2 March 2007

While planning for Saturday’s lunar eclipse, which will probably be clouded, rained and snowed out here, I made a digression into Moon size. This is a continuation of my previous study on this topic, which was initiated as a result of information found in Cherrington’s description of the full Moon.

Peter and I had a discussion about this a couple of weeks ago and he wondered if any size change would be eaten up by the actual change in the distance of the Moon from Earth over a period of observation. Cherrington doesn’t mention this as being a consideration and I think the local distance change over a day from the rotation of the earth will be greater than any change due to the relative position of the earth and Moon due to the ellipse of the Moon’s orbit. At perigee where the Moon is moving fastest there would be more of a change from position in the orbit over a moonrise/moonset period than when the Moon is at apogee and that is something that I should look at in another analysis.

To test this out, I graphed the apparent size of the Moon vs. it altitude at hourly intervals from rising through setting (actually an hour after rising and before setting so Excel could make a chart without negative numbers which it doesn’t do well).

I tried using Excel to create a bubble chart showing different size bubbles against time on the x axis and altitude on the y axis but something went awry with the chart so I recreated the chart as altitude vs. time on a scatter plot. That worked better but didn’t show time in an easily understood way.

I tried plotting altitude against time and that gave me the nice bell curve I was looking for but it didn’t say anything about apparent size.

Then I plotted size against time and again got a nice bell curve, but it left out the altitude component I needed.

I gave the bubble chart another try and got it to work this time, but there isn’t enough change in the size of the moon between moonrise/moonset and culmination (1.14%) that it can be seen in the bubbles produced on the graph. So I had to have Excel put the diameter values next to each bubble.

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The NY Times is reporting that there is likely to be a slip in the Crew Expedition Vehicle first flight to a decrease in funding and that there will be a four-year – at this point – period between the retirement of the Shuttle and the first flight of the CEV when the US will not be able to put astronauts in space on its own. That does not take into account any future delays in CEV development or time to correct craft deficiencies before meaningful flights can take place.

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It rained heavily overnight (but still some ice from the previous storms persists) and it looks like there will be a clearing after the storm. CSC is showing clear skies tonight and good transparency although I think they are optimistic on the transparency side with all the water that is on the ground here and evaporating into the atmosphere.

NOAA seems sureer today that we will have clouds and precipitation tomorrow night at the time of the eclipse.

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Observing Location	TotL
Observational Period	2000-0200 EST
Atmospheric Conditions	Cloud Cover Clear Temperature 40sF Wind Calm gusting to Moderate Breeze Humidity Moderate Feels Like Cool The temperature was up near 60°F today, maybe above, and hadn't dropped much by the time we left. The breeze and moisture in the air made it feel a little cool though. The breeze was buffeting the scopes, particularly Harry, but even SAR, and making it hard to see. It appeared clear but the shy was not really black, even in the optics. Transparency Good Seeing II
Instruments	SAR: Coulter CT-100 Newtonian reflector - Charlie Celestron Omni 20mm Celestron Omni 2x Barlow Kellner 20mm (possibly a university Optics) Peter lent me this lens which is original equipment for the CT-100. It has no markings on it to show who made it or its focal length. It had a helical diopter adjustment built in to permit fine focusing of the CT-100, which came stock without a focuser. It made focusing a breeze. Harry (the Kite): 150mm DIY Newtonian Reflector - Peter Takahashi 22x60 binocular - Peter Pentax 20x60 binocular - Kin
Observing Party	Charlie Ridgway Peter Tagatac Kin Lee Time’s Up Central Park Moonlight Ride

Target Moon Constellation Cnc Category Lunar Time yyyymmdd.hhmm 20070302.2015 EST Comments Lunation 1041 Phase Waxing Gibbous Full -22h3m Age 13d9h00m Distance Light Time (from earth) 396,000 km 1.32s Elongation 169.72°E % Illuminated 99.2% Magnitude -12.4 Angular Size 30'13" Altitude 37.64° A couple came by and wanted a look before I had completed setting up so I found the Moon for them. I didn’t look much myself wanting to preserve my night vision a little longer. When the bikers came through I put the scope back on the Moon and looked a little. The limb in the S is still a little lumpy but otherwise lacks texture.

Target M42, Great Orion Nebula Constellation Ori Category DSO: EmNeb Time yyyymmdd.hhmm 20070302.2025 EST Comments The nebula looks good but not spectacular. Another object for the couple.

Target Saturn Constellation Leo Category Planet Time yyyymmdd.hhmm 2007 EST Comments Object Class Classical Planet Elongation 157.89°E Distance Light Time (from Earth) 8.27 AU 1h9m Distance (from Sun) 9.19 Au Angular Size 20"x17.7" Ring Angular Size 45.4"x11.5" Ring Inclination 14.63° Magnitude +0.1 Altitude 56.36° I only got a few looks at the planet in Peter’s scope between the bikers. I could see the Cassini Division but didn’t note anything else. In my scope it just looks a little bit like a football. Even with the Barlow I am not able to separate the rings from the planet.

Target M44, Praesape, Beehive Cluster Constellation Cnc Category DSO: OCl Time yyyymmdd.hhmm 2007 EST Comments Someone has asked what Praesape means and I didn’t remember ever having read it. I looked it up in the Audubon guide which says it means the manger in Latin.

Target M41 Constellation CMa Category DSO: OCl Time yyyymmdd.hhmm 20070302 EST Comments The sky around the cluster looked a little gray and I didn’t see many stars tonight.

Target M35 Constellation Gem Category DSO: OCl Time yyyymmdd.hhmm 20070302 EST Comments I tried hopping to this but it was so high that I couldn’t see through the red dot finder to get the scope in the neighborhood. I came back to it later in the night and had better luck but when I found it I thought I was on the adjacent NGC based on what I was seeing in Planetarium. Peter said he has never seen the NGC and I was seeing M35. It was faint.

Target M48 Constellation Hya Category DSO: OCl Time yyyymmdd.hhmm 20070302 EST Comments Not Seen I hopped to it and Peter confirmed the star field, but neither of us saw anything.

I did not make any field notes again tonight so this is primarily a list of the places I went rather than what I saw there.

Target Fauna Constellation Category Time yyyymmdd.hhmm 2007 EST Comments The goose flock seems to be getting bigger every day. The other night I saw then flying up toward the reservoir in a V formation for the first time. I fry the impression that they are gathering to begin their migration north. The make a great noise when they fly overhead. There is constant honking but also the sound of their wings. They sound like hinges in need of oil as they pass overhead. Tonight they seemed to be flying much lower than usual so were consequently more audible. There is a much smaller population of ducks that hasn't swollen noticeably over the winter. The ducks don't quack to each other when they fly. The sound of their wings in the air is a much higher pitched squeak from that of the geese. The raccoons were very active tonight. They spent most of their time in the grass north of the lawn and didn’t get into the garbage cans while I was looking.

Target Flora Constellation Category Time yyyymmdd.hhmm 2007 EST Comments Kin had been talking about pink and white blossoms around the Obelisk that sound to me like dogwoods. I took a ride down there tonight on Kin’s scooter and they are huge buds but no flowers yet. I checked all of the trees and none of them have labels on them. On the way back to TotL I swung out to the crosswalk at the East Drive just north of the Met where I thought there were similar trees and found a bunch of younger trees which also had huge buds. I am reasonably certain these are dogwoods although on the way out Peter said he thought they were cherry blossoms. We will have to wait until the flowers open to be sure.