In California there is actually no right to see the radar, it is up to the discretion of the police officer that makes the stop. Some officers may let the motorist see the speed on the radar since it will only help their (the officer's) case in court if the driver decides to fight the ticket. Other officers choose to not let the speeder see the radar due to safety reasons and we have heard they get tired of the speeder then saying "how do I know it was my car you locked onto with the radar" once they see the speed captured by the equipment.
There is no law in any state that we are aware of that requires an officer to show you the reading on the radar or laser gun. In fact if anything most jurisdictions discourage this as a matter of safety. If the officer does show you, it is a courtesy only. If the officer says you were speeding and their radar was calibrated as required by law than that is typically all the proof the judge needs to find you guilty in court.
In 1992, the United States Supreme Court ruled in a Kentucky case that defendants do not have to be shown the radar gun. As we mentioned it is mainly due to safety issues since most radar guns are located in the front seat of the patrol car and many officers do not want to allow the motorist to have access to the front seat his or her vehicle. While a majority of drivers may only check their radar speed there are people that would take advantage of the situation and touch items in the patrol car they should not.
Information how officers must calibrate and use a radar gun should be available to you if you read through your state's laws. Instead of looking up this information on your own you may instead want to contact a local lawyer familiar with the state and local laws and procedures of where you obtained the ticket.
So in New Hampshire you would not have the right to look at the radar gun though some officers may allow you to do so, just as you found in California some do allow it. Police have no obligation to show you the radar gun or laser gun although some might do it as a personal preference to help their case if you fight the ticket in court. Some jurisdictions may in fact prohibit their officers from showing the radar to drivers due to safety issues.
Neither in CA or NH is there a requirement for a law enforcement officer to show you the radar however in both states you should have the right to challenge the officer's radar training and the calibration of the radar unit. Again if you are not familiar with these laws for NH in your present situation you may want to seek legal counsel then determine if you wish to fight your traffic ticket or plead guilty.
If you were not speeding or think it is incorrect, you should take it to the jude. Follow New Hampshire's state motto: "Live free or die"