Definition of a DSO

[MorningMajor]

Was reading an earlier thread when the OP asked if he'd be able to see DSO's with his scope (same as mine below).

It got me thinking, what is your definition of a DSO - is M42 one - or Amdromeda Galaxy? or does it depend on what equipment you're using to view them?

[brantuk]

I reckon you could say it's any object outside the solar system really

(M42 and M31 are both dso's)

[Whippy]

I reckon you could say it's any object outside the solar system really

(M42 and M31 are both dso's)

That's how I would classify DSO's too .

Tony..

[MorningMajor]

I reckon you could say it's any object outside the solar system really

(M42 and M31 are both dso's)

Valid point, for sure, but although say, Betelgeuse is very much in deep space I wouldn't call it a DSO in the common or garden term, would it be fairer to say that DSO's are generally described as objects that can't be discerned with the naked eye?

[John]

The astronomy author Peter Lancaster-Brown included multiple stars as deep sky objects in his book "Star and Planet Spotting". I've always been content to accept that "deep sky" was anything outside our solar system as well.

There are lots of DSO's which are naked eye visable - M31 (on a good night) M44, M45 etc.

[RikM]

I agree. It is a distance thing and not a visibility thing.

[Nexus 6]

would also agree it is a means of classifying any objects outside the solar system, has nothing to do with what equipment is used to observe or image them

[MorningMajor]

Excellent, thanks. I can now tell the the poster of the original question that yes, he'll be able to see plenty of DSO's with his Celestron!