Thanks for suggestion. My problem with mirrorless camera is the low battery life. Most of my travel destinations don't have reliable power supply, so long battery life becomes important. Also, the price . I am not buying Panasonic because of high prices and less availability of accessories and spares compared to Nikon and Canon.
Your point about sticking to Canon is right, but I only have basic kit lenses 18-55 and 55-250 and am thinking of selling them off. I am considering Nikon, because in sub 1 lakh budget, there are a lot more Nikon options than Canon. Latter has better options if the price is more than 1 lakh according to what Ifound.
To be honest, I got interested in to asto-photography only 6-7 months back during my Lahaul Spiti visit. Most of the time living in cities, there is hardly any thing that once can do in this field. I'd like to take pictures of planets whenever possible as well as wide field, but I suppose buying such lenses will be out of my budget.
I fully agree that mirrorless cameras has high power consumption compared to DSLR. This is the only drawback I see and a big one. I think the newer Sony's battery can be charged by an external battery via USB when actually shooting. Like a cell phone.
I have also been bitten by the astro photography. I especially do plenty of timelapse video of night sky. For timelapse any modern DSLR will work however for deep sky you'll need a tracker to shoot multiple images and then merge it. Its a different ball game. I warn you, once you get hooked up you'll end up spending lots.