EAF on SCT - Another suggestion

rac

For astrophotography, I find that the numerous optical configurations available (from f/2 to f/25) for SCT require the mirror to be moved to different positions. Examples include HyperStar, 0.4, 0.5 & 0.63 reducers and 2.0 & 2.5 Barlow.

platini

+1 for this request, i just bought 2 EAFs for my SCTs and found after installing them found this issue and got here to this forum. I agree the best solution is the x steps per count, in fact some others focusers use that. In my C11 i had to use 2 steps
Just an example, this other focuser has also a limit of 65k values, however it implements the configurable steps per tick value, and also in my case has to be 2 to cover a range of 114800 steps (59000-1600)*2 to cover the required turns. It originally defaulted to 1 but if you needed to expand the range you an apply an arbitrary integer multipler at the expense of decrease of precision) I think this kind of solution just requires really small development and can easilly be implemented in EAF Firmware, as other focusers do.

WOuld like to get feedback from ZWO to see if i should return my two newly purchased EAFs or not. This is a standard feature on all other decent focusers.

Tech@ZWO

platini this other focuser has also a limit of 65k values, however it implements the configurable steps per tick value

Please provide some links about this other focuser and let us understand its mechanism first.

platini

IN a few hours i found 4 post requesting same solution. No response from ZWO here?

Juanchys

I use to have the Celestron focuser and it has a calibration process were the system move at the edges and stop base on an increase of motor current (as there is no more movement allowed). In the case of ZWO, I have to go from 60K back to 0 and then change the current position to 60K so I can go further. Is a burden when I’m setting planetary image train since going from f7 to f25 requires about 90k-100k steps. If the software allowed me to at least determine the full range, I can write down my reference points and setup will be less painful.

platini

@tech@zwo#49438

https://starizona.com/products/microtouch-autofocuser-wired

https://cdn.shopify.com/s/files/1/0327/2569/6648/files/MicroTouch_Install_Win10_NoASCOM.zip

Tech@ZWO

platini
Hello,
I don't see any bracket or Flexible coupling, looks like a complete different product to me. I don't think this is as easy as a firmware update which can make two different design works the same way.

platini

I just measure the full run of my C11 and it has 215510 steps of the ZWO focuser or about 37.5 turns. For me a 4x step multiplier would make the 60K steps of the focuser to fit the telescope focus run

Mfratto

@tech@zwo#48694 Sorry, no, this is a poor answer. I use this focuser with an SCT. When I switch from visual to camera, I have to make 13 revolutions, 2.5 more than I can make with the EAF, to get to focus. This should be a simple fix in firmware or software.

platini

Mfratto

@tech@zwo#49521

Completelly agree that it is a very poor answer from a company that doenst care of its customers. That should be a really easy ti implement fix that would easy the life of several customers as you can see in this forum.

Kring

@platini - do you know that you can go another 60k steps by simply changing the current position?

It works by say you want to go 120,000 steps down. Set current position to 60000, tell EAF to goto 0, when it reaches 0, set current position to 60000, tell EAF to goto 0. rinse & repeat. this is a pretty simple workaround for the VERY rare case that someone needs more thank 60K steps AND they swapping visual to AP.

platini

Kring Yes i know that i can do that, in fact that is what i end doing. However that has a lot of problems.

1) lose automation using SGP
2) lose end of carrier demarcations (to avoid forcing the mirror screw and motor)
3) as mentioned before, lot of trouble switching between f/x / hyperstar and visual, when with other focusers i just have a table with the estimated focus position for all of them.

charles18

I agree with this thread, 60000 steps is just not enough when switching between Hyperstar, f/6.3 reducer, and f/10 configurations (which can all happen in the same night). It is possible to get to focus by reshuffling the zero point, but it is fairly frustrating.

Tech@ZWO

We forwarded this to our engineer. The limition is on the firmware, it will be more troublesome to modify, and there will be compatibility problems to upgrade the firmware.

platini

Thanks a lot ZWO for updating firmware and responding to the users requests. That is what I expect from a trusted company. You will keep having my business for cameras because of this.

abaylus

I am interesting on seeing what other people have their EAF settings set to for successful focusing on a SCT.
the Fine
Coarse
Limit
Backlash

I noticed that my scope has a run of 233,383 from one end to another.
I have the setting se to 300,000 (take the new firmware update - it should allow a 600,000 max. I just installed it but I have not had the chance to set up and test the variable to see what works best - another week of poor astro).
Fine 10 Coarse 30 Limit 600,000 Backlash 0

If you have this working on your SCT (and not like me with once in a blue moon) I would be interested in seeing what your working settings are.