Review of the Intes Micro Alter M703 180mm Maksutov Cassegrain

by Ralph Kantrowitz

This is a 7.1 inch f/10 Maksutov Cassegrain manufactured by the Russian company Intes Micro. I purchased this scope from ITE Telescopes in February, 2003. It arrived a few weeks later after a stop-over in Jupiter, FL for a collimation and certification by Mike Palermiti. The scope is the standard coatings version with a certified final wavefront error of one-sixth wave and 0.7 arc second bench-test resolution.

The scope was packed in the carrying case surrounded by newspaper and Styrofoam. I had expected a large amount of bubble wrap instead; nevertheless nothing was broken. The scope came with a 2” SCT diagonal with 1.25” adapter, a 30 mm finder scope, camera mounting bracket, 12mm Erfle, 2.4X Barlow and saddle mounting plate, all Intes Micro products. An Astro-zap soft dew shield was also ordered – this was delivered separately. The scope tube had a couple of minor black scratches and the corrector plate had an edge chip outside of the optical path, otherwise the scope was in good condition, with a cream finish and ventilated housing for corrector plate. However the clamping bolt on the saddle mounting plate was received bent outside the used thread and needed to be carefully straightened to avoid ruining the rest of the bolt.

First night images were excellent and I was very happy with my purchase. I noticed a clanking noise when I turned the scope 180 degrees. This was traced to a loose retaining ring that holds the secondary in the corrector plate. I snugged down the threads to just finger tight and touched up the collimation. Skies were cloudy for most of that spring – I couldn’t get good observations of Jupiter and Saturn, so I’ve waited a couple of years to write up my assessment.

The 30mm finder had a plastic reticle and port for an illuminator, but I chose to substitute my own homemade 50mm finder and eventually purchased an Orion 9×50. The only finder ring base that will fit the scope is the one that it came with, so I substituted shorter adjustment screws for the wider tube. Within a couple of months, I noticed that the included diagonal gave dimmer views than my Intes 2” diagonal or vintage Vernonscope 2” enhanced diagonal. My final substitution for the SCT diagonal is an Astrophysics MaxBright diagonal and 2” visual back.

Views of the Moon and Planets

My views of the moon have been excellent. The irregularities in the Hyginus Rille are clearly visible. The central craterlet in Plato can be glimpsed as a craterlet, the remaining 3 larger craterlets as white spots. Copernicus is outstanding and the craterlets in the ejecta blanket are clearly visible.

I was lucky enough to own this scope for the close opposition of Mars in 2003. I used magnifications of 270-360x on Mars and made several drawings. The image was bright enough to use colored filters. I could not see details in the polar cap but had memorable views of Sinus Meridiani, Solis Lacus and Syrtis Major. I was able to make out differences in shading of the albedo features and easily picked up limb hazes.

I’ve had the best contrast on Jupiter at magnifications of about 200-225x. At magnifications above 250x, the loss of contrast often became important for suburban skies. However, the shadows of small satellites, i.e. Io, were best seen on steady nights with magnifications of 360x. The color of the Great Red Spot was salmon. I’ve had few really good nights with Jupiter and have not had any interesting views of seldom seen garlands and festoons. On good nights, the Galilean satellites show distinct disks, the main equatorial belts have irregular edges and I can pick out some dark lineaments in the south temperate zone. The split in the SEB following the GRS is easy to see and occasionally I’ve seen the twists in it.

I have not have many good opportunities to view Saturn with the M703. On a good night, the image is brilliant and sharp, the Cassini division visible as well as the major banding and the dusky polar region. The difference in color between the ball and the rings is apparent when Saturn is high in the sky. I’ve managed to see Titan, Rhea, Dione and Tethys but never Enceladus or any other dim moon.

Uranus and Neptune remain tiny disks without any detail. Pluto is too dim to see with this scope.

Double Stars

One of the selling features for Maksutov Cassegrains over Schmidt Cassegrains is better definition, especially on double stars. I do think this is true. I’ve had outstanding views of the companion to Antares, and have split 36 Andromedae (0.9”), as well as 52 Orionis and the closer components of Nu Scorpii. The splits of Antares and 36 Andromedae are definitely better than what I remember of my MK66, 6” Maksutov- cassegrain. A couple of springs back, the components of Gamma Virginis were at about 0.7 arc seconds apart and I was able to see two Airy disks nearly in contact at 400x. However, I’ve been unable to split Zeta Bootis (0.8”), so the Gamma Virginis observation was made on a uniquely clear and steady evening. Epsilon Lyrae, Alpha Herculis, Gamma Andromeda and Epsilon Bootis are all easy to see and beautifully split.

Deep Sky

I’m not much of a deep sky fanatic, so this scope has been enough to satisfy my cravings. The showpiece globulars M3 and M13 are resolved into stars, M17 and the Lagoon look great with a nebula filter. I’ve seen M65, 66 as well as their dim companion NGC 3628. The Eskimo and Ghost of Jupiter are easy to see. I’ve seen the E-star in Orion’s Trapezium without a problem and glimpsed the F-star with great difficulty. M11 and M37 are lovely, as are M57 and M27. I’ve also been able to see portions of the Veil Nebula, as well as the Helix nebula with the aid of a nebula filter. The Pleiades fit in the field of a 2” Plossl eyepiece with 50mm focal length; I’m looking forward to seeing them with my Burgess 38mm, which has a wider field.

Comparisons with other Telescopes

Except for the ability to provide low power views, the M703 beats my 4” apo on all objects. There is no noticeable mirror shift when focusing. The M703 has better star images than my second-hand C9.25, but the light gathering power of the C9.25 gives much brighter views of globular clusters, galaxies and planetary nebulae. One evening a fellow amateur brought his new C9.25 out to the field. He was amazed that the M703 provided such a sharp, but dimmer image of Jupiter. However, the big test for me was how the M703 would compare against my 5” AstroPhysics Starfire.

For this test, I dragged two mounts and both scopes out to the field for testing. The seeing seemed to be about average with stars of about 5th magnitude visible to the naked eye. It was an April spring evening, so winter constellations were still visible. I used my AP MaxBright and Vernonscope enhanced 2” diagonals. At ~50x, the contrast and brightness of M42 was about the same in both scopes. The 5” had sharper star images, but the M703 was slighter brighter; possibly due in part to the MaxBright Star Diagonal. Delta Geminorum was better in the 5”, with a single diffraction ring. Multiple rings in the Mak shimmered with convection. Saturn was sharper and steadier in the 5” using ~250x in both scopes. I swapped star diagonals and looked at some deep-sky objects. On M51 there was not much of a difference, but it was slightly brighter in the M703. M104 was brighter in the M703, but the edge-on disk was shorter than in the 5” – the thinner edge disappeared. The proportions of the image in the 5” were closer to the proportions in a friend’s 10” Meade LX200, although dimmer.

The big test was Jupiter. It was definitely brighter in the M703, but the increase in planetary contrast was offset by the difference in image steadiness. The 5” was definitely the scope of choice for Jupiter. During an Io occultation, the image was much steadier in the 5”. The GRS hollow was visible in both scopes, but sharper in the 5”, although the image was slightly dimmed and yellowy compared to the M703. A recent comparison of the M703 versus the C9.25 on a night of average seeing gave me the same difference in steadiness of image, but in this case, it was the M703 coming out far ahead of the C9.25.

During the 2003 Martian apparition, I generally used the M703. However, there were a couple of nights that I set up my 5” refractor. One evening in late September, I was amazed at how clear, sharp and steady the image was in my refractor. I didn’t bother to set up the M703 for comparisons, but it was the same kind of difference in image steadiness noticed on Jupiter that April night.

Conclusions

The M703 is a fairly close alternative to a good 5” refractor, but with brighter images. I didn’t care for the accessories, although the only really bad accessory was the Barlow, due to field curvature. The OTA carrying handle, light weight and scope case make this a very easy scope to travel with and mount. During the past couple of years, it has had more use than any of my other scopes and has only needed collimation a couple of times. However, it is a pricey scope, now costing over $2K without a mount. The focuser is slightly too firm; Mike Palermiti had no easy solution to smoothing it other than regular use. I do not like the mirror coatings; when I shine a flashlight at them, they do not seem to reflect as much light as the Celestron StarBright coatings on my C9.25. I came close to mailing the secondary back so that Mike could make a determination on whether it required re-coating. After taking out the corrector plate and getting the mirror ready for shipment, I realized that the mirror was very reflective, but that the coating seemed a bit porous. I think the rest of the reflectivity issue is the thickness of the corrector plate. Unlike a Schmidt-Cassegrain, the corrector plate is about a half inch thick. However it has a spherical figure, making it very easy to re-align the optics.

I use the scope on a Losmandy GM-8 mount in the field and on a Super Polaris mount on my balcony. Please note that the SP mount is a bit too light for this scope.

The sharp planetary and double star images are very satisfying, but I think most amateurs today would rather have a good Go-To SCT of 8”-10” aperture in order to find faint deep-sky objects. SCT quality has come a long way in the past decade. However, I like the independence of a German Equatorial mount that can be used for many scopes, and can be broken down into components weighing 25 pounds or less, as opposed to an SCT tripod and 40-plus pound SCT fork assembly.

The ideal customer for this scope would be an advanced amateur who already owns a good equatorial mount and optical accessories. Aging amateurs in this category might welcome such an easy-to-handle scope and may not need Go-To capability to find favorite objects. The high cost of this OTA relative to SCTs would probably not make it suitable for novices or deep-sky enthusiasts. As of this date, the only importer in the U.S.A. is ITE Telescopes, now based in Jupiter, FL.