ZWO ASI 120MC & guiding

[groberts]

I want to build a widefield set-up - Samyang 135 f2 + ZWO 1600mm Cool & or DSLR - and would like to add guiding.  I use a Lodestar X2 + WO 50mm guidescope on my main refractor rig which uses PHD2 and works well but would like to have a seperate guidescope and camera for widefield, so I don't have to break-down the main rig.

1. I already have a USB 2.0 ZWO ASI120MC camera - can this be used for guiding, preferrably pulse guding + PHD2?
2. Any thoughts on a suitable guidescope - perhaps another WO 50mm or the SW Evoguide?

Any related thoughts or advice much appreciated.

Thanks, Graham

 

 

 

[Frank the Troll]

1. Yes, you can use your ZWO, how about adding it to this guider  --  https://www.firstlightoptics.com/zwo-accessories/zwo-finder-and-guider-scope.htm

[groberts]

Thanks for the reply:

- does that mean you can pulse guide with it or only using ST4?

- the scope & price look good but the reviews are mixed?

Graham

[johngm]

28 minutes ago, groberts said:

Thanks for the reply:

- does that mean you can pulse guide with it or only using ST4?

- the scope & price look good but the reviews are mixed?

Graham

Hi Graham,

Pulse guiding in a nutshell means you interface through ascom direct from PC to mount, or via the hand controller.  What mount will you be using for your widefield rig ?

Also, for what you want to do, you may as well just use a 9X50 guidescope and by an adaptor from modernastronomy for your ASI120MC. What may i ask do you want to pulse guide rather than via the ST4 port ?

John

[groberts]

Thanks John,

I'll be using an AZ-EQ6 mount. I currently pulseguide using +/-5m USB connection, which ideally I'd just move over to the alternative set-up. 

Graham

 

[groberts]

OK following the above comments + looking around more, I've narrowed it down to either (A) the ZWO Finder-guider f/l 280mm f4.67 or (B) the ZWO Mini guide scope f/l 120mm f4, which probably fits better with the widefield rig size I'm setting up.

For the moment will probably use the guidescope with my ZWO ASI120MC which seems to fit well with (B) but might one day would want to pair it with a Lodestar x2 - would that be a probelm?

Based on the above - any comments please?  

  

 

[groberts]

I purchased my ZWO 120MC in 2014 - one of the first - and it is therefore only USB 2.0 compatible but should, I believe, still be OK for guiding?

I obviously need to know the pixel size for PHD2 but being somewhat old not sure what this would be, as  the various current 120MCs now comes with different pixel sizes.  Anybody able to help please?

Graham  

 

Edited March 13, 2020 by groberts

[tooth_dr]

@groberts I think it's probably 3.75um pixels.  PHD2 autopopulates this data when I plug in my 120MM (same as yours only mono)

[groberts]

Great + thanks

[groberts]

Still prevaricating over a guidescope to go with the AstroKraken Samyang 135 rig using a ZWO120MC camera. 

Was erring towards a smaller scope like the ZWO Mini Guide Scope oe smething similar. But (a) there's a lack of stock and (b) reviews are mixed.  Wondering if something like the RVO equivalent version https://www.rothervalleyoptics.co.uk/rvo-32mm-f4-mini-guide-scope.html or the larger SW Evoguide 50ED might be a better choice?

Any thoughts / personal experience of these please?  

 

Edited March 19, 2020 by groberts

[Skipper Billy]

The bog standard SW finderscope works a treat - as does the Evoguide 50 - the Evoguide is made to a better quality and has a better focuser but its more expensive.

[groberts]

Thanks Billy.

[Avocette]

I personally am having success with the SW 50mm Evoguide and the ASI120MC-S (i.e. USB3.0 version of your camera). However if I understand it correctly, the USB2.0 interface of the earlier model is slightly out of specification and so doesn’t always work with software drivers (like Indi). In my case when guiding an ED80 primary scope, I set the guide camera binning to 2x2 which I think averages out the Bayer filter pattern of this colour camera, although it does work on 1x1 binning as well.

Edited March 23, 2020 by Avocette
Clarication

[groberts]

Thanks Avocette thats helpful.

I bought this ZWO ASI120MC camera not long after they first appeared - about 2015 /16 I think - and had some problems getting it to work at all at first.  Finally discovered it would ony work with a USB 2.0 port but not at all with USB 3.0 i.e. not back compatible.  Notwithstanding, I successfuly used it a few times for planetary imaging using Firecapture which worked OK.  However, I have never used it for guiding. 

My core softare is now VIA EQASCOM which works very well with EQMOD / CdC / PHD2 / APT but never know with ZWO stuff it can be fickle at times with other software.

As a matter of interest are you using the ST4 guide connection direct to the mount or pulse guiding via a computer + any issues /advice?    

Graham

[Avocette]

4 hours ago, groberts said:

As a matter of interest are you using the ST4 guide connection direct to the mount or pulse guiding via a computer + any issues /advice?    

Graham

I'm not using the ST4 connection. My guide camera is connected via a USB 3.0 powered hub into a USB 3.0 port on the Raspberry Pi 4 but I'm sure it would run fine on USB 2.0. You mention that your camera is not compatible with USB 3.0 connections, but I'm pretty sure that I read on one of the relevant forums (maybe SGL, CN or perhaps Indilib) that the earlier version of the ASI120MC is not entirely compatible with the specification even of USB 2.0. I have an astro friend who lent me a mono ASI120MM of the older type, before I received my ASI120MC-S but I couldnt get it to work with my RPi4 system.

[groberts]

Don't know anything about RPi4 but does that mean it's pulse guiding OK?

Yes my ASI120MC was very temperamental - euphamism for wouldn't work with anythng at first - but with the correct driver and only using the USB2.0 port on my laptop it's been OK.  Not surpirisingly it sounds like things have moved on since then.

Graham