Monday, 23 May 2016

Summit Relocations – The 500-Metre Tops of England and Wales – The Deweys

Esgair Greolen (SN 835 920)  

Michael Dewey has confirmed that the summit of Bryn yr Ŵyn (SN 83919 92571) is relocated to the higher summit of Esgair Greolen (SN 83574 92022) and therefore replaces Bryn yr Ŵyn as the hill listed in his 500-Metre Tops of England and Wales, which is affectionately known as the Deweys.

My word you’ve been busy in the Pumlumon area. Excellent work and I know it’s going to be appreciated by the people doing the Five-hundreds.  I’m pleased to accept the summit relocations of Bryn yr Ŵyn at grid reference SN 83919 9257 and Esgair Greolen at SN 83574 92022.

Michael Dewey (May 2016)

Esgair Greolen (SN 835 920) centre left of photo and Bryn yr Ŵyn (SN 839 925) on right of photo

The listing to The 500-Metre Tops of England and Wales appeared in Michael’s Mountain tables book which was published by Constable in 1995.  Since that date there have only been a few summit relocations which have resulted in replacement summits being confirmed, those affecting Wales include:

Pen y Bedw East Top (SH 784 470) replaces Pen y Bedw West Top (SH 779 469)

Cerrig Llwydion (SN 909 731) replaces Sychnentydd (SN 909 724)

Esgair Greolen (SN 835 920) replaces Bryn yr Ŵyn (SN 839 925)

Mountain tables by Michael Dewey

This summit relocation and replacement summit was confirmed by a survey conducted over two days; 05.05.16 and 13.05.16 with the Trimble GeoXH 6000.  In all five data sets were taken from the summit of Bryn yr Ŵyn and four from the summit of Esgair Greolen.  Each summit height has been averaged from these combined surveys:

Esgair Greolen 501.4m (converted to OSGM15) summit at SN 83574 92022

Bryn yr Ŵyn 499.9m (converted to OSGM15) summit at SN 83919 92571

Gathering data from the summit of Bryn yr Ŵyn

Gathering data from the summit of Esgair Greolen

If wanting more detail please consult the blog post for the 1st Trimble survey and the 2nd Trimble survey of these summits.  All details relating to each data set taken during the two days which took in these surveys are given in the Trimble Survey Spreadsheet.

Myrddyn Phillips (May 2016)


Myrddyn said...

This looks like another fine piece of measuring that helps tidy up a Mountain list.

Back in 2011 when I was wandering this area of hills collecting Dewey’s, I was aware that the “massif” had two little occurrences of the 500 metre contour, and my roughly accurate but precisely wrong home made pocket “theodo-lite” could not separate the two very similar tops.

My main concern with the pair of tops was that of relative height. From the col 300 metres WSW of the summit of Esgair Greolen, my notes say that I thought it was not much over 28 vertical metres up to the summit tuft of rough grass.

Knowing your diligence on such things you obviously measured it and it must have come out at over 30 metres, or we would be reading a different story!

What was the result?

John Kirk.

Myrddyn said...

Hi John

The drop for Esgair Greolen as measured by the Trimble is 30.3m. I took 16 data sets from the area of the bwlch over the two days I spent on these hills. Thankfully the weather was hospitable with lovely sunshine.