Baldwin’s Latest Mirrors

Here are some of the mirrors completed from the Baldwin Optical Shop. We’ll try to load more when we think of it.

 

1501      23.625” f/3.76. Data from SIT shows 1/24 wave P-V, RMS of 3.1 nm on the surface, which is 6.2 nm on the wave-front, which is 1/89 wave RMS, and a Strehl Ratio of 0.995. However, all optical tests render claims that are actually better than the optic, so I stand by my promise that the mirror has a P-V less than 1/10 wave, RMS less than 1/26 wave, and a Strehl Ratio greater than 0.94.  Below is the SIT test data sheet, far more reliable than Foucault.

 

1502      12.5” f/8

 

1503      6” f/5. Data from SIT shows 1/25 wave P-V, RMS of 3.2 nm on the surface, which is 6.4 nm on the wave-front, which is 1/86 wave RMS, and a Strehl Ratio of 0.995. However, all optical tests render claims that are actually better than the optic, so I stand by my promise that the mirror has a P-V less than 1/10 wave, RMS less than 1/26 wave, and a Strehl Ratio greater than 0.94.  Below is the SIT test data sheet, far more reliable than Foucault.

 

 

 

1504      32” f/2.82, data from SIT test shows1/18 wave P-V, 5.2 nm RMS on the surface, which is 10.4 nm RMS on the wave-front, or 1/53 wave RMS on the wave-front, and a Strehl Ratio of 0.986. So our claim is 1/10 wave P-V, 1/26 wave RMS, and a Strehl Ratio of 0.94. This was a repeat mirror, originally we made it at f/3.6, but it was too long, so we reduced it to f/2.82, which created a whole new set of challenges. Nonetheless, the mirror came out quite good.

 

 

 

1505      17.5” f/3.9

 

 

 

1601      24” f/3.73, data from SIT test shows 1/12 wave on the original analysis with a Strehl of 0.996, which included a minor hill dead center. This hill is in the secondary mirror shadow and was 22 nm tall. However, since it is in the shadow of the secondary mirror as is in no way part of the optic of the telescope, the below graph shows a more appropriate analysis of the mirror. The Strehl is 0.999, P-V wave-front error is around 1/31 wave, but we are still only claiming 1/10 wave P-V, 1/26 wave RMS, and a Strehl of 0.94.

 

 

 

1602      17.5” f/3.9, data from SIT tests shows 1/13.82 wave, Strehl of 0.985, mirror claim is 1/10 wave, 1/26 wave RMS, and a Strehl of 0.94.

 

 

 

1603      12.5” f/4.65, data from SIT test shows 1/18 wave, Strehl of 0.966, mirror claim is 1/10 wave P-V, 1/26 wave RMS and 0.94 Strehl.

 

 

 

1702      18” f/4.38, data from SIT test showing 1/16 wave, Strehl 0.990, mirror claim is 1/10 wave P-V, 1/26 wave RMS, 0.94 Strehl.

With the secondary mirror in place, the optical figure appears even better.