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andib479

Help ..no image only bright white circle

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I have a celestron astromaster 130eq. When I look through the eye piece, all I see is a bright which circle of light. Please note, the moon wasnt out last night. 

All lights were off in the house. It was pitch black outside. I moved the eye piece to try and home in on anything but it will not. The viewing focal is fixed, doesn't move and is held in place by screws. This isn't a case of blurred items, this is the scope not focusing on anything.

 

I've taken the eye piece out and when I look in the scope my eyes central. I've looked through the eye piece while it's not in the scope and I can see in the distance, all be it very blurred.  The caps are all off, theres nothing in the tube that should be there.

 

Any ideas? I've tried day and night 

20200125_155734.jpg

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Hello and a warm welcome to the SGL. When you turn the wheels on the focuser does the eye piece move freely in and out of the focuser ? You  may have to loosen the locking screws to achieve this.
 

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Hello and welcome to SGL. How far away was the object you were trying to focus on ? If it was too close the telescope might not be able to reach focus at that distance. Alternatively, you didn't adjust the focusing.

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It does. I've taken the eye piece out and put it back in having turned it fully 360. As I did this a black shadow like an eclipse was visible, so I rotated it until this disappeared then secured with the screws again. 

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17 minutes ago, andib479 said:

It does. I've taken the eye piece out and put it back in having turned it fully 360. As I did this a black shadow like an eclipse was visible, so I rotated it until this disappeared then secured with the screws again. 

Focusing is achieved by turning the wheel on the side of the focuser, not by rotating the eyepiece.

137969320_turnthis.jpg.e374d5ff4861c05fcfe1dd1d2ef2803b.jpg

 

 

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This is the wheel I'm turning. This is all I see. Its day time right now. If I wave my hand in front it's very faint but I can see a shadow pass 

20200126_143346.jpg

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So - just to check - when you turn the wheel that @Cornelius Varley has circled, does the eyepiece move in and out?

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In addition to the above, please take a photograph for us looking down the main telescope tube.

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Thanks for baring with me. When the whee is turned the eye nozel does move in and out. I will take a pic inside and upload tomorrow :)

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It definitely sounds like you are not in focus, and not able to achieve focuis, but I am puzzled by the white circle at night time.

Also by the offset of the white circle I suspect your collimation is out.

Carole 

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12 hours ago, carastro said:

I am puzzled by the white circle at night time.

Yes me too. What were you looking at that was the bright white object in your photo andib479?

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U can try using it in the daytime.

Try a building chimney pole or tree but at least 100 meters away then turn the focus wheels up and down slowly untill u see an image

Joejaguar 

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By the way what eyepieces did u use ?

Most new people use them in wrong order maybe u were using the highest power?

In daytime just use the o e market 20 or 25 only.

Joejaguar 

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Still.nothimg tonight despite trying to focus on the moon. Here are the pics of inside my telescope and the view finder. I'm most about to give up. :(

20200127_201221.jpg

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I've no idea why it was white when I was looking at a black sky. I am very confused. I bought this really for my little boy and I'm worried if I dont get this sorted it will forever ruin his interest, which will be mortifying:( 

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Thats really curious to see white if you are looking a a black sky, could there be a reflection from inside the house that could cause this? Also, ensure that the eyepiece is placed as far into the focus tube as it will go as this is the best place to get focus and use the low powered one like the 20mm.

It is also worth checking the collimation if you feel up to it, look online for tips but it could be that something has been knocked out of alignment during delivery and it needs to be set right.

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Can you take a picture with the eyepiece removed and looking straight down the eyepiece holder ?. Try and get the camera lens as central as you can over the hole where the eyepiece would be.

 

 

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First of all welcome from Land Down Under

Did you buy the scope new or second hand?

Definitely sounds like a collimation issue

If you not able to resolve focus issue, then rock up one night to your local astronomy club, the guys there will only be too happy to resolve your issues, and same time show you their gear as well

With my club, I have become the goto guy for Dob scopes

Had new member recently, and brought a scope second hand 8'' Dob he brought on Gumtree, had similar issue

When looked down the tube, noticed that the secondary was not centered, and used bit of paper to mark off the supporting veins, and the secondary was off to one side

Once fixed that, then used a laser collimator, and to align secondary and primary, and had perfect image

John

 

 

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You are not trying to use Barlow lens as well as the eye piece are you as that will only increase your problem.  Just use the lowest power eye piece (higher the number lower the power) until we have you up and running.  

If bought 2nd hand, did the previous owner happen to do imaging, as he might have moved the mirror further up the tube in order to get focus with a camera. In which case you'll not manage to get focus without an extension tube.  

Talking of which, if you are pointing at the Moon and can see an out of focus white thing, try pulling the eyepiece further out to see if that gives focus.  

Carole 

Edited by carastro

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Basically, there are two routes open to you: either take the telescope to somebody who has the experience and expertise to see what is wrong and put it right, which they would probably be able to do quickly.

Or do the work of obtaining said expertise yourself: learn how telescopes of this type are adjusted and tested (collimated), and what you can expect to see as the telescope goes in and out of focus, and how critical the focal adjustment is.

Possible reasons for inability to focus: telescope severely needs collimating, it has been modified for camera use, you have inadvertently included (or excluded) some tubular extender which changes the eyepiece position.  Typical of this design of telescope is that the mechanical range (in/out) of the focuser is fairly limited compared with some other designs where one can hang any accessory on the telescope and still get it in focus.

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11 hours ago, andib479 said:

I've no idea why it was white when I was looking at a black sky. I am very confused. I bought this really for my little boy and I'm worried if I dont get this sorted it will forever ruin his interest, which will be mortifying:( 

Apologies for the really obvious question, but are you taking the telescope outside or using it to view through the windows? It's not clear from your previous postings. It may well be you are seeing a reflection within the double glazing if the telescope is not square on to the window.

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Is it just me or does the angle of the eyepiece look slightly skewed on the first picture of the scope above? Does the eyepiece slide smoothly into the eyepiece holder? Could be just the lens cap being wonky I suppose...

image.png.a01d8c85a02d89a9a88c6953c02f0f87.png

 

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