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GSO 200mm f5 Newtonian Telescope

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#1 Olympian

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Posted 21 September 2023 - 02:08 PM

I just recently purchased a GSO 200mm f5 newtonian telescope from Agena the company who has replaced OPT in California who closed their doors and sold their inventory. They sell most items that OPT was selling. This telescope is sold under different names but the Agena GSO seems to be the best. They claim each telescope is throughly checked out in appearance, mechanically and the mirror throughly checked out. They even include a certificate showing this. 
GSO seemed to successfully address the problems with this line. The dust cap was almost impossible to remove without forcing it off because it was so tight when pushed in. It now is so soft and and easy placing it in and taken it off the tube. The rings were so tight that even if you loosen the rings it was still hard to rotate or move up and down without completely unlocking the rings. Now you can rotate and move up and down much easier. It seemed that the inside tube surface was matte and powdery and if you touched the finish that some black stuff would come off on many of the models. Now the finish is still matte but it is absolutely silky smooth and when you touch it nothing comes off. The collimation was a little off but took seconds to get a perfect red dot in the center of the secondary mirror and seconds to collimate the primary with a quality laser aided by installing bobs knobs. The actual collimation screws were actual Philip screws and not that tiny screws that most reflectors use. The bob knobs just made it even more easier.

Observing was fantastic. Perfect looking stars and very sharp especially the moon which was razor sharp as well as Jupiter, Saturn, Uranus and Venus. The double cluster was bright and sharp along with M42 which i observed with high power. The whole field of view was greenish billowing hazy smoke.

The white gloss tube is well constructed and a flawless finish. Two speed focuser works great. Nice and smooth. They had a limited amount and I bought the last one available. $589.00 no tax and free shipping.

I just want to add that last night at dawn I saw the three brightest objects besides the moon in the night sky. In the eastern sky was the beautiful brilliant crescent phase the morning star Venus. In the southern sky was Sirius and in the western sky was Jupiter. Sirius paled in comparison to Jupiter and especially Venus. Combined with Orion and Auriga there we’re so many bright stars out.

 

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Edited by Olympian, 21 September 2023 - 02:28 PM.

  • happylimpet, N3p, Echolight and 2 others like this

#2 Echolight

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Posted 21 September 2023 - 02:27 PM

Nice! I bought an Orion 203 f4.9 a few months ago. Synta version I guess.

It's a lot more manageable size than an f6.



#3 happylimpet

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Posted 21 September 2023 - 02:47 PM

A lovely type of scope, and a good implementation by the sounds of it. Happy days!



#4 gstrumol

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Posted 21 September 2023 - 02:59 PM

Looks fantastic, and the price is more than just right! waytogo.gif  

 

I have one question though. Since it's on a GEM how do you deal with the location of the EP, as you target different parts of the sky? Do you have to keep rotating the OTA in the rings, or do you have cirque du soleil contortion skills? wink.gif  

 

Pardon my ignorance, but my only Newtonian is an Astroscan; I just rotate the ball to bring the EP to a comfortable spot.


Edited by gstrumol, 21 September 2023 - 03:00 PM.


#5 Echolight

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Posted 21 September 2023 - 03:18 PM

Looks fantastic, and the price is more than just right! waytogo.gif  

 

I have one question though. Since it's on a GEM how do you deal with the location of the EP, as you target different parts of the sky? Do you have to keep rotating the OTA in the rings, or do you have cirque du soleil contortion skills? wink.gif  

 

Pardon my ignorance, but my only Newtonian is an Astroscan; I just rotate the ball to bring the EP to a comfortable spot.

I will say that the eyepiece gets rather high when viewing high in the sky with my 203mm f4.9 if used on a standard height tripod. Step stool high at least.

 

I've tried mounting it low on a Unistar and "40 pound capacity" Bogen 3068. Although I think the Unistar might be alright, this Bogen tripod is a little squirrely for the weight and moment arm.

IMG_20230524_200640101~3.jpg


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#6 fabio_lima

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Posted 21 September 2023 - 05:04 PM

Good to know.

Recently ordered and waiting one GSO 150mm/F5.

Wishing it could have performance and build quality similar to yours.



#7 happylimpet

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Posted 21 September 2023 - 07:24 PM

Looks fantastic, and the price is more than just right! waytogo.gif  

 

I have one question though. Since it's on a GEM how do you deal with the location of the EP, as you target different parts of the sky? Do you have to keep rotating the OTA in the rings, or do you have cirque du soleil contortion skills? wink.gif  

 

Pardon my ignorance, but my only Newtonian is an Astroscan; I just rotate the ball to bring the EP to a comfortable spot.

during my many years of visual newt use of a GEM, i always kept the eyepiece at 180 degrees to the image shown at top - pointing back 'towards the mount'. i thought a much bettrer generl purpose orientation. please forgive typos, am in the dark imaging jjupiter and cant see keyboard.



#8 Oldfracguy

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Posted 21 September 2023 - 09:11 PM

Good to know.

Recently ordered and waiting one GSO 150mm/F5.

Wishing it could have performance and build quality similar to yours.

Not to redirect this thread, but since somebody asked, the build-quality of the GSO 6" Newts is very good as well.  I think what sets the GSO Newts apart from the Synta-made ones (Celestron and Sky-Watcher), and I've owned multiple models from each manufacturer, is the excellent, rock-solid focuser.  Not only does the focuser track absolutely straight in and out, the insides and outsides are blackened:

 

101_2422.JPG

 

 

Here's a GSO 6" f/5:

 

101_1644.JPG

 

Here's the stock single-speed focuser on the 6" f/5:

 

101_1645.JPG

 

I upgraded the focuser to a Dual-Speed. It took about all of 5 minutes to install the upgrade kit.  (NOTE: The GSO 8" Newts come with Dual-Speed focusers standard.)

 

101_2195.JPG

 

 


Edited by Oldfracguy, 21 September 2023 - 09:19 PM.


#9 Oldfracguy

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Posted 21 September 2023 - 10:05 PM

OK, a question for Olympian, our OP:

 

Looking at this drawing, can you measure the distance "a" from the middle of the Secondary mirror to the Focal Plane with an eyepiece installed and the scope in focus?   

 

GSO 8-in f5 Newtonian.jpg

 

For simple eyepieces like 1.25" Plossls, the focal plane will usually be very close to the point where the eyepiece fits up against the 1.25" adaptor on the focuser, as shown by the yellow arrow below: 

 

101_1645(2).JPG

 

NOTE: The distance "b" can be found by subtracting the measured distance "a" from the focal length, in this case 1,000 mm.

 

 

 



#10 N3p

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Posted 22 September 2023 - 06:46 PM

I just recently purchased a GSO 200mm f5 newtonian telescope from Agena the company who has replaced OPT in California who closed their doors and sold their inventory. They sell most items that OPT was selling. This telescope is sold under different names but the Agena GSO seems to be the best. They claim each telescope is throughly checked out in appearance, mechanically and the mirror throughly checked out. They even include a certificate showing this. 
GSO seemed to successfully address the problems with this line. The dust cap was almost impossible to remove without forcing it off because it was so tight when pushed in. It now is so soft and and easy placing it in and taken it off the tube. The rings were so tight that even if you loosen the rings it was still hard to rotate or move up and down without completely unlocking the rings. Now you can rotate and move up and down much easier. It seemed that the inside tube surface was matte and powdery and if you touched the finish that some black stuff would come off on many of the models. Now the finish is still matte but it is absolutely silky smooth and when you touch it nothing comes off. The collimation was a little off but took seconds to get a perfect red dot in the center of the secondary mirror and seconds to collimate the primary with a quality laser aided by installing bobs knobs. The actual collimation screws were actual Philip screws and not that tiny screws that most reflectors use. The bob knobs just made it even more easier.

Observing was fantastic. Perfect looking stars and very sharp especially the moon which was razor sharp as well as Jupiter, Saturn, Uranus and Venus. The double cluster was bright and sharp along with M42 which i observed with high power. The whole field of view was greenish billowing hazy smoke.

The white gloss tube is well constructed and a flawless finish. Two speed focuser works great. Nice and smooth. They had a limited amount and I bought the last one available. $589.00 no tax and free shipping.

I just want to add that last night at dawn I saw the three brightest objects besides the moon in the night sky. In the eastern sky was the beautiful brilliant crescent phase the morning star Venus. In the southern sky was Sirius and in the western sky was Jupiter. Sirius paled in comparison to Jupiter and especially Venus. Combined with Orion and Auriga there we’re so many bright stars out.

Cool, I would buy something similar a second time because it's It's a perfect instrument for sketching. I am very glad to see people interested to such a setup. Very nice!



#11 Olympian

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Posted 23 September 2023 - 07:01 AM

during my many years of visual newt use of a GEM, i always kept the eyepiece at 180 degrees to the image shown at top - pointing back 'towards the mount'. i thought a much bettrer generl purpose orientation. please forgive typos, am in the dark imaging jjupiter and cant see keyboard.

 

during my many years of visual newt use of a GEM, i always kept the eyepiece at 180 degrees to the image shown at top - pointing back 'towards the mount'. i thought a much bettrer generl purpose orientation. please forgive typos, am in the dark imaging jjupiter and cant see keyboard.

 

Looks fantastic, and the price is more than just right! waytogo.gif  

 

I have one question though. Since it's on a GEM how do you deal with the location of the EP, as you target different parts of the sky? Do you have to keep rotating the OTA in the rings, or do you have cirque du soleil contortion skills? wink.gif  

 

Pardon my ignorance, but my only Newtonian is an Astroscan; I just rotate the ball to bring the EP to a comfortable spot.

With this telescope the focal length is 1000mm. Its actually 36 inches from tip to tip. I have it sitting on the AVX mount. I had no problems with the different positions the eyepiece would be in observing many different objects which were many because I had the AVX properly aligned and the GO TO was close to perfect in all directions of the sky all night long. Also tracking was very accurate and consistent. I do have some contortion skills but was not needed with this set up. Most all positions were comfortable except one time I needed a three step ladder using the first step to align in the two set up alignment on Alcor in the handle of the Big Dipper which was getting low in the northwest. 
 

It’s when I use my skywatcher 200mm 1200mm focal length and especially the Orion 254mm 1200mm focal length Newtonian that I need more use of that three step ladder. Also with the 8 inch skywatcher the tube could hit the legs overhead at certain positions and not as much with the Orion ten inch because the mirror on that is so heavy that I can placed the tube higher to the front making it less chance hitting the tripod legs. I’m around 5’ 11” tall. Anything overhead with the GSO I can comfortably stand straight up but I actually had to bend down slightly to observe. I was thinking of raising the tripod legs around two inches to be more comfortable standing straight up with objects overhead.




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