105 etx blurry image on all my eyepieces

[Mattyd87]

Hi,  I recently brought a second hand telescope after using binoculars for 6 months, I'm really getting into astronomy after ploughing through about 6 textbooks and using the binoculars.  I got sold a 105 etx with a motorised mount. 

I have got 4 eye pieces with the scope but every single one is showing me a blurry image with no Barlow. Even with Barlow I get a blurry image. 

I did a test last night pointing it at the moon. I got it definitely lined up as I took the eyepiece out and looked down into the small mirror and could see the moon brightly bouncing back at me from the main mirror. I can also see my eye bouncing back at me in the small mirror by the refractor. 

However the moment I put any eye piece in, the moon is just a giant ball of smudge, no out line or anything just the whole eye piece showing white. Even if I change the focuser on the side it makes zero difference. 

Any one got any ideas what the problem could be? 

Thanks

[bomberbaz]

sounds like a focusing issue matty, welcome btw. When you turned the focuser, was there actually any movement ie, did it go in and out?

[HowardHopkinson]

Take a look at the manual below and see if there's anything that could explain your issue.

https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwjjn9aGqtHKAhVCWRoKHYnsBToQFgggMAA&url=http%3A%2F%2Fwww.meade.com%2Fdownloads%2Fdl%2Ffile%2Fid%2F31%2Fproduct%2F0%2Fetx_90_105_125_ec_manual.pdf&usg=AFQjCNEv_fY5pZVx5AmOWov-pLxE5qCiqg&sig2=4Pc3zVzAIv-OxmdYEYsmPQ

[Oddsocks]

HI Matty and welcome to SGL

The ETX 105 is a Maksutov-Cassegrain optical design and focussing is made by moving an internal mirror, on the ETX I think it takes about forty turns end-to-to end for the full range so maybe you did not turn the focuser far enough. Did you allow long enough for the scope to cool, with the closed tube design and no built-in fans for circulation the ETX 105 takes about forty five minutes to cool after taking out of a warm house, during that time any object will appear to continually shift and shimmer and not come to focus, once the tube temperature reaches ambient then the image will settle and appear sharp.

Other things to check, was the dust cap removed from the diagonal? It is possible to insert the diagonal in the visual back and leave the transparent dust cap fitted, later diagonals shipped with a black dust cap and it was more obvious that you might have left it attached.

Has your ETX got the camera flip mirror fitted on the visual back, this has a flip up position for when a camera is fitted and flip down for viewing with an eyepiece, not all ETX had those, but if it is there then make sure the lever is flipped away from the camera position...

Lastly, try the scope in the day time, pointed at some distant landmark and with the scope cool try to focus it, as long as you choose a far-off object when you next get under the night sky the focus should be pretty close.

[RT65CB-SWL]

9 hours ago, bomberbaz said:

sounds like a focusing issue matty, welcome btw. When you turned the focuser, was there actually any movement ie, did it go in and out?

Hi Matt and welcome to SGL.

I agree with what 'bomberbaz' has said. You should be able to see movement of the primary mirror.

Can you hear any movement if you turn the 'scope; ie if you have it pointing straight up towards the zenith and then point it down 180 degrees to the ground? Reason I ask is that this happened to my ETX105. I was very concerned.

To cut a long story, short, I contacted SCTelescopes (phone: +44 7934 063893 / internet: www.sctelescopes.com) and made an appointment to get it seen to and overhauled. What happened to mine was that the collar that glides/slides on the baffle tube, and holds primary mirror to the support cell had become loose. Steve, (the propieter), dis-assembled my ' scope, tightened up the collar, re-assembled and then collimated it. Mine was done in less than two hours.

From your description it sounds like to me that the focus push/pull rod may have come apart from the mirror support cell or it has been badly collimated at some point, (though this is highly unlikely as they were collimated during assembly at the factory and do hold collimation). I doubt it is an opaque end cap as I cannot fit an eyepiece in to the holder if I forget to remove it before use. Another thing worth looking at is the flip mirror. Does it look clean? You may be able to remove the rear plastic cell, as it secured by the 6/32" machine screws. They can be very tight, so go easy when unscrewing them as the heads may get damaged with a screwdriver tip.

I would not advise you not to do it yourself as Mak's & SCT's optics have be perfectly aligned and collimating an ETX is not easy.

[Mattyd87]

Hi guys, 

Many thanks for your help.  You wouldn't believe what the problem was.....

Thr viewfinder was totally off course to the main scope.  So I used a laser pen or top of the scope to point at a object (tree). Then looking through the main scope I took the advice and slowly moved the focus knob. Very slowly some leaves came into focus. I looked through the viewfinder and it pointed at blank sky. 

So the scope wasn't damaged but the viewfinder was out of line to the scope.  I spent about a hour refocusing the viewfinder crosshair to point at the same location as the scope. 

All is well. Many thanks to all for your help

Hope to see you around here... 

[Charic]

Always good when the user finds out the fault for themselves, and often the fault is a minor one, nonetheless it will cause confusion until solved. Well done
In a nutshell, as you have discovered, align and lock the telescope onto some distant target, then align the finder to the same target, job done.

Welcome to the SGL.

[RT65CB-SWL]

Congratulations Matt. 

To me the '105 was the best of the ETX series. I have had a look though the '90 & '125 and they did not quite cut the mustard in my opinion.

Should you wish to de-fork it from the supplied mount and attach it on a GEM or Giro type alt-az mount, I found that an eight inch dovetail bar, two Jubilee clips/rings, some self adhesive felt works. See my post "My 'modded' Meade ETX105 OTA - part 2" in the DIY astronomer section. If you, (or other SGL members), have any questions about my 'modded' ETX105 please ask.

[Mattyd87]

6 hours ago, Philip R said:

Congratulations Matt. 

To me the '105 was the best of the ETX series. I have had a look though the '90 & '125 and they did not quite cut the mustard in my opinion.

Should you wish to de-fork it from the supplied mount and attach it on a GEM or Giro type alt-az mount, I found that an eight inch dovetail bar, two Jubilee clips/rings, some self adhesive felt works. See my post "My 'modded' Meade ETX105 OTA - part 2" in the DIY astronomer section. If you, (or other SGL members), have any questions about my 'modded' ETX105 please ask.

Thanks Sub, I will look up your post.

Also many thanks to all, I am just waiting for a clear night to give the scope a round 2 outside, really looking forward to it. Any one got any suggestions to look at for end Jan/early Feb. I heard Jupiter should come into view at around 10pm GMT in the SE?

[Mattyd87]

6 hours ago, Philip R said:

Congratulations Matt. 

To me the '105 was the best of the ETX series. I have had a look though the '90 & '125 and they did not quite cut the mustard in my opinion.

Should you wish to de-fork it from the supplied mount and attach it on a GEM or Giro type alt-az mount, I found that an eight inch dovetail bar, two Jubilee clips/rings, some self adhesive felt works. See my post "My 'modded' Meade ETX105 OTA - part 2" in the DIY astronomer section. If you, (or other SGL members), have any questions about my 'modded' ETX105 please ask.

I think I might be ok, my scope looks like the photo attached with a good electric mount. Thanks for the link anyway.

[RT65CB-SWL]

Hi again Matt.

A useful site for all things ETX is Mike Weasner's mighty ETX site at www.weasner.com