Why certain stars seem to move very little in the sky

  • B
  • Thread starter Ittiandro
  • Start date
  • #51
54
3
Your original post was concerned mainly about a specific object in the night sky and why it didn't noticeable move as the seasons passed. You spent almost the entirety of your first post talking about it. The first paragraph of that post, which is what you re-wrote just above, is not the full question (or, rather, it's a more general question). This is why so much effort has been spent trying to pin down which object you saw.

Everything about parallax and orbital motions is just general information on why and how things move in the sky, which mostly answers your more general question that was the first paragraph of your first post.
I see that we are reaching a common ground..
The confusion arose not so much from a lack of clarity of what I was saying from the point of you of language, as from the very premisses of my post, one of which I now believe it was wrong.
1. I could not identify that object.
2. I assumed that I was seeing the same object throughout the night and throughout the seasons, in spite of the orbital motion of the Earth. The reason for this assumption was that this body seemed to hover around in an almost circular motion with a radius contained within the span of only three or four hands, admittedly a very crude measurement, but I couldn't do better.So I though it was the same object. It didn't certainly help that I couldn't be more precise.

While I couldn't do anything to identify that object, I must admit that I may have been plainly wrong in the 2nd premiss.
I think that I was not looking at the same object. Somebody in this Forum gave me compelling reasons for this and I won't argue . You people know more than me about astronomy.
Perhaps the fact that those two bodies,( which I initially mistakenly took for the same body ) cropped up almost in the same location, was a mere coincidence.

I thank you all for your help

Ittiandro

PS: Just after posting this , I received a comment from somebody asking me to stop acting like a victim.
I didn't even bother to see who sent this comment. Whoever he is , I believe that what I just said in this post proves this contention wrong.
 
Last edited:
  • Skeptical
Likes davenn
  • #52
DaveC426913
Gold Member
18,796
2,274
Yeah, I'm a registered professional mechanical engineer and I went to a popular electrical forum to ask a question that overlaps the two disciplines and they just hammered me about it -- questioning whether I was fit to be licensed. It was brutal and I haven't been back.
I feel a little better now. I went to a photog forum to get some ideas about how I could extend the ability to do macro work with my point-n-shoot camera and got "if you won't spend the money, just live within your limits". Thanks, guys.
 
  • Like
Likes russ_watters
  • #53
russ_watters
Mentor
19,663
5,948
Point well taken!
I knew, though, that bright objects in the sky ( except Polaris) move, both because of the Earth’s rotation and the Earth’s revolution. In fact, what prompted me to start the thread was that I was surprised not that they move, but that they move so little, especially considering the millions of miles traveled by the Earth in its orbit. !
That's still a very poor description that doesn't make it clear what motions you are or aren't taking into account. On the one hand you are acknowledging that they move due to Earth's rotation and revolution, then you suggest "they move so little" which is basically the exact opposite statement. Other than the circumpolar stars (which are few), *all* stars and planets traverse basically the entire sky every day/night -- and every year, just different timing.

So whatever you mean by "move so little", it doesn't seem to reflect any observational reality that I can tell.
but that they move so little, especially considering the millions of miles traveled by the Earth in its orbit.
In point of fact, all of the observed motion of the stars happens in one day, every day, during which time the Earth moves very little. Take even the sun as an example; it rises in the east in the morning and sets in the west in the evening. All of that motion happens due to Earth's rotation, not due to the motion of Earth in its orbit.

If we eliminate the Earth's rotation, we're left with the Earth's revolution in its orbit, and motions over the course of a year. And, in another important fact: the so-called "motion" of the stars over the course of a year(the fact that you see different stars in winter vs summer) is simply an artifact of our system of keeping time, which has the sun fixed and the stars moving due to the Earth's orbit. Astronomers use a different system, by which the stars don't move at all, and the sun does.

But again, it isn't clear to me if you are accounting for either of those motions or not.
I think that the only way out of this quandary is for me to admit that perhaps I am not looking at the same object within the span of a few hours during the night. Also, when I say that the very same object appears to be visible in winter and summer with a very little change in its position in the sky, I am told that this is not possible and I begin to realize why.
I'm glad you are starting to understand. I would still encourage you to put more effort into your observation in order to reinforce it. If you are indeed seeing different objects at different times of the night or year, the solution to that is to pay more attention. Have you downloaded a sky map program/app yet...? Ultimately, your ability to articulate what you are seeing won't matter much if you have and use an app that you can literally point at the object and it'll tell you exactly what you are looking at.
 
  • Like
Likes davenn
  • #54
DaveC426913
Gold Member
18,796
2,274
Have you downloaded a sky map program/app yet...?
OP doesn't even need to download anything.

I got all those maps simply by going to this free online skymap: https://stellarium-web.org/ on my computer.
Set location, date and time and poof!
 
  • Like
Likes russ_watters
  • #55
54
3
Right, so that part is simply impossible. Which means that it is possible the question is unanswerable.
The inference you make in the 2nd part from the 1st part is logically faulty: even though my post raised a question based on the wrong premise ( I was looking at the same body) , this question was fully answerable! How was it answerable? Simply by saying and showing ( as somebody eventually did) that it was IMPOSSIBLE that I was looking at the same body . This came up only much later and I accepted it, without arguing . .

The fact that, in your case, a bunch of scientifically untrained individuals in a popular electrical forum had the brash to question the knowledge of a fully competent, university educated mechanical engineer like you, cannot be brought to bear on our discussion because I ( the scientifically " uneducated" OP) never had the brash ( and, I'd say the stupidity..), to argue back that it must be the same body .
On the contrary I admitted that I was wrong( and I would have readily admitted it) if only this answer was brought up after my first post. .
This discussion has strayed from one about science to one about language and it is very difficult, if not impossible, to keep both feet in one shoe...
 
  • #56
Vanadium 50
Staff Emeritus
Science Advisor
Education Advisor
2019 Award
24,593
7,504
You going to keep complaining about people who generously devoted their time to help you? Do you think this will make things more likely or less likely that people will help you in the future.

You brought up parallax. Then complained that we did. Not cool.

Furthermore, you yourself brought up the point that this was not a sensible motion. You said "I’d expect to see this body at almost diametrically opposed points of the compass at the winter and summer solstices." People agreed that this was not a sensible motion over and over until you finally accepted it - two days and 45 messages later. And somehow this is our fault?
 
  • Like
Likes davenn
  • #57
berkeman
Mentor
57,510
7,534
Thread closed for Moderation...

Thread will remain closed. Thank you everybody for trying to help the OP.
 
Last edited:

Related Threads on Why certain stars seem to move very little in the sky

Replies
6
Views
1K
Replies
12
Views
2K
  • Last Post
Replies
1
Views
3K
Replies
8
Views
11K
Replies
20
Views
2K
  • Last Post
Replies
11
Views
3K
Replies
4
Views
14K
  • Last Post
Replies
3
Views
3K
  • Last Post
Replies
5
Views
2K
Top