Celestron StarSence DX6 10mm eyepiece focus problems

[ianoliver]

Hi, we have a Celestrong StarSense Explorer DX6 Schmidt-Cassegrain as our starter telescope. It is supplied with two eyepieces: a 40mm and a 10mm.   So far we've been successful with the 40mm in getting that to focus and general usage of the telescope - the "easy" targets: Jupiter, Pleiades, Orion Nebulae etc - we can view with good clarity and the stars are proper pinpoints.  The 10mm however defies all of our attempts to get it focussed - when turning the focus knob on the scope we can at best get a fuzzy shape rather than anything well defined - any ideas or is the eyepiece "broken" in some sense?

One piece of advice was to collimate the telescope - as far as I have read and seen this is fine and I guess the problem lies elsewhere and I'm at a total loss to figure out what to do or try

THanks in advance,

[Cosmic Geoff]

The kit 10mm and 9mm eyepieces from Celestron and Sky-watcher do not have a good reputation.  I'm surprised you find it that bad, but you would find it worthwhile to invest in another 10mm eyepiece of better quality, plus a 25mm to fill out your range, as an absolute minimum.

[ianoliver]

So do you recommend I return the eyepiece as not being usable?

[Cosmic Geoff]

2 hours ago, ianoliver said:

So do you recommend I return the eyepiece as not being usable?

Not unless you have incontovertible evidence that it's faulty. Anyway those 10mm starter eyepieces are all poor. Just buy a better one.

[Shimrod]

4 hours ago, Cosmic Geoff said:

Not unless you have incontovertible evidence that it's faulty. Anyway those 10mm starter eyepieces are all poor. Just buy a better one.

I think there is a difference between poor and not being able to get focus at all. I doubt Celestron would ship an eyepiece that would not work with the telescope at all unless it is faulty - there is more likely another explanation for the failure to reach focus which buying another 10mm eyepiece would not resolve.

 

On 06/01/2022 at 20:49, ianoliver said:

Hi, we have a Celestrong StarSense Explorer DX6 Schmidt-Cassegrain as our starter telescope. It is supplied with two eyepieces: a 40mm and a 10mm.   So far we've been successful with the 40mm in getting that to focus and general usage of the telescope - the "easy" targets: Jupiter, Pleiades, Orion Nebulae etc - we can view with good clarity and the stars are proper pinpoints.  The 10mm however defies all of our attempts to get it focussed - when turning the focus knob on the scope we can at best get a fuzzy shape rather than anything well defined - any ideas or is the eyepiece "broken" in some sense?

Your telescope will have quite a large focus range and although you might not think you have to change it much when switching between eyepieces, it can sometimes require quite a bit of turning of the focus knob!

Have you tried using the telescope during the day to test focus? Set it up a pick something in the distance - preferably at least half a mile away, but anything from a couple of hundred metres should be fine. With your 10mm eyepiece in, wind the focus knob all the way through from one end of the focus to  the other (this can be as many as 30-40 full turns for the full focus range) checking to see if the eyepiece comes into focus. If this works, put your 40mm eyepiece in and could how many turns (and which direction) it takes to bring that into focus - this will help you when swapping eyepieces in the night. 

Have you also tried holding the 10mm eyepiece up to the light and checking if you can see clearly through it- it is possible that an internal lens has been put in the wrong way round or there is some residue on the eyepiece. Depending on how you stored the 10mm eyepiece before swapping over, is it also possible that dew has formed on the eyepiece which may also be causing your focus problems?

[Cosmic Geoff]

A new SCT should not need collimating, but it is worth checking that the collimation is in fact good.  A star should look like a point, or with a high power eyepiece like a tiny dot with circles around it (in good seeing).  (This assumes you have a good quality eyepiece, not one of those starter kit things. Which is one reason I suggested buying a good eyepiece). When out of focus, a star should look like a circle with a hole in the middle.  It should not look like a badminton shuttle.

If you suspect this is the problem, I suggest you contact your dealer for advice, rather than trying to correct the problem yourself.