11 replies to this topic

[Kim2010]

So far my plan is to use my Celestron Zoom only for 24mm and 8mm (the 2 ends of the Zoom) because it is so hard to set the zoom to exactly the same per eye because there are no clicks at each focal length. And then I will get another Svbony 7 to 3mm, and that has a click at every focal length.

 

For now, would this suffice especially for planetary? Or do you think I should get noon-Zoom EP as well or would that be redundant?

[betacygni]

I’ve not personally done it, but I hear matching zooms without clicks isn’t very hard. The eye can accommodate for slight differences well as I understand it.

Zooms give pretty narrow AFOV at the 24mm setting typically, which also results in a pretty narrow TFOV, so my only thought might be something a little wider there, but that’s not absolutely necessarily. I’d use the zooms as is and see if you end up with preferred focal lengths, then maybe upgrade those if you aren’t happy with the zoom performance.

Edited by betacygni, 12 February 2024 - 04:05 PM.

[donniesoprano]

Agree with betacygni.  Additionally, consider a barlow or some OCS to amplify the image in front of the binoviewer instead of eyepieces lower than about 10mm.  Generally speaking, short F/L eyepeices are harder to use in a binoviewer.  However, many people do use them.

 

IIRC, RolandC recommends using nothing lower than 10mm eyepeices and suggests using a barlow to get higher mags with binoviewers.

 

ds

[Kim2010]

I have a Celestron Omni Barlow (2X) and a Meade 3X shortie Barlow. I assume those would be good as is, and I won't need a higher-end Barlow?

[donniesoprano]

I have a Celestron Omni Barlow (2X) and a Meade 3X shortie Barlow. I assume those would be good as is, and I won't need a higher-end Barlow?

I would use what you have first and then decide if you need something else.

 

ds

[betacygni]

I have a Celestron Omni Barlow (2X) and a Meade 3X shortie Barlow. I assume those would be good as is, and I won't need a higher-end Barlow?

They are going to provide very high powers in the binoviewer, probably at least 3x for the omni, and 4-5x for the Meade. No harm in trying them to see if you already have them though, as long as you expect higher powers.

Edited by betacygni, 13 February 2024 - 08:56 PM.

[Bob4BVM]

So far my plan is to use my Celestron Zoom only for 24mm and 8mm (the 2 ends of the Zoom) because it is so hard to set the zoom to exactly the same per eye because there are no clicks at each focal length. And then I will get another Svbony 7 to 3mm, and that has a click at every focal length.

 

For now, would this suffice especially for planetary? Or do you think I should get noon-Zoom EP as well or would that be redundant?

"because it is so hard to set the zoom to exactly the same per eye"

... NOT so IME !

Have you actually tried this ? Most who have not tried it might agree with you, but I still remember when i first tried it, I was shocked how easily my eyes told me when the images were matched.  That was with a pair of Nikon zoom with no click stops.

I also use a pair of BHZ-4's but i pay no attention to the clicks, my eyes tell me when they are matched.

 

I would suggest a little practice, give yourself a little time on a good target .  Start with one eye, set the zoom, then bring the other one up till you get a synced L/R image.

For a first attempt, to train yourself on this, there is no better target than the moon. After a while you will find it easy to do !

CS
Bob

Edited by Bob4BVM, 13 February 2024 - 09:00 PM.

[donniesoprano]

Yep, but 24mm on 3x puts you at 8mm, and 24mm on 4x to 5x puts you at 5-6mm.  You can go higher from there if needed.

 

ds

[betacygni]

Yep, but 24mm on 3x puts you at 8mm, and 24mm on 4x to 5x puts you at 5-6mm. You can go higher from there if needed.

ds

Yes, but zooms are pretty poor (shorter eye relief and very narrow AFOV) at the 24mm setting. The 3x might be useful, giving the zoom a range of 8mm to 2.6mm, but the higher power 4-5x barlow is going to be too extreme.

[Kim2010]

Speaking of focusing one eye over another and one Zoom over the other, how do you deal with the shakiness when doing this since it is not knob-based, i.e. you have to turn the eyepiece or the eyepiece holder itself and that introduces a lot of shakiness which doesn't help in exact focusing

[Spikey131]

I have two identical Baader Zoom eyepieces.  Identical except one clicks and one barely clicks.  It is hard to tell what setting I am at, and often need to look.  Which is OK when viewing planets, but not so good for deep sky.  Clicking zooms would be preferred.

 

It is best to avoid using short focal length eyepieces with binoviewers, because they magnify optical imperfections in them.  Rather than getting another 3-7mm zoom, consider putting a barlow in front of the diagonal and use the your longer FL zooms.

[Bob4BVM]

Speaking of focusing one eye over another and one Zoom over the other, how do you deal with the shakiness when doing this since it is not knob-based, i.e. you have to turn the eyepiece or the eyepiece holder itself and that introduces a lot of shakiness which doesn't help in exact focusing

Hopefully by now you are not needing to focus the 2 sides individually. The fixed difference of L/R eyeball focus should be corrected with a parfocal ring. then you only need to adjust the main focus knob as needed for the pair which stays in unison focus.

 

As for changing the FL setting, yes there is some shake, adjust a little, then let go and see how it looks. I find the shake when changing zoom FL is no problem, just watching the image seems to work for me. If its a really shaky mount, that is a separate matter that needs to be addressed anyway.