im not sure why you would want a bunch of stray light when your doing astronomy
but i use , LED Voltmeter DC-DC 4.5-32V to 5-52V XL6009 Boost , to control my cob leds from a battery
it has full dimming through voltage control, its a 10 to 15w module
there are other boost drivers that can handle more power , i prefer the ones with only voltage control, current control is not needed
the voltage adjustment gives a wide range of dimming
if you want a brand name driver with more power go for this
https://www.digikey.com.au/product-detail/en/mean-well-usa-inc/LDH-45A-1050W/1866-5295-ND/7704776it requires an extra purchase of a 1k potentiometer and 7.5k resistor if you want to use the dimming feature
pic shows the wiring of the pot and resistor , i had trouble wiring it at first