The absolute right time to buy bitcoin is when the market is experiencing a dip which is commonly known as buying the dip, as explained many times this strategy is beneficial because buying in bulk becomes cheap compared to buying at a bullish price range. Sell your coin when the market is in a favorable range, hold for the long run and wait for the bullish season then you can successfully sell your profit.
That's not true the right time to buy bitcoin is not when the market is undergoing some dip that's absolutely telling people that they need to wait for the dip before they can start buying bitcoin.
The right time to start buying bitcoin is when you have figured out if you have some discretionary income to get started with, so you can start up immediately when your discretionary income is available, you can use the dca method to regularly be buy BTC so you don't wait for dip to buy, although you can buy more bitcoin during the dip that is if you have a better discretionary income to do that or you could also buy through your reserve funds since you are buying bitcoin in a cheap price and hold for long, and again you don't have to sell when the market is up unless you have gotten to your bitcoin over accumulation phase then you can choose to take some profit from your bitcoin holding.
It will be misleading to make people to think the right time to buy bitcoin is only during a dip. If someone has been able to figure out their discretionary income, they can start buying bitcoin using DCA strategy rather than waiting for a dip to occur in order to buy at a desired price.
With the DCA strategy they won't stress themselves by trying to time the market. Someone that is doing DCA strategy can still buy the dip if there is an extra cash that is available for them to do so, but they must not used money that is meant for their essential needs for buying the dip. The most important thing is to adopt to a strategy that best fits ones financial situation.