6/16 Observation Log


Time Name Comments
18:00 Arrival Arrived fairly early this evening, as I intended to ‘stake out’ a place for Hannah in the observing room. I wrote in a previous post about how she was upset that she didn’t get to move the telescope in our previous session. As it turns out we were to have a large crowd, and we had lots of help. There were about 100-120 visitors over the course of the night, and there were several large aperture telescopes (10″ or better) set up on the pads outside of the observatory. Hannah and I got to run the Challenger telescope for most of the evening. This was good practice for us since we have it reserved on July 13th. The Challenger is a 30-inch f/4.8 newtonian reflector on an english cross mount. The focal length of this telescope is 3658mm, or almost exactly 12 feet. There are various eyepieces available for it, and we used several different ones during the night.
19:30 Venus We were able to zero in on Venus while the sun was still high in the sky. I consulted 2sky on the Palm to see where I should look, and sure enough in about 30 seconds I had it in sight, well before the other astronomer in the room at that moment. I moved the Challenger around, put in the 40mm eyepiece, ( about 91X ) and started letting people look. The visitors were quite surprised that we could see Venus during the day (technically, twilight). I spent some time explaining the magnitude system, and that Venus was at -4.31 magnitude, or about 53 times as bright as the brightest star we would see tonight (Vega, Mag 0). (For a discussion of this by a *real* astronomer, see this link ). During the observing I had to explain several times that no, we were *not* looking at the moon, we were looking at Venus, and explaining why Venus looked like a first quarter moon. We watched Venus until we ran through everybody who wanted to see it, and then moved on to Saturn.
20:45 Moon, Venus, Saturn & Regulus When we moved on to Saturn, the cresent moon, Venus, Saturn and Regulus were making a nice, nearly evenly spaced line along the ecliptic. It was quite striking!
20:45 Saturn I put Saturn in the ‘viewfinder’ of the Challenger (we use a 5″ refractor as the viewfinder!) and zeroed in on it. I used the 40mm eyepiece at first, and then switched up to the 24mm eyepiece (152X). I was struck by the clarity of the viewing, it seemed especially calm for that low angle, so I moved up to the 19mm eyepiece (192X). I hopped down from the ladder, and sent Hannah up first, and she was awestruck. We could not only see the rings, the Cassini division was quite clear, and we could also make out at least two cloud bands and the shadow of the ring on the planets surface. I told the assembled visitors what an extraordinary treat they were getting, and started moving them through the viewing as quickly as I could so that each one could spend a minute or so viewing. There were so many “Ooohs” and “Aaahs” I lost count. Several people were saying that they could see moons, and I tried not to be too discouraging about that. Probably the only moon that could be visible would have been Titan (mag 8.4) The next brightest moon would have been Iapetus at mag. 11.2, and we were not even out of the evening sunset glow at that point. We watched Saturn for quite a while, with several people taking multiple turns. There is nothing quite as satisfying as having a youngster up on the observing ladder looking at Saturn for the first time, and hearing their excited reaction. We watched Saturn until it started to get too low for comfort (the observatory does not have a dome, but rather a roll-off roof, so the walls can interfere with low angle viewing) and then moved on to Jupiter.
22:00 Jupiter and moons At about 10:00 PM we moved on to Jupiter, the King of the planets. I swapped back to the 40mm eyepiece and zeroed in on it, and then moved back to the 24mm. I was able to get Jupiter and all four of the Galilean satellites in view at once, although Callisto was way off to the side. For theose who had been in the observatory during the Saturn viewing, I explained that while the moons of Saturn were fairly faint, the four largest moons of Jupiter were fairly bright. During some of the viewing, I was able to zero in on Jupiter with the mounted 11X80 binoculars and have people see if they could pick out the moons. Some of them were incredulous that they could be seen with binoculars, and I told them that Galileo’s telescope could only go up to about 8X. Many of the comments I got were about the brightness of Jupiter. By this time it was full dark, and at mag -2.54 Jupiter was very bright. Bright enough that as people came up to the eyepiece, I could see the light of Jupiter reflecting off of their cheek. I was looking around for some filters, but all of the 2-inch filters were in use on some of the smaller scopes. I briefly went to a higher power eyepiece (I believe it was a 15mm, which would
have been about 244X) and let people pick out the cloud bands, and see if they could see the great red spot.
23:00 M4 The bad moment of the evening came when I was trying to zero in on M4, having exhausted my Jupiter watchers. By this time Hannah was running out of steam, and wanted to go home. I was delaying her a bit longer because there was nobody available to run the Challenger at that time. I was having some difficulty because in the orientation I was trying to set, the telescope was tending to drift downward. It was taking me a long time, and some of the guests were wandering around impatiently. I was swapping back and forth between eyepieces and moving back and forth from the top of the ladder to the telerad and the spotting scope, trying to get the cluster centered. Ron walked in, and tightened up one of the delrin block pressure pads which resolved that issue. However, right after that I hopped up the ladder and managed to dislodge the 40mm eyepiece which I had left sitting on the top of the ladder. It came bouncing down the ladder (thunk, thunk, thunk) and landed on the carpeted floor of the observatory with a disheartening THUD. I was sure I had broken it.For those of you who don’t know from my previous posts, Ron is the director of instruments at FPOA. He’s in charge of keeping the equipment in good condition. Also, there’s a rule against leaving eyepieces on the top of the ladder (for obvious reasons). I was beside myself with guilt, I thought for sure I had screwed up royally and would be asked to leave the observatory and maybe buy a new eyepiece. However, Ron looked at it, mumbled something and put it back in the case. I looked at it and couldn’t see any damage. David (another astronomer) looked at it with me and said “These eyepieces are pretty robust, it’s probably just fine”. I felt really bad about it for the rest of the evening, and I still feel terribly embarrassed at dropping it. Fortunately it was not as bad as I feared. My flashlight was also on the top of the ladder, and some of the noise was it dropping along side the eyepiece.

Still, I’ve learned my lesson. NO EYEPIECES ON THE LADDER!!!!

After all of that there were about 5 guests still in the room, and I had them look at M4, explaining that it was a globular cluster, talked about Charles Messier and how this was one of the objects on his list of “objects to ignore”.

While the guests were taking turns at the Challenger, two of the interns from Hartnell college were trying to find M4 in the 11X80 binoculars and I helped them out with that.

0:00 Departure Hannah was quite happy to get into the car and head for home. I didn’t feel like she had as good of a time as she usually does. Next time I’ll have to make sure she wants to come up, and is not coming because she thinks I want her to. Perhaps she was overly tired, or just didn’t feel well.
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