When I found that the wavefront of the image surface of Cassegrain-type Ritchey Chretien telescope to have a hole in the center (as shown below) , I wonder how it is formed.
Thanks a lot if anyone can explain it !
Solved
Why does the wavefront of Cassegrain-type Ritchey Chretien telescope have a hole in the center?
Best answer by David.Nguyen
Hi DDDD,
I’m not exactly sure without seeing your system in more details, but typically, the secondary mirror obscure the central portion of the incoming ray pencil. Thus creating a “hole” in the wavefront.
Perhaps this picture from Vladimir Sacek (found on his website) can help:
Ignore the text, just look at the beam path in yellow. Do you notice the missing cone after the secondary mirror? This is why the wavefront can’t be calculated.
I hope this helps.
Take care,
David
+2Hi DDDD,
I’m not exactly sure without seeing your system in more details, but typically, the secondary mirror obscure the central portion of the incoming ray pencil. Thus creating a “hole” in the wavefront.
Perhaps this picture from Vladimir Sacek (found on his website) can help:
Ignore the text, just look at the beam path in yellow. Do you notice the missing cone after the secondary mirror? This is why the wavefront can’t be calculated.
I hope this helps.
Take care,
David
1 person likes this
David.Nguyen wrote:
Hi DDDD,
I’m not exactly sure without seeing your system in more details, but typically, the secondary mirror obscure the central portion of the incoming ray pencil. Thus creating a “hole” in the wavefront.
Perhaps this picture from Vladimir Sacek (found on his website) can help:
Ignore the text, just look at the beam path in yellow. Do you notice the missing cone after the secondary mirror? This is why the wavefront can’t be calculated.
I hope this helps.
Take care,
David
Hi David :
Thanks for your help !
David.Nguyen wrote:
Hi DDDD,
I’m not exactly sure without seeing your system in more details, but typically, the secondary mirror obscure the central portion of the incoming ray pencil. Thus creating a “hole” in the wavefront.
Perhaps this picture from Vladimir Sacek (found on his website) can help:
Ignore the text, just look at the beam path in yellow. Do you notice the missing cone after the secondary mirror? This is why the wavefront can’t be calculated.
I hope this helps.
Take care,
David
Hi David :
I have some further questions , hoping that you may help.
I now need two telescope to intefere ,I expect the result to have no hole in the center.
I think after the process of focusing , the result should be a point, the wavefront should have no “hole”. But the result seems to have a “hole” in the center.
Sincerely
DDDD
This is the file I used.
+2Hi DDDD,
You need to give us more details about what you are trying to achieve. I downloaded your file, but there’s only one telescope in it, as far as I can tell.
Let me know if I’m overlooking something.
Take care,
David
David.Nguyen wrote:
Hi DDDD,
You need to give us more details about what you are trying to achieve. I downloaded your file, but there’s only one telescope in it, as far as I can tell.
Let me know if I’m overlooking something.
Take care,
David
Hi David :
The result after intefering should have no “hole”. I used the inteference formula to get the inteference result of two identical focused wavefronts but it has “hole” so I am confused.(So I just used one zmx file as shown above.)
Sincerely
DDDD
Reply
Enter your E-mail address. We'll send you an e-mail with instructions to reset your password.
Need more help?
To Chinese users:
Do not provide any information or data that is restricted by applicable law, including by the People’s Republic of China’s Cybersecurity and Data Security Laws ( e.g., Important Data, National Core Data, etc.).
不要提供任何受适用法律，包括中华人民共和国的网络安全和数据安全法限制的信息或数据（如重要数据、国家核心数据等）。