2036 replies to this topic

[Rac19]

Second question I have is that the limits 0-60000 does not seem to handle the full range of the focusknob should it be like this? or should be the whole range handeled I can use by manual using the focusknob?

I am not sure how relevant this is to your situation but hopefully the comments below will be helpful.

 

The first question is how many steps are needed for 1 revolution of the focus knob. Celestron SCTs typically require 40 to 50 turns for full mirror travel. For example the ZWO EAF has 5,760 steps per turn so that a numeric range of 0 to 60,000 represented about 11.6 turns, not enough for various reducers, Barlows and HyperStar. After many requests from SCT users, ZWO added another zero making the numeric range of 0 to 600,000 or 116 turns.

 

You probably don't need to use the full mirror travel but various optical configurations can require quite bit of travel (turns) to traverse between the mirror positions required, certainly more than 11.6 turns.

 

EDIT: The Celestron Focuser, by the way, has 1,000 steps per revolution (turn) so 0 to 60,000 is plenty.

Edited by Rac19, 26 December 2023 - 08:35 AM.

[masi]

I am not sure how relevant this is to your situation but hopefully the comments below will be helpful.

 

The first question is how many steps are needed for 1 revolution of the focus knob. Celestron SCTs typically require 40 to 50 turns for full mirror travel. For example the ZWO EAF has 5,760 steps per turn so that a numeric range of 0 to 60,000 represented about 11.6 turns, not enough for various reducers, Barlows and HyperStar. After many requests from SCT users, ZWO added another zero making the numeric range of 0 to 600,000 or 116 turns.

 

You probably don't need to use the full mirror travel but various optical configurations can require quite bit of travel (turns) to traverse between the mirror positions required, certainly more than 11.6 turns.

 

EDIT: The Celestron Focuser, by the way, has 1,000 steps per revolution (turn) so 0 to 60,000 is plenty.

Good point :-) 

I have a Celestron 9.25 SCT, it neeeds roughly 48 revolutions for a full mirror move. 

With the current setup of the ULN driver it tooks 4900 Steps for1 revolution means I need to have 236000 steps for the full mirror move :-)

So I believe playing with focus.microsteps will not help, it just increases the speed and does not lower the steps itself for a full revolution or I am wrong, let me have a look in the source.

Thanks

Martin

Edited by masi, 26 December 2023 - 10:32 AM.

[mlord]

Focus micro steps won't help. Don't fiddle with them.

But perhaps we could introduce a new HBG3 setting for "focus.factor" or something, so one could set that to "2.0" to have each of the 60000 possible steps actually perform a double-step, making the range 0..120000 in even increments. Or 1.5, or 3.0, or..

Edited by mlord, 26 December 2023 - 04:45 PM.

[Rac19]

But perhaps we could introduce a new HBG3 setting for "focus.factor" or something, so once could set that to "2.0" to have each of the 60000 possible steps actually perform a double-step, making the range 0..120000 in even increments.  Or 1.5, or 3.0, or..

Celestron obviously considers that 1,000 steps per revolution provides enough precision for fine focus, so the focus.factor could be as high as 5.0.

Edited by Rac19, 26 December 2023 - 03:35 PM.

[masi]

But perhaps we could introduce a new HBG3 setting for "focus.factor" or something, so once could set that to "2.0" to have each of the 60000 possible steps actually perform a double-step, making the range 0..120000 in even increments.  Or 1.5, or 3.0, or..

I love it, thanks

[mlord]

Okay. Remind me about this after New Years Eve. Thanks.

[Rac19]

To keep in mind for next year. Implementation a steps per count (focus.factor) could require logic to manage the resetting of the "real" count from 60,000 to 0 or 0 to 60,000 a number of times as the mirror moves through it's full travel. This is possibly why ZWO elected to increase the numeric range to 600,000 after both solutions were suggested by various users. I don't know if the same applies, or is even an option, in this situation.

 

EDIT: While 0 to 600,000 sounds excessive, it means that if you set the count to 300,000 (wherever the mirror happens to be) there is no risk of exceeding the count range in either direction.

Edited by Rac19, 26 December 2023 - 06:27 PM.

[mlord]

[ focus.factor scaling value ]

I love it, thanks

I want YOU to test this feature.  Can you build/install it from source code, or should I provide you with a flashable binary instead?

 

Thanks

[masi]

[ focus.factor scaling value ]

I want YOU to test this feature

Source is enough.

[mlord]

Source is enough.

Here you go.  It builds, but I am away from my HBG3+Stepper so not tested:  [nuked]

 

Experiment with setting focus.factor to values like 0.5 and 2.0 etc.

 

   set focus.factor 0.5

   save

   reset

 

Thanks

Edited by mlord, 28 December 2023 - 11:20 AM.

[masi]

set focus.scale 0.5

 

I assume its focus.factor, focus scale does not exist

 

but checked both.

 

1. using get all it's no showing up

 

15:59:02.872 -> emulate.ssag:
15:59:02.872 -> focus.backlash.neg:
15:59:02.872 -> focus.backlash.pos:
15:59:02.872 -> focus.calibrated: 0
15:59:02.872 -> focus.limits:
15:59:02.872 -> focus.microsteps:
15:59:02.872 -> focus.only:
15:59:02.872 -> focus.presetC:
15:59:02.872 -> focus.presetZ:
15:59:02.872 -> gps.disable:

 

2. set command focus.scale or focus.factor is not confirmed with an ok

 

3. focus is only moving counterclockwise

Edited by masi, 28 December 2023 - 11:20 AM.

[Zoroastro]

OTA update . Built with Dew Heater setup.

 

 

 

 

 

 

[mlord]

Awesome!

[Astro Andy]

OTA update . Built with Dew Heater setup.

Is that a Celestron heat ring? Looks great 

[Zoroastro]

That's my 3D printed box for the HBG3 with the Dew Heater add-on! I have indeed a Celestron Dew Ring on my C11 but it's not in the image. The sintered metal rod is the TSH30 probe.

 

I will do next some testing with the heater to check the temperatures of the MOSFET, I don't want to melt the PETG

Edited by Zoroastro, 28 December 2023 - 04:54 PM.

[dlwmacgregor]

OTA update . Built with Dew Heater setup.

 

1703783786208-min.jpg

 

1703783786251-min-min.jpg

Could you show the inside?

Thanks.

[Zoroastro]

[mlord]

I assume its focus.factor, focus scale does not exist

..

3. focus is only moving counterclockwise

Okay, I'm back.  And yes, it has that one-direction issue.  Working on it now. 

[masi]

This "focus.factor" version works for me: hbg3.ino.txt

 

This is what I tested so far using NEMA 17 with TMC2209

 

Using hand controller of celestron to move the focuser using move in/out function

 

1. set focus.factor 0.5
2. save
3. reset

4. Position reseted (30000)

5. check with putty if value is still set -> ok
6. Steps counting
7. motor is moving into both directions
8. total count of 6 evolutions in the full range 0 - 60000
9. after power on/off position reseted to random value 15000 or 30000

 

1. set focus.factor 1
2. save
3. reset
4. check with putty if value is still set -> failed
5. value is not set and empty
6. values are counted once, motor is not moving in any direction

 

1. set focus.factor 2
2. save
3. reset
4. check with putty if value is still set -> failed
5. value is not set and empty
6. values are counted once, motor is not moving in any direction

 

1. set focus.factor 1.0
2. save
3. reset

4. Position reseted (30000)

5. check with putty if value is still set -> ok
6. Steps counting
7. motor is moving into both directions
8. total count of 12.5 evolutions in the full range 0 - 60000
9. after power on/off position reseted to random value 15000 or 30000

 

1. set focus.factor 2.0
2. save
3. reset

4. Position reseted (30000)
5. check with putty if value is still set -> ok
6. Steps counting
7. motor is moving into both directions
8. total count of 25 evolutions in the full range 0 - 60000
9. after power on/off position reseted to random value 15000 or 30000

 

I will repeat the test with CPWI, SkyPortal and Nunchuck but it will take a while as I am out for the next 2 days.

I will also build a second device with UN2003 driver as soon I have all parts and repeat testing as well

 

Thanks Mark for the effort and the new function.

Edited by masi, 29 December 2023 - 01:37 AM.

[dlwmacgregor]

1703801817751-min.jpg

Thanks for that.

Did you make a hole in the side for the GPS module or does it detect OK thru the plastic case?

 

Another quick question...

 

What is the heatsink for on the Dew Heater board?

 

Attached Thumbnails

• 

Edited by dlwmacgregor, 29 December 2023 - 10:01 AM.

[masi]

Here is the latest now, with hopefully working FRAM again:  hbg3.ino.txt

Tried it quickly

focus.factor set to 3.0, FRAM is detected

 

Moved Focuser to 39800

power switch off

waiting 60 seconds

power on

Focus value is 43266

 

Cheers

Martin

[mlord]

Moved Focuser to 39800

..

power on

Focus value is 43266

Right.  Found/fixed that issue now:  hbg3.ino.txt   295.48KB   18 downloads

[Wyphy]

I will do next some testing with the heater to check the temperatures of the MOSFET, I don't want to melt the PETG

Might want to drill/cut some holes into the box at the bottom and top of whichever way it is oriented so you can get convection airflow through to aid cooling.

If possible, turn the heatsink so that the fins are vertical to aid in heat dissipation.

Hope that all makes sense.

 

Looking at the pictures again, may want to move the GPS unit over (I know there's a depression there for it) to keep it cooler.

Edited by Wyphy, 29 December 2023 - 12:46 PM.

[Zoroastro]

Yes, ventilation holes are a good suggestion. Thanks!

 

If it runs too hot I could also

 

a) reduce the PWM frequency now at 8192,

b) put the radiator outside through a cutout.

 

At any rate, this is the assembled box connected to the venerable AS-GT :-)

 

 

 

 

[mlord]

I don't see how changing the PWM frequency would significantly affect how warm anything gets.

That said, I did notice on my scope that Celestron uses a PWM frequency of only 4 (four!).

 

My own Dew MOSFET is inside a small project box with no ventilation holes yet.

Shouldn't be a problem for me -- here, the Dew Control is only active in cooler temperatures.

Edited by mlord, 29 December 2023 - 01:51 PM.