Pickering's Triangle is part of the Veil supernova remnant in the NW portion near NGC6979 and NGC6974.  It does not have an NGC number but is also known as Seimis 3-188 located at RA 20h 48m 24s and DEC +31d 27m 19s. It is 1,400 light years distant in the constellation of Cygnus.  The filamentary segments represent an expanding shell or shock front of the supernova explosion that took palce 5,000 - 10,000 years ago that are now five times the size of the full moon.  As visual observer's can attest to with the use of OIII filters, Pickering's Triangle is strongly enriched in OIII.  This image was taken only with H-a (red) and OIII (blue, green) narrowband filters to bring out the fine filamentary detail. This image is presented with North to the lower left and is ~ 35' x 35'. 

Data were acquired automatically with CCDAutoPilot4 running MaximDL4.62 and PinpointPro for plate solving.  The system was guided using an SBIG ST-402 camera on an Astrodon MonsterMOAG off-axis guider.  The U16M was operated at -25C and 30 minute exposures were taken. Astrodon 3 nm narrowband filters were used.   The data were processed in CCDStack and Photoshop CS3.