Mak 127 9/10mm EP

[sticks]

Does anyone succesfully use the supplied 9mm or 10mm EP with their nextar or SW Mak 127? I'm finding it impossible to use a high mag EP due to the FOV, shake.. and the "approximate" slewing of the goto or manual adjustment. If you do get on with it any advice would be very welcome.

[ronin]

The eyepiece should be usable, it will be giving 150x.

The FoV will be around 1/3 degree, 20 arc minute, so yes it is narrow, that is a consequence (downside) of high magnification.

Don't think any commercially available goto will be exact, you would have to have set it up perfectly, as in accurate all round to less then 1/3 degree. There is too much give in the drive mechanism.

The shake is again a consequence of the magnification and the mount. Those motors and the drive are not silky smooth and vibration free. This gets transmitted round the mount. One other factor in shake is a person looking through the thing.

When slewing to another object swap eyepieces, take the 10 out and drop a 25 or 32 in. More shake while swapping.

Centre everything and use the PAE feature every so often.

Alternatives: Wider angle eyepieces. The plossl you have will be 52 deg, BST's are 60 deg, WO SWANs are 68. After that they get expensive. BST's don't do a 10mm WO do a 9mm. There are other SWANs that seem to be copies of WO's at a lower price.

[Tyr]

Sticks,

Yes I have a 9mm one witch came with my celestron 127, the mount is pretty similar to the sky watcher one.

Is it the image shaking or the mount / scope shaking?

It might just be that the seeing is bad (I think seeing is the correct term anyway) due to a lot of air movement, which will cause the image to appear to shake or move around and will be more obvious at higher magnifications.

There are a whole load of things you can do to help stabilise the mount, such as

Making sure you've balanced the weight of the OTA (including finder and EP), so that the mount isn't struggling as its trying to track.

Make sure you've got the location information set as accurately as possible, I got a GPS app on my phone and used that but you can use google maps + an overlay works too.

Make sure you've got the accurate time and time zone set correctly, I spent months setting the timezone to +1 and then saying daylight saving (doh!) when I'm in the UK, which would cause objects to wander out of the FoV at higher magnification while I was looking at them.

Try not extending the mount legs fully, it seems to be more stable with the legs extended less and check the level using a small spirit level, the bubble level in the mount might not be accurate.

Even after all this I wouldn't always expect the GOTO to slew to an object every time within the FoV of my 9mm EP, as Ronin says expect to swap to your other wider field of view EP between targets.

Check you've allowed the OTA to cool down as well, if it's better after an hour of viewing that could be the cause of some of the image instability.

If you find manual slewing uncontrollable with the 10mm EP there's probably a way of changing the slewing rate on the SW mounts too.

I hope some of that helps

Tyr