25 October 2007

I got alerted to a new comet by the Guild of Manhattan Sidewalk Astronomers and the NY Sidewalk Astronomers groups at Yahoo. 17P/Holmes is brightening in the Fishhook of Perseus and is around Mag 2.8, another naked-eye comet. Unfortunately we will not be seeing this well placed comet soon as the weather for the foreseeable future is the pits. The comet has not appeared on the recent comet sightings web page yet and the explanatory page referenced by the group mailings is missing so I don't know if this is expected to be a brief flareup or a prolonged event.

JDT	2454240.5
q	2.053169
e	0.432429
Perihelion	24.2585
Node	326.8675
Inclination	19.1132
Period	6.88 years

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Observing Location	PSC & MetOval
Observational Period	1100-0030 EDT
Atmospheric Conditions	Cloud Cover Scattered Clouds Temperature 55°F Wind Calm gusting to Gentle Breeze Humidity Moderate Feels Like Cool I was about to go to bed and the sky outside was very bright so I opened the curtain and the Moon was in a big hole in the clouds and it looked clear out to the E so I got dressed and went out for the comet. While standing on the oval at PCS it was gusty and I was in a blizzard of falling leaves. I located the comet but was being blown around so much that I wasn’t getting a good view of it with the small binocular, and didn’t want to sit on the benches since it had been raining, so went home and got SAR and headed up to MetOval. The oval there is more exposed but the air was calmer. I don’t know if it was a difference in the wind or if it was just being channeled between the buildings around PSC. The rain seemed to have cleared out the atmosphere and the air was stable. Transparency Excellent Seeing I
Instruments	Brunton 8x21 compact binocular - Charlie SAR: Coulter CT-100 Newtonian reflector - Charlie Celestron Omni 20mm (21x) Celestron Omni 2x Barlow
Observing Party	Charlie Ridgway

Target 17P/Holmes Constellation Per Category Comet Time yyyymmdd.hhmm 20071025.2300 EDT Comments The comet is an easily seen naked-eye object that just looks like another star which is confusing the constellation. It is on a line between α Per and λ Per, about 1/3 of the way from Λ Per, the barb of the fishhook. It has a bright core with a transparent halo around it that is displaced to the N. There is no tail evident. It is not as bright as α Per and is brighter than δ Per and ρ Per. Cartes du Ciel graphic α Per 1.79 17P/Holmes 2.? δ Per 3.01 ρ Per 3.32

Target Moon Constellation Ari Category Lunar Time yyyymmdd.hhmm 20071025.0000 EDT Comments Lunation 1049 Phase Waxing Gibbous Full – 0h52m Age 14d22h58m Distance Light Time (from earth) 351.826 km 1.17s Elongation 175.7° E % Illuminated 99.9% Morning Terminator Colongitude (λ E) 90.2° Evening Terminator Colongitude (λ W) 270.2° Libration in Latitude -5°06’ Libration in Longitude -0°49’ Magnitude -12.8 Angular Size 33.96' Altitude 64°40’ Virtual Moon Atlas graphic This is the largest Full Moon of the year. There is still some lumpiness on the southern limb between Grimaldi and Langrenous. I see lots of stark white spots freckling Mare Insularum, Mare Cognitum, Mare Nubium and the sotuthern part of Oceanus Procelarum. The mountains beneath Plato are also bright white. The ejecta blanket around Kepler is obvious in this lighting. It looks like Mare Australe is visible below Langrenous.

Target Mars Constellation Gem Category Planet Time yyyymmdd.hhmm 20071026.0020 EDT Comments Object Class Classical Planet Elongation 112.5° Distance Light Time (from Earth) 0.806 AU ms Distance (from Sun) 1.50 AU Angular Size 11.6" Magnitude -0.5 Central Meridian 103° Altitude 25.8° As I was packing up I noticed something bright and orange coming from behind a tree and apartment building. It was Mars which I looked at in the binocular since the scope was already mostly packed and would not have provided much of an improvement on the view anyway. The planet is still nowhere as big as the Moon.

I was able to see six stars of the Pleiades.