Jump to content

Banner.jpg.b83b14cd4142fe10848741bb2a14c66b.jpg

5" SCT F10

steve_bham

Recommended Posts

arad85

arad85

Posted
Posted

Hi Steve,

What eyepieces do you currently have?

And do you mean a 2" focuser or a 2" diagonal? There is a noticeable improvement in contrast going to a decent 2" diagonal (but you'd also need the SCT back->2" adaptor - the WO dielectric diagonal comes with one, but they cost about £20 if not).

Link to comment
Share on other sites
arad85

arad85

Posted
Posted
yeah i know theres one built in but you can by a 10:1 reduction one for fitting on the back. Just wondered if they are worth the £'s
You can buy a 10:1 reduction one to replace the knob (or at least you can for the larger ones). An additional focuser will make the scope more likely to catch on the SE mount when you are looking overhead. TBH, I would worry about other things such as a decent diagonal and eyepieces first.

Which eyepieces do you have at the moment?

Link to comment
Share on other sites
Mark at Beaufort

Mark at Beaufort

Posted
Posted

Steve

Be careful not to buy a large focuser because your Nexstar will be difficult to balance. You can buy a SCT 2" diagonal which I had. However, when I installed the big Moonfish 30mm 2" EP balancing was a problem. Personally if you want a wider FOV then something like the Hyperion 24 has good eye relief and 68 degree FOV. You could use this EP on both a 1.25 and 2" focuser. You could also consider a 6.3 reducer.

Mark

Link to comment
Share on other sites
John

John

Posted
Posted

I think you have a Nexstar 5 ?

Do check that there is sufficient clearance to fit a 2" diagonal in and not have it hit the mount when the scope is pointing towards the zenith region - I used to have one of those scopes and I recall clearance space being a little limited in that region.

Also a 2" diagonal + a 2" eyepiece adds a lot of extra weight to the rear of the scope tube - you don't want to affect the accuracy of the drives and GOTO system by getting the scope too unbalanced. There is a special adaptor that you can fit to the scope which enables it to slide up and down on a sort of dovetail bar - then you can both adjust the balance of the tube and create a bit more clearance at the back end.

In the end I decided to stick with 1.25 inch eyepieces with my Nexstar 5 and get a focal reducer for wider field, lower power views as Mark suggests above.

John

Link to comment
Share on other sites
Mark at Beaufort

Mark at Beaufort

Posted
Posted

Steve

I am sure that the diagonal from WO will be excellent. I used an Antares diagonal from scopesnskies - see link - Antares Antares 2" mirror star diagonal for Meade & Celestron SCTs

There was clearance when the Nexstar pointed to the Zenith but it was very close. I also tended to remove the Moonfish 2" EP when slewing to different objects to keep the accuracy of the goto which worked okay. However, in the end for wider FOV I preferred the focal reducer and the Hyperion 24mm EP. This gave me a mag of 33x, a true FOV of 124.4' (about the limit of this scope - see Swanson book that you have) and an exit pupil of 3.8.

Before spending your bonus wait for the Salisbury starparty and try different EPs if you can. Steve and James/FLO will be there and I am sure that they will have a good selection of diagonals and EPs. I am hoping to come for the Saturday night and will bring the Antares diagonal and the hyperion if you want to try them.

Mark

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.