Focusing the ZWO mini guide scope

[Astro_mark_c]

Hi,

 

I have the ZWo mini guide scope with the ASI 120mm mono guide camera, any tips on getting the guid scope focussed?

 

Kind Regards,

Mark

[michael8554]

Hi Mark

The Guidescope has a 120mm Focal Length, so measure 120mm from the front element, that's where the guidecam sensor has to be located.

Roughly eyeball that with the rotary focuser about halfway if possible, then try during the day with SharpCap on Auto Exposure, pointing at a distant landscape.

Fine tune at night on a star, if using PHD2 you can adjust for minimum HFD on the Star Profile window.

Michael

[Len1257]

When you focus in the daytime on a distant object find something that includes a closer item as well as a further item. Then you can deduce which way it will need to go when you do find a star. I've got the info safely stored in one of my notebooks if only I could find it! 

Len

[Astro_mark_c]

Thanks for the help, managed to get it working!

[Ande]

I had one of these turn up this morning. Managed to get a rough, daytime focus. Have to say though, the quality isn’t very good for the price. There is way too much slop in the focus tube, that when you get to the correct focus and try to lock it in place, there is a huge amount of movement, resulting in being out of focus again. I had to resort to locking it, then slackening off, moving it a tiny bit, locking it off again. Rinse and repeat several times before a satisfactory point is achieved. Very tempted to return it and throw the extra money at a Williams Optics one.

[nephilim]

19 minutes ago, Ande said:

I had one of these turn up this morning. Managed to get a rough, daytime focus. Have to say though, the quality isn’t very good for the price. There is way too much slop in the focus tube, that when you get to the correct focus and try to lock it in place, there is a huge amount of movement, resulting in being out of focus again. I had to resort to locking it, then slackening off, moving it a tiny bit, locking it off again. Rinse and repeat several times before a satisfactory point is achieved. Very tempted to return it and throw the extra money at a Williams Optics one.

I've read some negative comments about this guide scope, I went for the Skywatcher 50ED which seems really good quality.

 

Edited January 13, 2021 by nephilim

[Ande]

25 minutes ago, nephilim said:

I've read some negative comments about this guide scope, I went for the Skywatcher 50ED which seems really good quality.

 

Very wise. I think the ZWO’s main redeeming feature is that it is small, and lightweight. But the love affair ends there for me.

[david_taurus83]

I had the Astro essentials mini guide scope which is very similar in design. The front barrel was also loose on that before you tightened. A good upgrade is to get the non rotating helical focuser which makes focusing a breeze after you get rough focus with the front barrel. I'd hazard a guess the SVBony helical focusers available on ebay for half the price of the ZWO are identical..

 

[Astro_mark_c]

53 minutes ago, Ande said:

Very wise. I think the ZWO’s main redeeming feature is that it is small, and lightweight. But the love affair ends there for me.

I think i will eventually go for the skywatcher one, but it came in a bundle and it was purely down to cost.

[nephilim]

53 minutes ago, Ande said:

Very wise. I think the ZWO’s main redeeming feature is that it is small, and lightweight. But the love affair ends there for me.

I agree, with the planned setups we both have with the Samyang 135 I'm hoping my 50ED wont be a bit too big. I only bought it as my original imaging tool was going to be either the WO ZS 73 or GT 81 although i'll be getting one of them at a (much) later date now.

[Astro_mark_c]

1 hour ago, nephilim said:

I've read some negative comments about this guide scope, I went for the Skywatcher 50ED which seems really good quality.

 

just realised i replied to the wrong person lol

I think i will go for the skywatcher one, but the ZWO came as a bundle and it came down to cost and also availability during covid. 

[nephilim]

1 minute ago, Sidecontrol said:

I think i will eventually go for the skywatcher one, but it came in a bundle and it was purely down to cost.

I know what you mean mate, this hobby isnt cheap.

 

[teoria_del_big_bang]

1 hour ago, nephilim said:

I've read some negative comments about this guide scope, I went for the Skywatcher 50ED which seems really good quality.

 

The Skywatcher Evoguide  50ED is a brilliant guidescope. Not exactly cheap but quality.

Steve

[Astro_mark_c]

Just now, nephilim said:

I know what you mean mate, this hobby isnt cheap.

 

yea lol 

I've got my eye on the 50ED and the L-Pro filter.  Thankfully I'm very happy with my scope.  I was wondering whether the skywatcher field flattener would be much of an upgrade to the OVL one. 

[nephilim]

1 minute ago, Sidecontrol said:

yea lol 

I've got my eye on the 50ED and the L-Pro filter.  Thankfully I'm very happy with my scope.  I was wondering whether the skywatcher field flattener would be much of an upgrade to the OVL one. 

If you mean for the 50ED, its not really needed for just guiding. There is one available for it if you want to use it as a small widefield frac but its quite expensive.

[nephilim]

3 minutes ago, Sidecontrol said:

yea lol 

I've got my eye on the 50ED and the L-Pro filter.  Thankfully I'm very happy with my scope.  I was wondering whether the skywatcher field flattener would be much of an upgrade to the OVL one. 

I also wouldnt use a filter on a guidescope as you need maximum star brightness 🙂

[nephilim]

6 minutes ago, teoria_del_big_bang said:

The Skywatcher Evoguide  50ED is a brilliant guidescope. Not exactly cheap but quality.

Steve

I agree mate. Its a really nice piece of kit.

[Astro_mark_c]

Just now, nephilim said:

I also wouldnt use a filter on a guidescope as you need maximum star brightness 🙂

the filter was for my scope lol didnt think you'd put one on a guide scope 😛

[nephilim]

1 minute ago, Sidecontrol said:

the filter was for my scope lol didnt think you'd put one on a guide scope 😛

Sorry mate...It has been done before 🤣

[Ande]

1 hour ago, david_taurus83 said:

I had the Astro essentials mini guide scope which is very similar in design. The front barrel was also loose on that before you tightened. A good upgrade is to get the non rotating helical focuser which makes focusing a breeze after you get rough focus with the front barrel. I'd hazard a guess the SVBony helical focusers available on ebay for half the price of the ZWO are identical..

 

That looks like a nice upgrade.  And I agree that the SVBONY one is probably identical. The only thing that stops me grabbing one is that it is all extra weight. And, given that I’m perching everything on a Skyguider, I have to be a bit weight conscious. 

[Ande]

Well, the poor quality has got the better of me and I’ve ordered a replacement scope. Went with this one from Williams optics: https://www.firstlightoptics.com/finders/william-optics-32mm-slide-base-uniguide-scope.html

A fair bit lighter than the ZWO Mini, and also like the measurement marking guide printed along the side. Handy for if it ever gets packed away.  Just hope it’s better quality. 

[Astro_mark_c]

15 hours ago, Ande said:

Well, the poor quality has got the better of me and I’ve ordered a replacement scope. Went with this one from Williams optics: https://www.firstlightoptics.com/finders/william-optics-32mm-slide-base-uniguide-scope.html

A fair bit lighter than the ZWO Mini, and also like the measurement marking guide printed along the side. Handy for if it ever gets packed away.  Just hope it’s better quality. 

Let us know how it is, once you've tried it!

[Ande]

Will do 🙂

[Ande]

On 15/01/2021 at 13:22, Sidecontrol said:

Let us know how it is, once you've tried it!

It turned up a couple of hours ago. I haven’t had a chance to test it yet, but it does seem a nice step up in quality. It feels like it actually represents the price paid, whereas the ZWO felt like fifteen quid’s worth.

[amartinwest]

I am having problems focusing this device, wish I read this before buying 😞

The focal point seems to about 30 cm behind where it should be. I took this picture ...

 

 

Edited January 31, 2022 by amartinwest
replace heic with jpg