OVER 2 YOU, 112 (24/12/02)

EXCEL SCRIPTS

Does anybody know how to get Excel to show a negative minutes and seconds value? My work involves timing TV scripts - having done an initial estimate of a scene length, I enter it formatted as minutes and seconds. In the next column when the scene is recorded, I enter the actual time the scene lasted. In the third column is a formula to show the difference between the two, which when it’s a negative figure appears unhelpfully as ‘#####’. Is there any way round this?

Helen Stephens, via email

By default, Excel (for Windows) uses the 1900 date system. In order to represent "negative" tie values, you should change to the 1904 date system. This can be achieved (in Excel 2002) by going to Tools -> Options -> Calculation and checking the "1904 Date System" checkbox. For more information visit http://support.microsoft.com and search the Knowledge Base for article 182247 ("XL: Negative Date/Time Value Displayed as Pound Signs (###)"). The direct link to this article is http://support.microsoft.com/

default.aspx?scid=kb;EN-US;182247.
Mike Ormond, Microsoft UK

Thanks for the challenge! This formula should enable Helen Stephens to show negative minutes and seconds when subtracting two times.  The result is a number for positive values, but a string for the negative case. A1 & B1 are the two times -
=IF((A1-B1)<0,("-"&TRUNC((B1-A1)*24*60,0)

&":"&TRUNC((((B1-A1)*24*60)-TRUNC(
(B1-A1)*24*60,0))*60,0)),A1-B1)
Bryan Bowen

This can be solved by using an IF function, combined with deducting from 24:00. As an example, if one time is cell C4, the other cell D4, then the countdown difference will remain positive by using: IF (C4>D4, C4-D4, TIME(24,0,0)-(C4-D4)). The countdown cell should be formatted (cell format/time with the first option (in Excel 2000) for which the program's example is 13:30.
Allan Beardsworth, via email

One possible solution: In the column after the current time difference, use the ABS function to get rid of any negative results. Then use Conditional Formatting on the new column to display (say) red text if the original result was negative. Assuming the new column is "D", then the formula will be "=ABS(Cn)" and the Conditional Formatting is "Formula is - =Cn<0" where "n" is the row number. Positive differences will show black and negative red.   You'll also need to use normal cell formatting to set whatever "time" display you need.  If you want to get a total time difference for a list of individual timings, SUM column C and use the above on column D.
Bryan Peak

I can’t find a way to overcome the Excel defaults. However, here is a work-around: Assume she places estimated and actual times in cells B2 and C2. The formula for the difference in cell D2 is then:

=CONCATENATE(IF((B2-C2)<0,"- ","+ "),

ROUNDDOWN(ABS(B2-C2)*24*60,0),"m ",ROUNDDOWN((ABS(B2-C2)*24*60-

ROUNDDOWN(ABS(B2- C2)*24*60,0))*60, 2),"s")

The format should be set to General or Text. Note that she won’t be able to do any maths on this expression because it’s text composed of the extracted components of the time. However, her original formula for the time difference (B2-C2), although not displayed correctly, could be displayed as a number with the General format, and a number of them could be added together to get a total time difference. The above formula could then be applied to this cell.
Dave Parker, Whitchurch, Aylesbury

EL ALAMEIN MEMORIAL

Does anyone know where I can obtain the names of soldiers listed on the El Alamein War Memorial who died on the 9th December 1942, with no known grave? Is there a Memorial website with listed names? In the past I recorded the names by hand but I lost the list in a recent house move.

Derick Jonner, via email

Concerning memorials of soldiers, airmen and sailors who have died in wars, your correspondent should contact the Commonwealth War Graves Commission, 2 Marlow Road, Maidenhead. Tel 01628-634221. (web site www.cwgc.org or by e-mail casualty.enq@cwgs.org .

A few years ago I wanted to find out about my cousin who died after the Normandy invasions.  All I knew was that he was injured and died when a hospital ship was torpedoed in the Channel and had no grave.  I was a child at the time.

A called the War Graves Commission and they supplied me with more information, and directed me to a Memorial at Bayeux.  They even told me on which panel I would find his name.  I think I was the only family member who ever visited this memorial I was very honoured to stand before his name and lay a poppy on the ledge at the base of the Memorial.

Sheila Ryle

STATISTICAL DISTRIBUTION

Does anyone know of a piece of mathematical software or a website, preferably free, that will show if a data set fits a statistical distribution, such as normal or Poisson distribution?

Roger Thornhill, via email

Mintab is excellent mathematical software that can be used to confirm if a data set is normal or not to a 95% confidence level. You can download a free 30-day demo of this software from their web site: www.minitab.com/downloads/index.htm. In addition the UK based help desk is very helpful.
Chris Lakin

I would recommend that rather than obtaining a specific piece of software he buys himself a copy of Numerical Recipes (Cambridge University Press). This book describes a huge variety of mathematical problems (including Statistics) and comes with a disc (code written in Pascal, FORTRAN, C or BASIC), which provides general solutions to all the problems described. There must be at least 150 different programs included each of which is fully described and can be incorporated with any routines written elsewhere in the same language.

Owen Pike

I have frequently used the program "BestFit" to do exactly that.  The program, alas not free, is easy to use, has a wide range of statistical functions to which it fits the data and ranks each in goodness of fit.  The results can be shown in graphical and tabular form.  The contact web site is:  www.palisade.com

E T Taylor

I suggest that Roger Thornhill contacts WBGillamJR@aol.com. Mr. Gillam will provide a copy of Grafprog f.o.c. if it is not required for commercial purposes.

Jim Mercer

PC TELESCOPE

Since retiring I have become interested in astronomy and recently bought a modest Newtonian telescope. It's getting a bit nippy outside so I wondered if there was a way I could connect a video camera to the eyepiece (the fitting tube is 32mm in diameter) and stargaze on my PC? Might it also possible to control the azimuth and inclination, presumably using some kind of motorised attachment?

Henry Tyler, via email

It is perfectly possible to connect a CCD camera to a telescope, but they are far from cheap. Because of the low light received from stars, the camera has to be much more sensitive that the CCDs in digital cameras and camcorders. Models start at around £500 and go up to £2000. Control of the telescope is also common. Most of the current crop, from the likes of Meade, Celestron, Orion and so on have either built-in motors or the option of motorised mounting. However, it depends on what model of telescope you have as to whether it is possible. The following websites can give you a better idea of what is on offer.
http://www.dhinds.co.uk/frames.html
http://www.swoptics.co.uk/home.asp
http://www.sherwoods-photo.com/homepage.htm
http://www.orionoptics.co.uk
Andy Parker, jupiter@crosswinds.net

Extremely good results can be obtained by using a high-resolution low-light B/W camera fitted to an extension tube directly to any telescope without the need of a camera lens or a telescope eyepiece lens. Such cameras are relatively inexpensive. Telescope steering electronics and electronic starguiders are commercially available, at a price.

Try Broadhurst Clarkson and Fuller: 020 7405  2156 for electronic telescope servos and electronic starguiders. Also extension tubes and C mount camera fittings.

or, David Hinds Optics: 01442 827768.  for all of the above items. 

For cameras try Y3K Digital CCTV (0870 442 2020). type PBC 104 or similar, or Henry's Radio (0207724 0323) for B/W Camera type 1014.

Paul Brooke

ROCKET BACKPACK

Does anyone recall the rocket backpack in the James Bond film Thunderball? I believe such a device did actually exist but did it ever go into production and if so, where can I get one?

D. Lewin, via email

Information about past and current projects, together with links to the external sites of the developers, can be found at: http://www.techtv.com/news/scitech/ story/0,24195,3372941,00.html

T.M.F.

There was a real backpack made by the Bell aviation company of the US (A helicopter company). If you wish to see a homemade experiment then check out: 
http://home.earthlink.net/~tompsk/Home.html/ my son and I had a little fun with this one.
David Tompkins

Rocket backpacks being marketed on www.firebox.com, and they’re even better than the James Bond one! Firebox.com is a gift website. Look under "expensive stuff". The backpack is the "Solo Trek XFV".

Ann Holmes, via e-mail.

Sad to say that the James Bond backpack only had an operational flight time of 1.5 minutes anyway so it isn't long distance transport. He might however have a look at http://www.howstuffworks.com/personal-jetpack.htm, which shows a modern version in a more practical form. Howstuffworks.com has a number of articles on future transport including hover boards and flying cars. Be warned the site is addictive for any technophobe!

http://www.flying-contraptions.com/history.html also has some information on the original Bell jet pack of James Bond fame.

Richard Harris

CAN YOU HELP?

I was recently given a Sony Aibo ERS-111 robotic dog. Unfortunately ‘Softy’ seems to be very sick. Sony tells me it has to be sent to France and wanted over £100 just to look at it, plus scary sums to replace limbs or the head. Are there any robotic vets in the UK who can see to my poorly plastic pooch?

Emily Trainer, via email

I was amazed to find that my new pre-loaded Windows ME system does not have a fax function and Microsoft offer neither an apology for this or any solution. Can anyone recommend an easy to install fax program, which will allow me to send faxes in the way they were handled in Window 95?
Hal Thomas, via email

I am entering a competition for a motorcycle design. I have plenty of ideas, but no means of expressing them in a technical format. My entry needs to be submitted by e-mail, can anyone suggest software for technical drawings?

Paul Reynolds.