Baader Q-turret 2.25x barlow and BST Starguiders

[Yearofthegoat]

Hi All,

Quick question re. the Baader Q-turret 2.25x barlow: is it compatible with BST Starguider EPs? In particular, can the 1.3x screw-out element be used with the Starguiders?

Christmas is round the corner and am thinking about a reasonable barlow (and a fourth eyepiece, likely a third BST).

Also currently on my list are:

Revelation 2.5x

Revelation 2" 2x

Skywatcher 2" 2x deluxe

and of course the option of not getting a barlow and getting two EPs instead.

Cheers!

[John]

If you use the 1.3x screw out barlow lens element from the Q-Turret barlow you need an eyepiece with an empty 1.25" barrel section because the barlow element goes some way up inside it. Many eyepiece designs (including the BST's I seem to recall) have lower lens sets in their 1.25" barrels so, unfortunately, you can't use the Q-Turret barlow in that way with them.

[Yearofthegoat]

Hi John, thanks for your quick answer.

Would have been nice to have the 1.3x option in addition to the 2.25x (I'm assuming I could still use the barlow in the normal way).

Am torn between the Baader and the Revelation 2.5x.

[John]

You can still use the Baader Q-Turret as a conventional 2.25x barlow with any 1.25" fitting eyepiece. Optically I think it's a little better than the Revelation 2.5x but the finish of the Revelation is nicer with a compression ring fitting.

[Yearofthegoat]

Thanks - I think I'll go for the Baader.

I also need to think about an eyepiece or two to fit between the 28mm Skywatcher, and the 15mm and 3.2 BSTs.

It's so hard to decide and I'm trying to avoid overlap when EPs are  barlowed - thankfully the 2.25x is 'odd' enough to not create overlaps too much when used with the BSTs.

That said, I find I'm drawn to looking only at BSTs now that I have two. I should consider other EPs, e.g. plossls. I wear contacts/glasses so am concerned about eye relief with short FL plossls, but perhaps at the longer end they'd be okay.

Maybe I should just buy some second-hand ones and see how I get on with them.

Decisions decisions!

[Reeny]

The Revelation 2.5x Barlow is 3-element, and I believe it is a much better Barlow than the other two you have mentioned.

The disadvantage is that there are no threads on the 2.5x barlow for 1.25" filters.

It would be easier for me to swap eyepieces when observing the moon or nebula if I could leave the filter in place.

Saying that - a 2" Barlow won't take the 1.25 filters either.

Have a look at the £55 BST 3-element 2x Barlow.

http://www.ebay.co.uk/itm/BST-Starguider-1-25-Short-2x-Apochromatic-3-element-Barlow-lens-/381210448281?hash=item58c1e9d199:g:t40AAOSwv0tVGUHb

It makes the Revelation seem like a bargain at half the price.

[Reeny]

My apologies, I was away checking my 2.5x barlow when you replied Goat.

The Baader should be a good-un with the removable 1.3x element.