Napoleon and Josephine

[Jimi Lowrey]

I read the article in the March 2013 Sky&Telescope Cosmic Extremes by Bryan Gaensler and was intrigued by the section Weakest Gravity. The galaxies with the weakest know gravitational attractions SDSSj113342.7+482004.9 and SDSS j113403.9+482837.4 or as Gaensler named them "Napoleon and Josephine". The two galaxies are 370,000 light years apart and are bound to each other by gravity and are in a slow orbit.

I wondered if these small faint galaxies were within reach of my telescope so I used the SDSS photometry to see what the approximately visual magnitude is.

Napoleon- Ra 11 33 42 DEC +48 20 04 is 17.28 V MAG

Josephine- RA 11 34 03 DEC +48 28 37 is 17.6 V MAG

At 17.6 for the dimmest one Josephine look from the SDSS image to be more spread out and blue color which from my experience with the SDSS a blue color galaxy is low surface brightness. I also determined that both galaxies would fit in my 13 Ethos eyepiece field @ 375X

POSS 2 image Josephine is at the top.
500

I observed these two galaxies last Wednesday night under good conditions here in West Texas here are my brief notes

Napoleon----- 375X 488X 610X Very small direct vision bright stellar core with faint small halo two galaxies near by one is a edge on the other very faint popping in and out of view with AV.

Josephine----- 375X 488X 610X By a fairly bright star could hold it with averted vision at375x much easer at 488X direct vision very faint face on soft glow looked fuzzy very LSB.

I did a eyepiece drawing at 375X
501

I was very happy to have tracked down and viewed this small and unassuming pare with the long distance attraction I have always liked a good viewing quest with a good story like Napoleon and Josephine.

[Ivan Maly]

Interesting objects. Great observation. I should use this source for faint V mag's - I assume you used this: http://tdc-www.harvard.edu/catalogs/sdss.html

[Jimi Lowrey]

Hi Ivan.

This is what I use http://skyserver.sdss3.org/dr8/en/tools/chart/navi.asp to get the SDSS if you click on GET IMAGE on the left you will get the image of Hanny's Voorwerp.

If you add the G and R mags together and average them you will get the approximate visual magnitude.

If you enter the RA and DEC on the left you can navigate to any place in the sky that is in the SDSS footprint.

Hope this helps.

[Ivan Maly]

Thank you, Jimi.

[Steve Gottlieb]

If you don't mind grabbing a calculator, a more accurate formula is V = .42*G +.58*R, but when you round off to the nearest tenth you'll likely have the same value as just averaging. I believe this model was designed for stars, but works well for compact galaxies.