Talk:Level (optical instrument)

Technical Name

Is "Dumpy level" a nickname or the name you read in the catalogue? "Automatic level" seems more appropriate to me, but it could be a regional thing.--Commander Keane 08:17, 11 November 2005 (UTC)

• It's certainly not regional. A quick google search should reveal that it is used in all English-speaking countries. Luigizanasi 08:30, 11 November 2005 (UTC)
• It's an older term for the original style of level, depending on the amount of gray you have in your beard will depend on your familiarity with the term ;-) Automatic levels are a modern, easier to use version which have basically replaced the dumpy. *Sigh* I remember.... I've expanded on it in the article — Graibeard 10:51, 11 November 2005 (UTC)
• If my memory serves me right, the old dumpy level used to reverse the image. That is you would see the staff upside down. I have been told to stop using the term Dumpy, when the correct usage is Auto level. This is in Australia. Old habits die hard.billbeee 20:58, 5 March 2007 (UTC)
• Concur with Graibeard' on dumpy level term, but can severely expand on it. Dumpy level was actually a very specific design. There were also 'Y' levels, aka Wye Level, Convertible Y levels, tilting levels and precision tilting levels. (now counting my grey hairs..). I also have backing source info in the form of surveying equipment catalogs, some as old as 1902. I think the dumpy level needs to be limited to just that form of level. I also feel that a header or 'break out' page that will refer to the specific types of level. With respect to a dumpy level reversing the image. Not all of them do, but the older the instrument is, the more likely that the image is inverting. The reason is somewhat involved.Ucodegen 05:57, 23 August 2007 (UTC)

Transit vs level

This is what I've always heard called a transit. Is transit a misnomer?

Yes. See the article on Theodolite for a description of the transit. Briefly, a transit measures angles while a dumpy or builder's level measures, well, levels. Luigizanasi 01:24, 22 June 2006 (UTC)

• This needs a slight correction. There are such devices as "transit levels", whose angle resolution is very poor and may only have a horizontal circle. There is a bit of continuum around the Convertible Y levels to Builder's TransitsUcodegen 05:57, 23 August 2007 (UTC)

The transits of the early 20th century had a horizontal circle and often had both a vertical circle and a spirit level. They could be considered as a universal instrument that both could do the work of a theodolite and that of a dumpy level. The main difference between a theodolite and transit of that day though was that a transit could transit. By taking readings then transit the telescope, rotating it 180 degrees around both the horizontal and vertical axles, and taking readings again and calculate the average values you could rather simply eliminate almost all instrument errors except for if the vertical axis of the instrument wasn't being vertical. Johan G (talk) 20:46, 10 August 2009 (UTC)

Inclusion of 'Usage'

While I don't dispute the factuality of Billbeee's section on checking levels, I don't believe that this should be included in Wikipedia. Point 4 of Wikipedia is not an indiscriminate collection of information instructs that articles should not include "how-to"s and therefore I side with Veinor in removing this section. This information may be more appropriate in a Wikibook. AuroraD 20:18, 6 March 2007 (UTC) Sorry guys, my mistake, no more how-to's.billbeee 20:44, 6 March 2007 (UTC)

Temporary adjustment of level

Selection of suitable postion : A suitable position is selected for setting the level. From this position, it should be possible to take the greatest number of observations without any difficulty. The ground should be fairly level and firm.

Fixing level with tripod stand : The tripod stand is placed at the required position with its legs well apart, and pressed firmly into the ground.

The level is fixed on the top of the tripod stand according to the fixing arrangement provided for that particular level. It should be remembered that the level is not to be set up at any station or point along the alignment. —Preceding unsigned comment added by 116.72.11.27 (talk) 06:05, 13 January 2010 (UTC)

How To Use a Dumpy Level

The Dumpy level is fixed to a tripod, then depending on the type of level, some are self levelling and some are levelled manually using the three turning screws at the base of the level, by moving these screws you will alter the position of the bubble in the two small spirit levels also found at the base of the level, you need to get the bubbles in the centre, once this is done turn the level on the tripod and make sure the bubbles are still in the correct position. The operator looks through the eyepiece of the telescope while an assistant holds a tape measure or graduated staff vertical on the point of where you want to set your level from, if for instance you were setting out a garage base you would place the measuring staff at the point or height you have chosen the garage floor to be at, then you look through the level and your operator can either make a mark on the staff or tape at the point of were the cross hairs of the scope fall, he can then move around to different areas of the site, when he reaches another point you want to create a level, you then look through the scope again while your workmate lifts or lowers the staff or measure until the cross hairs are back on the same mark, the bottom of the staff will be at exactly the same point as the previous position. You carry on with this process until you have all the level point you require to give you a true level platform to work from.Dumpy Level Image — Preceding unsigned comment added by Kirk stansfield (talk • contribs) 07:14, 16 October 2012 (UTC)

Kirk stansfield (talk) 02:06, 2 August 2013 (UTC)

How different?

I have just spent time on Wikipedia, and using Google. I can find nothing that gives the slightest hint how the Wye Level, the Dumpy Level, and the Theodolite differ. They all seem identical to the educated layman (me). Nwbeeson

• Level - telescope with crosshairs and a system for levelling its axis, a spirit level on the tube. Usually (these days) also has stadiametric marks on the graticule and sometimes an azimuth scale. These traditional levels with a Galilean telescope are inconvenient, because achieving their accuracy relies on having a long tube. Levels are all used with their tubes levelled.
• Y level or wye level - an accurate level, where the azimuth bearing supports a Y-shaped beam (more usually a fork or a horizontal beam with uprights). This beam then supports the delicate telescope tube near its ends. This is all done to avoid bending forces, and thus inaccuracies, on the telescope tube when moving it (it's bad form to handle such a level by its tube).
• Dumpy level - a short level. More convenient to transport, yet just as accurate. Uses more sophisticated internal optics to allow a shorter external tube.
• Autoset level - a dumpy level, but with an internal pendulum that controls a levelling prism. Rather than manually levelling the tube from outside, the tube is set approximately level and then its innards do the fine adjustment optically.
• Cowley level - an automatic level resembling a brick. Dumbed down for builders, not engineers or surveyors.
• Theodolite - Similar to a level, but with both azimuth and elevation scales. A combination of the surveyor's previous instruments, the level and the alidade. Unlike a level, the theodolite tube can be tilted in elevation and make measurements away from the horizontal plane.
• Transit theodolite - a theodolite where the tube can be flipped over in elevation to point accurately backwards, rather than using the azimuth adjustment (the accuracy of the elevation bearing in its plane being better than the azimuth scale graduations). More accurate for some particular sorts of surveying, such as setting out a surveyor's transit - a long line of aligned points. Note that this does not take its name from an astronomical transit, even though there were specialised telescopes for watching those (you can see one at the Royal Observatory at Greenwich).

Andy Dingley (talk) 09:52, 26 September 2013 (UTC)