Esprit 150 Focuser

[darrellx]

Hi All

I have an Esprit 150 with the standard focuser. The focuser seems to be “loose”.

When I put on a light load, all is good. By a light load I mean using either my DMK21, ATIK 314 or ASI 224, with or without a PowerMate.

When I start to load up the focuser with my ASI 1600 and Filter Wheel, the focuser will not stay in place and slowly winds out. Not a lot, but more than enough to totally go out of focus. There is not enough friction in there to hold the load in place.

The knobs do turn quite easily.

When I look under the focuser (Pic 2) I have checked each of the bolts and they seem quite firm. There is a small locking lever towards the front of the focuser. Is it normal for the focuser to slip out under load, and should I be using the locking lever once I am in focus? Seems to be a PITA way of doing it.

Also, on the right hand knob there is a “plastic sleeve”. (Pic 3) I cannot use that knob when the sleeve is on. But this knob turns very easy when the sleeve is removed. This is also a hugh PITA to hold the left hand knob once in focus and slip on the plastic sleeve.

Any suggestions?

I have also been in touch with MoonLite with a view to upgrade the focuser. This could turn out to be an expensive option, but will be another question.

Thanks
Darrell

[Marke]

I have the 80mm and no problem with a 1600 on it . You can adjust the tension with the hex screws underneath . I do have a motor on mine which stops any movement anyway but was not an issue before that.

[casstony]

The plastic sleeve is a protective cover for shipping only, to prevent the microfocuser from being bent.

It's common for the Esprit focusers to arrive poorly adjusted.
Tension on the drawtube can be increased by slightly tightening grub screws on the focuser which press slides against the drawtube.

Load holding could be increased by tightening a nut which applies pressure to the microfocuser bearing (pinion assembly needs to be removed to do this) but this important adjustment was not possible on my Esprit 80 because they used red Loctite.

Applying pressure to the drawtube and partly apply the focuser lock are work-arounds, but if the scope is new send the focuser back under warranty and get them to adjust or replace it.

Motorizing the focuser is another way to increase load holding but some of us want to focus manually.

WARNING: if you remove the pinion assembly, don't slide the drawtube out or dozens of tiny ball bearings will run all over the place.

[brisen]

Hi Darrell

I have an Esprit 120 and it has the same focuser setup. If the lever in the second pic is where it is when you have the imaging train attached it will slip as you describe. You need to use the lever to lock the focuser in place and this will prevent the slippage with you are experiencing. I have had about 1.5 kgs hanging off the back off mine and with the lever tensioned I can image with the scope vertical and no slippage.

The lever operates on a cam from what I can ascertain and it just needs to be pulled back until firm. There is no focus shift when this is locked from my experience, even if focusing before I lock it. Just ensure that you tighten the lever itself into its socket - it has a habit of working loose if you transport the scope. Mine fell out and I didn't realise until I went to tighten it. Fortunately it fell out in the case and not at the dark sky site I had set up at the night before.

Brian

[darrellx]

Thanks guys. I found the grub screws and nipped them up a bit. Just a tiny bit more tension in there now.

I have done a bit of practicing with the lever underneath. I can see how that works and it makes a hugh difference. Obvious now that it has been pointed out.

I am confident the focuser will now support the 1600 and filterwheel.

I am pleased that the issue of manual focus was raised. I have spent a lot of time to automate my system, but I get so much enjoyment sitting there attending the mount and scope. I actually do like doing the manual focus. I thought I must have been the odd one out. I really do enjoy the peace and solitude of sitting under the stars.

My dilemma now is whether to upgrade to a Moonlite (maybe non-motorised).

Darrell

[kosborn]

I have the 100mm and would like to add a motorised focuser. Which one did you get and did you have any difficulty installing?


Kevin

[brisen]

Hi Kevin

I have the Esprit 120 and just pulled the trigger of getting an Esprit 80 to go with it. I have the nstep focus motor and setup from Rigelsys in the US. Leon just needs a photo of the underside of the focuser to confirm the layout so that he is sure he is supplying the correct mounting plate. Simple process of screwing the plate on, and attaching the cog provided to the focus shaft - it just slides on and you attach the motor with two screws also provided. These can be tensioned to suit. It is fully ascom compatible and if using the Sky X it works really well with @focus3. I am communicating with Leon at the moment to get the nstep for the new scope as well as I am more then happy with the one on the 120. The best part is it just works and goes together without any hassle.

Brian