Baader Q Barlow question.

[Franklin]

According to their website the Baader Q Barlow has a dual power factor of 2.25x and 1.3x when used with barlow barrel and without barlow barrel respectively.

My question is are these figures for when used with an eyepiece directly or when used on the nosepiece of the Baader Q Turret? Is there any difference where you place it?

When used on the Q Turret nosepiece the barlow would be slightly further up the optical path a bit like when a barlow is placed before a diagonal rather than after it and then yields a different power factor. Some of what I've been reading on this seems to be in conflict. Does anyone know?

Thanks.

[John]

I think those figures relate to the use of the optical element of the barlow with the Q Turret or one of the Baader Classic range of eyepieces.

The amplification figure when it's used with other eyepieces might vary depending on the length of the eyepiece barrel.  Not hugely, but it won't be precisely 1.3x.

The exact amplification that is delivered depends on the focal length of the barlow lens element and it's distance from the lowest lens in the eyepiece. Not always easy to calculate !

Any eyepiece that the Q barlow is used with needs a more or less empty barrel so that precludes a lot of designs that have a lower lens group within the eyepiece barrel.

 

Edited June 19, 2021 by John

[Franklin]

Thanks John, that's kind of what I thought. If I unthread the barlow lens from its barrel and put it on the turret nosepiece it should give about 1.3x hopefully when used with the BCO's and BCP. I just ordered the Q set to use with a long focus refractor. Should be good for lunar I reckon. 

[Franklin]

Maybe my IQ is suspect but I think I've had a eureka moment. Baader Classic Q set can be used as follows.

1. All 4 eyepieces in Turret to be used at their native focal lengths.

2. Q Barlow lens element unscrewed from Barlow body and fitted to the Turret nose-piece will allow all 4 eyepieces to be used with 2.25x factor.

3. Q Barlow complete, used with a single eyepiece for 2.25x factor.

4. Q Barlow lens element unscrewed and fitted to the nose-piece of a single eyepiece for 1.3x factor.

I was hoping to be able to use the 1.3x factor of the Q Barlow and still be able to switch eyepieces with the Turret but that is not possible. 

[Louis D]

2 hours ago, Franklin said:

I was hoping to be able to use the 1.3x factor of the Q Barlow and still be able to switch eyepieces with the Turret but that is not possible. 

Sure it is.  Just buy three more Q Barlow elements and mount them in each eyepiece. 😁