Post on 03-Dec-2021
Rosie Bolton 1SKA1 LayoutWP2 Meeting Oxford October 2010
SKA Phase 1 Generic
Configuration
Rosie Bolton, Rob Millenaar
Rosie Bolton 2SKA1 LayoutWP2 Meeting Oxford October 2010
Configuration work
• Site specific configurations are under development –
CTF has worked with both the Aus and SA teams over
the summer to develop preliminary layouts for both sites.
• These layouts are as close as possible to the generic
configurations, after taking into account the various
constraints (waterways, roads, towns etc).
• However, we are waiting for one final mask layer before
finishing the layouts.
• …so, we have developed example layouts at a generic
location with no constraints, that can be used for
preliminary investigations.
Rosie Bolton 3SKA1 LayoutWP2 Meeting Oxford October 2010
Quick overview• Phase 2:
– 300 dishes, 2400 of which are within 180km of array centre.
• PAF capable dishes (so PAFs would sit on an undetermined sub
set of these 3000 dishes).
– 250 AA stations for each AAlo and AAmid
• Separate cores for all collector technologies, separated by a few km
(>6km centre-centre)
• Phase 1:
– 250 Dishes, all within 100km of array centre.
• 125 within 500m radius
• 175 within 2500m radius
• 75 dishes clustered into groups of 5 sitting on 3 spiral arms,
logarithmically spaced from 2.5km to 100km. (15 clumps)
– AA (Low freq): 50 stations assumed, each 180m in diameter.
• 25 within 500m radius, 35 within 2.5km radius, remaining 15 co-
located with dish clumps.
Rosie Bolton 4SKA1 LayoutWP2 Meeting Oxford October 2010
SKA P2 Dish layout
Core:600 dishes within 500m radius
•Inner region: 1500
dishes within 2500m
Rosie Bolton 5SKA1 LayoutWP2 Meeting Oxford October 2010
Mid range: 900 dishes between 2.5km
and 180km radius
“Skirt” from 2.5 to
13km (350 dishes)
•Beyond 13km
dishes are grouped
into clumps of 11
Rosie Bolton 6SKA1 LayoutWP2 Meeting Oxford October 2010
5 spiral arms out to
180km radius
50 clumps of dishes
(not assumed to be
beamformed)
Logarithmic
distribution in radius
Rosie Bolton 7SKA1 LayoutWP2 Meeting Oxford October 2010
Shadowing in the centre• Worst case dish cannot
see 50% of the sky (dark
red)
Rosie Bolton 8SKA1 LayoutWP2 Meeting Oxford October 2010
Shadowing in the centre
• No shadowing at 45
degrees elevation or
higher
• 400 dishes shadowed at
15 degrees elevation
Rosie Bolton 9SKA1 LayoutWP2 Meeting Oxford October 2010
Phase 1 Dish layout
Randomly filled gaussian core with 125 dishes
within 500m radius
Rosie Bolton 10SKA1 LayoutWP2 Meeting Oxford October 2010
Phase 1 Dish layout
175 dishes within 2500m radius
Rosie Bolton 11SKA1 LayoutWP2 Meeting Oxford October 2010
Phase 1 Dish layout
Beyond 2.5km radius,
there are a further 75
dishes. These are
placed in groups of 5,
along 3 of the 5 Phase
2 spiral arms.
These dish positions
have been selected
from the available
generic Phase 2
positions…
Rosie Bolton 12SKA1 LayoutWP2 Meeting Oxford October 2010
Rosie Bolton 13SKA1 LayoutWP2 Meeting Oxford October 2010
Rosie Bolton 14SKA1 LayoutWP2 Meeting Oxford October 2010
Rosie Bolton 15SKA1 LayoutWP2 Meeting Oxford October 2010
Rosie Bolton 16SKA1 LayoutWP2 Meeting Oxford October 2010
Phase 1 Dish layout
…so the three spiral
arms are not equally
spaced, and the dish
placement is not
perfectly logarithmic
Rosie Bolton 17SKA1 LayoutWP2 Meeting Oxford October 2010
P1 Dish uv coverage
• 5km
scale
Rosie Bolton 18SKA1 LayoutWP2 Meeting Oxford October 2010
P1 Dish uv coverage
• 10km
scale
Rosie Bolton 19SKA1 LayoutWP2 Meeting Oxford October 2010
P1 Dish uv coverage
• 20km
scale
Rosie Bolton 20SKA1 LayoutWP2 Meeting Oxford October 2010
P1 Dish uv coverage
• 100km
scale
Rosie Bolton 21SKA1 LayoutWP2 Meeting Oxford October 2010
P1 Dish uv coverage
• 5km
scale
Rosie Bolton 22SKA1 LayoutWP2 Meeting Oxford October 2010
P1 Dish uv coverage
• 10km
scale
Rosie Bolton 23SKA1 LayoutWP2 Meeting Oxford October 2010
P1 Dish uv coverage
• 20km
scale
Rosie Bolton 24SKA1 LayoutWP2 Meeting Oxford October 2010
P1 Dish uv coverage
• 100km
scale
Rosie Bolton 25SKA1 LayoutWP2 Meeting Oxford October 2010
P1 Dish and AA layout
Rosie Bolton 26SKA1 LayoutWP2 Meeting Oxford October 2010
AA Core: 25 in 500m radius
Requirement for 25
AA stations within
500m radius leads
to a close-packed
layout on a 190m
triangular grid.
Rosie Bolton 27SKA1 LayoutWP2 Meeting Oxford October 2010
AA P1 Core snapshot uv
Uv plane gridding at D/2.4 (=75m)
Rosie Bolton 28SKA1 LayoutWP2 Meeting Oxford October 2010
AA uv coverage
5km
scale
Rosie Bolton 29SKA1 LayoutWP2 Meeting Oxford October 2010
AA uv coverage
5km
scale
Rosie Bolton 30SKA1 LayoutWP2 Meeting Oxford October 2010
AA uv coverage
10km
scale
Rosie Bolton 31SKA1 LayoutWP2 Meeting Oxford October 2010
AA uv coverage
10km
scale
Rosie Bolton 32SKA1 LayoutWP2 Meeting Oxford October 2010
AA uv coverage
20km
scale
Rosie Bolton 33SKA1 LayoutWP2 Meeting Oxford October 2010
AA uv coverage
20km
scale
Rosie Bolton 34SKA1 LayoutWP2 Meeting Oxford October 2010
AA uv coverage
100km
scale
Rosie Bolton 35SKA1 LayoutWP2 Meeting Oxford October 2010
AA uv coverage
100km
scale
Rosie Bolton 36SKA1 LayoutWP2 Meeting Oxford October 2010
End