Guide :Optics : NexStar 11 GPS (660 x 279mm) Telescope

Focusing Issue Last night, I used my Celestron 11" NexStar11GPS for observing and astrophotography, and it worked like a charm. Tonight, with the same equipment, I am unable to focus the telescope at all. I turned both the coarse and fine focus knobs counterclockwise as far as they will go, but every object is still out of focus--and once I reach a certain point in turning the focus knobs, the object simply moves in the eyepiece rather than becoming more focused. This problem is present with or without the use of a diagonal. The only thing I did with the telescope between last night and tonight was to mount a Celestron StarPointer (a holographic sight-type finderscope) onto the side of the telescope tube's back end with some 8x32 3/8" screws using pre-drilled screw holes. What happened?

Posted by coderedd on Jun 25, 2008

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We did not find results for: focusing issue last night i used my celestron 11 nexstar11gps for observing and astrophotography and it worked like a charm tonight with the same equipment i am unable to focus the telescope at all i turned both the coarse and fine focus knobs counterclockwise as far as they will go but every object is still out of focus and once i reach a certain point in turning the focus knobs the object simply moves in the eyepiece rather than becoming more focused this problem is present with or without the use of a diagonal the only thing i did with the telescope between last night and tonight was to mount a celestron starpointer a holographic sight type finderscope onto the side of the telescope tube s back end with some 8x32 3 8 screws using pre drilled screw holes what happened.

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Focusing Issue Last night, I used my Celestron 11" NexStar11GPS for observing and astrophotography, and it worked like a charm. Tonight, with the same equipment, I am unable to focus the telescope at all. I turned both the coarse and fine focus knobs counterclockwise as far as they will go, but every object is still out of focus--and once I reach a certain point in turning the focus knobs, the object simply moves in the eyepiece rather than becoming more focused. This problem is present with or without the use of a diagonal. The only thing I did with the telescope between last night and tonight was to mount a Celestron StarPointer (a holographic sight-type finderscope) onto the side of the telescope tube's back end with some 8x32 3/8" screws using pre-drilled screw holes. What happened?


The screws should be short enough not to stop the primary's travel, but pull them out and try it again. Good luck! George.
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Having a clear sky last night i took my new scope out and started to view the night sky, but focusing on a star ! i found that when viewing it at magnification a could clearly see the the area infront of the scope the supports the viewing prism/mirrow and the cross braces that support it, am i trying to view a subject that is "too far" i am VERY new to all this and i am using a celestron 114EQ scope from new any help appreciated Ray


Stars are ALWAYS pinpoints of light when the scope is focused no matter how much magnification is applied.You are NOT focused properly -- when you are you cannot see the secondary mirror or the "spider" bracket that holds the mirror.You will NEVER see a star as a disk, only as a pinpoint light. If you are seeing what looks like a donut with a dark center you are not focused.
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I use a celestron astromaster 130 eq. When I focus on an object such as a planet at night, the silhouette of the secondary mirror and its mounts overlays the image of the planet. I do not experience this problem in the day time when viewing terrestrial stuff.


You need to collimate your telescope. This site has a really easy to understand diagram and instructions. Hope this helps. http://www.astro-baby.com/collimation/astro%20babys%20collimation%20guide.htm Good luck. Astronomyforums.net and cloudynights.com are two really good sites for information.
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Celestron nexstar 8 i series alignment trouble


Kind of late with my answer...BUT if you pop off your GPS unit and then just tilt it up and down CAN YOU HEAR a ball bearing moving inside...??? YOU SHOULD....that is how the GPS actually finds the level position of the OTA....sounds like it is stuck..OR even worst that you have a CN-16 unit that was designed for a GEM mount which is not designed at all for leveling the OTA...Next thing.. exactly what version is your hand controller...version 2.3 ???? Bob G
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I have a CPC11GPS telescope that was working the last time I used it, which was 6 months ago. It is in NEW NEW condition. I pulled it out last night, turned it on, allowed the system to align itself using the GPS system aboard. I then tried to center the first star using the RA and DEC directional buttons. The Dec buttons moved the telescope up and down, but the telescope would not move in RA. I also connected the scope to my SKY program, it also moved the scope in Dec, but not in RA. What could have happened since it was last used? The only previous problem I encountered was alignment and intermittent RA movement, I sent the scope to Celestron, who worked on it and returned it. Those problems were never corrected by Celestron, a year ago.


The clutch is not engaging in RA. Maybe the gears are not actually meshing together? A loose worm gear?You can open it up and look and see if anything obvious is loose. Otherwise it's a trip back to Celestron.
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Inability to focus on close objects


Thats most likely its focal point. 50 yards you will have to unscrew the view lens and make an adapter out of a paper towel roll and keep working with it till you get what you want. Its just the way it was made.
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Hey guys! My brothers chipped in to get me a telescope for my birthday. It's a celestron sky prodigy 70. I took it out a few times with zero experience except for what I picked up from reading the owner manual. Please excuse my language as I do not know any common terminology nor am I very good at trig but I at least know the terms relating to math( if thats what it really is talking about). So, when I look through the lens I get a nice sharp and crisp image with the factory provided lens. I know this is an entry level telescope but I want more magnification. So I bought an x-cel lx 2x Barlow lens and a 24mm-8mm zoom lens. I know the max magnification is 165x and the focal length is 700 so that puts my strongest eye piece at a little over 4mm meaning a 5mm is pretty much what I'll get out of it. I tried the Barlow and the zoom lens a smidge over 8 (9 I hope it was at) and the image is very soft. Then again I am in Los Angeles and looking out of my window through a fairly heavy marine layer. But the image comes out sharp if I use my factory lens, or just the zoom, or my already provided 24mm with the Barlow or the zoom at a lower magnification with the Barlow. My provided 9mm with the Barlow produces a blurred image and I tried to focus but it still seems blurry at best. I think I'm safe to say a 9mm on a 2x Barlow is still within the max effective range of zoom? I'm wondering if I shouldn't expect much out of the telescope or if I should return either the Barlow or the zoom lens or both and get some higher quality object specific lens instead. Or maybe I'm not focusing correctly? Or a zoom should not be used on a Barlow? Any insight would be very helpful.


Hi, I can see you'r statring a interesting journey in amateur astronomy. Which can be really amazing but also disappointing, because usually people are expecting too much (specially after viewing beautiful astronomy pictures on internet).Before we go back to your question lets go over some basics here:Your telescope has a F10 aperture (Focal lenght / Diameter).So to be able to see the maximum amount of details from it, the smallest eyepiece you need is a 10mm (eyepiece mm = to f number of thetelescope).Then it's easy to find the maximum useful magnification: 700mm (focal lenght) / 10mm (eyepiece) = 70x Ok but why does the manufacturer say that it can be at a max of 170x... they are not really lying, if you get a smaller eyepiece it will make the image bigger but will show no additional details than a 10mm one. But the image being bigger it can make details easier to see.That for the questions about magnification an image quality.The more pieces you put between you eye and the telescope mirror, the dimmer and less contrasty the image will be. Especially after you go higher that the maximum useful magnification.Hope this helps. And enjoy wathching the stars and planets, it is a always a beautiful sight.
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Focus knob turns but nothing moves


The Celestron manual for this scope has nothing to say, but on the underside of the focuser assembly, between the 2 focus knobs, you may see 2 screws.They might be thumbscrews or some other screwhead type. One is the adjustment for the focuser internal clearance, or looseness, and the other is a focus travel lock.If present, try backing both off 1/2 turn from tightness, and then experiment to see which is which. The focus lock will have no effect until tight, when the focuser will cease moving, as is now. The other screw will gradually remove looseness and rattle from the focuser until it just moves smoothly, with no back and forth loose feeling at the knob.If neither of these screws is visible you will have to take it to a binocular and telescope shop, where they should not charge much.
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I can target moon or planet in view finder and see same using just the 45 degree mirror;but, when I put in lens the object of course is blurred.My question is...How do you focus???...I had a telescope previously and you had a knob to turn on lens to focus...Lens that came with scope had none and additional barlow 2x is same type lens I know to add...But can't figure out how to focus...Please help....David


The knob on the back of the tube is the focuser-- put in the eyepiece with the largest number written on it and try again.It's harder to focus at HIGH magnification the sweet spot is very tiny.Go here and download a manual:http://www.celestron.com/c3/downloads.php
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We had the 20mm eye piece in and we turned the focus all the way clockwise so the eye piece was all the way in. We had the cover off, we had a very clear starry night, we live in the country, moved the scope around for 20 minutes, trying to find any star, and could not see anything...did we do something wrong? When you are looking through the star finder with the LED, so you psotion your head behind the scope barrel and try to put the star in the LED or do you 6" away or where, because as I moved my head, the site changed. By using the scope in the daylight, looking at an object and focusing it in, how does that correspond to us being able to use it at night? We are excited to use this, but are frustrated .... thanks for your help.


First find a local Astronomy club -- the members will help you.Second, you must first align the red dot finder with the main tube-- there are knobs on the side and bottom (usually) to move the red dot. Point the scope at the top of a telephone pole in the distance during the day time-- wget the top in the center of the eyepiece of the main tube. Without moving the main tube adjust the red dot so it points at the exact same spot.Turning it all the way in or out is NOT how you focus-- there is a small "spot" when the eyepiece is in focus, and every other eyepiece must be refocused. Turn the knob slowly until the star or the moon comes to sharp focus.Read my tips on my profile page. www.telescopeman.orgwww.telescopeman.uswww.telescopeman.info
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