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I agree

Which Barlow ?

23 Jul, 2019 07:29

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 ?

Edited 23 Jul, 2019 07:30
23 Jul, 2019 09:44
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.  smile
23 Jul, 2019 10:06
Hi Adel,thnakx fpr the tip…I`ll see… smile
23 Jul, 2019 10:13
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

23 Jul, 2019 15:39
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

You usually get that you paid for  smile  You may get best results with APO barlow, Tele Vue and Bresser are great but quite expensive
23 Jul, 2019 16:10
Almost clear….the more expensive the better the quality
24 Jul, 2019 09:10
Without question the Tele Vue Powermate 2.5x gives superior results. Rod
24 Jul, 2019 10:14
thanx rod
24 Jul, 2019 19:38
I agree with Rod.  I have ben using mine for the past year on my 10" SCT.  Image quality is amazing.
29 Jul, 2019 11:59
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.
29 Jul, 2019 12:37
thanks jeff,
yes i know 3x is too much too…perhaps 2.5 is ok (only when seeing is good)
25 Aug, 2019 11:54
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,
25 Aug, 2019 15:02
Thanks for the tip robert smile
05 Sep, 2019 10:04

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
05 Sep, 2019 11:16
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.

Edited 05 Sep, 2019 11:17
05 Sep, 2019 13:13
thanks Robert for the tip with 2x2 binning

06 Sep, 2019 17:17
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.
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