Baader zoom ?

[NGC 1502]

 

I’ve two questions and I’d be grateful for advice please.

Some time ago I tried a friend’s Mark 1 Baader Hyperion zoom 8-24mm with my 10” F4.8 Dob.   Whilst I greatly enjoyed the convenience I was disappointed with the edge of field correction, obviously made worse by the coma inherent with an F4.8 mirror and no coma corrector.

So, two questions -

1. Do the later versions of this eyepiece have better off axis performance ?

2. When adding the dedicated Baader 2.25x barlow, are off axis corrections improved ?

I do have a TeleVue 2x barlow, and using that with regular fixed focal length EPs can improve off axis performance, but I’d prefer the much more compact dedicated 2.25x barlow.

Thanks in advance, Ed  👍

[iPeace]

I use the Baader Mk IV Zoom, and enjoy it very much - for what it is. I don't regard myself as especially discerning in these matters, but I do notice that the view towards the edge of field is not as nice as towards the centre. It doesn't bother me, which probably has to do with how I use it - namely, for the zoom function, and mostly with wide-field refractors. I have owned and used the matching barlow, but have since passed it on. It's a very nice combination, but if you are particularly interested in high-power zooming with excellent edge performance, you can do (a bit) better. The elephant in this particular room bears green lettering.

My 'management summary' would be: with a fast, manual dobsonian, don't expect too much from the Baader Zoom. If you're particular enough to query the barlowed edge performance, you may well be a TeleVue 3-6 Zoom man.

P.S. This may read as an injustice to the Baader Zoom. To be sure, it can serve as one's only eyepiece. Many use it as such and are ecstatic. I love mine.

[Piero]

I cannot comment on the Baader zoom, but on my zooms, the views always improve when I add a barlow. This happens both on-axis and off-axis. 

I largely use my zooms for high power. 

[iPeace]

 

 

[Paz]

I have a Mk IV and the views are better in a f15 Mak than a f5 refractor although admittedly that's not quite the same thing as it's different scopes as well as different focal ratios.

The views in my zoom eyepiece are certainly not as good as my fixed eyepieces but the zoom is my most used eyepiece due to the convenience.

[John]

I've owned 3 of the Baader zooms - a MK II and a couple of MK III's. They edge correction in my F/5.3 12 inch dobsonian was certainly better with the zooms than it is with the fixed focal length Hyperions or the Hyperion Aspheric 36mm 2 inch eyepiece. It's not perfect but I thought the zooms quite useable my my dob. F/4.8 is quite a bit more challenging though.

I'm not aware that the MK IV version has a different optical prescription.

[NGC 1502]

 

Thanks to all for the valued advice, read with interest.

👍