Barlow question

[Apollo_95]

I am looking for advice on Barlows please. I currently have Skywatcher  130p Heritage with the 2 stock EPs 10mm & 25mm. Ive also added the starguider 8mm EP. Im now considering getting the starguider shorty Barlow. My understanding of Barlows is that they double or treble the magnification of the EP & make the images bigger but not necessarily any sharper. Is this correct? My main interest is planetary observation although I do also like looking at fainter objects. If I was to add the Barlow to my 8mm would the image be as sharp compared to say the 3.2mm or the 5mm? Im basically weighing up whether I am better spending my money on a Barlow or the 3.2/5mm eyepieces. Any advice would be much appreciated. 

[Nyctimene]

I have the same scope, and use it frequently with the Baader 2.25x Turret Barlow:

https://www.teleskop-express.de/shop/product_info.php/info/p5503_Baader-1-25--Q-Turret-Barlow-and-photo-converter---2-25x-und-1-3x.html

A lightweight, compact and very sharp shorty Barlow; combined with the Seben 8-24 zoom, I frequently crank up the magnification to 183x. When the seeing is very good, I use it with the Skywatcher UWA 6 mmf (mag 244x), e.g. to separate the double star Pi Aquilae (1.4" distance!), and for moon details. It isn't much behind it's famous  brother, the Zeiss Abbe 2x Barlow. Very recommendable, and quite affordable.

Stephan

 

[rwilkey]

Generally speaking, the more you crank up the magnification, the more the object becomes fainter and less sharp.  Yes, the object is larger, but you loose detail.  The Moon and Saturn can take a lot of magnification though (250x).  Jupiter not so much, about 150x. 

[Louis D]

1 hour ago, rwilkey said:

Generally speaking, the more you crank up the magnification, the more the object becomes fainter and less sharp.  Yes, the object is larger, but you loose detail.  The Moon and Saturn can take a lot of magnification though (250x).  Jupiter not so much, about 150x. 

In my experience, it's more dependent on exit pupil, seeing conditions, and fineness of optical figure than absolute values.  With my well cooled 15" Dob and steady Texas skies, I was able to view Jupiter just fine at well more than 200x in the past to see festoons and barges within the belts.  With a 130p and typical UK skies, I would expect 100x to be about the useful max on Jupiter.  An 8" Dob should be capable of 125x to 150x on Jupiter.

[Louis D]

7 hours ago, Apollo_95 said:

My understanding of Barlows is that they double or treble the magnification of the EP & make the images bigger but not necessarily any sharper. Is this correct?

For low contrast objects like Jupiter, they'll actually appear less sharp once a certain point of no return is passed in terms of magnification.  A zoom eyepiece is useful to determine exactly what that Goldilocks magnification is.

For high contrast objects like star clusters, there's very little breakdown of image sharpness with increasing magnification.  In fact, some globular clusters could be partially resolved in your scope with enough magnification.

[joe aguiar]

Get a good quality Barlow tho the low quality ones will degrade image where the good ones wont or barely anything

Joejaguar