Author Topic: How to read the year  (Read 3681 times)

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Offline nomadbird

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How to read the year
« on: March 04, 2011, 07:10:37 AM »
Hi Guys,

I tried to identify the year number on the saudi arabia coins and learn t that it is from the Hijri Islamic calendar year. Are there any standard conversions available for Islamic to Christian calendar ?

Thx
Nomadbird

Offline Abhay

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Re: How to read the year
« Reply #1 on: March 04, 2011, 07:21:53 AM »
Dear Nirmal,

Yes, at the beginning of any standard Coin Catalogue (More particularly, the Standard Catalogue of World Coins- SCWC in short), you will find a conversion table for converting Hijri Years to Christian years.

Alternately, you can use the "TIME MACHINE" to convert the year.

Abhay
INVESTING IN YESTERDAY

Offline nomadbird

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Re: How to read the year
« Reply #2 on: March 04, 2011, 07:26:11 AM »
Dear Nirmal,

Yes, at the beginning of any standard Coin Catalogue (More particularly, the Standard Catalogue of World Coins- SCWC in short), you will find a conversion table for converting Hijri Years to Christian years.

Alternately, you can use the "TIME MACHINE" to convert the year.

Abhay

Good morning Abhay... for a Year 1423.. the result i got was 2044.... how can this be possible ?
Thx
Nomadbird

Offline Abhay

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Re: How to read the year
« Reply #3 on: March 04, 2011, 07:31:57 AM »
Yes, you are right Nirmal. I noted that the Afghanistan system works on Solar Hijri system.

Now try the Time machine with Lunar Hijra calendar. Here, the results are OK.

http://apps.creounity.com/time_machine/en/index.php?go=arab.php

Abhay
INVESTING IN YESTERDAY

Offline FosseWay

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Re: How to read the year
« Reply #4 on: March 04, 2011, 09:10:54 AM »
The old-fashioned method, which I learnt from a book called Coin Collecting for Beginners that I had out of the library when I was a kid, is:

• Deduct 3% from the Islamic date (standard, non-solar, as used in most Sunni countries)
• Add 622 (the year AD from which the Islamic calendar begins, when Muhammad migrated with his followers to Medina because his life was in danger in Mecca)

Deducting 3% is required because the Islamic year is 354 days long (96.9% of the Western year).

So to convert AH 1400 to AD:

• 3% of 1400 is 42
• 1400 – 42 = 1358
• 1358 + 622 = 1980

Offline nomadbird

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Re: How to read the year
« Reply #5 on: March 04, 2011, 09:20:18 AM »
• Deduct 3% from the Islamic date (standard, non-solar, as used in most Sunni countries)
• Add 622 (the year AD from which the Islamic calendar begins, when Muhammad migrated with his followers to Medina because his life was in danger in Mecca)


That worked perfect for my 1423  - 3% = 1380 + 622 = 2002. Same I got in the website which Abhay gave

thanks Guys
Thx
Nomadbird

translateltd

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Re: How to read the year
« Reply #6 on: March 04, 2011, 09:29:03 AM »
The 3% rule is a good, quick rule of thumb.  Another formula that I got from some banknote book long forgotten is:

(AH date x .970224) + 621.5774 = AD date

In these days of computer calculations, that's probably no slower to work out than the 3% rule above :-)




Offline asm

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Re: How to read the year
« Reply #7 on: March 04, 2011, 10:14:33 AM »
The 3% rule is a good, quick rule of thumb.  Another formula that I got from some banknote book long forgotten is:

(AH date x .970224) + 621.5774 = AD date

This one may be more accurate. Multiplying by 0.97 (rounded off to the nearest 2 decimals) is the same as deduct 3% and adding 621.5774 (when rounded off will be 622).

Amit
"It Is Better To Light A Candle Than To Curse The Darkness"

Offline nomadbird

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Re: How to read the year
« Reply #8 on: March 04, 2011, 10:57:16 AM »
(AH date x .970224) + 621.5774 = AD date

I did the math and found some error in rounding..... the best formula was

(AH date x .970224) + 621.3714 = AD date
Thx
Nomadbird

Offline FosseWay

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Re: How to read the year
« Reply #9 on: March 04, 2011, 03:09:47 PM »
The most likely cause of a ±1 error in the conversion is not a rounding error in the calculation but the fact that the respective New Years may be ~6 months apart from one another. Hence at some point in AH 1400 the Western year will have become 1981, but the calculation would still yield 1980, however many decimal places you use for the multiplier. The only way round this would be to put the correct fraction of the year as a decimal after 1400.

This phenomenon can lead to date-related varieties on coins dated in both systems if the mint concerned is scrupulous about changing the date when each calendar ticks over. For example, a coin dated AH 1400 could exist in varieties carrying the AD dates 1980 and 1981, while a coin dated AD 1980 may have varieties dated AH 1399 or 1400. When you get three-way dating, as on some Princely States coins, it gets fiendishly complicated! Luckily, or not, depending on your viewpoint, most dual-dated coins in my experience carry only one date in each system before both are changed simultaneously.

Offline SpaBreda

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Re: How to read the year
« Reply #10 on: March 04, 2011, 09:39:29 PM »
Those double dates are fun to look for  :D
Here are 2 examples (Algeria and Kuwait)

Paul.

Offline africancoins

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Re: How to read the year
« Reply #11 on: March 04, 2011, 09:58:50 PM »
Here's another...

Thanks Mr Paul Baker

Offline asm

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Re: How to read the year
« Reply #12 on: March 07, 2011, 02:32:48 AM »
At around the same time, Some Indian Princely States had coins with 3 different era dates on them (Bhawalpur). 2 was very common (Kutch had 2 dates for many years).

Amit
"It Is Better To Light A Candle Than To Curse The Darkness"

Offline Coinsforever

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Re: How to read the year
« Reply #13 on: March 07, 2011, 02:53:27 AM »
I would add one more Indian state  with 3 dating system on their coins - Jaora state refer the details.

Cheers ;D
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