Autofocuser help please

[tooth_dr]

I bought a used Tak with a Moonlite autofocuser. I’m not sure if there are setting up procedures that need to be done, but as it stands i dont think the behaviour of the focuser is right. 
 

If anyone can comment I would be very grateful.

1) range of travel of my focuser goes from around 2500 to around 3800 steps

2) if I set the focuser to a position above 3800 steps it maxes out the focus travel, the drawtube can’t move any more and I can see the silver wheel still turning. This actually causes APT to crash.  It does the same on inward travel, if I set the position to 2500 or less. 

3) I measured the movement using callipers. In 550 (2900-3450) steps it moves the drawtube 9.4mm. This works out at 17 microns per step. Moonlite says it moves 4 microns per step or 2 microns per half step.  My scope has a CFZ of 10 microns.  It looks like I need better accuracy they what I’m achieving currently.

4) I’m using a hitec astro MHP V3 to control the focuser vis ascom. I don’t have a Moonlite controller so I have no access to Moonlite control (as far as I am aware).  Am I missing some settings maybe? The focuser software I’m using is APT.

 

I understand drawtubes are different lengths so can the focuser be calibrated? Ir is it even necessary? When I connect the focuser it says range 0-65k (can’t remember the exact value) - how come my range is somewhere between 2500-3800?

Any help or input welcomed 

Adam.

Edited December 23, 2019 by tooth_dr

[tooth_dr]

I found this thread and it send someone else has the same issues

http://www.astronomyforum.net/telescope-accessories-forum/201617-hitec-mount-hub-pro.html

[tooth_dr]

Anyone? No reply on the other thread, I posted on it too. 
 

cheers!

[banjaxed]

Sorry I can’t help you accept to suggest that you be patient until our normally very helpful members have had time to get over their Christmas celebrations 🥳 

[tooth_dr]

5 minutes ago, banjaxed said:

Sorry I can’t help you accept to suggest that you be patient until our normally very helpful members have had time to get over their Christmas celebrations 🥳 

Its cloudy and I’m off, so patience isn’t in abundance 😩

[newbie alert]

Sorry Adam, I've got a moonlite focuser also but haven't set it up yet as when it's clear I want to do some imaging,  waiting on some semi clear nights to set it up

You say you haven't got the controller?  So no tempature gauge?  Once set up are you going to set it to focus say every 5 frames? As I assume the tak will focus shift more so than the 80ed ..

[tooth_dr]

12 minutes ago, newbie alert said:

Sorry Adam, I've got a moonlite focuser also but haven't set it up yet as when it's clear I want to do some imaging,  waiting on some semi clear nights to set it up

You say you haven't got the controller?  So no tempature gauge?  Once set up are you going to set it to focus say every 5 frames? As I assume the tak will focus shift more so than the 80ed ..

Thank you! I bought the hitec astro Mount hub pro to control the focuser. It seems the problem lies with it.  I have read the 180ed is very tolerant of temperature changes but I’ve yet to try it out. 

[newbie alert]

21 minutes ago, tooth_dr said:

Thank you! I bought the hitec astro Mount hub pro to control the focuser. It seems the problem lies with it.  I have read the 180ed is very tolerant of temperature changes but I’ve yet to try it out. 

Strange that,  I have the same hub....

But control most of it through APT 

Edited December 28, 2019 by newbie alert
Added info

[tooth_dr]

20 minutes ago, newbie alert said:

Strange that,  I have the same hub....

But control most of it through APT 

I use APT too. There is the option to change advanced settings but I don’t want to break anything. 

[david_taurus83]

What's the total drawtube travel anyway? It maxes out on outward travel but what about inward travel? Is this the same score it came on? I'm just wondering if there some sort of calibration procedure done when you first fit the focuser and tell it the limits of drawtube travel?

[Davey-T]

IIRC I used the Lakeside utility that came with the Lakeside focuser, wound it out a thousand steps then measured how far it had travelled, divided by a thousand and that was the step size entered into autofocus software, then wound it nearly all the way in, set as maximum in travel, then wound out well past focus point and called that maximum out.

Don't think step size was as big as 17 microns think it was in single digits.

Drove it manually back to focus point and that should do to start from.

Dave

Edited December 28, 2019 by Davey-T

[Starflyer]

I don't know the Moonlite system, but for the Lakeside I had to calibrate the focuser on first use, I assume the Moonlite would need a similar procedure.  I had to rack it all the way in, press a button in the Lakeside Utils software to tell it the minimum position, then rack it all the way out and tell it the maximum position.

It's there a Moonlite utility to do the same in the ASCOM driver, or something in APT where you can calibrate the focuser?

[tooth_dr]

2 hours ago, david_taurus83 said:

What's the total drawtube travel anyway? It maxes out on outward travel but what about inward travel? Is this the same score it came on? I'm just wondering if there some sort of calibration procedure done when you first fit the focuser and tell it the limits of drawtube travel?

I just measured it = 24.6mm.  It also maxes out on inward travel too.

APT crashed again today using it.  The reading was 1970 steps at most inward position, I moved it out to 3000 steps and it crashed and it was still within travel range.

I can see that the step numbers in the hitec astro MHP interface don’t tally up with APT. So I’m guessing something isn’t talking properly. Also the steps I focus at has changed. It was 3120 up to a few days ago now its 2598 - I thought a stepper motor was absolute. 

Doing my head in 

 

[tooth_dr]

36 minutes ago, Davey-T said:

IIRC I used the Lakeside utility that came with the Lakeside focuser, wound it out a thousand steps then measured how far it had travelled, divided by a thousand and that was the step size entered into autofocus software, then wound it nearly all the way in, set as maximum in travel, then wound out well past focus point and called that maximum out.

Don't think step size was as big as 17 microns think it was in single digits.

Drove it manually back to focus point and that should do to start from.

Dave

Thanks Dave. It should be 4 microns or even 2 microns on the half step.  The issue is with my Hitec Astro controller I believe. 

[tooth_dr]

16 minutes ago, Starflyer said:

I don't know the Moonlite system, but for the Lakeside I had to calibrate the focuser on first use, I assume the Moonlite would need a similar procedure.  I had to rack it all the way in, press a button in the Lakeside Utils software to tell it the minimum position, then rack it all the way out and tell it the maximum position.

It's there a Moonlite utility to do the same in the ASCOM driver, or something in APT where you can calibrate the focuser?

I don’t seem to be able to access the Moonlite utility because I’m using the Hitec Astro MHP as the controller.  Hopefully I’m wrong and I can get into it to do settings 

[Davey-T]

Just now, tooth_dr said:

Thanks Dave. It should be 4 microns or even 2 microns on the half step.  The issue is with my Hitec Astro controller I believe. 

I thought all focus controllers used the same protocol so all responded the same to being controlled by various software via their ASCOM  drivers.

Have you got anything else to autofocus with, just a demo version of something, does the Moonlite  have an ASCOM driver ?

Dave

[tooth_dr]

4 minutes ago, Davey-T said:

I thought all focus controllers used the same protocol so all responded the same to being controlled by various software via their ASCOM  drivers.

Have you got anything else to autofocus with, just a demo version of something, does the Moonlite  have an ASCOM driver ?

Dave

I’m going to head out now for 30 minutes and have a go.  The MHP software download incorporates the ASCOM driver. I have the Moonlite ASCOM driver installed but when I try to use it it can’t find the moolite controller.  I think buying the mini V2 controller would solve my issues but kinda makes the MHP I bought a bit redundant  

[Davey-T]

4 minutes ago, tooth_dr said:

 I think buying the mini V2 controller would solve my issues but kinda makes the MHP I bought a bit redundant  

Could be, maybe these things won't run without their own little controllers, I use the Lakeside box with the Lakeside and a SharpSky one with the SharpSky, dear old hobby, always something to spend more money on, you can always sell the MHB.

Bit confusing as MHP claims to control stepper motors but Hitec focuser comes with control box so would you still need both ?

Dave

 

[whipdry]

Hello Adam, 

Are you using the latest MHP driver version: 1.56?

Not sure if the focuser settings within the MHP software have an influence but perhaps a screenshot showing yours would help? 

Maybe someone might spot an issue!

 

Peter 

Edited December 28, 2019 by whipdry
Remove repeated name

[tooth_dr]

1 hour ago, whipdry said:

Hello Adam, 

Are you using the latest MHP driver version: 1.56?

Not sure if the focuser settings within the MHP software have an influence but perhaps a screenshot showing yours would help? 

Maybe someone might spot an issue!

 

Peter 

Hi Peter

I’ve attached a screenshot of the settings. There aren’t many, and when you click advanced settings it’s gives a warning not to change them unless advised by Hitec Astro.

 

[tooth_dr]

I’ve since had an email from Hitec Astro, offing to do a firmware update. I’m going to send my MHP over to England for this, should bring the step size down to 4um

[whipdry]

44 minutes ago, tooth_dr said:

I’ve since had an email from Hitec Astro, offing to do a firmware update. I’m going to send my MHP over to England for this, should bring the step size down to 4um

Ok that seems like the best way forward. 

I have a Focus Master it always worked best with 1/2 steps set.

Maybe ask them about the step size setting perhaps it could be as low as 0.5 as I'm guessing that would also be 1/2 steps. 

[tooth_dr]

12 minutes ago, whipdry said:

Ok that seems like the best way forward. 

I have a Focus Master it always worked best with 1/2 steps set.

Maybe ask them about the step size setting perhaps it could be as low as 0.5 as I'm guessing that would also be 1/2 steps. 

Thanks peter. I changed the advanced settings but it made no difference. The MHP needs the chip replaced so it’s not just a software update. HA have kindly offered this for just cost of postage. It should do half steps at 2um too. Hopefully this will help me get in focus. Cos as mad as it sounds I think I can tell by eye when zoomed in that the diffraction spikes don’t ever fully line up - it keeps missing exact focus point - they don’t converge. 

Edited December 28, 2019 by tooth_dr

[tooth_dr]

I just wanted to update this now.

Last night I bought SG Pro.  Despite not getting on the best with the trail version, I decided to buy it.  It now includes the mosaic wizard for free, this was previously a charged extra iirc, and this is what I really wanted.  The fast Epsilon should be efficient at creating mosaics.

Back to the focuser issues.  I loaded up the MHP interface and then SGP.  I racked the focuser right in to the minimum and set the MHP interface to zero.  I noted that this immediately updated the SGP data.  I worked out I have about 1250 steps to be close to max - it gives me leeway of 100 steps each side.  I was able to enter these parameters in SGP under an options setting, so now I have the ability to go in and out without over doing it.  I can see there is some backlash, but I wont bother calculating this until I've sent the MHP back for a firmware update.  Currently 1450 steps covers the entire drawtube movement of almost 25mm.  If I get the firmware update working correctly, I should be able to get this down to over 12000 steps for the complete drawtube range.  This was probably doable in APT, but I couldn't immediately see where to change these settings.

 

Thanks for all the help in the thread so far.  I'll get the hub posted off after new year, and update this thread with the results.

 

CS

Adam.

 

 

 

Edited December 29, 2019 by tooth_dr

[tooth_dr]

This is what the autofocuser routine looks like, thin cloud tonight but sufficient for testing stuff out.