Which Barlow ? - Forums

Topic starter

Jul 23, 2019 · Edited: Jul 23, 2019

Hi,

I'm seeking a barlow lense for my equimpent (C 9.25 and asi 290mm)
Can anyone give me advice which would be suitable for my system ?

CS
Werner

Adel Kildeev

Jul 23, 2019

I would suggest Celestron 2” x2.5 Barlow (very good quality). Theoretically you can try x3 and even x5, but for SC (not APO) it may be too much (I tried x5 Bresser with my Meade 8” ACF - no good results.

Planetarios_3

Topic starter

Jul 23, 2019

Hi Adel,thnakx fpr the tip…I`ll see…

Planetarios_3

Topic starter

Jul 23, 2019

I think maybe a tele vue barlow 2.5x … of the quality should they be superior to various opinions of the celestron?
I don*t know if its true

CS
Werner

Adel Kildeev

Jul 23, 2019

I think maybe a tele vue barlow 2.5x ... of the quality should they be superior to various opinions of the celestron?I don*t know if its true

CS
Werner

You usually get that you paid for ;) You may get best results with APO barlow, Tele Vue and Bresser are great but quite expensive

Planetarios_3

Topic starter

Jul 23, 2019

Almost clear….the more expensive the better the quality

Rod Kennedy

Jul 24, 2019

Without question the Tele Vue Powermate 2.5x gives superior results. Rod

Planetarios_3

Topic starter

Jul 24, 2019

thanx rod

dzurron

Jul 24, 2019 · Edited: Jan 18, 2020

I agree with Rod. I have been using mine for the past year on my 10" SCT. Image quality is amazing.

Well Written

Jeff Coldrey

Jul 29, 2019

Depends a bit on your seeing conditions.
When using a C9.25, I found a Powermate 2x to be excellent, but a 4x was too much.

Well Written Concise

Planetarios_3

Topic starter

Jul 29, 2019

thanks jeff,
yes i know 3x is too much too…perhaps 2.5 is ok (only when seeing is good)

astropical

Aug 25, 2019

Hello Planetarios_3,
I would opt for a 2x or 2.5x which is at least a 3-element fully multi-coated barlow.
They are available at under 100 USD (for instance GSO brands).
Note that when you sandwich a, say, 2x barlow between focuser and
diagonal the magnification will be 3x :-) A matter of seeing (and budget).
All the best,
Robert

Helpful Concise

Planetarios_3

Topic starter

Aug 25, 2019

Thanks for the tip robert

Planetarios_3

Topic starter

Sep 5, 2019

Hi,

Now I have the opportunity to buy a (used) TV powermate 2.5 … I'm afraid that this is too much for my system (c 9.25 and asi 290mm and two filter wheel) (oversampling?)
Can anyone help me in this regard
Thank you
Werner

astropical

Sep 5, 2019 · Edited: Sep 5, 2019

Hello Werner,
Even without a barlow oversampling will occur anyway at FL=2350mm in combination with an ASI290MM, but no big issue with accurate guiding and good seeing when imaging moon and planets (undersampling would be much worse). You can always compensate a bit for oversampling by 2x2 binning your ASI290MM.

I don't know what the used 2.5x Powermate will cost you, but I'd assume this is a rare opportunity and you can also enjoy its fine optics for visual.

Since this is a subjective view, please expect other opinions before you buy.

Cheers
Robert

Well Written Helpful Insightful Respectful

Planetarios_3

Topic starter

Sep 5, 2019

thanks Robert for the tip with 2x2 binning

cs
Werner

Tareq Abdulla

Sep 6, 2019

Why not Powermate 2x instead? that will serve you more than PM 2.5x, i can buy 2.5x or all Powermate models because i have more system than you to use with, and for now i am using 2x for my Mak and 5x later for my 8" Newtonian and also upcoming 20" Dob in future, but i am planning to buy 4x first and then 2.5x just to have the collection whenever i need.