Televue 3x Barlow

[davesellars]

Quick question...

Would there be any issue with buying a TV 3x barlow that is approx 9 years old? Apparently only used a couple of times and stored for 9 years... Apart from a possibility of fungus because it may not have been stored in a sufficiently dry environment? I can't remember what the price of these were new that long ago...

[Bigzmey]

TV 3x barlow is a top notch. You will be happy with it's performance. If it was not abused, dropped, etc., should be a safe buy.

[davesellars]

Many thanks. I've read that the TV 3x is one of the best and actually better performance than the 2x... Will fit in well either using the Baader BCO 10mm or the 10mm Delos or even the 7mm Pentax for double stars at 306x

[Bigzmey]

Many thanks. I've read that the TV 3x is one of the best and actually better performance than the 2x... Will fit in well either using the Baader BCO 10mm or the 10mm Delos or even the 7mm Pentax for double stars at 306x

I had TV 2x and 3x for a while, both are great barlows. I also liked the planetary views with 3x better than with 2x, although both were good. My suspicion that this is not because of barlow optical quality but of the fact that to achieve the same power one uses longer FL EP with 3x barlow.

Let's say you want effective focal length of ~3mm. With 2 x barlow one need to use ~6mm EP, with 3x barlow 9mm EP. 9mm EP will likely have less optical aberrations to start with and will get cleaned up by 3x barlow a bit more.