True Performance Never Fears Change

It Defies The Status Quo

Comparison of outside optician's "smooth" finish versus Dream's re-finish of the same surface/mirror (click image).

RMS Surface Roughness Data (smallest scale errors)

from Dream's in-house polishing

Concave 247mm CA, f2.27

The above RMS surface roughness test was conducted in the mirror's center, showing an average of 6.42Å.

The above RMS surface roughness test was conducted at roughly the 50% zone of the mirror, showing an average of 7.39Å.

Dream averages 6-9Å RMS surface roughness, which is 2.2-3.3x better than the industry standard spec for visual spectrum of 20Å.

**Dream's founder, Shane Santi, ground and polished his first mirror in 2001. Since Dream was established in 2003 it has evolved into a more vertical company that has leveraged its expertise in designing and engineering the zeroDELTA lightweight mirrors into fully processing, including finishing, these high-performance and ground-breaking modern mirrors. Dream's extensive use of modern engineering tools and intelligent design breaks the paradigm that most associate with lightweight mirrors. Numerous examples over the years have proven that Dream's high-level of engineering and expertise allows the zeroDELTAmirrors to be processed with conventional methods and to a finish equal to that of solid mirrors, without the baggage that comes with solid mirrors.

**This paper shows an example 396mm CA, f1.376 mirror finished with low Mid-Spatial Frequency (MSF) errors, as well as low RMS surface roughness.

**The below high resolution interferometry data from a 415mm, f3 concave paraboloid shows how smooth (extremely low Mid-Spatial Frequency errors (MSF, historically called primary ripple)) are in a Dream zeroDELTA engineered lightweight mirror when processed by Dream. The zeroDELTA mirror had a face of roughly 0.1" thick. This is a superb example of why real and extensive engineering matters, setting Dream mirrors apart from others. The band number is defined toward the top of the graphic, giving a description of the physical size of MSF error being evaluated in that column.

**The above primary mirror was used inside a Dream Cassegrain telescope for IR use. The 2-mirror portion of the telescope achieved 0.83 arc-second image resolution from a less than ideal location. See this telescope within this white paper. Dream finished this aspheric primary mirror to within 0.009% of the nominal radius. Our typical radius tolerance is +/-0.1%, but as this example shows, we can achieve far tighter.

**Dream's dedicated polishing and testing room is 68°F, +/-1°F and 60% RH, +/-10% year-round. Although Dream's zeroDELTA lightweight mirrors equalize exceedingly fast, the tight temperature and humidity control is ideal for test equipment repeatability, as well as consistency & control of the engineered pitch & polishing compound that Dream uses.
**The ceiling of the room is equiped with a 44" x 44" trapdoor that allows vertical testing of mirrors. This can allow comparative data of the mirror performance in the final mirror mount at different angles. It can also allow finishing of a primary mirror in its final mirror mount, an ideal way to ensure the highest quality and performance in final use.

Click the image to the right to see the quality and tight specifications that can be achieved on a convex secondary mirror. Dream can also provided dedicted athtermal carbon fiber mirror mounts and finished telescopes.

Contact Dream to discuss your project's needs.

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