The best advice (post below) is to attend a club and have a look at what others are using, before you buy - it can be a minefield - one that I have recently traversed.
Astrophotography, can be quite addictive and very expensive compared to observing - with a similar budget, you will need to buy very carefully and make some compromises here and there. Inevitably, spending more at a later date. In anycase, adding 20-30% to your budget is not unrealistic - and possibly more.
4K in the hands of some telescope retailers, or over eager enthusiasts, can dissipate rapidly, and your expenditure will increase
