Auto focuser.

[Mick the Lob]

Hello folks whilst I am a bit of a newbie I have done some home work and over the course of several years, I have now managed to aquire my ideal set up. I have used some of my gear to half reasonable effect and still have plenty to learn, it's a bit of a all the gear no idea scenario. I am so deep in the rabbit hole it's hard to escape. My question is "What would be a good auto focuser for a William Optic FLT 132 Scope with reducer Flattner attached?" could als do with a few points in the right direction for an auto focuser for a GT 71 with flattner reducer. Thank you in advance for any of your superior knowledge that I do know abounds on this site.

Regards Mick. 

[StevieDvd]

If you ever plan to use the ZWO Asiair Pro or Plus then the ZWO EAF would be a good idea. Other than that Pegasus also have a good hub system (power, usb, dew etc) and on the top of the range support auto focusers (their own and other brands).

Either of those focusers will can work on thier own and have options to use manually. When you get into serious astro-photography then the focusing is done 'automatically' by Nina/Ascom/Asiair/INDI etc.

There is a seller Deepskydad who does belt driven focusers who gets good reviews too.

[Jerry Barnes]

I have the ZWO focuser and it works fine when controlled  by NINA but I think your scope might be too heavy for it.

 

[Padraic M]

The PrimaLuceLabs Sesto Senso 2 doesn't need a mounting bracket, and is rock-solid on my scopes. Works well with Nina but won't work with ASIAir as it's not ZWO.

[jacko61]

I have ZWO EAF on both my WO ZS73 and ALTAIR 150EDF, both with flatteners, and I've had no issues with the EAF managing the weight.  Very easy to fit and the set up in software takes minutes. The EAF can also be bought with a plugin handset to use without a computer (although it does need a USB 2 cable for power).

Graeme

[barbulo]

Happy with the ZWO EAF under APT. 

[Clarkey]

I have 2 of the Senso Sesto units which have been good, but the ZWO EAF or others would also work well. To be honest I think it is down to what peripherals you are using with and whether they are compatible. In most cases the focusers can be moved from one scope to another relatively easily.

[The Lazy Astronomer]

Another NINA controlled EAF here. All you need to do is make sure you configure the backlash compensation correctly and it works a treat 👌

[Mick the Lob]

Thanks for all your answers I do not have any of the zwo equipment so looking like a Senso sesto unit when I have saved enough loot to purchase one. 

[Len1257]

Well when you have saved enough loot to buy 2/3 of a Senso Sesta just buy an ASI EAF and save the rest for other gear. I have one each on WO GT81, 150PDS with Baader Steeltrack Focuser, RC8 also with Baader Steeltrack Focuser. All work flawlessly with NINA.

Incidentally the size of the scope and flattener has little to do with what the focuser has to cope with. It's the image train that counts i.e. camera, filerwheel, OAG etc. You haven't mentioned that at all?

[Padraic M]

1 hour ago, Len1257 said:

Well when you have saved enough loot to buy 2/3 of a Senso Sesta just buy an ASI EAF and save the rest for other gear. I have one each on WO GT81, 150PDS with Baader Steeltrack Focuser, RC8 also with Baader Steeltrack Focuser. All work flawlessly with NINA.

Incidentally the size of the scope and flattener has little to do with what the focuser has to cope with. It's the image train that counts i.e. camera, filerwheel, OAG etc. You haven't mentioned that at all?

Actually a commonly-held misconception.

The ZWO from FLO, when you add the extra temperature sensor, hand controller and mounting bracket is €302 (£259), whereas the Sesto Senso from PLL, which comes with all of the bits in the box, is €245 €265.

Obviously customs duty may change the situation, but the PLL is cheaper than the ZWO ex-works on a like-for-like basis.

Flip a coin to select one I suppose, but I like that the scope can still be focused manually with the PLL in place (by turning the coarse-focusing knob) and it doesn't need a hand controller. I also like not needing a mounting bracket. It makes mounting and removing it really easy. I'm sharing one between two scopes at the moment (while I save for a 2nd one) and it's very easy to swap.

Edit: slight correction - the Sesto Senso doesn't come with a temperature probe so +€20 for that.

Edited May 6, 2022 by Padraic M

[Jerry Barnes]

2 hours ago, Len1257 said:

Incidentally the size of the scope and flattener has little to do with what the focuser has to cope with. It's the image train that counts i.e. camera, filerwheel, OAG etc. You haven't mentioned that at all?

Duh!  Thats so obvious when you point it out, I should have realised that before.

[Richard_]

@Padraic M, you also have to remember that the PLL SS2 is designed to fit couplers with a diameter of 25mm. If your focuser doesn't fall into this category (as my WO FLT120 did, which I believe has the same focuser as OP's FLT132) then you need to purchase the extra adapter (£70).

https://www.rothervalleyoptics.co.uk/primaluce-lab-33mm-adaptor-for-sesto-senso.html

@Mick the Lob you may want to check out my "FLT120 owners thread" as I've provided step by step instructions for the ZWO EAF and PLL SS2 installation. Both of our telescopes feature a 3.3" R&P focuser so we could assume they are one and the same, so the installation and use would be the same. See link to thread below. 

The ZWO EAF worked fine with the WO flattener, ASI533MC-Pro and mini-EFW but I can't comment for heavier setups (ie mono camera with large filter wheel). There was some slight backlash which I didn't resolve as the EAF was only a temporary solution from another telescope but otherwise it's straight forward to resolve. 

The PLL SS2 is very different to the EAF. For starters, you'll need an adapter to fit to your telescope and you need to ensure there's no slippage in your fine focuser as discussed in my thread below before you install it. You can check for slippage by pointing your telescope to zenith and with your flattener and imaging setup installed, move focus tube inwards with the fine focuser. If there's no slipping and the fine focuser moves the focus tube inwards, you're good to go with the installation (lucky you!), if not, you'll need to resolve this. After I resolved my slippage issue, I've come to find that the PLL SS2 truly has no backlash, or at least it's so small that I can't detect it. It's a brilliant focuser which also let's you manually focus with the coarse knob (as long as you've disconnected the power). However, if you make manual adjustments you'll need to repeat the PLL calibration routine as the motor essentially "forgets" the current position. 

 

[Len1257]

9 hours ago, Padraic M said:

The ZWO from FLO, when you add the extra temperature sensor, hand controller and mounting bracket is €302 (£259),

The ZWO EAF comes with a standard L shaped bracket and costs £184 from FLO. As I use NINA for control and use HFR increase to trigger auto-focus runs I don't need a manual controller and don't use the temperature sensor. So no, £184 it is. As for moving stuff about I would much ratjher set up the focuser profile in NINA for each system and I'm definitely not messing about recaibrating my focusers before use. YMMV of course.

Edited May 6, 2022 by Len1257

[Len1257]

Despite my seeming to be an EAF enthusiast I have had a QC issue that I took up with FLO. The last EAF that I purchased had a distinct bevel to the mounting face. Looked as though it had been finished on a linishing machine. First couple came with a dead-flat mirror finish, this one was essentailly curved across the mating surface. The result tilted the drive shaft perceptibly out of true. I just skimmed the surface flat on my mill and sorted it out. If anyone gets one that doesn't lie flat to the bracket then kick it back to FLO pronto. Other than that mine have, as previously said, worked flawlessly.

[Mick the Lob]

On 06/05/2022 at 08:37, Len1257 said:

Well when you have saved enough loot to buy 2/3 of a Senso Sesta just buy an ASI EAF and save the rest for other gear. I have one each on WO GT81, 150PDS with Baader Steeltrack Focuser, RC8 also with Baader Steeltrack Focuser. All work flawlessly with NINA.

Incidentally the size of the scope and flattener has little to do with what the focuser has to cope with. It's the image train that counts i.e. camera, filerwheel, OAG etc. You haven't mentioned that at all?

Hello Len 1257 I have got a Starlight express mini oag filter wheel, lodestar x2 guide camera and the black Trius 814 main camera 7nm HOS filters and LRGB 7nm all mounted on the skywatcher eq/az 6 mount. 

Regards Mick. 

[The Lazy Astronomer]

1 hour ago, Mick the Lob said:

Hello Len 1257 I have got a Starlight express mini oag filter wheel, lodestar x2 guide camera and the black Trius 814 main camera 7nm HOS filters and LRGB 7nm all mounted on the skywatcher eq/az 6 mount. 

Regards Mick. 

EAF can support 5kg so as long as you're below that no problem

[Mick the Lob]

Think I will be well under 5 kg not a great deal of weight hanging off the focus tube.