Paul Alsing
August 6th, 2018, 06:11 AM
Object of the Week – August 5, 2018 – IC 4593, “The White-Eyed Pea”, PN G025.3+40.8, PK 025+40.1, ARO 27, Fleming 96 - Hercules
R.A.: 16h11m44.5s Dec.: +12°04'17" (2000)
Apparent size of 12 arcsec
Magnitude: 11.0
IC 4593, discovered in 1907 by Williamina Fleming, is a relatively tiny planetary nebula located about 6800 light years away in the southwestern corner of Hercules close to the border of Serpens Caput… but the distance is quite variable when different sources are referenced, ranging from 3,000 to 10,000 light years depending on where you look.
3147
Very similar to NGC 6543 (Cat’s Eye Nebula), IC 4593 has an extended halo that is 3 times bigger than the brighter inner disk, which is almost perfectly round. This inner disk is decidedly green to my eyes, but the 11.3 magnitude central star is quite white, which is where this planetary nebula got the moniker “White-Eyed Pea”. Although this little guy is fairly easy to see at low power, it is very small, and really needs a lot of power to show its stuff, I’ve pushed it to about 500X on a very good night. It responds really well to blinking with a nebular filter, and it also ‘grows’ with averted vision as well. Employing averted vision also starts to let you detect some of the extended shell, especially near the northern edge, if the transparency and seeing are good.
About 11 arcminutes to the south-southwest of IC 4593 is a very nice double star, STF 2016 = ADS 9959, 8.18+9.74 magnitudes with a separation of 7.20”. It is always a treat to have divergent objects in the same FOV, it is one of my favorite pastimes!
As always, give it a go and let us know.
R.A.: 16h11m44.5s Dec.: +12°04'17" (2000)
Apparent size of 12 arcsec
Magnitude: 11.0
IC 4593, discovered in 1907 by Williamina Fleming, is a relatively tiny planetary nebula located about 6800 light years away in the southwestern corner of Hercules close to the border of Serpens Caput… but the distance is quite variable when different sources are referenced, ranging from 3,000 to 10,000 light years depending on where you look.
3147
Very similar to NGC 6543 (Cat’s Eye Nebula), IC 4593 has an extended halo that is 3 times bigger than the brighter inner disk, which is almost perfectly round. This inner disk is decidedly green to my eyes, but the 11.3 magnitude central star is quite white, which is where this planetary nebula got the moniker “White-Eyed Pea”. Although this little guy is fairly easy to see at low power, it is very small, and really needs a lot of power to show its stuff, I’ve pushed it to about 500X on a very good night. It responds really well to blinking with a nebular filter, and it also ‘grows’ with averted vision as well. Employing averted vision also starts to let you detect some of the extended shell, especially near the northern edge, if the transparency and seeing are good.
About 11 arcminutes to the south-southwest of IC 4593 is a very nice double star, STF 2016 = ADS 9959, 8.18+9.74 magnitudes with a separation of 7.20”. It is always a treat to have divergent objects in the same FOV, it is one of my favorite pastimes!
As always, give it a go and let us know.