31 December 2004

Observing Location	Parkchester South Condominium Oval, The Bronx, NY
Observational Period	1440-1530 EST
Atmospheric Conditions	I saw sun on the building attached to mine and checked the satellite imagery that showed we were in a window in the clouds so I sent out to take a look at the sun. Thin cirrus clouds were almost always passing in front of the sun in varying degrees of thickness. Several times denser patches of cloud covered the sun so that I had to stop observing for several minutes at a time. By 1530 EST the limb of the sun was becoming very unsharp due to the amount of atmosphere and the sun was dropping into the branches of trees and about to go behind a building.
Instruments	Canon 15x50 Image Stabilized binoculars with Baader solar filter film and 45% objective mask
Observing Party	Charlie Ridgway

Target	Sunspots
Constellation	Sgr
Category	Solar
Time	1440
Comments	Sunspot 715 appears at about 10:30 and about 2/3 out toward the limb. It is composed of two spots, possible connected. The upper spot is less "dense" and the lower one is tadpole shaped with the tail pointing toward the limb. There appears to be a white ring around them which is not affected by cloud movement. There is another tiny spot at about 9:30 and a little closer to the limb. This spot does not show on the SOHO images but I am sure it is there. [I detected the spot, number 716, on the 1600 hrs full size image and it can be clearly seen on this magnetogram.]

I have been reading an article on binocular performance which Ben forwarded (http://www.cloudynights.com/lab/technical/performance.pdf). In it the author says that using an objective mask on binoculars will decrease chromatic aberration. Since aberration is most evident when viewing big bright objects I decided to give it a try today with the sun. I used a mask limiting my objectives to 30mm and found that the aberration was greatly reduced. There is a slight wash of flesh color around 5:00 and again around 9:00. And at the tip of the field around 1:00 there is a faint spot of turquoise. Viewing brightness is very comfortable, but I can't say how much of that is owing to the clouds.