OMC-140 Maksutov Cassegrain Telescope Review

Author: Robert Geake


Telescopes and Mounts:
Skywatcher Evostar 150
Konus MotorMax 90
Orion(UK) Europa 250
Skywatcher EQ-6
Meade DS2114
Orion(UK) OMC 140
Meade ETX-90EC
Skywatcher Startravel 80
Synta Skywatcher EQ-6 EQ6
TAL 100R Refractor
Film Astrophotography
Minolta SRT100X
Canon IXUS 330
Other Stuff:
Baader Fringe Killer
My Latest Astro Picture
Star Hopping Guide
Stacking images
Bits and bobs

My astronomical experience

I have, in the last 3 years gained more and more experience with telescopes and all fields of astronomy. Although i am hardly a professional i do have a very good working knowledge of telescope types and use as well as observing practices. I have been using all the equipment mentioned on this site along with other equipment at star parties. Read on for the first section of my review.

OMC-140 technical specification

Aperture = 140mm
Focal Length = 2000mm
Focal Ration = f/14
Aluminum tube assembly
9X30 Finder(replaced with 9X50)

The Journey

The OMC-140 was purchased second have from an advert placed in A trip to Oxford was required to pick up the scope, having spent alot of time driving in Europe the 240 mile round trip did not pose any kind of trouble so of we set at 11am on a saturday morning!!! My experience of driving in Europe include a tour of mid and northern Europe, as far East as Poland, a total of 2500 miles in one week! Also a drive from Rome to Mount Etna in Sicilly and back(about 1200 miles). Driving in the uk could not be any different, 4 whole hours to drive 120 miles??? That is just wrong! Anyway, i digress! On our return home i check some sat pics and decided we may well get a little observing donw through the gaps in the cloud!!!

My first observing session

Again, as with all my other astronomical purchases and completely conflicting to the law of Murphy, the sky was clear enough for me to actually try the scope on the day of purchase!!! I did a simple polar alignment by pointing the scope along the polar axis of the telescope and using ALT/AZ adjustments to center Polaris. This is good enough for visual observations. Mars was rising in the east but currently not high enough to be observed with any kind of detail although i did have a quick look and as suspected nothing but a boiling orange blob! The moon was very low in the west and had taken on the orange colour it does when it gets closer to the horizon. I aimed the OMC-140 at the low moon with a 40mm plossyl the first thing i noticed was the increased magnification. At 2000mm focal length the 40mm ep was returning 50x, this means im going to need to get a longer eyepeice for those wider objects(M31, Double Cluster).

The moon looked orange, and without a moon filter quite bright given the phase was well over half illuminated. The craters where showing fine detail with a clearly visible shadow line on the inside and outside of the wall. The Moons is still a most facinating subject to observe even after many many hours. Huge open plains and tall mountain ranges, the OMC's performance appears to be better than anything i have yet looked through. The difference between plains and mountain is emense. On one plain i could see what appeared to be huge sand banks laid out as sand dunes in the desert are. This is the first time i have seen this feature and as always, i did not make any note of it anywhere! From the moon i moved onto some of the brighter objects in the sky that i am familiar with, always a good way of determining the differences between scopes. First the perseus double cluster, this is one of my favourite objects, the multitude of colours and spacings between stars makes for a marvel of natural beauty. At 50X its hard to get the whole thing in the feild of view so i had to examine one cluster at a time. From Perseus on to Cygnus and its famous double Alberio, this double looked stunning in the OMC-140, nothing but blackness(the moon had now set) between elements and such a difference in the colour of the two stars. The clouds are now starting to close in and i fear, are bringing and end to the session.

From my first session with the Orion Optics OMC-140 i can already tell its optical performance is very good, even for such a small apeture. The mechanical build quality of the scope is good too. A micrometer focuser a sturdy tube and 2 finder scope mountings. I will be adding to this review as time goes by and observing session become more frequent. Please check back for updates.

Update: 2008-09-19

Alas I have now sold this scope. It was a far to specialised gadget for my astronomy requirements. I have however, used the money from the OMC-140 to purchase a TAL100R. A telescope that I have owned before and found to be an excellent choice.


Author: Robert Geake
Valid XHTML 1.0!