Guide :Optics : RCX400 12 Telescope

Focus I am suddenly unable to focus the telescope, I have scewed all the way in and out with no luck

Posted by billstar on Sep 15, 2007

Research, Knowledge and Information :

Prime Focus Problem - Unable to focus telescope - Beginners ...

Prime Focus Problem - Unable to focus telescope ... This came out in focus, but, I have a lot to learn ... indicates that Prime Focus is the easiest way of obtaining ...
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Out of Focus NikonD40 Camera to Celestron 130EQ telescope

Out of Focus NikonD40 Camera to Celestron 130EQ ... I am unable to focus the telescope on anything further ... and it works better than all of the other way I have ...
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Society for Popular Astronomy -Starting to Use Your Telescope

Starting to Use Your Telescope ... the image should get brighter and smaller as you approach the focus point. If it’s way out of focus and you’re not ...
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Installation Instructions – Meade Telescopes

removing the original focus assembly. If the telescope is not ... the MicroFocuser all the way out to ... out of focus, so you should have to turn the ...
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I have had my first reflector telescope and I am having problems viewing anything other than the moon. When i focus on a planet mars for instance all I can see is the ...
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Fixing Common Telescope ... all the way out, ... or there seems to be a "ring" of best focus. Your telescope mirror has spherical aberration-- the same ...
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Troubleshooting my reflector telescope ... with people unable to focus my scope. ... I am sure it can be figured out :-) have you tried it during the day at a very ...
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Refractor Vs. Reflector Telescopes. Updated on March 25, ... They would focus the blue and suddenly the red would come out of focus. ... a telescope. I have two boys ...
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Telescope Reviews, Page 27

Telescope Reviews Page 27. By Ed Ting . ... the focuser wound up getting racked all the way out (and I mean ALL the way out, ... 5:15 AM, Nikon D100 @ prime focus, ...
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Suggested Questions And Answer :

Focus I am suddenly unable to focus the telescope, I have scewed all the way in and out with no luck

Are you using a ccd or are you attempting to focus visually?
Read More At : RCX400 12 Telescope...

Trouble focusing Vivtar telescope

The telescope is designed to use the diagonal - it adds the necessary length to reach a focus point.
Read More At : (1607225) Telescope...

Trouble focusing Vivtar telescope

Put the diagonal into the telescope, DO NOT use the 2x barlow if you have one. Put the eyepiece with the largest number written on it into the telescope and try again.Read my TIPS on my profile page.
Read More At : (1607225) 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?

The screws should be short enough not to stop the primary's travel, but pull them out and try it again. Good luck! George.
Read More At : NexStar 11 GPS (660 x 279mm) Telescope...

Can't focus my telescope

If there is nothing on the objective lenses or eyepiece lenses then it most likely needs collimation. This is where you adjust the secondary mirror while viewing an out of focus star. You need stable sky conditions to do this.There are most likely three small screws at the front of the telescope and these are what you use to adjust it. As one screw is loosened then another is tightened. Do this in very small increments. If you have your manual it should outline how to perform this. If not go to this web site: It will show examples of how objects look both in and out of collimation. There is a section further down the page for SCTs.A very handy tool for this is to replace your screws with Bob's Knobs ( . These replace the screws and allow you to adjust it by hand instead of a screwdriver.The other focusing problem I've experience with my Celestron SCT is to have the focus knob loosen up and then slip as I turned it so that I could never focus with it.Good luck and clear skies!-jodair
Read More At : Meade...

ETX-90 Focus My telescope was working properly before it was moved to Florida by a moving van. I can not now get the telescope to focus properly. I have tried adjusting the focus knob but no luck. I am also not sure if the eyepiece has been tampered with or not. Is there an illustration showing how the lenses should be placed in the eyepiece?

I suggest trying a different eyepiece first to see if that's the problem. Otherwise, if it was moved without adequate protection, there is a chance the mirror was shifted or damaged. A damaged mirror can't really be fixed since it's specs are very rigid. If it turns out to be a problem with the mirror the best thing to do is find an expert on telescope mirrors to try and fix the problem.
Read More At : ETX-90 (48x90 mm)...

I've just purchased a used TAL 1 telescope complete with eyepieces and Barlow lens. However I can only get objects into focus by moving the focuser to it's limit and then physically lifting the eyepieces part-way out of the eyepiece holder. I don't think this is a collimating problem and my searches on the internet turned up a possible cure - a focuser extension tube (11/4"). Your assistance will be appreciated.

Yes, the "back focus" is too short. That extension should work.
Read More At : 3" Reflector Telescope w/Talking Guideand Tripod...

I own the 80mm williams optics refractor, it's four years old and in very good shape never been dropped. The problem I'm having is the focuser is very loose and wants to slide all the way back to the end of its travel as if there is no friction holding it back. I can adjust the set screw to hold in place, but this makes it to where you can't fine adjust the focus. The slightest tilt upward will make the focuser inopertive. I heard somewhere that there was a simple way to adjust the slide fiction..If you can help it would be greatly appreciated.

Post this question on the REFRACTOR TOPIC on discussion forum.
Read More At : ZenithStar 80 Telescope...

Hi, Original focus knob fell off my atx 70 and now the 'focus rod' goes inside the telescope instead of moving front part. Is there any way to fix it?

The knob had a tiny set screw on the side of it-- that tightened down on the shaft.See if you can tighten it back up. If it is missing take it to a well stocked hard ware store and see if you can find a replacement Allen style set-screw.
Read More At : ETX-70 (240 x 70mm) Telescope...

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.
Read More At : AstroMaster 114EQ (100 x 114mm) Telescope...

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