Parallax - A Factor?

[KenMiller]

I see that the diameter of the Earth's orbit is on the order of 186 million miles and that the parallax resulting from viewing stars six months apart allows estimations of their distance.

If I collect images six months apart will the relative positions of the stars be noticeable?

Does one need to take this into account when collecting image data to later be combined?

[pizwiz]

No Ken,
A parallax of one arcsecond, which is about the best resolution our scopes can measure, would be produced by a star which is approximately 3 1/4 light years away.
( you probably recall that this distance is called a "Parsec" )
Since our nearest star outside the solar system is over 4 LY away, you just might detect a tiny difference in position. The parallax is a very limited method for measuring distance. ( Although very important ) Only a few hundred stars have ever had their distance measured via Parallax. The angular separations are just too tiny to measure anything not in our immediate neighbourhood.

Adolph

[KenMiller]

Thanks Adolph. I presume that since seeing is rarely that good astrophotographers need not worry about it - especially with objects further away.

[pizwiz]

You are right Ken.
In my neck of the woods, in Upstate NY, we might get less than a handful of nights when the seeing gets to one arcseconds or better.
BTW, I just read a book on this subject, and you would not believe how long it took and all the problems that were encountered before someone was able to measure the Parallax to the first star.

Adolph

[KenMiller]

What's the title of the book?

[pizwiz]

Strangely enough, the title of the Book is "Parallax"
It is an older book but is still in print.

Adolph

[KenMiller]

By Steven Holl?

[pizwiz]

The Title is: PARALLAX ( The Race to Measure the Cosmos) by Alan W. Herschfeld.
Co 2001
Published by henry Holt and Co. New York.

Sorry for the delay, the book was in my Basement Library in the workshop.

Adolph

[KenMiller]

Thanks! I've ordered a copy.

[KenMiller]

Why is it that so many things astronomical take so long to obtain?

I ordered this on December 11th.

I just received ANOTHER notice from Amazon that there is a delay with my order.