Jump to content

Question on changing Celestron 9.25 to a 2" diagonal.


Recommended Posts

I have a Brandon 2" 48mm eyepiece that I'd like to use on my new Celestron Nexstar Evolution 9.25. Instead of purchasing the Celestron diagonal, I bought the Celestron SCT to 2" adaptor so that I could just use the 2" diagonal that originally came with my Brandon 94mm some 30 years ago. However, I notice that the adaptor is much longer than the 1 & 1/4" adaptor that came with the Celestron, and the diagonal is a lot bigger as well, with the ultimate result that the total pathlength of the light from the Celestron to the eyepieces will be much longer. The last clear night we had was almost a month ago, so I've not had the chance to see how this works, so my question is this ... can I still focus all my eyepieces using  the much longer pathlength that results from this 2" setup on my Celestron 9.25? (I also got an adaptor so I can use the 1 & 14" eyepieces on the 2" diagonal.)

Link to comment
Share on other sites

  It all depends if the extended length takes one or more of your eyepieces outside the focus range of the built in focuser.  Rain aside, have to tried to focus on a terrestrial target during the daytime, if the focuser allows you to focus on the object and inside and outside of focus there is a good chance all will be ok with the night sky environment. 

I would pick a medium and max range visible target and attempt to focus them. Note direction of focuser movement from near to far target, if when  you achieve focus on the distant target there is no further focuser movement it is unlikely you will be able reach focus on the DSO’s. Try this for all eyepieces and you should have your answer.

Link to comment
Share on other sites

Thank you, MartinS, for that response. It is yet another overcast day here, so I'll try it on some distant objects. I can see one that is at least a half mile from here (I live half-way down the side of a valley, so am a bit limited, but I think that should give me an idea. Thanks again.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...