Help needed: Sky Watcher 10" Dob can only focus on very close objects
Hi, have brought my first telescope which is a Sky Watcher 10" collapsible dob. Currently having issues trying to focus with it. At night I have tried it on the moon which only appeared as a white featureless disk. Have been unable to even see out of focus stars.
Due to these issues I have tried the telescope during the day. Tried to focus on trees varying from a 100m to a few kms away but always have a very blurry view. Yesterday had it out looking at the moon. Once again very blurry and unable to make out even the shape of the moon. Really it was like looking at blurry blue with a hint of blurry white. When I was nearly finished trying to get it working I noticed I was able to focus on some fence wire a few meters away. So figure something must be up as I thought you should not be able to focus on close object.
Have looked through forums and checked I have not made the common mistakes people make when they cant focus. The telescope seems collimated to my uneducated eye. I have it fully extended. Am not using the the 1.25" eye piece adapter with the 2" adapter. Also used some high and low profile adapters to adjust focal length from a mate who looked at the telescope. He couldn't see what was going wrong either.
Any thoughts on what the issue could be would be appreciated
If your scope will focus on close objects but not further away it must be because your objective lens is too far away from the primary mirror. Ie, it needs to be brought closer somehow. Usually the focussed does this for you, but if there is not enough 'in'travel, then there's something else wrong. Make sure there are no unnecessary extension tubes attached in your focusing train. As a last resort you can look at shortening the path by raising the primary mirror up the ota tube, but since this is a store-bought scope, you should not have to do that.
Hope this helps. Brian
Have looked at a video of someone using the same telescope. Everything seems the same. There is nothing that allows the distance of the mirrors to be adjusted other than for the primary mirror. Top part of it clicks into place when you extend it.
Have looked at a video of someone using the same telescope. Everything seems the same. There is nothing that allows the distance of the mirrors to be adjusted other than for the primary mirror. Top part of it clicks into place when you extend it.
Sounds very strange Steven.
Are you using the supplied eps (eyepieces), have you tried all supplied eps?
Sounds like a trip back to the supplier.
You don't want to do anything to void your warranty.
BTW Welcome to IIS
You have chosen a great scope, very unusual to have this sort of problem.
Top part of it clicks into place when you extend it.
Hi Steven,
From your comments, it looks like you've read my posts on a similar topic.
But just to be certain, the Skywatcher 12" collapsible has two clicks on the struts - it clicks when you initially extend it and then you have to give it an extra tug and it extends to the second click. Perhaps the 10" is the same?
From your comments, it looks like you've read my posts on a similar topic.
But just to be certain, the Skywatcher 12" collapsible has two clicks on the struts - it clicks when you initially extend it and then you have to give it an extra tug and it extends to the second click. Perhaps the 10" is the same?
Hi Paul,
I don't think that is the case with all SW flex dobs.
Certainly not with my 12". Or my previous 10 Flex Dob.
But mine are probably older models.
Yes I have tried both eye pieces supplied and a few of a mates.
Have been extending it fully to the 2nd click.
It's all very frustrating when its a telescope many people don't have issues with and brought from a telescope store. Hoping I dont need to get them to look at it as im in Canberra and dont want to make a trip to Sydney.
Steven,
I assume the secondary and primary mirrors look clean and bright.
When you look through the eyepiece holder. With no eyepiece- what do you see? I know you said the collimation looked OK but just double checking.
A couple of photos of the set-up. May be helpful.
I'm sure it's not a serious problem, we just need to get a better understanding.
When I look through the focuser without the eye piece I see my eye and the 3 clips. Could say it may be the tiniest bit off but was struggling to get it any better.
Also tried moving the primary forward but didn't make any difference. still could only focus a few meters away.
Is it possible the wrong primary mirror was installed.
Steven,
You seem to have a 40mm or so spacer fitted between the eyepiece and the focused. What result do you get when this is removed?
I don't think it needs to be there.
What looks like a spacer is the adapter for 1.25" eye pieces. Instructions say to use it. Can't see anyway to make the eye piece fit into the focuser without it
The flat fronted plate with a bevelled rear face is correctly mounted into
the open end of the focuser. The front face has a male thread that the eyepiece holder screws onto, which appears to have been done, but from the pic I can't see if it is screwed hard up against the flat face. The eyepiece holder is indeed about 35-40mm long, and is intended to be in that position.
It can't have an f/4 mirror installed because the focal point would be radically different, so nothing would come to focus. Perhaps a member
with knowledge of these scopes who lives near you could come to your place to check it out.
raymo
After further study of the pic it looks like the eyepiece holder is fitted
inside the male threaded stub rather than screwed onto the male thread,
and therefore doesn't go far enough in. The eyepiece holder should have a female thread. I think you have the wrong eyepiece holder.
raymo
I was remembering wrongly, the eyepiece holder does screw in as shown
in NoTan2's pic. The male thread screws into a T-ring. Ocellaris's set up
is correct, so the problem lies elsewhere. Maybe the extension rods are
incorrectly adjusted.
raymo
Just my luck to be having an issue with this. My son is getting so desperate to see saturns rings. Takes me 30mins to get him to sleep because he keeps asking questions about space.
Has anyone had any issues trying to phone Bintel. Have been trying but calls have not been answered. Though have only tried yesterday and today as I wanted to wait until a friend looked at it incase I was doing something dumb.
