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Armagh, Northern Ireland

Coding classes in Armagh

What are the best coding classes in Armagh?

The Armagh settlement had 16,310 usual residents at the 2021 census, within the Armagh City, Banbridge and Craigavon district of 218,656. Armagh Observatory and Planetarium says the Observatory opened in 1790 and that its director J.L.E. Dreyer compiled the New General Catalogue, still the principal catalogue of nebulae and galaxies used by astronomers. Armagh learners aged six to sixty-seven study with our teachers in India over live video, individually or in a group of five to ten at the same stage, at times set around the Northern Ireland school and working day. The first lesson is free; after that a group place is USD 100 a month and one-to-one lessons USD 150.

Dreyer's New General Catalogue numbers 7,840 objects, and it runs very nearly in order of position across the sky. But the sky coordinates astronomers use today are not the ones of the 1880s. How out of order is the list now? Our teenagers answer by counting inversions, the pairs listed in the wrong order, using merge sort. Checking every pair would take 30,728,880 comparisons; merge sort needs 63,917. The first answer, 359,626 inversions, is wrong: right ascension goes round in a circle, and the last 40 entries have slipped past midnight. Treat the circle properly and the true count is 47,634, with the objects near the poles by far the most scrambled.

Facts last verified 23 September 2026. Teaching is online; no Armagh branch is claimed.

Course picks for Armagh

Four courses for the observatory city

Choose the course closest to what the learner already enjoys. All four open with a free live lesson that needs no payment details.

Browse the course atlas for more than one hundred options and use the coding roadmap to check prerequisites.

The four we are known for

Python, AI, vibe coding and agentic coding

These run underneath everything above. Every one is live and online, placed by ability rather than by age, and the first class is free.

Armagh today

A small city in a district of young families

Census 2021 figures from the Northern Ireland Statistics and Research Agency for the Armagh settlement, the Armagh District Electoral Area and the Armagh City, Banbridge and Craigavon district.

Armagh and its district, Census 2021, usual residents
AreaUsual residents
Armagh settlement16,310
Armagh District Electoral Area32,405
Armagh City, Banbridge and Craigavon218,656
Northern Ireland1,903,175

Children

In the district, 7.2% of residents were aged 10 to 14 and 7.1% aged 5 to 9 in 2021, against 6.7% and 6.5% across Northern Ireland.

Young adults

People aged 20 to 24 were 5.3% of the district, a little below Northern Ireland's 5.9%, and 14,175 residents were under five.

Villages around the city

Nearby settlements include Tandragee with 3,545 residents, Keady with 3,343, Richhill with 2,738 and Markethill with 1,912.

Our Armagh groups bring the city and its villages together. A P5 child in Richhill might be building a first game, a Year 11 student in Armagh working towards CCEA GCSE Digital Technology, and an adult in Tandragee learning Python for work, each in a small group at the right level.

The Observatory

Stars and weather since the 1790s

From Armagh Observatory and Planetarium's own history and weather pages.

1790

The Observatory opened, founded by Archbishop Robinson. Weather measurements began in 1794 and daily readings in 1795, and they have continued uninterrupted ever since.

6 January 1839

On the Night of the Big Wind, director Thomas Romney Robinson logged a "tremendous gale in the night", an event the Observatory says inspired his cup anemometer.

1882 onwards

After Robinson's death on 28 February 1882, having served as director for 59 years, J.L.E. Dreyer, a Dane, took over and compiled the New General Catalogue of Nebulae and Clusters of Stars.

The Observatory says Dreyer's catalogue is probably the single most important contribution to science to have come from Armagh, and that it remains the principal catalogue of nebulae and galaxies used by astronomers around the world. We have no connection with Armagh Observatory and Planetarium, Armagh City, Banbridge and Craigavon Borough Council or the OpenNGC project. The catalogue is on this page because it is a real, famous, carefully ordered list, which makes it the ideal test of how to measure order.

Where the positions come from

OpenNGC is a free database of the NGC and IC catalogues, released under a Creative Commons attribution share-alike licence, giving each object's modern position as right ascension and declination for the year 2000.

Signature project

How out of order is Dreyer's catalogue today?

An inversion is a pair of items listed in the wrong order. Counting them measures how unsorted a list is: zero for a perfect order, and every possible pair for a list in reverse.

OpenNGC, 7,840 NGC entries in catalogue order, compared by modern right ascension
MeasureResult
Pairs to check one by one30,728,880
Comparisons made by merge sort63,917
Inversions, counting right ascension as a straight line359,626
Inversions, treating right ascension as a circle47,634 (0.155% of pairs)
Typical distance from sorted position4 places

1. Split and merge

Merge sort splits the list in half, sorts each half and merges them. When an item from the right half jumps ahead of items still waiting on the left, each of those is one inversion.

2. Spot the wrap

Right ascension runs from 0 to 24 hours and then starts again. NGC 7840 now sits at 0 hours 7 minutes, seconds away from NGC 1, so the last 40 entries look out of order when they are not.

3. Count by region

Split the sky by declination and count again. Near the equator only 0.076% of pairs are inverted; south of minus 60 degrees it is 0.760%, and north of plus 60, 0.343%.

A circle is not a line

Our first count, 359,626, was almost entirely an artefact: 311,992 of those inversions came from 40 objects that had crossed midnight in right ascension. Nothing about the sky was wrong; the code had treated a circular quantity like a ruler. It is one of the most common mistakes with angles, times of day and dates across New Year, and the only cure is to think about what the numbers mean before trusting a count.

Once the circle is handled, the pattern makes physical sense. The slow wobble of the Earth's axis shifts sky coordinates over the years, and right ascension shifts fastest close to the poles, where the lines of right ascension crowd together. The most displaced entry of all is NGC 2573, just 40 arcminutes from the south celestial pole: it now sits 1,923 places from where its modern right ascension would put it.

Measuring order

Five questions before trusting a sorted list

Learned on Dreyer's catalogue, then used for search results, rankings of every kind, version histories and the checks that compare two recommendation lists.

Choices behind an inversion count
QuestionFor the NGCWhat goes wrong if you skip it
What is the sort key?Modern right ascension for each entryComparing positions from different eras
Is the key circular?Yes: 24 hours wraps to 0Hundreds of thousands of false inversions
How fast is the count?Merge sort, 63,917 comparisonsTens of millions of checks for one number
What counts as an entry?The 7,840 plain NGC numbersSub-components counted twice
Where is the disorder?By declination bandA single average hiding the poles

The fourth row is a judgement call. OpenNGC also lists extra entries for objects that split into parts; we used only the 7,840 plain numbers so that each catalogue number counts once. A different choice would change the count slightly, and the honest report says which was used.

Younger learners

Lining up numbered cards, counting how many pairs are in the wrong order, and finding the quickest way to tidy them.

Teenagers

Merge sort in Python with an inversion counter, run on 7,840 real catalogue entries, with the circular right ascension handled properly.

Adults

Comparing orderings at work, from rankings to schedules, with keys, wrap-arounds and duplicates checked first.

We are not connected with Armagh Observatory and Planetarium, the OpenNGC project, NISRA or Armagh City, Banbridge and Craigavon Borough Council. The catalogue data and census tables are published openly; the counts, unwrapping and band comparison on this page are our own work.

Learning ladder

From numbered cards to merge sort

Treat the ages as a guide; the free lesson finds where each learner should start.

Ages 6 to 10

Out of order

Sorting numbered cards and counting the pairs that are in the wrong order along the way.

Scratch Coding for KidsProblem Solving and Computational Thinking for Kids
Ages 11 to 13

Sorting in code

Writing simple sorts in Python and timing them on longer and longer lists.

Python and AI for KidsMaths Through Coding
Ages 14 to 18

Divide and conquer

Merge sort with an inversion count, tested against checking every pair on a real star catalogue.

Python for TeensData Science for Teens
Ages 18 to 67

Orderings at work

Measuring how much two rankings or schedules disagree, fast and without wrap-around mistakes.

Python Automation CourseData Science Course
Coding and AI

AI ranks everything from search results to songs. Why should an Armagh teenager count inversions in a star catalogue?

Because comparing two orderings is how ranking systems are tested, and the count only means something if the keys are handled correctly.

When an AI system ranks results, engineers measure how far its order is from a trusted one, often by counting pairs in the wrong order. A learner who has done exactly that on 7,840 real objects, and caught a 311,992-pair error caused by a circular key, knows both the method and its most common trap.

The speed lesson matters too. Checking every pair of 7,840 items takes over thirty million comparisons; merge sort does it in under sixty-four thousand. As data grows to millions of items, choosing the right algorithm is the difference between an answer now and an answer never.

So an Armagh teenager should keep learning to code in 2026, in the city where Dreyer ordered the heavens: computers can sort anything instantly, but someone has to know what the numbers mean before they count them. The longer argument is in why coding is worth learning in 2026.

Delivery

Armagh, Keady or Markethill, all from home

The city is ringed by villages and small towns. Online, each of them is the same distance from the lesson.

City and villages

A learner in Hamiltonsbawn and another in Keady can share one class without a journey into Armagh.

Northern Ireland school years

Lessons use the names local schools use, from P1 to Year 14, including the transfer test years and CCEA GCSEs and A levels, and teaching is in English.

A lesson, not a pitch

The free session teaches a genuine task and ends with a recommended level, course and weekly slot. No card details are taken.

Stage, not postcode

Five to ten learners at the same level, from Armagh, across the UK and abroad, so every stage has a sensible time.

A twice-weekly pattern

Two fixed lessons each week, around eight a month, with holidays and exam weeks agreed with the teacher in advance.

Evenings in two time zones

A 5 pm lesson in Armagh begins at 9.30 pm in India during summer time and 10.30 pm in winter, because India never changes its clocks; our teachers plan their evenings around families here.

Across County Armagh and beyond

Families in Portadown, Lurgan, Banbridge or Newry join exactly the same groups, since every lesson is online and groups are formed by level.

Fees

Armagh lesson fees

The first lesson is free, then there is one monthly fee.

First classUSD 0

A full lesson at no charge, ending with our advice on level, course and weekly time.

Group tuitionUSD 100

About eight live lessons a month in a group of five to ten learners at one stage.

Private tuitionUSD 150

About eight live lessons a month, with the teacher focused on your learner alone.

Families in Richhill or Tandragee pay in US dollars, as every family outside India does, and our pages carry no pound prices. The free lesson comes first, with billing only after a course and weekly time are agreed; the pricing page explains pauses, missed lessons and switching between group and one-to-one teaching.

Reviews

Six Google reviews from families, exactly as written

Rated 4.9 across 547 Google reviews. These are real reviews, reproduced as written.

★★★★★

"The one step solution for my son. Modern Age Coders make learning coding so simple that kids love it. The teachers explain complex concepts clearly with practical exercises and interactive content."

Ria Mukherjee

Parent

★★★★★

"Modern Age Coders has been a game-changer for me. I struggled to grasp IT concepts and coding before joining, but their classes transformed everything. I can now confidently write complex programs with ease."

Samriddha Mondal

Student

★★★★★

"One of the most wonderful education centres out there. Education is not limited to school syllabus but focuses on skill development."

Vansh Agarwal

Student

★★★★★

"My child Dhairya is really enjoying the Modern Age Coders classes. This is his first online class and he eagerly looks forward to it. I can already see his improvement, and the teachers are very cooperative."

Sonam Oswal

Parent of Dhairya

★★★★★

"Modern Age Coders have wonderful teachers who teach in a clear, easy and practical way. The teacher boosts students' confidence and inspires them to learn without hesitation."

Sonu Goyal

Parent

★★★★★

"I highly recommend this computer coding class! The teachers are incredibly knowledgeable and passionate about coding."

Ritu Kedia

Parent

Free placement class

Book a free lesson for an Armagh learner

The first task is chosen for the learner: a card-sorting game for a young child, a short Python program that sorts a list for a beginner, or Dreyer's catalogue and merge sort for a teenager ready for real data.

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FAQ

Armagh coding class questions

The questions Armagh families ask us most.

How many people live in Armagh?

Census 2021 counted 16,310 usual residents in the Armagh settlement, 32,405 in the Armagh District Electoral Area and 218,656 in the Armagh City, Banbridge and Craigavon district.

How does the district compare with Northern Ireland?

It has slightly more children: 7.2% of residents were aged 10 to 14 and 7.1% aged 5 to 9 in 2021, against 6.7% and 6.5% across Northern Ireland, while 5.3% were aged 20 to 24, against 5.9%.

What is an inversion count?

The number of pairs in a list that appear in the wrong order. It is zero for a perfectly sorted list, and it can be counted quickly with merge sort instead of checking every pair.

How out of order is the New General Catalogue today?

Using modern positions from OpenNGC, 47,634 of its 30,728,880 pairs are in the wrong order, 0.155%, once right ascension is treated as a circle. Objects near the celestial poles are the most displaced.

Where does the catalogue data come from?

From OpenNGC, a free database of NGC and IC objects released under a Creative Commons attribution share-alike licence, which gives each object's position for the year 2000.

Who was Dreyer?

John Louis Emil Dreyer, a Dane, became director of Armagh Observatory after Thomas Romney Robinson died in 1882, and compiled the New General Catalogue of Nebulae and Clusters of Stars. We are not connected with the Observatory.

When are Armagh lessons?

Families in Armagh usually pick a slot after school, on a weekday evening or at the weekend, and we agree the time in the free lesson. India is four and a half hours ahead of Northern Ireland in summer and five and a half in winter.

Is there a centre in Armagh?

No. There is no Armagh centre and we have no premises anywhere in the UK, as every lesson is live online. A learner needs a computer with sound and a steady connection, and our phone number is Indian.

What do lessons cost for an Armagh learner?

The first lesson is free. After that, a group place is USD 100 a month for two live lessons a week, about eight a month, with five to ten learners; one-to-one lessons on the same timetable are USD 150 a month. Nothing is charged until the course, format and time are agreed.

How are learners grouped?

By level, pace and goals rather than age or address, with five to ten learners at one stage. When no group fits the learner's week, we offer one-to-one lessons.

Explore Northern Ireland and the UK

Northern Ireland and beyond

In Belfast, the Belfast page runs PageRank over the city's bus stops. Learners working towards CCEA GCSE Digital Technology or A level Software Systems Development have their own pages. The Northern Ireland guide explains school years, and the UK coding page links every other city.

Free Armagh classCall +91 91233 66161

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