IC 2120 and Kronberger 18 (PK 169-0.1 and DSH J0518.6+3737) Bright Nebula and Open Cluster in Auriga

Center of field at approximately: RA 05 hours 18 minutes 26 seconds, Dec +37 degrees 36 minutes 15 seconds

Size: 60" and ~6.0' Magnitude: -- and -- Class: 'Compact' HII region and ?

North is up

West to the right


 14.5" f5 Newtonian reflector


 ST-8XME, self-guided, binned 1x1, temp -20c, camera control MaxIm DL 4.56


Lumicon Red filter, 820 minutes (82 x 10 minute subs), 01/4/10/11/12/2018; seeing 2.9-5.5 FWHM per CCDStack

Processing: CCDStack 2.94.6355.18107, Photoshop CS5.1

 Rolling Roof Observatory, Thousand Oaks, CA 91360 (+34d 13m 29s -118h 52m 20s)


This combination was imaged as a planetary nebula and an unusual open cluster ... My charting software (Megastar v5.0.14) lists IC 2120 as a planetary nebula, and does not have Kronberger 18 in its database. I first found Kronberger 18 in Deep-Sky Planner (, and noticed that IC 2120 was in the same imaging field. Kronberger 18 is the grouping of stars about 7 arc minutes ENE (upper left) of IC 2120 (the object that "looks" like a planetary). The CDS confirms both the HII nature of IC 2120, and the identity of Kronberger 18 as an open cluster.

See the CDS image/data for this field.

I started this as the high clouds were moving in (1/4), then had to wait for the rains to end and the winds to diminish to tolerable speeds. Only nights with 'normal' seeing were the 10th and 11th ... the 12th was breezy with poor seeing.