MOUNT WILSON OBSERVATORY. 233 



small nebulae and nebulous stars. This group is worthy of attention, 

 as it contains several spindles, several spirals in plan, and an inter- 

 esting double spiral. 



Mr. Duncan made long-exposure photographs of N. G. C. 6960 and 

 M 16 and 33 with the 60-inch telescope and of the Andromeda Nebula 

 and M8 with the 100-inch. He also photographed the Dumb-bell 

 Nebula with the latter instrument. 



Mr. Hubble has photographed the following nebulae and nebulous 

 stars with the large reflectors, using the Newtonian focus: 



In the course of this work Mr. Hubble has added three planetary- 

 nebulae and two globular clusters to the lists of known objects. 



Faint Novae have been found in the Andromeda Nebula as follows : 

 No. 14 by Miss Ritchie, No. 15 by Mr. Duncan, No. 16 by Mr.Shapley, 

 and No. 17 by Mr. Humason. No. 16 was observed visually with the 

 100-inch reflector, probably the first visual record of a Nova in the 

 Andromeda Nebula since that of the seventh-magnitude star, No. 1, 

 which appeared in 1885. No. 17 was nearer the center and brighter 

 than any Nova since No. 1. 



A number of color-photographs of nebulae have been made by Mr. 

 Scares during the year, but no discussion of the data has thus far been 

 possible. Panchromatic plates exposed behind a red filter transmitting 

 to the red of X5700 confirai the earlier results on spirals obtained with 

 isochromatic plates and a yellow filter. A four-hour exposure on M51, 

 for example, gives strong red images for the central and secondary 

 nuclei, but shows no trace of the arms of the spiral. A yellow exposure 

 on the Dumb-bell Nebula gives a result strikingly different from the 

 usual violet-blue photograph. The yellow hght is less widely distrib- 

 uted and presents the appearance of diffuse nebulosity, with no trace 

 of the rich detail revealed by an ordinary plate. 



