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GRAZING OCCULTATION OF ZC 35 - 2005 November 12
A spectacular grazing occultation of magnitude 6.2 ZC 35 occurs shortly after 11.20 pm NZST on Saturday November 12 (i.e. 12.20 am NZDT on the morning of Sunday November 13) for New Zealand observers. For those situated close to the graze path the star will be seen to alternately wink out as it disappears behind mountains on the edge of the moon, and then reappear in the lunar valleys between the mountains.
Finding the star:
The diagram below shows the position and path of the star relative to the moon as would be seen by the naked eye. (In a telescope the view may appear inverted or back-to-front).
NOTE: Even though the star is relatively bright, you will not be able to see this event with the naked eye because of the Moon's glare. A small telescope will definitely be required.
The Path:
What makes this graze most unusual is that the path runs up the east coast of New Zealand's South Island directly crossing Dunedin, Christchurch, and regions of Marlborough, before crossing Cook Strait and passing across regions of northern Wellington. It then follows State Highway 1 up the southern North Island before crossing Palmerston North and passing west of Napier/Hastings and Gisborne. As such this graze presents the first time in at least the last 25 years that we have had an opportunity for the entire country to participate in a single graze event. Given good weather, and if upwards of 50 timing stations can be organised along the length of the country this will allow us to resolve features on the edge of the moon to within few metres accuracy.
An overview map of the graze "limit line" is available here. (Click the map for more detailed predictions for the graze).
To view maps showing the path in more detail (and its proximity to various cities and towns) click the following links. These maps show the graze "limit line" in red. This is the line from which an observer on the surface of the earth would see the star just graze along the edge of the moon, if the moon's limb were perfectly flat. However the Moon's limb is not flat, and indeed the point of timing grazing occultation events is to determine how "bumpy" the edge of the Moon actually is.
Detailed Path Maps:
North Island - East Cape to Hastings
The graze profile below shows the expected shape of the southern limb of the moon. However the detail of these graze profiles is often incorrect, and it is our aim to obtain much more complete and accurate data. (Note: This profile is drawn for the region of Wellington. The profile will be slightly different as seen from other localities along the graze track).
Because this graze occurs on the southern limb of the Moon, solid moon is at the top of the profile, and deep space at the bottom. The "0km" line shows the "limit line" above - i.e. the path the star would follow if an observer was situated on the "smooth moon" line drawn on the maps linked to above. The scale on the sides of the profile shows distances in kilometres (measured perpendicularly) north or south of this "limit line". The region of interest for this graze is particularly wide and extends from about 6 km NORTH to about 5 km SOUTH of the limit line.
Observing the Graze:
The graze should be relatively easy for anyone to see using a 10cm or larger aperture telescope and some simple timing equipment. Although the moon will be 85% sunlit, the star is quite bright. Further, because the star grazes roughly 14 degrees into the dark limb of the Moon as measured from the bright southern cusp, interference from the bright lunar limb should be minimal.
For more information about how to observe this graze visit this page.
To particpate in this graze please contact (as soon as possible):
Path Co-ordinates:
North Island - Napier to Wellington
South Island - Wellington to Amberley
South Island - Amberley to Waimate
South Island - Waimate to Southland
Graze Profile:
North Island Observers: Graham Blow
South Island Observers: Brian Loader
Grazing Occultation of 35 K0 Magnitude 6.2
Date 2005 November 12 (Saturday) Nominal site altitude 0m
E. Longit. Latitude U.T. Sun Moon TanZ PA WA CA
o ' " o ' " h m s Alt Alt Az o o o
168 0 0 -48 38 25 11 29 45 34 326 1.46 142.7 164.76 13.97S
168 7 30 -48 29 41 11 30 5 34 326 1.46 142.7 164.74 13.99S
168 15 0 -48 20 56 11 30 26 34 325 1.46 142.7 164.73 14.00S
168 22 30 -48 12 12 11 30 47 34 325 1.46 142.7 164.73 14.00S
168 30 0 -48 3 28 11 31 8 34 325 1.46 142.7 164.72 14.01S
168 37 30 -47 54 45 11 31 29 35 324 1.45 142.7 164.71 14.02S
168 45 0 -47 46 2 11 31 50 35 324 1.45 142.7 164.71 14.02S
168 52 30 -47 37 20 11 32 11 35 324 1.45 142.6 164.70 14.03S
169 0 0 -47 28 38 11 32 32 35 323 1.45 142.6 164.69 14.04S
169 7 30 -47 19 57 11 32 54 35 323 1.45 142.6 164.69 14.04S
169 15 0 -47 11 17 11 33 15 35 323 1.45 142.6 164.68 14.04S
169 22 30 -47 2 37 11 33 36 35 323 1.44 142.6 164.68 14.05S
169 30 0 -46 53 58 11 33 58 35 322 1.44 142.6 164.68 14.05S
169 37 30 -46 45 20 11 34 19 35 322 1.44 142.6 164.67 14.06S
169 45 0 -46 36 43 11 34 41 35 322 1.44 142.6 164.67 14.06S
169 52 30 -46 28 6 11 35 2 35 321 1.44 142.6 164.67 14.06S
170 0 0 -46 19 30 11 35 24 35 321 1.44 142.6 164.67 14.06S
170 7 30 -46 10 56 11 35 46 35 321 1.44 142.6 164.66 14.06S
170 15 0 -46 2 22 11 36 7 35 320 1.44 142.6 164.66 14.07S
170 22 30 -45 53 49 11 36 29 35 320 1.44 142.6 164.66 14.07S
170 30 0 -45 45 17 11 36 51 35 320 1.43 142.6 164.66 14.07S
170 37 30 -45 36 46 11 37 13 35 320 1.43 142.6 164.66 14.07S
170 45 0 -45 28 17 11 37 34 35 319 1.43 142.6 164.66 14.06S
170 52 30 -45 19 48 11 37 56 35 319 1.43 142.6 164.67 14.06S
171 0 0 -45 11 21 11 38 18 35 319 1.43 142.6 164.67 14.06S
171 7 30 -45 2 55 11 38 40 35 318 1.43 142.6 164.67 14.06S
171 15 0 -44 54 30 11 39 2 35 318 1.43 142.6 164.67 14.06S
171 22 30 -44 46 6 11 39 24 35 318 1.43 142.6 164.68 14.05S
171 30 0 -44 37 44 11 39 46 35 317 1.43 142.6 164.68 14.05S
171 37 30 -44 29 23 11 40 8 35 317 1.43 142.6 164.68 14.05S
171 45 0 -44 21 4 11 40 30 35 317 1.43 142.6 164.69 14.04S
171 52 30 -44 12 45 11 40 52 35 317 1.43 142.6 164.69 14.04S
172 0 0 -44 4 29 11 41 14 35 316 1.43 142.6 164.70 14.03S
172 7 30 -43 56 13 11 41 36 35 316 1.43 142.7 164.70 14.02S
172 15 0 -43 48 0 11 41 58 35 316 1.43 142.7 164.71 14.02S
172 22 30 -43 39 47 11 42 21 35 315 1.44 142.7 164.72 14.01S
172 30 0 -43 31 37 11 42 43 35 315 1.44 142.7 164.73 14.00S
172 37 30 -43 23 28 11 43 5 35 315 1.44 142.7 164.73 14.00S
172 45 0 -43 15 20 11 43 27 35 315 1.44 142.7 164.74 13.99S
172 52 30 -43 7 15 11 43 49 35 314 1.44 142.7 164.75 13.98S
173 0 0 -42 59 10 11 44 11 35 314 1.44 142.7 164.76 13.97S
173 7 30 -42 51 8 11 44 33 35 314 1.44 142.7 164.77 13.96S
173 15 0 -42 43 8 11 44 55 35 313 1.44 142.7 164.78 13.95S
173 22 30 -42 35 9 11 45 17 35 313 1.44 142.7 164.79 13.94S
173 30 0 -42 27 12 11 45 39 35 313 1.45 142.7 164.80 13.93S
173 37 30 -42 19 16 11 46 1 35 312 1.45 142.8 164.81 13.92S
173 45 0 -42 11 23 11 46 23 35 312 1.45 142.8 164.82 13.90S
173 52 30 -42 3 32 11 46 45 35 312 1.45 142.8 164.84 13.89S
174 0 0 -41 55 42 11 47 7 35 312 1.45 142.8 164.85 13.88S
174 7 30 -41 47 54 11 47 29 35 311 1.45 142.8 164.86 13.87S
174 15 0 -41 40 9 11 47 51 34 311 1.46 142.8 164.88 13.85S
174 22 30 -41 32 25 11 48 13 34 311 1.46 142.8 164.89 13.84S
174 30 0 -41 24 43 11 48 35 34 310 1.46 142.9 164.90 13.82S
174 37 30 -41 17 3 11 48 57 34 310 1.46 142.9 164.92 13.81S
174 45 0 -41 9 26 11 49 19 34 310 1.46 142.9 164.94 13.79S
174 52 30 -41 1 50 11 49 41 34 310 1.47 142.9 164.95 13.78S
175 0 0 -40 54 16 11 50 3 34 309 1.47 142.9 164.97 13.76S
175 7 30 -40 46 45 11 50 24 34 309 1.47 142.9 164.98 13.75S
175 15 0 -40 39 15 11 50 46 34 309 1.47 142.9 165.00 13.73S
175 22 30 -40 31 48 11 51 8 34 309 1.48 143.0 165.02 13.71S
175 30 0 -40 24 23 11 51 29 34 308 1.48 143.0 165.04 13.69S
175 37 30 -40 17 0 11 51 51 34 308 1.48 143.0 165.05 13.68S
175 45 0 -40 9 39 11 52 13 34 308 1.49 143.0 165.07 13.66S
175 52 30 -40 2 21 11 52 34 34 307 1.49 143.0 165.09 13.64S
176 0 0 -39 55 4 11 52 56 34 307 1.49 143.1 165.11 13.62S
176 7 30 -39 47 50 11 53 17 34 307 1.50 143.1 165.13 13.60S
176 15 0 -39 40 38 11 53 38 34 307 1.50 143.1 165.15 13.58S
176 22 30 -39 33 28 11 54 0 34 306 1.50 143.1 165.17 13.56S
176 30 0 -39 26 21 11 54 21 34 306 1.51 143.1 165.19 13.54S
176 37 30 -39 19 16 11 54 42 34 306 1.51 143.2 165.21 13.52S
176 45 0 -39 12 13 11 55 3 33 306 1.51 143.2 165.23 13.49S
176 52 30 -39 5 13 11 55 25 33 305 1.52 143.2 165.26 13.47S
177 0 0 -38 58 14 11 55 46 33 305 1.52 143.2 165.28 13.45S
177 7 30 -38 51 18 11 56 7 33 305 1.53 143.2 165.30 13.43S
177 15 0 -38 44 25 11 56 28 33 305 1.53 143.3 165.32 13.40S
177 22 30 -38 37 34 11 56 48 33 304 1.53 143.3 165.35 13.38S
177 30 0 -38 30 45 11 57 9 33 304 1.54 143.3 165.37 13.36S
177 37 30 -38 23 58 11 57 30 33 304 1.54 143.3 165.40 13.33S
177 45 0 -38 17 14 11 57 51 33 304 1.55 143.4 165.42 13.31S
177 52 30 -38 10 32 11 58 11 33 303 1.55 143.4 165.44 13.28S
178 0 0 -38 3 53 11 58 32 33 303 1.56 143.4 165.47 13.26S
178 7 30 -37 57 16 11 58 52 33 303 1.56 143.4 165.50 13.23S
178 15 0 -37 50 41 11 59 13 33 303 1.57 143.5 165.52 13.21S
178 22 30 -37 44 9 11 59 33 32 302 1.57 143.5 165.55 13.18S
178 30 0 -37 37 39 11 59 53 32 302 1.58 143.5 165.57 13.16S
178 37 30 -37 31 12 12 0 13 32 302 1.58 143.5 165.60 13.13S
178 45 0 -37 24 46 12 0 34 32 302 1.59 143.6 165.63 13.10S
178 52 30 -37 18 24 12 0 54 32 301 1.59 143.6 165.65 13.08S
179 0 0 -37 12 4 12 1 14 32 301 1.60 143.6 165.68 13.05S
Path coordinates are referred to WGS84 (as used by GPS).
Librations Long +2.60 Lat +0.14
P +165.7 D +1.0
Illumination of moon 85%+
Elongation of Moon 135
Vertical Profile Scale 3.27 km/arcsec at mean distance of moon
Horizontal Scale Factor 1.66 deg/min
Limiting Magnitudes for various telescope apertures (in mm)
CA\Tdia 50 100 150 200 250 300 350
9.0 5.0 6.5 7.2 7.7 8.0 8.2 8.3
11.0 5.3 6.8 7.5 8.0 8.3 8.5 8.7
13.0 5.3 6.8 7.5 8.0 8.3 8.5 8.7
15.0 5.4 6.8 7.5 8.0 8.3 8.5 8.7
17.0 5.4 6.8 7.5 8.0 8.3 8.6 8.7
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