I have previously visited the observatory at Greenwich and found it to be much more interesting than I expected and it’s the same here. This is a large open air site, with various astronomical instruments including apparently the biggest sun dial in the world. There are lots more devices measuring planetary movements such was and still can be the Indian fascination with astrology. It’s wise to have a guide to make sense of it all. It’s a lot of fun though so well worth visiting and not just for those interested in science.

This site is set up as an astrological park where all of the instruments are permanently constructed out of concrete and metal. But if you wandered around on your own, you would never actually understand it. You need a guide to interpret the meaning of these things because it would have no significance otherwise.

The guides are not knowledgeable, on top of it they are arrogant. They don’t share much, cannot answer any of your questions. But they are the most expensive. Don’t waste money on them. At the far end of Jantar Mantar, they run a good documentary that explains you everything. Watch that first and then go around. You will know everything. No one tells you about this documentary because they want to make money.

Interesting place to visit. It's shows how our ancestors were so advanced in astrology and astronomy than the remaining world. Extract and precise calculating reflects even in today's time. We need to show this to our children's and school students. The time calculator, patrika and kundali making was awesome.

Very interesting. We had a very knowledgeable guide which was helpful. Very hot day and very busy. Spent about 40 minutes looking around which was about enough time. Worth a visit to see how time was told in the past.

The Jantar Mantar is an observatory comprising of 19 instruments to measure the position and distances of celestial bodies. These 19 instruments are structures carved out of stone, depicting interesting geometric shapes. Vrihat Smarat Yantra is a huge sun dial at the centre of Jantar Mantar observatory.

This is such a fascinating place, must do with a knowledgeable guide to explain the movements of the sun & astrology aspects. Can spend up to 2 hrs there. Go early where the crowds haven’t yet arrived. By midday its too busy to be able to really appreciate the sights.

Jantar Mantar is an astronomical observation site. This was probably the busiest attraction I had seen in Jaipur. This is a UNESCO World Heritage Site. Highly recommend. Very interesting and I learnt a lot. Astronomy plays a major role in the lives of many people in India. Keep your ticket with you as they will 'tear' it as you exit. I am guessing so you can't come back again. Also to note there is a separate line for Indian citizens and foreigners / guides to purchase tickets. The foreigners / guides line was very short and I was inside within a few minutes. Also check your change as they decided to only give me some change back! After I protested, they gave me the rest. If you can, give the exact money.

Having visited Delhi Jantar Mantar, this one has more instruments and is better maintained. It's located in a very busy area. You can give it a miss if you have seen such observatories earlier. The ticketing was very busy and guards outside indulge in malpractice of giving faster ticket for favour. Strongly suggest to take online ticket from Rajasthan Tourism website beforehand.

Excellent and didactic experience. .Without a guide does not make much sense as they are able to describe you how all the instruments work and learn some astronomy basics. There are official gov guides at the entrance and they charge 400 rupees to groups up to 4 people