Calf Top (SD 664 856) – Dewey deletion
This is one in a series of retrospective Hill
Reclassification posts that detail hills whose status has altered in the
listing of the Deweys and where I have had direct association with the status
change. These posts will tie in with a
forthcoming Change Register giving detail to this list and its alterations
since publication in the Mountain tables
book.
Calf Top (SD 664 856) |
The
500-Metre Tops of England and Wales
are affectionately known after their hill list compiler; Michael Dewey. This list mixes metric and imperial height in
its criteria to bookend up to the 2000ft height band and takes in all hills in
England, Isle of Man and Wales that are 500m and above and below 2000ft
(609.6m) in height that have 30m minimum drop.
This list formed
one of a number of lists that appeared in the Mountain tables book published by Constable in 1995 and at the time
of publication comprised 373 hills with 164 in England, 5 in the Isle of Man
and 204 in Wales. The Deweys have
undergone extensive revision since first publication with the initial stages
forming the basis of this revision given below:
1995 Mountain
tables published by Constable with 373 hills listed as Deweys.
April
2000 Strider (LDWA quarterly booklet) publishes contact details for
David Purchase and Myrddyn Phillips who have found and list 24 and 14 possible
new 500m tops respectively.
It
was expanded versions of the above two lists that formed the basis of the next
publication:
25th
May 2000 List of Possible 500 Metre Tops by Michael Dewey listing 44 hills.
David
Purchase expands his Additional Dewey
500m Hills and Myrddyn Phillips produces lists of English 500m hills to measure and Welsh 500m hills to measure.
These
lists formed the basis of the next publication:
29th
June 2000 Possible/Probable 500’s by Michael Dewey listing 77 hills. Michael adopts following protocol; if one person proposes that a top should
qualify as a 500 by personal survey, and is then confirmed by a second person,
it should then be promoted to the main list.
April
2002 The 500+ Tops of England and Wales – The ‘New Deweys’ published in
the Strider booklet and listing 66 new qualifying hills.
25th
May 2006 Rob Woodall republishes
Michael’s main and possible/probable lists on the RHB Yahoo group file
database.
The details for this deletion appear below:
The name the hill is listed by in the Deweys is Calf Top, and it is adjoined to the Ingleborough group of hills which are situated in the central Pennines of northern England, and it is positioned with the A683 and the M6 roads to its west, and has the small town of Sedbergh towards the north and the small community of Barbon towards the south-west.
The name the hill is listed by in the Deweys is Calf Top, and it is adjoined to the Ingleborough group of hills which are situated in the central Pennines of northern England, and it is positioned with the A683 and the M6 roads to its west, and has the small town of Sedbergh towards the north and the small community of Barbon towards the south-west.
This hill was included in the original 1995
Constable publication and listed with a 609m summit height which is adjoined to
a triangulation pillar given the flush bracket height of 609.600m in the OS
Trig Database, and which appears as a spot height on the Ordnance Survey
1:50,000 Landranger and 1:25,000 Explorer maps.
As its 609m summit spot height was near the
benchmark height of 2000ft (609.6m) it was prioritised for a GNSS survey and
this took place on the 15th April 2010. The summit of this hill was surveyed by John
Barnard, Graham Jackson and Myrddyn Phillips using a Leica 530 with two hours
of data gathered, resulting in a summit height at the time of 609.61m.
Gathering data during the first Leica 530 survey of Calf Top |
As this result was so close to the benchmark height of 2000ft (609.6m) it was decided to re-visit and gather a further four hours of data. The second survey was conducted on the 20th May 2010 by John Barnard, Graham Jackson and Myrddyn Phillips using a Leica 530, resulting in a summit height at that time of 609.62m. As the results from these surveys were so close to the 2000ft / 609.6m height the two data sets were sent to Ordnance Survey and were processed using their Bernese software, resulting in a summit height of 609.58m.
Gathering data during the second Leica 530 survey of Calf Top |
This result was re-assessed in August 2016 when Ordnance Survey adopted their new OSTN15 / OSGM15 model which replaced their OSTN02 / OSGM02 model. The adoption of the OSTN15 / OSGM15 model increased the known height of hills in England by an average of 2cm - 4cm, and in the case of Calf Top this resulted in its known accurate height increasing to 609.61m, which is higher than the maximum 2000ft (609.6m) height for Dewey status.
These details were forwarded to the list author; Michael Dewey and the hill was deleted from his list in September 2016.
These details were forwarded to the list author; Michael Dewey and the hill was deleted from his list in September 2016.
The full details for the
hill are:
Name: Calf Top
OS 1:50,000 map: 98
OS 1:25,000 map: 2
Summit Height: 609.61m (converted to OSGM15, Leica 530)
Summit Grid
Reference: SD 66450 85624 (Leica 530)
Col Height: c 289m (interpolation)
Col Grid Reference: SD 68178 86259 (interpolation)
Drop: c 321m (Leica 530 summit and interpolated
col)
Myrddyn Phillips
(October 2020)
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