Barlow advice and thoughts

[A McEwan]

Hi!

I'm sure this has been discussed already, but things do change. If this thread is redundant, please remove or direct me to the appropriate thread.

I am out of touch with Barlows. To be honest, I've never had much experience with them. I think I had a Meade Shorty 2x back when I started, and currently have a 2" Revelation ED which I've had for a while.

I'm interested in getting a 1.25" 2x BArlow or tele-extender for several purposes: to make it easier to attain high magnifications with my Tak FC100, and to do the same job in my other scopes that are limited to a 1.25" diagonal.  Ideally I would like the Barlow to be as "transparant" as possible, introducing no negative effects, and making it possible to get as good a view as possible using my longer f-length eyepieces, particularly Plossls, Orthos and  Kelners, Huygens (!) etc in the 20-30mm focal lrngth range.

I know there are plenty out there, but what are the best ones that I should be putting on the short-list?

Thanks,

Ant

[Littleguy80]

Hi Ant,

 I have a Baader VIP Barlow. It’s superb optically and the T2 system gives so many options in terms of adjusting the magnification factor or connections. Alternatively, for a cheaper option, the Baader Q 2.25x has an excellent reputation. 
 

[Star Struck]

Personally I would go for a  TeleVue 2.5x Powermate.

 

They come up reasonably often used.

[Stu]

The VIP is a very versatile choice I agree. If you want something simpler, how about the Televue x2.5 Powermate? These have the advantage of not pushing eye relief out which can be a problem on longer focal length plossls/orthos (or a benefit with shorter ones). Excellent quality and ‘invisible’ as you are looking for.

[mikeDnight]

Then at the cheaper end of the market, there's the Skywatcher Delux 2X Barlow, which is remarkably good even in a Tak FC100D. I currently use an old Celestron Ultima SV Barlow in my FC100DZ when I use my binoviewer, and there's no hint of CA.  The SW Delux is equally colour free in the binoviewer too.  The Delux certainly won't break the bank, and although the Celestron Ultima SV is nolonger in production, it can still be found second hand for around £45 to £50. Takahashi offer a 2X barlow that goes before the diagonal, but in all honesty, I found it no better than the SW Delux or Ultima SV.  If you want to use a truly top class amplifier,  Then buy yourself a Takahashi 1.6X extender-Q. You could even combine the Q with a 2X barlow to really boost your power when the seeing allows.

[JTEC]

One more for the Televue Powermates - superb optically and mechanically, pretty much invisible in the train. 

[A McEwan]

Thank you guys for the very useful info so far!  

[John]

Another vote for the Powermate 2.5x here. I've owned a couple of them and the 2 inch 2x as well and they are totally invisible visually apart from the amplification you get.

A close alternative is the Explore Scientific 2x Focal Extender which has similar properties and performance to the Powermates at quite a bit less cost. 

I currently use a Baader Q-Turret with my Tak FC100 DL and that works well combined with a 7.2-21.5 zoom but I don't use the barlow with prime eyepieces so I don't know how it does with those.

 

 

[billhinge]

If you want a fluorite no expense spared

https://www.baader-planetarium.com/en/accessories/optical-accessories/barlow-lenses-coma-and-glaspathcorrectors/fluorite-flatfield-converter-(ffc)--3x-8x.html

https://www.astro-physics.com/bpffc

I believe you can get x2 with minimum distance, maybe  overkill though 🙂

As this product was designed to provide perfectly round stars - without increasing their size - to cover the 90 mm diameter field of a 6x6 medium format camera,
the performance is even much more impressive when it is used visually. Many people call it "worlds sharpest barlow lens" - we don´t disagree.

Answer by: Baader Web Team (Admin) on Oct 9, 2017 8:37:00 AM

[A McEwan]

Thanks to your advice, I decided I'd prefer a tele-extender over a Barlow this time round, but with the Meade and ES ones being hard to find, I have ordered an "Altair Astro 2x 1.25" Flat Field Extender Barlow" (phew - that's a mouthful!) It looks pretty similar to the ES extender (which in turn seems to be identical to the Meade, so we'll see how it turns out)

Cheers!    

[Ricochet]

14 hours ago, A McEwan said:

Thanks to your advice, I decided I'd prefer a tele-extender over a Barlow this time round, but with the Meade and ES ones being hard to find, I have ordered an "Altair Astro 2x 1.25" Flat Field Extender Barlow" (phew - that's a mouthful!) It looks pretty similar to the ES extender (which in turn seems to be identical to the Meade, so we'll see how it turns out)

Cheers!    

If you've got any flocking material I would recommend flocking the inside of the telextender between the two lens groups, as this really cuts down on stray light and improves the telextender. I've not noticed any vignetting from the slight reduction of internal diameter in my (Meade branded) version.