this bright interacting pair turned out to be delightful, and nearly as detailed as the DSS image above.

N4485_N4490_Arp269_crop.jpg N4485_N4490_Arp269_cropinverted.jpg

My sketch above simulates the view on an average night in western Oregon (21.25 SQM) through my 28 inch f4 Newtonian using 253x.

The larger galaxy, NGC 4490, is evidently called the “Cocoon Galaxy” but the only time I’ve seen it referred to as such was when I was researching this OOTW. Is this a commonly known nickname?

About 25 million light years away, these galaxies are pulling away from each other, which is illustrated well in the HST image of NGC 4485 – you can see the trailing edge being shredded into star forming tufts and clumps as it pulls away from NGC 4490, just outside the lower right corner of the photo below.

HST_NGC 4485.jpg

4490 has a visual magnitude of 9.8 and 4485 is magnitude 11.9, so this bright Arp galaxy pair should be well seen in scopes from 8 inches on up.

I saw a distinct dark lane on the northwest side of 4490, which in photos looks more like space between a detached area of star formation than an actual dust lane. 4490 also had a slender and graceful S shape visually, but is much more ragged looking in photos – it’s clearly been disrupted by 4485.

What do you see?

"GIVE IT A GO AND LET US KNOW"