TrigpointingUK

(In case anyone reads this forum but not the Trigonomy Yahoo! group messages.)

It's recently come to light that the Berntsen listed on T:UK as Ballards Ash 2 has nothing in the way of documentary evidence to prove that it is in fact a passive station, or indeed linking it to the Ordnance Survey in any other way. Does anyone have knowledge of how this item came to be listed as a passive, other than the immediate proximity of Ballards Ash itself?

Not me. Think it makes sense to merge it with the main Ballards Ash page. NB Ballards Ash seems to have two Berntsens equidistant from the SB.

Another Passive with an associated Berntsen is Failand http://trigpointing.uk/trig/287 - in that case included on a single trig page. Bailbrook http://trigpointing.uk/trig/292 is another SB with Berntsen; Bosawsack http://trigpointing.uk/trig/328 another - daresay there are others.

There's another in the Scottish Central Belt but I can't just recall where (up a scruffy little lane south of a main road) - I struggled to find the SB; never did find the Berntsen and from the various logs thought there may be two Berntsens there.

This seems an intriguing little corner of the OS/trig world.

Sometimes there is an FBM / SB / Berntsen close pair/trio and they each have their own station numbers - I think?

Moor Fields http://trigpointing.uk/trig/7325 in West Yorkshire
is another instance of an OS Surface Block C1SE2227
https://www.ordnancesurvey.co.uk/gps/le ... n/C1SE2227
with a Berntsen just a few metres away; the latter is non-OS as far as we know.

ted wrote:Moor Fields http://trigpointing.uk/trig/7325 in West Yorkshire
is another instance of an OS Surface Block with a Berntsen just a few metres away; the latter is non-OS as far as we know.

Thanks Ted - that was the one I was thinking of, near Leeds, not Central Scotland

From others' Moor Fields logs, I thought there must be two Berntsens there, but failed to find anything other than the SB.

Turning the question around, are there any instances of Passives with Surface Block and Berntsen close together with each having its own station ref?

An example of an FBM with SB and Berntsen close together is the Oswestry FBM Aux 1 Berntsen H2SJ2724 http://trigpointing.uk/trig/606 which is close to the Llynclys surface block C1SJ2824 http://trigpointing.uk/trig/181
but they are 0.4km from each other. There are other such trios IIRC.

Are there any examples without a FBM involved?

It might be interesting to add this info to the Passive Stations wiki page http://trigpointing.uk/wiki/Passive_station

However at present there's nothing there at all - anyone able to make a start? I've never been at all clear on how passives were used, and whether they still are ...

Hi Rob,

<geek alert!>

As regards proximity, offhand I can't think of any instances of an
FBM + OS bolt/block passive + OS Berntsen passive group where the
stations are in the order of 10 metres from eachother. 100 metres
or more seems to be the norm.

The most compact passives group I can think of is at Hibaldstow:
http://trigpointing.uk/trig/7247 (FBM, 1987) H1SE9301
http://trigpointing.uk/trig/602 (Berntsen) H2SE9301
http://trigpointing.uk/trig/168 (Rivet) C1SE9301
(The FBM has been relocated but I'd guess the Berntsen and Rivet
were placed at some point after this occurred).

In general, I think its the case that where a Berntsen has been found without
a nearby FBM then either its a replacement for an earlier Surface Block
or else its non-OS.

For example theres this Bolt/Berntsen pair without an FBM:
Stokes Bay http://trigpointing.uk/trig/7886 (Bolt) C1SZ5998
Stokes Bay Two http://trigpointing.uk/trig/469 (Berntsen) C2SZ5998
(The Trigpoint logs are a bit muddled with various non-OS marks recorded.)

The OS Station record for C1SZ5998 Stokes Bay seems to have gone; however it
still has the sketch record at:
https://www.ordnancesurvey.co.uk/gps/St ... SZ5998.gif

The station record for C2SZ5998 Stokes Bay Two exists:
https://www.ordnancesurvey.co.uk/gps/le ... n/C2SZ5998
which leads to a photo and sketch; the latter is at:
https://www.ordnancesurvey.co.uk/gps/St ... SZ5998.gif

The sketches for C1 and C2 are the same as far as I can tell.
Stokes Bay Two is recorded in Trigpointing UK as a Berntsen.
But I suspect that the C2 passive was a replacement for C1 and so
the two stations never existed concurrently.


- Ted

ted wrote: But I suspect that the C2 passive was a replacement for C1 and so
the two stations never existed concurrently

Ted, does the 2 after the C not imply exactly that C2 was a replacement or C1?

I suppose theoretically C2 could just be the second station of that order in the grid square that follows, but isn't it always the case that the second station replaced the first rather than existing concurrently?

Anyway, if Ted doesn't know then nobody will, so I'm going to merge Ballards Ash2 into Ballards Ash now.

I've added some of this good stuff to http://trigpointing.uk/wiki/Berntsen#Berntsen Feel free to improve...