IC417 & NGC1931 - The Spider and the Fly

[Yoddha]

Total: 5h, WO 80FD @ f/5.9, QHY22, Astrodon HII 3nm, APT, PHD2, PI, PS 

The Spider and the Fly "pair" are visually close neighbors of the famous Auriga nebulae "Faming Star" (IC405) and "Tadpoles" (IC410). The smaller object in the upper part of the frame is NGC 1913 (Sh2-237) called the Fly. It is considered as smaller version of the Orion nebula – contains a young cluster, it’s Trapezium, has an emission and reflection parts. The brighter object is IC417 (Sh2-234) which should be the spider who waits for prey, laying in the faint web (personally I see more obvious figure in the lower left angle). IC417 also hosts a young cluster (Stock 8) and the two small clouds above the brightest star hide stellar nurseries. The emission part dominates the region, however with the appropriate imaging time is possible show also the reflections from the hot and massive blue stars. A near infra-red study with Spitzer Telescope shows that the bright wave from the Spider towards the Fly hides packs of young stars that maybe form that interesting shape from the clouds located between them and us.

The distances to the objects in the region show curious facts. The two nebulae are ~500 ly away from each other. Respectively ~7 500 and ~7 000 ly from Earth for IC417 and NGC1931. It looks that there is no direct connection in this “pair” as well as with the neighbors - IC405 ~1 500 ly, IC410 ~12 000 ly away from Earth. The whole complex looks very close just visually, but is spread out on more than 10 000 ly in the Orion-Cygnus arm of Milky Way.

Definitely both the Spider and the Fly are interesting objects alone and in pair, so most likely next winter will get back to them for more data.

[Barry-Wilson]

Great detail in the 'fly' Ivo - this will look delightful with more data especially RGB.  Good job.

[Yoddha]

Many thanks Barry!

Next winter will bet back on it. It is getting too low now