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Posts Made By: Saied Mabrouk

September 23, 2008 09:04 PM Forum: Equipment Talk

Celestron CR-150 HD

Posted By Saied Mabrouk
Hi, I just bought a used Celestron CR-150 HD achromat. Does any one know how to remove the dew shield to clean the objective lens? Celestron tech support was of no help. Thanks. Saied

September 24, 2008 09:25 PM Forum: Refractors

Celestron CR-150 HD

Posted By Saied Mabrouk
I just bought a used CR-150 HD 6" achromat. I need help with three questions.
Is this model the old or the new version?
Is the objective cell collimatable/adjustable?
How to remove the dew shield? Thanks.

May 7, 2010 08:15 PM Forum: Refractors

Anti-fringe filter vs stopping down an achromat

Posted By Saied Mabrouk
I always wonder which is better for a 6" achromat, to use an anti-fringe (violet) filter versus stopping down the scope for better viewing? Would appreciate any thoughts or results of actual experience.

May 9, 2010 12:19 AM Forum: Refractors

Explore Scientific 152mm f/6.5 achromat

Posted By Saied Mabrouk
Does anyone have this Explore Scientific 152mm f/6.5 achromatic scope and would like to share his/her experience with it? It would be interesting to compare it to the Synta 150mm f/8 achromat. I have one ordered and should receive it in about a month (it is out of stock now)

June 6, 2010 02:06 AM Forum: Refractors

Vixen NA140SS vs NA140SSf

Posted By Saied Mabrouk
Hi, Does any body know if there is an optical performance difference between the old Vixen model NA140SS and the current model NA140SSf? The SSf model used to come with a single speed focuser and it now comes with a 2 speed focuser at higher price. I believe that the SSf is built in China, sent to Japan for "QC inspection", stamped built in Japan before it is sent out.

What I want to know if there is an optical performance difference between the SS model and the SSf model with single speed or with 2 speed focuser versions..

June 9, 2010 05:01 PM Forum: Refractors

Vixen NA140SS or NA140SSf CA and Star Test

Posted By Saied Mabrouk
Would anyone who has a representative example of the Vixen NA140SS or the Vixen NA140SSf be able to share images taken by the scope?

1. Of a bight object like the Moon to access its chromatic aberration (false color)

2. Star image at about X200 magnification in focus, inside focus and outside focus to access optical performance.

Regards.

July 9, 2011 11:49 PM Forum: Refractors

100mm ED 2" focuser draw tube

Posted By Saied Mabrouk
I have two virtually identical 100mm ED F/9 refractors. A Vixen and a Celestron/Skywatcher. The only difference is in the draw tubes. The Vixen's 2" draw tube has 3 baffles with the flat black paint. The Skywatcher 2" draw tube is threaded all the way and painted with the same flat back paint.

My question is: which draw tube has the advantage in reducing stray light?

Regards.

October 4, 2011 06:36 PM Forum: Refractors

Vixen ED100sf vs Vixen ED103S

Posted By Saied Mabrouk
I have the Vixen ED100sf and I am happy with it as a planetary scope. How does it compare to the Vixen ED103S on planets and color correction? I know that the ED103S is made in Japan (and the ED100sf made in China), better made, more expensive, is faster (F/7.7 vs F/9), and would be better for astrophotography.

Not to sound negative about the Vixen ED100sf, its longer focal length and its F/9 would make it ,in general, better for planets and easier to focus.

What I want to know is the difference between the telescopes as far as optical performance on planets and color correction, other differences????. Any opinion is appreciated.

June 19, 2014 03:40 AM Forum: Refractors

Vintage 90mm f=1000mm Orion Skyview achromat OTA

Posted By Saied Mabrouk
I am the second owner for this scope. I bought it to keep as a collector's item. But when I decided to sell it and tested it, it performed reasonably well, but its star test had an issue. I wrote about it in the cloudy nights forum, but so for I got few helpful comments.
Please read the cloudy nights short thread, below, and give me your feedback.
Regards.
http://www.cloudynights.com/ubbthreads/showflat.php?Cat=0&Number=6584666&page=0&view=collapsed&sb=5&o=all&fpart=&vc=1&PHPSESSID=

August 5, 2014 03:13 AM Forum: Refractors

Synta 100mm F/9 ED vs Synta 120mm F/7.5 ED

Posted By Saied Mabrouk
Did anyone perform a side-by-side comparison between Synta (Skywatcher, Orion, Celestron, Vixen) 100 mm F/9 ED refractor and Synta (Skywatcher, Orion) 120 mm F/7.5 ED refractor as far as color correction and contrast for lunar and planetary observation?
I understand that both doublets use FPL53 ED glass and have the same 900 mm focal length. Of course the 120 mm refractor will collect more light, but this is not a big issue for the Moon or planets.
What I am after is this: If you have a very good example of the Synta 100 mm F/9 ED, would moving to the 120 mm F/7.5 ED is worth the extra cost and the extra physical weight when it comes to lunar and planetary observation?

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