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View Full Version : Object of the Week October 18, 2020–NGC 7569 “The Little Starfish”



Jimi Lowrey
October 18th, 2020, 06:38 PM
NGC 7569, UGC 12472, 3ZW100

Pegasus

Ra
23 16 44
Dec
+08 54 19

Mag 14.4P

Type S0?

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NGC 7569 is a small peculiar galaxy it was found by Lewis Swift with his 16” refractor on September 6, 1886. It is classified as a S0 type galaxy but looks like a Peculiar type merger to me. It looks to me like a starfish in deep images of it. I understand that was a problem with the ID of this galaxy by a bad RA and Dec reported by Swift hopefully Steve Gottlieb knows the story of this error and can shear with us the story.

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From My brief notes on this galaxy I wrote At 610X NGC 7569 small bright nuk North east arm seen with direct vision the other faint arms seen with averted vision and are Extremely faint. I also observed nearby the edge on 15.1V mag galaxy 2mfgc 17454 that is just East of NGC 7569. If you look at the image below you will see several faint challenge type galaxies in the nearby field.

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I would be interested to hear if anyone can see the faint bend in 2MFGC 17454.

As Always
Give it A Go!

I wish you great viewing and good health in these challenging times!

Steve Gottlieb
October 19th, 2020, 04:40 PM
Unfortunately, Swift wasn't careful verifying his positions, so NGC 7569 was lost for a century. His description reads "very faint; very small; round; 3 faint stars south-following form a small right angle triangle."

But there are no galaxies near Swift's position nor is there a group of 3 stars forming a small right triangle. But Harold Corwin was able to identify UGC 12472 as NGC 7569. Apparently Swift made a 2° error in declination and if you look at the SDSS image, there is a right triangle of stars close southeast just where Swift placed them.

Unfortunately older catalogues such as UGC, CGCG, MCG, PGC don't list NGC 7569 and it's called "non-existent" in MegaStar.

The late Rick Johnson, who seemed to image every strange object, has a write-up and image here (http://www.cloudynights.com/topic/529918-ngc-7569-a-galaxy-with-jets-and-patches-or-plumes/).

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Jimi Lowrey
October 19th, 2020, 04:52 PM
Thanks Steve for the information. I know Swift was not very good at reporting accurate positions.

Steve Gottlieb
October 19th, 2020, 06:29 PM
Jimi, is "The Little Starfish" your nickname -- a miniature version of NGC 6240, the "Rumpled Starfish"?

By the way, Bill Keel called NGC 6240 the "Lobster" galaxy in his 1993 article in Mercury magazine "The real astrophysical zoo - Colliding galaxies". But I guess that nickname didn't stick.

Jimi Lowrey
October 21st, 2020, 04:38 PM
Yes Steve it is my nickname. I thought it looked like a little starfish From the SDSS image of it.