Lunt 50mm moonlite focuser

[Pete Presland]

I finally decided  to take the plunge and upgrade the focuser from the helical supplied one. Ordered from FLO and here within a couple of days, excellent service as always! 

1st impressions were that it is a very well engineered piece of equipment, very robust in design. It has very smooth action, very easy to fit and adjust to the required position.

The following comments are purely based on imaging rather than visual use. All were with the Lunt double stacked.

It was clear on inspection that focus was going to be impossible with my trusty DMK21au618, due to the minimum length being around 53mm. Which is 5mm longer than the stock helical focuser. The DMK had the cut down nosepiece fitted that i always use. 

 I also tried my ASI120mm, which i screwed directly into the B600 filter rather than use the nose piece. Unfortunately i was unable to achieve focus at first, but this was easily solved by withdrawing the B600 filter out of the focuser by around 10mm approx. I didn't try the ASI with the nose piece, but this may well have worked as well.

I have already returned the focuser to FLO thank to them for there excellent service in helping me with this, 1st class! 

The Lunt feathertouch is supposed to be in the available by mid October according to telescope house. The minimum length of this is 48mm which is the same as the helical focuser supplied and the focus length of travel is 15mm so focus should be fine with dmk. The downside is its single speed, but i guess it maybe cheaper though? I will have to have shop around when they arrive, no rush at this time of the year.

If i had read the specs on the moonlite site i would have known the length would be a problem so i would not have ordered it. As for still using the DMK, the newtons rings just puts me off  using the ASI, but you never now in the future!

 

 

[Moonshane]

Seems very odd that they'd make it longer than stock given they were designing it for a specific scope.

[Pete Presland]

I think it was made as short as possible, I guess it's only an issue if you are using an imaging source camera. 

[DRT]

On 27/09/2016 at 17:41, Moonshane said:

Seems very odd that they'd make it longer than stock given they were designing it for a specific scope.

That is very strange given that one of the biggest problems with the stock focuser is the lack of inward travel.

I'm sure I read somewhere that the FeatherTouch will give 2mm extra inward and 3mm extra outward travel, which seems like a much more sensible enhancement.

[Pete Presland]

3 hours ago, DRT said:

That is very strange given that one of the biggest problems with the stock focuser is the lack of inward travel.

I'm sure I read somewhere that the FeatherTouch will give 2mm extra inward and 3mm extra outward travel, which seems like a much more sensible enhancement.

I believe the feathertouch is within the range of the original focuser. 

[DRT]

The FeatherTouch is now listed on the Starlight Instruments website in both dual and single-speed format. Both state a focus travel of 0.75" (19mm) but do not give a minimum length of the unit. I have emailed them to ask for that spec and will post it here when they reply. They are normally very responsive.

 

 

[Highburymark]

10 minutes ago, DRT said:

The FeatherTouch is now listed on the Starlight Instruments website in both dual and single-speed format. Both state a focus travel of 0.75" (19mm) but do not give a minimum length of the unit. I have emailed them to ask for that spec and will post it here when they reply. They are normally very responsive.

 

 

Also first pics of the Starlight focuser fitted to the telescope posted now on CN. Claimed to have exactly same in and out focus as the standard unit

[DRT]

2 minutes ago, Highburymark said:

Also first pics of the Starlight focuser fitted to the telescope posted now on CN. Claimed to have exactly same in and out focus as the standard unit

That's quite strange as I think the standard unit only has 10mm of travel. Surely it isn't too difficult for manufacturers of premium equipment to give accurate basic specifications!

[DRT]

This is the description on the Lunt website:

The standard helical unit is also 48mm minimum height.

[Pete Presland]

2 hours ago, DRT said:

The FeatherTouch is now listed on the Starlight Instruments website in both dual and single-speed format. Both state a focus travel of 0.75" (19mm) but do not give a minimum length of the unit. I have emailed them to ask for that spec and will post it here when they reply. They are normally very responsive.

 

 

Isn't the focuser for the Lunt LS50THa available in standard adjustment only?(no 10:1 fine) according to the Lunt Solar website. 

[DRT]

50 minutes ago, bunnygod1 said:

Isn't the focuser for the Lunt LS50THa available in standard adjustment only?(no 10:1 fine) according to the Lunt Solar website. 

The SI website lists both single and dual speed as being available with the Lunt 50 adapter. 

 

[Highburymark]

3 hours ago, DRT said:

That's quite strange as I think the standard unit only has 10mm of travel. Surely it isn't too difficult for manufacturers of premium equipment to give accurate basic specifications!

Doesn't appear as if manufacturer and aftermarket supplier always communicate terribly well before the launch of a product. Will wait for confirmation of spec (and prices) before deciding which focuser to go for. 

 

 

 

[Moonshane]

You'd think they would have tried one on a scope before launch.

[DRT]

To be honest I am struggling to see the point in the upgrade now. The stock focuser has two problems - lack of inward focus travel and it is a bit wobbly. The latter can be easily fixed by engaging the locking screw - the former has not been addressed by either MoonLite or Starlight Instruments. I'm not exactly sure what is to be gained from spending £300+.

[Pete Presland]

So if an adapter is going to be needed for either version,  I wonder if that will effect the length of the focuser?

[Highburymark]

11 hours ago, DRT said:

To be honest I am struggling to see the point in the upgrade now. The stock focuser has two problems - lack of inward focus travel and it is a bit wobbly. The latter can be easily fixed by engaging the locking screw - the former has not been addressed by either MoonLite or Starlight Instruments. I'm not exactly sure what is to be gained from spending £300+.

I tend to agree Derek - especially for visual only people. Understand why prices are high for small production runs, but it's a real shame they've not been able to squeeze any more in-focus out of the set up - even a mm or two would have made a difference as a couple of my eyepieces are right on the cusp of reaching focus. I think the main benefit for non-imagers - as jabeoo noted in a separate thread - will be controllability for focusing on particular details. I'm still hoping that the benefits will outwegh the rather considerable cost.

[jabeoo1]

Having been part of this project I thought I would mention a few points.  Moonlite / Ron were aware of the issue for more inward focus, and it was a discussion point during the planning and design process, however it was made as short as it could be.  I am guessing the worm gears etc take up a certain amount of the profile leaving only so much room for the rest of the hardware.  Maybe someone contact Ron and see if it could be at least in theory / on paper have some tweaks to achieve a variant that gains the desired in travel, there may be a solution !

I don't image at all & could only test the focuser visually. 

[Pete Presland]

As it mostly seems to concern imaging source cameras and a lot of Solar imagers are using ZWO cameras, it's probably not a big enough problem to worry about.

The imaging source cameras do seem to have been overtaken in recent years. 

[Highburymark]

The other factor is that the quality of the stock helical appears to vary greatly - can't say I'm emotionally attached to mine but it has worked just about ok. But for anyone who's had bigger problems either of the replacement focusers are likely to be a massive improvement.

[Pete Presland]

1 minute ago, Highburymark said:

The other factor is that the quality of the stock helical appears to vary greatly - can't say I'm emotionally attached to mine but it has worked just about ok. But for anyone who's had bigger problems either of the replacement focusers are likely to be a massive improvement.

My replacement was certainly better, at least the screw didn't come loose and it was fractionally shorter. It is not too bad with just a camera, it is when I fit an extension + Powermate that it really struggles. Particularly with the "in-travel" direction.

[Highburymark]

On 2 October 2016 at 14:38, jabeoo1 said:

Having been part of this project I thought I would mention a few points.  Moonlite / Ron were aware of the issue for more inward focus, and it was a discussion point during the planning and design process, however it was made as short as it could be.  I am guessing the worm gears etc take up a certain amount of the profile leaving only so much room for the rest of the hardware.  Maybe someone contact Ron and see if it could be at least in theory / on paper have some tweaks to achieve a variant that gains the desired in travel, there may be a solution !

I don't image at all & could only test the focuser visually. 

Am sure you're right James. If the combined efforts of Moonlite and Starlight couldn't extend the in-focus then it's probably not going to happen. Despite the price, I know I'm going to press the button on one of them before too long. Hope you're enjoying your new Moonlite. 

[Moonshane]

I take your point but it looks like the adapter could have been slimmed down by 5mm or so. It does look tight in fairness especially when you have the pressure tuner.