Use of Celestron focus motor to improve planetary imaging?

[Moonstruck]

Hi,
I am trying to improve my planetary imaging, and am told that an electronic focuser is the way to go. I am considering getting a Celestron focus motor that would attach to my C8 Edge (link below), and I am wondering how that could be used with Sharpcap. Ideally I would like to be able to remote into my laptop and control focus from inside my house when the weather starts getting cold. Is that possible, and if so, where can I find info on how to connect and control the focuser in Sharpcap? Or do I need to use the focuser utility software that comes with the focuser for control?

Also, if control of this focuser is possible in Sharpcap, is there a way to automatically focus an image? If so, where can I find instructions on how that would be done? I'd like to have the option of automatic or manual focusing from my laptop if possible. If you can get me started with this I'd appreciate it!

Link to focuser:
https://www.highpointscientific.com/cel ... e3118530b1

[admin]

Hi,

it looks like the focuser there is ASCOM compatible, which means that once you have it installed and have installed the software that goes with it, SharpCap should be able to control it. As long as you can connect it to your laptop via USB and provide it with a power connection then it should be OK. Of course normal limitations on USB cable lengths apply... Unfortunately I don't have direct experience of this model, but I don't recall seeing any complaints about it failing to work with SharpCap either.

SharpCap does have focusing assistance for both planetary/lunar and deep sky built in. There is quite a bit in the documentation on this, so if you start reading here - https://docs.sharpcap.co.uk/4.0/#!2!Introduction - you will learn all about it.

One thing to note is that SCTs tend to have lots of backlash in the focuser mechanism, and that applies with the motor focuser too. This means that for example if you find focus as position 21000 when moving the focuser in the direction of increasing values, if you come back down again, you might find best focus at position 17000 (and the difference could be as much as half a turn of the knob or so). SharpCap has a couple of different ways to deal with this by either setting the amount of backlash exactly or requesting all movement to be in a particular direction - see the Hardware settings page.

cheers,

Robin

[Moonstruck]

Thanks Robin. The Celestron focus motor is just one model I am looking at; there are a lot of other ones, including a variety of crayford focusers (moonlight, starlight, etc) that attach to the image train, and a feathertouch microfocuser that attaches directly to the focus knob. Do you have one you recommend? I am open to ideas and would like to find out about the best option(s). There are so many options out there that it is a little confusing and tough to find out the best one for the C8! Ideally I would want one that I could control from inside my house by remoting in, and preferably one that has an "autofocus" function, if sharpcap doesnt already do that. Thanks for all the info and the link you sent - I will read up on what you gave me. Let me know if you have any suggestions for a specific focuser model/brand.

Cheers,
John

[admin]

Hi John,

although I have an SCT, I have never tried to put a motor focuser onto it, so I can't give any specific recommendations about what might work well or not. I always used to put a clothes peg onto the focus knob, since it acts like a clock hand and you can therefore start to think in terms of position - was the focus better at 2 o'clock or 3 o'clock.

All my autofocus experience has been with refractors and perhaps an occasional Newtonian, so attaching to a Crayford or R+P focuser.

Might be worth having a wander around on some other forums to see if you can pick up any specific recommendations on motor focusers for SCTs.

cheers,

Robin

[Moonstruck]

Ok- thanks. I'll take a look on Cloudy Nights, etc. From what I have seen the Crayford focusers are the way to go with an SCT when doing planetary photography, as they are placed in the image train and don't involve touching the focus knob on the OTA (which is directly connected to the mirror and can cause image shaking/vibration). I just don't know which focuser to choose since there are a lot on the market!

[roelb]

The Celestron Electronic Focuser is a pretty good one and easy to handle with SC.

[CarlGreen]

Hi, I have one of these attached to my 9.25 evolution.

I connect my mount to CPWI, this gives me access to slew and focus control panels, which float, so that I can open sharpcap, put CPWI in the hardware settings bit and use the floating controls (Slew and Focus) whilst in the shapcap software.,
This works fine fo me.

Hope this helps

Carl

[Moonstruck]

Thanks for the info Carl and others - I appreciate it.