Binoviewers & slop on focus

[Hitman77]

Hi folks - I have a couple of questions I am looking for help and advice with. OK here goes :

- Having a lot of trouble reaching focus on my Equinox 80ED and 12" SW truss dob with my WO Binoviewers. I have read a ton of different opinions online and have even read that people have cut off a couple of inches from their refractor tubes or moved mirrors in the newtonian - I really am not up for any of that though. So far I have used the 1.6 mini barlow supplied on both scopes but it didn't work. Would popping the Bino's straight into the frac focus tube work as it seems to be in-focus I am short on. Anyone tried and had success on either of these kinds of scopes?

- On my Equinox there seems to be an issue where the focus tube just slides out completely if I have a 2" ep in it and it's pointing up toward the zenith or thereabouts. Is it normal to have to push the focus tube in at this angle as the focus adjustment does not work. It's fine when it is pointing lower but does not seem to "catch" when pointing up. Has anyone else encountered this and is there a quick fix for? I'm not very "handy" when it comes to these things but would give it a bash or send away to be fixed.

Really interested to view some of the solar system objects through the Binos as I have read so many great things and would hate to sell them on due to not using them. Any help appreciated

Andy

[Saganite]

Hi Andy,

I use Bino's most of the time, but to achieve focus in my 12" Dob I had to put 50mm of extension tube between the nose of the bino and the 1.6x barlow. This has the effect however, of increasing the barlow effect to approx 2.5X, which I find ok, as a pair of 20mm eyepieces will give approx 190x and for the Moon this is pretty stunning.

The same arrangement inserted straight into my TAL ( remove the diagonal)  also works superbly)

The extension tubes are easy to find.

 

Hope this helps.

[Fozzie]

Hi Andy,

I don't think your alone in struggling to find focus with BV's... and the issue with the focuser sounds like it needs some attention too!

Firstly the BV's, I found that the 1.6x supplied GPC didn't work in my frac (never tried it in the Newt) but interestingly the nose piece from a standard sky watcher Barlow did, which should be a 1.3x (?) lens.. You could always try that to see if it will focus with a diagonal in place.  I ended up with 4 options, the 1.6x a 1.3x (as before) a 2.6x GPC (365 astronomy for £30) and the nose piece from a 2.25x baader Q barlow (which gave a 1.25x GPC).. they all worked well but the magnification on all I estimated top be in a range from 190 to 240x..

 

In respect to the focuser, sounds like it needs tightening and tensioning using the allen key bolts below.  the focuser tube shouldn't slip out.  have a look at this from our good friends at FLO.

https://www.firstlightoptics.com/blog/adjusting-skywatcher-equinox-focuser-tension.html  hopefully that will help.

Thanks

Fozzie

 

[Hitman77]

Brilliant info guys - thanks very much. I will get onto these and report back

Andy

[Joseki]

Hi, with the sw truss dob you could try not extending the truss tubes fully - moving the focuser and secondary closer to the primary mirror. That works very well with my baby heritage 130p and WO binos. 

 

[Hitman77]

1 hour ago, Fozzie said:

Hi Andy,

I don't think your alone in struggling to find focus with BV's... and the issue with the focuser sounds like it needs some attention too!

Firstly the BV's, I found that the 1.6x supplied GPC didn't work in my frac (never tried it in the Newt) but interestingly the nose piece from a standard sky watcher Barlow did, which should be a 1.3x (?) lens.. You could always try that to see if it will focus with a diagonal in place.  I ended up with 4 options, the 1.6x a 1.3x (as before) a 2.6x GPC (365 astronomy for £30) and the nose piece from a 2.25x baader Q barlow (which gave a 1.25x GPC).. they all worked well but the magnification on all I estimated top be in a range from 190 to 240x..

 

In respect to the focuser, sounds like it needs tightening and tensioning using the allen key bolts below.  the focuser tube shouldn't slip out.  have a look at this from our good friends at FLO.

https://www.firstlightoptics.com/blog/adjusting-skywatcher-equinox-focuser-tension.html  hopefully that will help.

Thanks

Fozzie

 

Just had a look at the focus fix on FLO - Looks easy enough Fozzie - thanks again

 

[Hitman77]

3 minutes ago, Joseki said:

Hi, with the sw truss dob you could try not extending the truss tubes fully - moving the focuser and secondary closer to the primary mirror. That works very well with my baby heritage 130p and WO binos. 

 

Ah - I think I may have read that elsewhere also - I shall go for this first as it seems to be the least money or hassle. I'll let you know how I get on with that Joeski

 

[Dude_with_the_tube]

hi Hitman,

i binoview practically 100% of my observations and i use refractor.

You can use extension tubes+barlow to reach focus but that normally will introduce very high magnifications and will limit you to practically high power planetary observations.

other option is to do as you said:attach your binoviewer in straight through mode to illiminate diagonals light pass.Binoviewers normally add additional 100mm to your light pass and this is what you need to regain somewhere.removing diagonal can work,but this could and will put your viewing position in very awkward position,specially when nearing the zenith.

Most common is to introduce your refractor OTA to hacksaw blade and take off 4" of OTA at the back and then you will reach focus without the aid of barlows.I know it does sound drastic,but if you are really into binoviewing,native focus will open up a lot of viewing possibilities,including wide field (sort of) and also DSO as you do not need to magnify anything.

It is entirely up to you to decide what way to go.

As for newts,if you have the truss design one,then its simple.Do not extend them fully,if it is a solid tube,then either again you will have to get the barlows+extension tubes,but this could and will make your construction quite tall and bulky or alternatively you will need to move your primary up closer to secondary to reach focus.

Trust me,it is not that hard to do as it sound

Clear skies. 

[mitchelln]

Not sure what make Dob you have, but the later big SkyWatcher truss Dobs have a 2nd set of lock notches before full truss extension. On mine that then allows my WO binoviewers to achieve focus.