Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Prism or mirror for FS-102?

  • Please log in to reply
53 replies to this topic

#51 StarAlert

StarAlert

    Mariner 2

  • *****
  • Posts: 287
  • Joined: 11 Aug 2019
  • Loc: Claremont CA

Posted 09 April 2020 - 07:10 PM

No, because an Amici prism is called a "roof" prism, because of its shape.  The ridge line of the roof is what you see with bright objects.  With an ordinary prism there is no line at the reflection surface.  With a roof prism there are two reflections, insteaed of one.  The even number of reflections give the correctly oriented image. 

 

The original image is "upside down",  i.e. up is down and left is right.  I you stand on your head while looking at the image it would appear right side up.  This acrobatic feat is not recommended.  So enter the Amici roof prism.  The first reflection reverses "up/down" and the second reverses "left/right", thereby providing a correctly oriented image.

 

Dom Q.

I bought a regular prism and the bright horizontal line is now gone. I’ll use the Amici for daytime viewing. 



#52 lwbehney

lwbehney

    Lift Off

  • *****
  • Posts: 20
  • Joined: 06 Mar 2018

Posted 12 April 2020 - 05:32 PM

Dom Q.  

 

Thanks very much for responding to StarAlert's question about the horizontal line he sees in his eyepieces on bright stellar objects with his Amici prism. I noticed this also and furthermore, my prism diagonal results in a lot of color on Sirius and Venus that I do not remember seeing on my mirror diagonal. 

Wow, I gave up an otherwise excellent eyepiece, which I initially blamed for this effect. 

Incidentally, Markus Ludes is the one who recommended an APM mirror diagonal over a prism when I asked him what would be best for my FS 128.

 

Thanks again for your post,

 

Larry



#53 coopman

coopman

    Fly Me to the Moon

  • *****
  • Posts: 6,336
  • Joined: 23 Apr 2006
  • Loc: South Louisiana

Posted 12 April 2020 - 06:48 PM

I was thinking of maybe using the amici prism at low power to help me find my target with star atlas corelated views and then switch to a normal (prism or mirror) diagonal after that. I know that the amici prisms are limited in their astronomical usage, no matter what Baader's advertising says.

Edited by coopman, 12 April 2020 - 06:50 PM.

  • mikeDnight likes this

#54 StarAlert

StarAlert

    Mariner 2

  • *****
  • Posts: 287
  • Joined: 11 Aug 2019
  • Loc: Claremont CA

Posted 12 April 2020 - 10:28 PM

I was thinking of maybe using the amici prism at low power to help me find my target with star atlas corelated views and then switch to a normal (prism or mirror) diagonal after that. I know that the amici prisms are limited in their astronomical usage, no matter what Baader's advertising says.

The Amici works just fine at high powers. I was able to split many tight doubles using it at more than 200x. It’s just not good at bright objects. 




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics