Question: In 2012, when the first incarnation of Astronomy SE closed, the community at Physics SE felt compelled to give a home to astronomy questions and overwhelmingly [voted](https://physics.meta.stackexchange.com/q/1197/75633) to expand the scope of the site.

Not long after, however, Astronomy SE [was "reopened"](https://physics.meta.stackexchange.com/a/5327/75633), and is still [alive](https://astronomy.stackexchange.com/) and well, even if still in beta.

A degree of overlap in scope between the two sites is completely unproblematic, of course, but I believe there are questions on the more technical side of astronomy that, when there is an SE especially [geared towards them](https://astronomy.meta.stackexchange.com/a/101), should be redirected there, to the benefit of both communities (and of the OP).

**Question**: Is it time to rethink that decision a bit, and make off topic here questions about technical astronomical topics such as observation and equipment?

Example: [What light pollution levels are required to see the Milky Way?](https://physics.stackexchange.com/q/594633/75633), which a couple of users felt didn't quite belong to Physics SE and voted to close - only to be reminded by [ACuriousMind](https://physics.stackexchange.com/users/50583) that, as it stands, the question is actually fully on topic.

I **propose** the answer is *Yes*, see my answer bellow for details.

Answer: 
Thank you for your thoughtful replies.

In view of the current (3) answers and comments let me spell out my suggestion and perhaps clarify a few points first:

1. Emilio Pisanty [already provided](https://physics.meta.stackexchange.com/a/13232/75633) an important clarification, namely that adding Astronomy SE as a migration option isn't possible as long as the site is in beta; this is unfortunate, as it'd be my preferred option, but let's consider it out of the table, since I don't see us swaying SE on this;
2. Making the whole of astronomy off topic is of course nonsense;
3. *Ban* is also too strong a word - if we decide to make observational astronomy off topic here, it will still be up to the voters to decide themselves, for each post individually, where it best belongs;
4. Some examples of questions I'd personally consider migrating to Astronomy:

	* [Primary focal length of a cassegrain telescope](https://physics.stackexchange.com/q/580554/75633)
	* [What light pollution levels are required to see the Milky Way?](https://physics.stackexchange.com/q/594633/75633)
	* [Definition of a planet](https://physics.stackexchange.com/q/589394/75633)
	* [Group of stars moving](https://physics.stackexchange.com/q/273765/75633)
	* [Need help buying binoculars online for astronomy (10x50)](https://physics.stackexchange.com/q/26145/75633)
	* [Is there a simple yet accurate formula for where on Earth the Sun and Moon are directly overhead?](https://physics.stackexchange.com/q/25396/75633)
	* [What is the distance to the closest star similar to our Sun?](https://physics.stackexchange.com/q/165486/75633)that is, posts asking for observation instructions, equipment advice, etc.

**My two-part suggestion**:

1. Make *amateur observational astronomy* off topic now$^\*$.
2. Add Astronomy SE as a migration option when it becomes possible to do so.

$^\*$ And flag moderators so that they can take care of migrating them. This shouldn't be a lot of extra work, since these questions don't really pop up all the time.
Yes, I think it is. But I would prefer to migrate them rather than say they were off-topic.

I think there is a reasonably clear distinction between questions about astrophysics and questions about astronomy.

I do agree that questions about astronomy would be better to migrate to Astronomy SE.

Maybe the distinction here is to ask yourself, where would I go and look for the answer to this question - would I look on Astronomy SE or Physics SE?

For most professional astrophysicists/astronomers, they would appreciate the difference and head to the appropriate site, but if they didn't find it there then they would head to the other.

For the non-professionals and general public, the distinction is not that obvious - but they would tend to go to Astronomy SE first for anything "astro-related", and this would be especially true for astronomy questions (as opposed to astrophysics). In other words, an astronomy question asked on Physics SE, especially one which is about amateur observing or the night sky, is in danger of being lost to its likely audience.

My solution would be to migrate anything that you couldn't tag as astrophysics, cosmology or as some branch of experimental physics. And yes, I know there will be grey areas - but the question cited in this post is not an example.