Object of the Week – August 5, 2018 – IC 4593, “The White-Eyed Pea”

[Paul Alsing]

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.

IC 4593.jpg

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.

[Raul Leon]

Here's my observation from 10/5/2010: fairly bright; small; roundish; light blue tint; central star observed ic 4593.jpg225x 7mm Nagler 14.5 Starstructure Dob

[Bertrand Laville]

Hi All,

I had the opportunity to observe this PN with various scope, from 2" to 25", all in good conditions of southern Alps (NELM ~ 6.5v, SQM ~ 21.5 - 21.7)
Here are my reports, with Google translator:

LC 50/250 Mini Borg
x36 Nagler 7mm without filter
The NP is obvious, view V1. It's a 10th star, just a little blurry, and a little bluer than A * and B *
A * TYC 953 682, m9.398V, B * STF 2016


LC 80/550 Megrez Fluorite
x158 Nagler 3.5mm without filter
The NP is no longer a fuzzy star, but a small disc blur, very bright.
x158 Nagler 3.5mm / UHC
It's a very small disk, homogeneous, L7 or L8. No central star perceived.


TSC LX200 / 254 Meade
x127 Nagler 20mm without filter (?)
It's the same description as the MzF, in brighter, but no additional detail. I did not perceive lengthening, but S = 5!


TN 635 Dobson Obsession
x102 Nagler 31mm
NP is punctual, blurred, bluish star.
x390 Ethos 8mm without filter
The NP is small, and it should grow bigger., But the wind has risen: V2-3N. The field is very poor; three 18 th stars, not separated, at 1.3'N of the NP, are perceived as a small, very weak spot.
The CS * is punctual, bluish pronounced: C150 / S80 (?).
Halo external L3, round, blurred edges, blue C150 / S40, D ~ 20 - 25 ".
Inner halo L4, slightly elongated, a / b ~ 1.50 in 90 ° AP, blue a little more saturated, C150 / S50, d ~ 10 "x 7".
A * is ER *, B * is seen VI5. Few stars around.
A * U2 36131986, m15.90R, A2 0975 08187478, m15.4V, B * A2 0975 08188300, m17.3V
http://www.deepsky-drawings.com/ic-4593/dsdlang/fr

Clear skies
Bertrand
http://www.deepsky-drawings.com/dsdlang/en/


IC 4593 T635 BL.jpg

[Uwe Glahn]

Very nice PN with interesting inner structure. As you mentioned Paul, IC 4693 has an outer halo which I could catch as a very faint glow on the western side.

sketch: 27", 586x, NELM 6m5+, Seeing III
IC4593.jpg