1.7-1.8x barlow?

[Rick_It]

I'm looking for a low power barlow, around 1.7x - 1.8x.

Scope: VX8L 200/1200.

My eyepieces: 28mm 68°, 16mm 68° and 5.5mm 62°.

I have a gap between the 16mm and the 5.5mm. I could buy an eyepiece, but the 16mm is very good optically and has no internal barlow. Moreover, in that way I can also increase the power of the 5.5mm, something I will use rarely but it appeals me.

Problem is, a 2x barlow is a bit too much. Too much magnification for the 5.5mm (436x) and too small exit pupil for the 16mm (150x, i.e. 1.33mm e.p. while I was looking for something around 1.5-1.6mm e.p.).

Most importantly, any solution should not vignette my 16mm and should not be too expensive.

Any suggestions? Thanks!

[John]

Antares have a 1.6x 2" barlow that is of good optical quality. It won't vignette the 16mm.

https://www.rothervalleyoptics.co.uk/antares-2-16x-barlow-lens-with-twist-lock.html

[Rick_It]

Thanks, I was not aware of that product. Yeah, it's a 2", for sure it will not vignette the 16mm.

I wait for some other reply, maybe a 1.7-1.8x 1.25".

[John]

Tele Vue used to do a nice 1.8x barlow in the 1.25 inch fitting. You can pick those up used for £60-£75 I think.

 

[Louis D]

You might try a medium length barlow element like the Meade 140 2x screwed onto a shorty barlow's extension tube that's also 1.25" filter threaded.  That would shorten the distance decreasing the magnification factor.  It's such a neat idea that I haven't heard proposed elsewhere, and seeing as I have both, I'll have to give it a go sometime.  It might become a good use for my third, backup copy of the 140.  I have one for use on the binoviewer to reach focus, one as a normal 2x barlow, and one as a backup in case I shatter one.

[Rick_It]

I was thinking at the same solution, thanks. Probably I will look for a Meade 140 on the second hand market.

[Klitwo]

18 hours ago, Rick_It said:

I'm looking for a low power barlow, around 1.7x - 1.8x.

Scope: VX8L 200/1200.

My eyepieces: 28mm 68°, 16mm 68° and 5.5mm 62°.

I have a gap between the 16mm and the 5.5mm. I could buy an eyepiece, but the 16mm is very good optically and has no internal barlow. Moreover, in that way I can also increase the power of the 5.5mm, something I will use rarely but it appeals me.

Problem is, a 2x barlow is a bit too much. Too much magnification for the 5.5mm (436x) and too small exit pupil for the 16mm (150x, i.e. 1.33mm e.p. while I was looking for something around 1.5-1.6mm e.p.).

Most importantly, any solution should not vignette my 16mm and should not be too expensive.

Any suggestions? Thanks!

Check this out....>

https://www.siebertoptics.com/SiebertOptics-barlows.html

Klitwo