Problem with focusing an 11" Edge HD Celestron

[brisen]

I recently purchased an 11 " Edge HD scope and have only had a couple of chances to use it. I have tried it on the Moon and can not get the image clearly focused at all. I can see a blurry image but no real detail as it appears the scope is not focusing. Not sure if it is my eyesight failing or if I have simply purchased a lemon.

Any ideas would be great.

Brian

[Kunama]

Hey Brian, can you take a photograph of your scope all set up for viewing and give details of the attachments you are using including the eyepiece. That way others can see what is going on and hopefully solve the problem.

Oh and Welcome !!!!!!!

[brisen]

Hi Matt

Thanks for the welcome. I have attached an image of the setup (the eyepiece isn't attached). The scope came with a 23 mm Luminos ep, and I purchased 5mm and 13 mm Baader eps afterwards.

Brian

[torsion]

Hi Brain,

I got a 9.25HD. I presume you have read the manual (sorry for asking).

The photo looks OK (nice scope:)), with the diagonal. Make sure you have 'completely' backed off the locking screws, which are the other two screws on the back of the scope. If not they will prevent the primary mirror from moving back and forth and bring the image in focus.

I can get focus with the 23mm EP, incl. the diagonal so it is possible (just so you know).

cheers,
Bram

[brisen]

Thanks Bram. I went out last night here in the yard and had some success (there is a bit of smoke around) but did get a better focus than I have had previously. I backed the other two knobs right off this time and that made a bit of a difference.

Brian

[casstony]

Hi Brian, your 23mm eyepiece gives a magnification of about 125x which may be too high for observing conditions on a given night - you might buy a longer focal length eyepiece (35 or 40mm) which would be handy for DSO's and bring the mag down for unstable nights. You also need to let the scope reach ambient temperature before it will give stable images.

[sil]

I've also got a C11HD. I use Baader Hyperions and most of my observing is with the 21mm. If I go smaller though the seeing conditions deteriorate the image very quickly. Focus can be tricky but I have no trouble getting a crisp image with the 21mm EP. Your 5mm EP will probably never be able to be used on this scope unless the seeing conditions are exceptional.

Just make sure you loosen the mirror lock screws (don't go too far), get your focus, then slowly tighten them again (just watch through the eyepiece in case focus changes). As you move the scope to different parts of the sky the mirror can move (losing focus) so use the locking screws appropriately to hold the focus for the eyepiece.

[Camelopardalis]

Also if your focuser is a little stiff it might need some of the baffle tube lube spreading about a bit... to do this, turn the focuser one direction all the way to the stop, then back the other way to the stop and repeat back and forth a dozen times. It takes a few minutes but I found it helped with the finer focussing attempts quite a bit, but I could still focus before it was just more tricky, so not sure if this helps :)

[casstony]

I think it's best not to use the locking screws at all for visual; focus needs to be adjusted frequently anyway, particularly if the scope is still cooling. If you approach final focus with an anti-clockwise turn of the focuser the mirror is much less likely to move.

An anti-clockwise turn pushes the mirror up the baffle. A clockwise turn pulls the mirror down the baffle tube, after which the mirror can settle/drop on it's own, slightly changing focus.