I've used my Skan both indoors and out and never had a problem with lighting. If I remember rightly, the instructions caution against use under fluorescents and direct sunlight. In case of the former, you just turn the light off. The latter can be easily mitigated by placing a suitable shade.
I know there are some chronos with a faster clock speed which are thus more accurate, but the Skan has done all I've asked of it for air rifle use.
I took it to the second Springer bash and had it set up all day. A few folk took advantage of it - even with a couple of pop-outs and it performed faultlessly.
Happy Shooting!! Paul.
"We cannot solve our problems with the same thinking that we used when we created them" - Albert Einstein.