Meade UHTC vs Standard coatings

By anand; Published 02 Feb 2009


Meade UHTC Enhanced Coating Group vs. Standard Coatings

1) THE COATINGS ARE EXACTLY AS MEADE SUGGESTS THEY ARE....they are excellently done and WILL indeed, enhance limiting magnitude....object brightness.....color saturation....wavelength penetration (particularly in the emission spectra of red objects) and by FAR: CONTRAST in lunar, planetary and deep sky object viewing.


MEADE STATEMENT: "....transmission is increased by 21%. Averaged over the entire visible spectrum (450nm. to 700nm.), total light transmission to the telescope focus increases by about 20%"


After initial testing, the 10" UHTC telescope was compared outdoors with one of the friends 10" SCT telescope with standard coatings that has provided optimum performance and a limiting visual stellar magnitude of 14.5 at the dark sky site.

1. Planetary images - astounding. Fainter satellites of Saturn were clearly MORE visible in the UHTC coated telescope. Images of both Saturn and Venus were visibly brighter with the UHTC coated instrument.

2. Stellar images - bright star; diffraction pattern and assessment. No difference at all, although the very bright stars of YELLOW intrinsic coloration did exhibit perhaps a bit more blue false color with the standard coatings than without.

3. Deep Sky contrast - here is the main difference in my opinion. Using Messier 65 and 66 and M-81 and 82 as targets as well as the proverbial Messier 42, I found a considerable gain in contrast between the moon-soaked sky and the deep sky object with the UHTC group. In addition, M-65 and 66 were very near the full moon and the GLARE that was exhibited with the standard coated unit was very much absent with the UHTC group.

4. Limiting magnitude - again, full moon is hampering, but the Pleiades star field was used with the standard magnitude test stars. The faint 14th magnitude pair within the small easy-to-spot "triangle" of stars in the test field (14.4 and 14.8)were NOT visible in the moonlight with the standard 10".....they were CLEARLY visible with the UHTC-coated group. Turning the scopes to the variable star fields in the Orion Nebula also revealed considerably more faint stars embedded in the nebula with the new coatings.

5. Resolution - theoretically there "could" be a relationship with greater light transmission and better resolution, but in actual use, this is either doubtful or negligible. If anything REDUCTION OF GLARE will increase angular resolution and this perhaps is where the UHTC coatings have a slight edge.

6. stellar resolution: out-of-focus star images presented a very well defined Airy disk and pattern in both instruments; no visible difference in extra-or intra- focus could be detected. IN FOCUS, there was clearly a third diffraction ring encircling the star Procyon seen in the UHTC scope which was most definitely NOT visible in the standard coatings. This is believed entirely due to the remarkable cut-down on the glare of bright objects, which in itself makes this option worth the price.

7. Imaging with UHTC - no tests have yet been done with either film, digital nor CCD with these coatings. I expect similar results with imaging, although I suspect that when imaging in the reddish end of the spectrum, users will see remarkable gains in nebulae, comets and other such objects



1) These coatings do everything that Meade has claimed and in my opinion: "more." They are absolutely fantastic when clean and clear of debris and film.

2) In spite of the fact that there are thousands of Meade telescopes out there that CANNOT be retrofitted with these coatings, I HIGHLY RECOMMEND THE UHTC coatings as a major advance in amateur viewing and imaging.


The materials out of which these coatings are comprised:


[per meade: "....aluminum enhanced with a complex stack of multi-layer coatings of titanium dioxide (TiO2) and silicon dioxide (SiO2). The thickness of each coating layer precisely controlled to within +/-1% of optimal thickness."]


[per Meade: "...multiple layers of aluminum oxide (Al2O3), titanium dioxide (TiO2), and magnesium fluoride (MgF2)"]

suggest to me that - if properly maintained and cared for the coatings should remaing at near peak for at least several years. These combinations seem to have been selected as optimum transmission (corrector) and reflectance (mirrors) while MAINTAINING a minimal rate of ambient air oxidation. This proves to be an excellently durable mix.....

Only TIME and use will play this factor out into reality.

I was highly sceptical when first touted to increase transmissions into the 20% range, but I am absolutely convinced that - IF YOU KEEP THEM CLEANED PROPERLY - these coatings will provide marked increases in limiting magnitude, color and contrast and imaging response.