21 replies to this topic

[sportsmed]

HI, I love my 127mm Mak but dont care alot for the stock focuser, are there upgraded 2 speed focusers for Maks? I have seen some for SCT's but I have not researched this really. Is anyone using an upgraded focuser on their Maks and if so what companies are making them? Thanks!

[SMigol]

Depending on the focuser back on your model, you may consider a crayford style focuser to stop using the moving mirror.

 

I considered this option for my Orion Mak and went with an SCT adapter.  I found the available focuser I got from Scopestuff was too sloppy.

 

Maybe better performance with a second hand moonlight, not worth spending more on a solution.

 

Starlight Instruments does offer two speed focusers for SCTs and some *might* be adapted to a Mak.

[jkmccarthy]

Across the pond in the "Stargazers Lounge" forum, there's a nice thread by user johninderby documenting the upgrades he implemented on his (Meade-flavor) Bresser 127mm Mak, including the posts starting here (https://stargazerslo...comment=3749288) that show the 1.25" Crayford style focuser he installed onto the 2-inch SCT-size threads at the Bresser-127's exit port.   The author decided the size of the 1.25" focuser was more in-keeping with telescope size (and its usable FOV) than a 2" focuser would be, but you may or may not agree with him on this.  If you scroll back to page 1 of that thread, there's a post by user Paz that includes a photo of a 2-inch Crayford focuser attached to his/her Bresser-127.

 

For what it's worth (in terms of saving you time searching the net), the dual-speed (manual) 1.25" Crayford focuser selected by johninderby in 2019 is still offered by Teleskop-Service (located not far outside Munich, Germany), and the item details are found on-line here (https://www.teleskop...rains-----.html .... I just ordered one myself earlier this week, and FYI their delivery charge to California was 35 Euro).  By default that focuser comes with a 50.7mm I.D. bore and setscrews (for an adaptor) on the end that attaches to the scope, and if you need TS to make an adaptor to fit the exit port on your particular scope, they can do that for an additional charge (but note this also adds significantly to the delivery timeline ... ) - :

 

Sportsmed -- what brand is your 127 Mak ?   Note finally that for this focuser to work, the moving drawtube (whose O.D. is 43.3mm per the specs on the web) needs to fit into/through the Mak's exit port opening ... although if the Crayford is only going to be used for fine-focus (with the Mak's focus knob used to move the primary mirror for coarse focus) there is no need for the drawtube to be as long as it is on the 1.25" TS unit.  I don't know what it might take (other than a hacksaw?) to shorten the drawtube if its 43.3mm O.D. won't fit into/through your Mak's exit port, and all you need the Crayford for is (say) +/- 5mm of fine-focus.   Fortunately for the Bresser-127 at least, this is not an issue!

 

Hope this helps,

 

        -- Jim

Edited by jkmccarthy, 13 April 2021 - 11:23 PM.

[sportsmed]

Hey Jim thanks for the info, yea I have a Celestron SLT and I would like to be able to do fine focus on it. I will look at the links you posted and check it out but maybe a crayford focuser could be the key. Thanks again

[Eric63]

For what it's worth, I use a plastic clothespin on my 127Mak for fine focusing. It's a cheapo option, but I find it works great for fine focusing.

Eric

[jkmccarthy]

[RE: ...]   the 1.25" Crayford style focuser [user johninderby] installed onto the 2-inch SCT-size threads at the Bresser-127's exit port. [...]

 

[...]  I just ordered one myself earlier this week [...].  By default that focuser comes with a 50.7mm I.D. bore and setscrews (for an adaptor) on the end that attaches to the scope. [...]

The TS-ACUR1 focuser I ordered arrived late last week (amazing that the cheapest overseas shipping by TS resulted in 3-day delivery from Munich to Los Angeles), so I thought I'd report on my hands-on experience:

• It came in a box whose most prominent label said "ORION OPTICS UK / 1.25 Small Focuser / Made in Taiwan", accompanied by a smaller "TS Optics / ACUR1" label.
• A web search led me here (https://www.orionopt...cufocusers.html) but I do not see the 1.25" model listed, nor was I successful searching the orionoptics.co.uk site for it (neither ACUR1 nor ACU-1)
• Out of the box, I was impressed by how solid the build-quality of this focuser is, yet its mass (490g) is less than half that of the 2-inch and 3-inch models listed on the Orion Optics UK web page (link in bullet above).
• I initially had some concern because when turning either of the coarse-focus knobs, the focus-motion resistance (due to inertia of the drawtube plus internal friction) felt by my fingers over the 4cm travel of the drawtube seemed uneven, varying cyclically with each revolution of the coarse-focus-knob ... meanwhile the brass fine-focus knob moved smoothly with no perceptible variation in resistance.
• There were no user-adjustment instructions included with my purchase, so a naive assumption might be all the adjustments were "factory set" and the user shouldn't need to do any fine tuning -- wrong!. Turning to the web, I found the instructions created by Tommy Nawratil for the SkyWatcher Crayford Focuser on-line here (https://teleskop-aus...g_justieren.pdf) provided me valuable insight into how Crayford Focusers work, even though the adjustments on the TS-ACUR1 unit are fewer and less elaborate.
• I was able to get uniform coarse-focus-resistance using the "Tension Adjustment Screw" (identified in the middle of the first photo of the PDF in the bullet above).  Engaging this set-screw on the TS-ACUR1 unit (seen in the photo below, just peeking out below the small knurled drawtube clamp screw seen just below the printed U.S. Patent Number) with a metric 3mm Allen wrench solved the problem by pressing the nylon tip of that setscrew against the Crayford's rotating rod that moves the drawtube.   (Out of the box, this setscrew was backed out far enough to be disengaged from the rotating rod --- just a small to medium-light amount of pressure from the nylon tip of the setscrew nicely evened out the focus-motion resistance, which is now very smooth : - )

 

For what it's worth / someone's future reference,

 

       -- Jim

Edited by jkmccarthy, 20 April 2021 - 05:48 PM.

[alphatripleplus]

For what it's worth, I use a plastic clothespin on my 127Mak for fine focusing. It's a cheapo option, but I find it works great for fine focusing.

Eric

I do that too with my SW 102mm Mak, and the focuser is very smooth.  

[Nicole Sharp]

For what it's worth, I use a plastic clothespin on my 127Mak for fine focusing. It's a cheapo option, but I find it works great for fine focusing.

Eric

Can you provide a description or photograph of how to set this up?

[emh52]

My set up is posted on "post a picture of your mak" so I will not repeat it here, but it consists of a moonlight crayford and a motor driven focus- it works beautifully on my 180 mm mak but the caution is that it costs a large fraction of the skywatcher 180mm mak price. It does make it very functional so I think worth it. I can dial in moon features etc and when adding a bit more power with a power mate above its native FL it really shows its advantage.

[jkmccarthy]

My set up is posted on "post a picture of your mak" so I will not repeat it here, but it consists of a moonlight crayford and a motor driven focus- it works beautifully on my 180 mm mak but the caution is that it costs a large fraction of the skywatcher 180mm mak price. It does make it very functional so I think worth it. I can dial in moon features etc and when adding a bit more power with a power mate above its native FL it really shows its advantage.

For others like me who might like to see emh52's photo, I believe this link should take you to his post:  https://www.cloudyni...tup/?p=10890379

 

Nice !
 

[Eric63]

Can you provide a description or photograph of how to set this up?

No problem. This is what I currently use for my Mak and what I used on my Newt before I upgraded the focuser.

I get as close as possible with just the knob and then I add the clothespin. The clothespin acts as a lever and allows for very small adjustments. I just move it lightly with the tip of a finger without pinching the clothespin.





Eric

Edited by Eric63, 22 April 2021 - 07:51 PM.

[emh52]

For others like me who might like to see emh52's photo, I believe this link should take you to his post:  https://www.cloudyni...tup/?p=10890379

 

Nice !
 

Yes you found it, I like this setup is works great, but the offset is that cost is large fraction of the original telescope- on the good side if you want to dial in the moon's craters or sunspots focus it works quite well being hands off and the motor is very smooth and with my DSLR lifting capacity of the motor focus is no problem. The system for my Mak took just a few minutes to install.

[GKA]

The TS-ACUR1 focuser I ordered arrived late last week (amazing that the cheapest overseas shipping by TS resulted in 3-day delivery from Munich to Los Angeles), so I thought I'd report on my hands-on experience:

• It came in a box whose most prominent label said "ORION OPTICS UK / 1.25 Small Focuser / Made in Taiwan", accompanied by a smaller "TS Optics / ACUR1" label.
• A web search led me here (https://www.orionopt...cufocusers.html) but I do not see the 1.25" model listed, nor was I successful searching the orionoptics.co.uk site for it (neither ACUR1 nor ACU-1)
• Out of the box, I was impressed by how solid the build-quality of this focuser is, yet its mass (490g) is less than half that of the 2-inch and 3-inch models listed on the Orion Optics UK web page (link in bullet above).
• I initially had some concern because when turning either of the coarse-focus knobs, the focus-motion resistance (due to inertia of the drawtube plus internal friction) felt by my fingers over the 4cm travel of the drawtube seemed uneven, varying cyclically with each revolution of the coarse-focus-knob ... meanwhile the brass fine-focus knob moved smoothly with no perceptible variation in resistance.
• There were no user-adjustment instructions included with my purchase, so a naive assumption might be all the adjustments were "factory set" and the user shouldn't need to do any fine tuning -- wrong!. Turning to the web, I found the instructions created by Tommy Nawratil for the SkyWatcher Crayford Focuser on-line here (https://teleskop-aus...g_justieren.pdf) provided me valuable insight into how Crayford Focusers work, even though the adjustments on the TS-ACUR1 unit are fewer and less elaborate.
• I was able to get uniform coarse-focus-resistance using the "Tension Adjustment Screw" (identified in the middle of the first photo of the PDF in the bullet above).  Engaging this set-screw on the TS-ACUR1 unit (seen in the photo below, just peeking out below the small knurled drawtube clamp screw seen just below the printed U.S. Patent Number) with a metric 3mm Allen wrench solved the problem by pressing the nylon tip of that setscrew against the Crayford's rotating rod that moves the drawtube.   (Out of the box, this setscrew was backed out far enough to be disengaged from the rotating rod --- just a small to medium-light amount of pressure from the nylon tip of the setscrew nicely evened out the focus-motion resistance, which is now very smooth : - )

 

For what it's worth / someone's future reference,

 

       -- Jim

Hi , do you have a picture of your setup , and are you pleased with it? i have a skywatcher 127 as a grab and go and would like a better focuser on it , could you use a zwo eaf with it?

[jkmccarthy]

Hi , do you have a picture of your setup , and are you pleased with it? i have a skywatcher 127 as a grab and go and would like a better focuser on it , could you use a zwo eaf with it?

I've loaned my Bresser 127mm Mak to a work colleague temporarily, so at the moment I'm not able to snap a picture of the focuser on it ... but here are links to johninderby's photos of the focuser on his Bresser 127mm Mak:

 

https://stargazerslo...8d5abdc44b.jpeg

 

https://stargazerslo...7a902d68d9.jpeg

 

Hope this helps,

 

       -- Jim

Edited by jkmccarthy, 29 October 2021 - 03:04 AM.

[lakeorion]

Going the expensive route could land you with a Feathertouch 1.25" focuser and a custom adapter instead of the Lunt that they advertise - write and ask for an SCT thread instead.  This assumes you have an SCT thread or thread adapter on the back of the Mak.  I purchased one immediately on receipt of my Orion 127 and it hasn't (and probably can't) come off since.

 

I went this route intending to use focuser for 180 Mak lunar photography, but it fits fine on the 127.  A 2" focuser likely will hit the stock focus knob.  I went with single speed because by the math, my critical focus zone in IR (it's intended purpose remember) is a generous 3/4 of a millimeter.  If single speed isn't your thing there is a dual speed, and the ability to upgrade the single to the dual later on.

 

These are pics with the 180 Mak, just to show what it looks like.

 

[fcathell]

I initially used a clothespin approach like Eric 63 on my 102 Mak, but changed it to a rubber chair leg bumper with a 12 cm length of coat hanger wire shoved through the closed end.  I found the rubber "bumpers" for metal chair legs at ACE Hardware.  I measured the diameter of the Mak's focusing knob and found a rubber bumper that fit snug.  Works great.  Just don't let the coat hanger wire poke your eye!  I used needle nose pliers and made a tight curl on the end of the wire.

 

Frank 

Attached Thumbnails

• 

[GKA]

I've loaned my Bresser 127mm Mak to a work colleague temporarily, so at the moment I'm not able to snap a picture of the focuser on it ... but here are links to johninderby's photos of the focuser on his Bresser 127mm Mak:

 

https://stargazerslo...8d5abdc44b.jpeg

 

https://stargazerslo...7a902d68d9.jpeg

 

Hope this helps,

 

       -- Jim

Thanks , i definatly need to consider this.

[cmas]

Does anyone have an idea where to get one of these small 1.25" sc thread focusers in Europe at the moment? TS is out of stock.

[Jon Isaacs]

One thing to keep in mind:

 

Adding an external focuser adds to the optical path length, this means the mirrors are moved closer together in order to focus.  This can affect the spherical correction.. 

 

Jon

[doug mc]

One thing to keep in mind:

 

Adding an external focuser adds to the optical path length, this means the mirrors are moved closer together in order to focus.  This can affect the spherical correction.. 

 

Jon

It seems common knowledge that for say Celestron C8, the optimal place for the focal plane is somewhere between 100mm to 125mm behind the rear port opening.  Nobody seems to know that distance for Skywatcher maksutovs like mine. 

[Jim in PA]

It seems common knowledge that for say Celestron C8, the optimal place for the focal plane is somewhere between 100mm to 125mm behind the rear port opening.  Nobody seems to know that distance for Skywatcher maksutovs like mine. 

It's about the same for your scope.  They're designed so when you put a 1.25" diagonal in the provided back, you can achieve focus at the factory's specified focal length for the telescope.

 

I have a GSO Crayford on my 180 but find it's of limited value because like Jon said you have to crank the mirror forward.  It also doesn't do well with 2" diagonals and eyepieces.  It works quite well for planetary imaging, for visual I use the factory back.

 

[cmas]

Well, I put my DIY focus motor in and although the focus area is very "thin" I can now achieve good focus easily even without 1:10 reduction. I think it'll be sufficient for me so no additional external focuser for me, at least now. But if I would do visual without motor focuser the focusing issue would need to be solved as without 1:10 reduction achieving good focus is a real pita

And for the record, I have Bresser 127 which seems to have a nice build quality (when you throw all the accessories back to the shipping box and just keep the ota).

Edited by cmas, 24 June 2022 - 11:41 PM.