Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

Daniel3

Strange experience

Recommended Posts

I  have managed to get out tonight for the first time my experience as I have been testing my 25 mm lens 15 mm lens 10 mm lens also x2 Barlow  but I see no difference in the skies from the size of the Star....any advice.... I have been focusing on the brightest star but see no difference in size through the lenses I am using very strange.

 

regards Daniel 

Share this post


Link to post
Share on other sites

A star is a 'point source' - ie infinitesimally small and far away. You're never going to see sunspots on another star! Try a planet and you might see some detail.

Edited by laser_jock99
  • Like 2
  • Thanks 1

Share this post


Link to post
Share on other sites

As said above Stars will always be pinpoints of light in fact the quality of a scope/eyepiece is determined by how small you can get them.

Alan

  • Like 1
  • Thanks 1

Share this post


Link to post
Share on other sites
13 minutes ago, Alien 13 said:

As said above Stars will always be pinpoints of light in fact the quality of a scope/eyepiece is determined by how small you can get them.

Alan

Hi Alan, I have a Skywatcher Explorer 300 mm.

 

regards daniel

 

Share this post


Link to post
Share on other sites

As said above, stars will always appear as pinpoints of light no matter how much you magnify them. Providing they are in sharp focus that is. Either side of focus stars expand gradually into a disk but that is an artifact of the scope optics, not the stars true appearance.

 

  • Like 1
  • Thanks 1

Share this post


Link to post
Share on other sites

I think one of the problems that arises is from looking at the stars in an atlas. Here the stars are depicted as variously sized dots. The difference in the size of the dot does not mean that the stars will appear as different sizes in the scope. The size differences in the stars depicted is an indication of how bright they will appear. The larger the dot the larger the apparent brightness of the star.

  • Like 3
  • Thanks 1

Share this post


Link to post
Share on other sites
25 minutes ago, John said:

As said above, stars will always appear as pinpoints of light no matter how much you magnify them. Providing they are in sharp focus that is. Either side of focus stars expand gradually into a disk but that is an artifact of the scope optics, not the stars true appearance.

 

Under perfect conditions you should be able to see an Airy Disk

https://en.wikipedia.org/wiki/Airy_disk

Atmospheric turbulance and tube air currents in the scope will disturb the 'prefect' Airy Disk pattern. But with good optics, and undisturbed conditions it should appear round at least. A good test for your optics.

  • Thanks 1

Share this post


Link to post
Share on other sites
9 minutes ago, Ruud said:

Large telescopes and special techniques can resolve some stellar disks.

See here: https://astrobob.areavoices.com/2014/06/06/can-we-really-see-other-stars-as-true-disks-you-betcha/

Yes - the Hubble Space Telescope is one. The OP does not have that model though, unfortunately :smiley:

 

  • Like 2
  • Thanks 1
  • Haha 2

Share this post


Link to post
Share on other sites
16 minutes ago, laser_jock99 said:

Under perfect conditions you should be able to see an Airy Disk

https://en.wikipedia.org/wiki/Airy_disk

Atmospheric turbulance and tube air currents in the scope will disturb the 'prefect' Airy Disk pattern. But with good optics, and undisturbed conditions it should appear round at least. A good test for your optics.

Indeed. An optical artifact all the same though rather than the actual disk of the star.

 

  • Like 1
  • Thanks 1

Share this post


Link to post
Share on other sites
6 hours ago, Ruud said:

Large telescopes and special techniques can resolve some stellar disks.

See here: https://astrobob.areavoices.com/2014/06/06/can-we-really-see-other-stars-as-true-disks-you-betcha/

Excellent catch, Ruud! Thank you very much for this fascinating and well-illustrated piece!

Dave

  • Like 1
  • Thanks 1

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.