OBSERVER’S CHALLENGE* - FEBRUARY, 2021
by Glenn Chaple
NGC 1893 – Open Cluster in Auriga (Mag: 7.5, Size: 12.0’)
IC 410 – Emission Nebula in Auriga (Size: 40’ X 30’)
This month’s Observer’s Challenge takes us to the emission nebula IC 410 and its embedded open cluster NGC 1893. The cluster is comprised of several dozen members, some twenty of which are magnitude 9 to 12. Most are massive O and B-type stars. They appear relatively faint because the entire system is 12,000 light years away.
It’s the surrounding nebulosity that provides the real challenge. A haze surrounding NGC 1893 might be glimpsed with 6 or 8 inch scopes from remote dark-sky locations, but observers working from typical suburban environments will need as much as twice that aperture and possibly an assist from an O-III filter.
A distinctive feature of IC 410 is a pair of gaseous streamers northeast of NGC 1893 that point away from the cluster. Their similarity in appearance to larval frogs gives IC 410 the nick-name the “Tadpoles Nebula.” They appear in the accompanying close-up image of IC 410 taken by ATMoB member Mario Motta. For an ultimate Observer’s Challenge, see if you can spot them visually.
Located at RA 5h22.7m and dec +33°24’, this cluster/nebula complex is a quick star-hop from Melotte 31, a stellar group that includes the 5th magnitude star 16 Aurigae. About 20 arc-minutes west of 16 is the near-twin double star Struve 666 (magnitudes 7.85 and 7.89, separation 3.2”). Before moving on to NGC 1893/IC 410, give this little gem a look-see!
*The purpose of the Observer’s Challenge is to encourage the pursuit of visual observing. It is open to anyone who is interested. If you’d like to contribute notes, drawings, or photographs, we’d be happy to include them in our monthly summary. Submit them to Roger Ivester (email@example.com). To find out more about the Observer’s Challenge or to access past reports, log on to rogerivester.com/category/observers-challenge-reports-complete.
NGC 1893/IC 410 finder charts
Glenn Chaple, using the AAVSO’s Variable Star Plotter. Field is 1 ½° by 1°, with North up
NGC 1893/IC 410 image
NGC 1893/IC 410 close-up image with North up. Image by Mario Motts (ATMoB) 2.5 hours Halpha, 1 hour O3, 1 hour S2.