Beginner qns.

[dysam]

Hi guys, after buying a refractor telescope, i noticed that every time i look at something, that would be a blue hue around the object. How can i fix it? Thanks for viewing.

[Clifford60]

I guess that is CA and your refractors telescope is an Achromatic refractors and not an Apochromatic refractors.

http://en.wikipedia.org/wiki/Refracting_telescope

[cloud_cover]

You can fix it in a few ways:
1. Get a minus violet or Baader Semi-APO filter - will darken the image a bit
2. Use a UHC filter (strictly for nebulae and will severely darken the image even as it increases contrast)
3. Stop down your telescope: This increases the effective focal ratio and the higher the focal ratio, the less apparent the CA in a telescope.
4. Use lower powers: The lower the power the less the CA
5. Don't look at bright objects - CA is more apparent on bright objects
6. Get an ED/APO or reflector

[dysam]

Thanks for your quick ans guys.