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Orion ED 100

Posted by Wing Eng   01/01/2008 12:00AM

Orion ED 100
I have owned many scope in my time including many dobsonians, and several refractors, including a Televue 102. Presently, my refractor set-up utilizes a Televue Upswing Mount which is attached to a sturdy photo-tripod, but I had never put more than about 7 1/2 pounds onto it. I have had a lot of viewing success using this mount with an Orion ED 80 f/7.5 OTA, but decided to try out a brand new Orion ED 100 f/9 OTA (Cost is $899.95 for the OTA only), which weighs closer to 9 pounds taking into into account the 6X30 finder, the 2 inch diagonal with 1.25 inch adapter, the Televue 4 inch tube ring and the 1.25 inch plossl. Note: Orion states the weight of the 80mm ED OTA as being 5.7 pounds and the 100mm ED OTA as being 7.0 pounds. Also, the 80 ED OTA is about 2 feet long while the 100 ED OTA is about 3 feet long.

I opened up the new Orion 100mm ED purchase and noticed it is packed similarly to the way Orion packs the 80mm ED. The EDs are packed inside a separate, interior box; a box inside another box. Styrofoam with appropriate cut-outs support the OTA on both the objective and focuser ends. There is some amount of bubble wrap surrounding and running the length of the OTA, but it is the styrofoam that provides the main protection.

The 100mm, 3.94 inch, diameter ED objective is fully multicoated and reflects off a nice eye-pleasing greenish color. The cover for the dew-cap is black-colored plastic and has several "grips" that tend to scuff up the flat-black paint inside the dew cap. Being a stickler, I took off the threaded dew cap and carefully sanded and spray-painted the inside to be perfectly smooth. I then replaced the Orion dew cap with a felt-lined dew cap. The focuser is a Crayford style 2 inch type and is relatively smooth. It is perfectly smooth when turning the focusing knobs slowly, although a bit bumpy when turning them rapidly.

First Light (December 30, 2007): It was a terribly turbulent evening! All the stars and the planets Mars and Saturn were quite mushy and even my try at "star testing" the Orion ED 100 met with fuzzy images, plus the temperature hovered at 31 degrees. I viewed Sirius and it looked full of color, but thankfully, not due to the OTA as this star even appeared multi-colored as it resided about 10 degrees above my southeast horizon. So, I packed it up for the evening. But, the one thing that I did demonstrate to myself was that even with close to 9 pounds of weight and the 3 foot length of the OTA, the Televue Upswing Mount handled this set-up very nicely and with minimum bumpiness as I was able to slew from object to object without much effort.

Second Light (January 1, 2008): I took a bit of a nap after the New Year reigned in, and woke up around 1:15am. The sky had now cleared of its high nuisance clouds and I decided to dress up warmly (35 degrees outside temperature) to try out the Orion 100 ED once more. I noticed that the sky had an overhead limiting visual magnitude of about 5.0, at best, but there were no clouds at all and, best yet, the "seeing" conditions were about 8.5 out of 10! I excited tried out my set up once again using the following eyepieces: Meade Series 4000 - 26mm (35X), 15mm (60X), 9.7mm (93X) and 6.4mm (141X) plus an Orion Ultrascopic - 3.8mm (237X).

Viewing Results:

1.) The star test proved quite good with nearly identical concentric ring patterns inside and outside of focus at 93X.

2.) Double Stars: 2nd magnitude Polaris showed off its 9th magnitude companion at 60X, while 1st magnitude Castor showed 2 overlapping A and B stars at 60X and full separation at 93X. There was no violet halo color observed in viewing these stars.

3.) Mars: I could make out some dark markings on the red planet at 141X and 237X (60 times per inch aperture) with no image breakdown and no intrusive violet color surrounding Mars.

4.) Orion Nebula: I could make out the Trapezium at 35X although it took a bit of effort to see the 2 closest of these 4 stars. This great nebula showed off some bluish color to me at 60X and 93X, which I found impressive for a 4 inch scope.

5.) Saturn: This planet was wonderful to view! I saw one very dark belt on the planet although I normally would see 2 belts that are not quite as dark. The rings are getting towards being edge-on, but I could still clearly see "dark space" between the rings and the planet, itself. Even at 237X, my views of Saturn had no visual distortion and had no violet halo color.

6.) Last Quarter Moon: Craters clearly seen at all powers with no color on the surface of the Moon and no violet halo limb color, although a bit of yellow-brown color on the limb which may have been due to the moon at about 10 degrees above the southeast horizon as it was affected a bit by atmospheric waviness.

Overall Recommendation: Get this scope if you wish to have relatively wonderful, color-free, viewing of celestial objects. It is not as good as a Televue 102, but for about one-third of the price - you would be hard pressed to beat it!

Best Wishes,

Wing(1st name) Eng(last name)
San Ramon, CA