Can't focus my telescope with a barlow lense, what should I do?

[Lotinsh]

I just bought a 130p telescope and a 3x decent barlow lense, but whenever I put it in, it wont focus. It almost gets to focus when my focuser is completely on minimum, but as I can't turn it anymore, I can't seem to get it in focus. Is there something I'm doing wrong?

[Peter Drew]

Sounds rather odd.  If you can focus with just the eyepieces you should be able to focus with the Barlow.  Usually, a Barlow will bring the focus point out which seems to be the opposite of your problem.     🤔

[Dark Vader]

Can you tell us what eyepieces you're using it with?

[Lotinsh]

I'm using the stock 25mm Sky-watcher super MA and stock 10mm Sky-watcher super MA, and a 40$ omegon 3x barlow achro multi coated 

[wibblefish]

Interestingly I have a similar problem with my short tube refractor but I assumed it was related to that telescope design. I find if I have to much glass (usually barlow lens and then a filter) I cant bring it to focus. 
 

Have you tried bringing either the barlow (or the EP or both) back a little? Being careful not to have it to loose and risk falling / damage but you can sometimes not insert everything fully and that may help?

 

Did your 130p come with any little extension tubes to add? I vaguely recall someone mentioning this on another thread about this type of telescope.

[Neil H]

Hi if you still have your old Barlow remove the lens and use it as an extension of you get focus that tells you that you will need an extension , I thought PDS scope were set up for astrophotography a camera will come to focus closer the mirror so an eyepiece will focus away from the mirror , some one will correct me if I am wrong , I had all this fun when I changed to a low profile focuser on my VX8L could not focus an eyepiece

Edited April 11, 2021 by Neil H

[Les Ewan]

It may have something to do with your X3 barlow, X2 barlows are the usual norm for small scopes. Newts can have a narrow focus profile, your X3 may be mainly designed for refractors or a Cat which have a far wider focus range. I admit I don't really know its just a thought.

[Lotinsh]

@wibblefish No my 130p did come with an extension tube, but the problem isn't that focus is too far out, it's too far in, I can't screw my focuser even more in, it reaches the limit when it's starting to get a clear image.

I have tried all the way back, but that was the only time when it starts to focus, it's when I'm screwing it in.

@Neil H I don't know how to remove the lens and do what you said, I'm not skilled enough as this is my first scope.

@Les Ewan Possibly, I probably am going to return my barlow and buy a 2x one, should work hopefully.

[Neil H]

If you have the old Barlow that came with the scope the bottom part of the Barlow should unscrew this will then leave you with the tube section so then you can put eyepiece in the top of Barlow and use it as an extension

There is another way get the tube from an old toilet roll cut and stick it so it fits the eyepiece then put this in to focuser then try and focus  you can slide the tube in and out of focuser as well as moving focuser in and out , if you get focus then you do need extension 

It's normal to need extension tudes, my refractor needs the 2 it came with plus a 25mm to get my camera to focus, my Newtonian just needs the 25mm extension for the camera to focus both of my scopes are set up for visual this is why they need extension for the camera , if your scope is set up for astrophotography  then your need a extension for visual use

Edited April 11, 2021 by Neil H
More info

[Neil H]

I just re-read your posts ,you said it did have an extension put this on and try the eyepiece again the extension will move the focus point the eyepiece should focus at a point where your still have travel in the focuser

[doublevodka]

Ok a couple of things to consider here.

 

Firstly, do your testing with the 25mm and barlow only, the 10mm plus barlow will I suspect be pushing the limits and seeing conditions, cooling of the primary mirror and collimation will all be factors.

 

If using just the 25mm and barlow and you still can't quite get to focus, you could potentially unscrew the barlow lens from the unit and screw it directly to the eyepiece filter thread at the bottom, it won't quite give you the same magnification, but should allow for focus.

 

Just bear in mind that higher magnification highlights and magnifies any issues, so as a start make sure your scope has been outside cooling down with the cap off for a good hour before testing again, for example my 8 inch reflector shows all sorts of weird issues before the primary has cooled enough.

 

Hopefully this helps 👍

[fozzybear]

On 11/04/2021 at 00:32, Lotinsh said:

omegon 3x barlow achro multi coated 

This barlow  is it this one by any chance https://www.omegon.eu/barlow-erecting-lenses/omegon-3x-barlow-lens-achromatic-1-25-/p,2290#tab_bar_1_select the lower section in silver will unscrew and you should be able to screw this into the bottom of your eyepiece if the same thread size

[fozzybear]

any chance of a photo of how you have this setup in the focuser just for reference?

[Lotinsh]

Ok, I tried to screw the barlow lens in the eyepiece, it is too big to fit in the eyepiece. 

@fozzybear That's is the barlow I have, you guessed correct.

@doublevodka When I discovered this I was outside for at least an hour or half an hour, I both tried with the 25mm and 10mm. With the 25 mm I couldn't get it to focus and with the 10mm I couldn't get much at all, barley could see stars which were blurry.

 @Neil H Sorry still don't understand what you mean by just putting the barlow without the lens..? If I got it right, what's the benefit of this? As without the lens in the barlow is it really a barlow lens?

 

EDIT: I will get some pics later for those who are interested, also I'm really sorry for the late response, I was really busy yesterday.

Edited April 13, 2021 by Lotinsh

[fozzybear]

please post some photo's as speak a thousand words

[Lotinsh]

@fozzybear What kind of pic do you want? Like how its setup for me? Or something else?
 

[fozzybear]

5 minutes ago, Lotinsh said:

@fozzybear What kind of pic do you want? Like how its setup for me? Or something else?
 

how you have it setup would help

[Lotinsh]

Here are pics of how I set up the barlow with 25mm lens, sorry for bad quality images, I have only a desk lamp in my room as my main lamp went out.

[fozzybear]

Ok it could well be that , that barlow you have has a long tube length  have a ganders at this thread

 

[Bruce Leeroy]

As someone else says above, your barlow may have a removeable lens cell...if so then unscrew it and see if it will screw directly onto your eyepiece barrel you may be able to gain focus then, what this will do is reduce the barlow effect from 3x to a lower factor. If you can gain focus on a roof/tree of in the distance and still have some inward travel you will probably also have the possibility of infinity focus.

[fozzybear]

on your barlow can you unscrew the black section at the bottom of the barlow ? 

 

Edited April 13, 2021 by fozzybear
too small

[Lotinsh]

@Bruce Leeroy I said before that it doesn't fit in the eyepiece, but thanks.

@fozzybear Seems like some people have issues aswell on this telescope, what should I do in this case, return the barlow and buy a short 2x barlow or 6mm eyepiece? 

Edit: Yes I can unscrew the lens from the barlow, can't screw the lens in the eyepiece though.

Edited April 13, 2021 by Lotinsh

[fozzybear]

1 minute ago, Lotinsh said:

@Bruce Leeroy I said before that it doesn't fit in the eyepiece, but thanks.

@fozzybear Seems like some people have issues aswell on this telescope, what should I do in this case, return the barlow and buy a short 2x barlow or 6mm eyepiece? 

if poss send it back then up to you where you go forward as per some have have probs with a short 2x Barlow maybe speak to your astro supplier or was it Amazon?

[fozzybear]

Post the question on here as there bound to be Heritage owners who can help. in your title list what the scope is and what you want to achieve 

[Lotinsh]

@fozzybearThanks, you mean make a new post about 130p telesope and barlow?

Edited April 13, 2021 by Lotinsh