Celestron 127 SLT - Everything seems to be blurred.

[Dowina]

It's been a very long time since I did any star gazing. Last telescope I owned was when I was 15 and I am 58 now. Anyway recently bought a used Celestron 127 SLT. Apparently it is only a year old but given that the spirit level on the mount has dried out I am guessing it is a lot older than that. I think they came out in 2012? 

It all seems to work ok, motor works, controller works. Have not done any of the setup yet because due to lack of space I need to keep moving the scope across the room so just using it manually for now.

The problem is, everything I look at is blurred and hard to focus. I was looking at the moon the other night and it was so hard to focus. I assume this is down to atmospheric interference? It would come into focus for a split second and then it was like there was a heat haze in front of it. Frustrating to say the least! 

Trying to look at stars is pointless because they look clearer if I just use my eyes! I also tried with a cheap pair of 8x21 binoculars and they are just as good as the telescope! So by now I am starting think there is something not quite right here?

I have tried also focusing on a tree that is probably around 250 metres away during the day time. I can see it through the scope but nothing is clear. Surely it should be better than this?

To sum up nothing I have looked at yet has been in focus. I get it as sharp as I can but nothing is clear.

I have checked to make sure the eyepieces are clean (Celestron 9 & Celestron 25 included with scope) and right now I have run out of ideas. 

Am I expecting too much? Surely a scope like this should be better than a cheap pair of no name binoculars?

All suggestions welcome

Sol

[johninderby]

Sounds like it is out of colimation. These scopes don’t normaly need collimating but being used you never know what has happened to it.

Here’s a quick colimation check  vid. The Celestron and Skywatcher are the same scope. There are vids on Youtube that show the colimation process in detail.

 

[JamesF]

Collimation was my first thought, too.  Given some patience it's not too hard to sort out if that is the problem.

It's an excellent little scope for solar system targets.  I've even seen Neptune with mine.  Well, perhaps "seen" is going a bit too far.  "Picked it out from the background star field" is probably more accurate

James

[johninderby]

Worth taking a look at the heads of the collimation screws to see if there are signs of them having been used. If so previous owner could have messed up the collimation. ?

[Dowina]

Thanks guys. Will check that out tomorrow. Probably try the same thing with the led torch and foil. 

[cletrac1922]

Dowina

Have you tried setting up in day time

Focus on a tree, mobile phone tower, or something in the distance

Then you will know if collimation issue, of just condensation  

One of our club members also got given one, second hand a while ago

Same issue

Page 30 attached link is very helpful

https://www.nexstarsite.com/download/manuals/NexStar127SLT.pdf

 

John 

[Ruud]

7 hours ago, Dowina said:

I need to keep moving the scope across the room

If you are you trying to observe through a window, that may be the problem. Even with the window open, air currents from warm inside air escaping through the window are bad for the quality of the view.

[Cosmic Geoff]

Good suggestions above. I have the same scope and it is excellent.  I hope you manage to find out what is wrong with yours.  You need to use it outdoors.  Windows are not made with optical glass!  Open windows are no good either, as currents of warm air will disturb the view.

FYI, a star should look like a point of light with this scope, or at high magnification and good seeing, a minute dot with rings around it (this is an optical effect).  To see this ring effect you need a good quality 8mm or 10mm eyepiece - the 9 or 10mm eyepiece bundled with the scope when new is not good enough to resolve what the Maksutov is capable of showing.

[happy-kat]

Please can you show a picture of the mount, if it is the mount I think it might be on they are not designed to be moved manually.

[Dowina]

All useful info there. Thanks for that

Ok so I checked the collimation the same as in the video above and it looked fine to me. One thing I have noticed though. We did some testing today just focusing on trees in the distance using the 25 and 9 eyepieces but still difficult to get anything into pin sharp focus. Maybe I am just expecting too much? Going to buy a pair of decent binoculars and see they are any better..they shouldn't be right?

[Dowina]

Forgot, this is the sort of mount my scope has:

 

[happy-kat]

8*42 or 10*50 binoculars are great to compliment a telescope, nice wide field views.

It could be the eyepieces as the supplied one are just to get people started. Though the Moon with the 25mm I expect would look good.

As far as I know that type of mount needs power to move, so using the buttons on the handset.

A great setup to get going with.

[Dowina]

20 minutes ago, happy-kat said:

As far as I know that type of mount needs power to move, so using the buttons on the handset.

A great setup to get going with.

Yeah it's powered by 8 AA batteries or an optional power adapter. I have been just using the control to move the scope around but as I mentioned, have not used the auto setup yet because of where the mount sits. We don't have much space here so the whole thing get's moved back and forth around the room all the time.

I think I will set it up out on the balcony tonight and mark where the tripod is set up. I can then align it and see how that goes. 

[johninderby]

One other possibility is the diagonal. The basic cheap one that comes with the scope is plastic bodied and while usable isn’t the best and has poor build quality. One way to check is to remove the diagonal and look through it. Indoors is fine. The view should be nice and sharp. Also is the diagonal clean? 

[Ruud]

Observing from the balcony is a good idea! Much better than from indoors.

Out in the cool night air, the telescope takes 30-60 minutes to even out its temperature. Until then you still have air currents happening inside the tube. Once that's over the views should be as steady and sharp as the atmosphere allows.

According to this: https://www.meteoblue.com/en/weather/forecast/seeing/brighton_united-kingdom_2654710 , the sky over Brighton, tomorrow night, should be clear and the seeing good. Bookmark Meteoblue. They have a good astronomy forecast.

[Dowina]

1 hour ago, johninderby said:

One other possibility is the diagonal. The basic cheap one that comes with the scope is plastic bodied and while usable isn’t the best and has poor build quality. One way to check is to remove the diagonal and look through it. Indoors is fine. The view should be nice and sharp. Also is the diagonal clean? 

If I look through the scope without the diagonal everything is upside down and not actually any better in focus  Maybe that indicates something?

[dweller25]

Have you cooled the scope down ?

If stored indoors you need to leave it outside, pointing down with the rear port open for a good hour before use.

[Dowina]

3 minutes ago, dweller25 said:

Have you cooled the scope down ?

If stored indoors you need to leave it outside, pointing down with the rear port open for a good hour before use.

I am going to give it another try tomorrow night as the sky should be clear. Will leave the scope out on the balcony for an hour before attempting to align it etc. Wow learning stuff all the time here. I had no idea about cooling the scope, internal air currents and so on. 

[Cosmic Geoff]

I doubt that the diagonal is the problem.  The one I got with my 127mm Mak SLT was adequate.  Even the cheap diagonals are adequately flat and reflective, as careful surveys have shown.  The more expensive ones have better build quality, higher reflectivity, or longer life coatings.  Give the scope a cool down and use it in the open night air (not on a balcony) before assuming anything is wrong.  Any heat sources (open windows, chimneys, heater vents, idling trucks) in the light path will cause deterioration of the image. The Mak ought to totally outperform a pair of binoculars. 

[cletrac1922]

2 hours ago, Dowina said:

Yeah it's powered by 8 AA batteries or an optional power adapter. I have been just using the control to move the scope around but as I mentioned, have not used the auto setup yet because of where the mount sits. We don't have much space here so the whole thing get's moved back and forth around the room all the time.

I think I will set it up out on the balcony tonight and mark where the tripod is set up. I can then align it and see how that goes. 

Dowina

You also need a decent battery source for the mount

You using rechargeable batteries

Normal carbon AA batteries give you 1.4 Volts, where rechargeable only give you  1.2 volts

I use car jump start pack to power my EQ5  mount

John