Focusing Telescope Issue - Moon

[Cuto100200]

Just a quick question regarding focusing, I own a Bresser Messier 8" dob, I got it not too long ago as the moon came up today (still daylight) I tried focusing in on it with a 25mm, as I extended the focuser more and more back, I noticed it coming into focus slowly, though the focuser reached maximum extension before it reached focus, to fix this I just pulled the eyepiece out of the hole a bit and locked it back so it was protruding out a bit, this gave it enough length in order to focus but only just about.

Was wondering if this is common to not push the eyepiece all the way into the focuser when observing the moon or is this a sign of a problem?

I'm using a 2" to 1.25" adapter which also gives the eyepiece further extension back a bit, without this in I doubt I'd be able to lock the eyepiece in far enough back in order to focus on the moon at all if I owned a 2" eyepiece.

In the image ive actually moved both eyepiece and adapter back a little so the eyepiece isn't so close to nearly falling out 

Hopefully I'm just being silly 

Thanks for any suggestions

[Kev M]

You need an extension tube to use this optically, would be the most likely scenario.

I would imagine it would have originally came with one.

You could use a barlow lens with the element removed if you have one ?

 

 

[Kev M]

From a website, it should have an extender ?

"

• Bresser Messier Dobsonian 8-inch Specifications:
  
• Telescope type Newtonian Reflector 
  
• Parabolic primary mirror made from H-PZ33 low expansion glass material
  
• Telescope aperture 8-inch / 203mm
  
• f/6 1213mm
  
• Eyepiece included SPL 25mm
  
• Mount type Dobsonian
  
• Focuser Single Speed Hex-Focuser (takes 1.25" / 2" eyepieces)
  
• Optical 6x30 Finder 
  
• 1 Tube extender 37.5mm for 2.5" Hexafoc - IMPORTANT NOTE: this is packed in the mount box in a cutout insert the centre of the mount packaging"

 

[Kev M]

And this

https://www.telescopehouse.com/bresser-extension-tube-37-5-mm-for-2-5-hexafoc.html

May be available from other suppliers as well. couldn't see it on FLO's site.

 

 

 

 

Edited May 5, 2020 by Kev M
missed a bit

[John]

As above. The eyepiece should be fully inserted and the scope should have an extension tube supplied which needs to be in place for eyepieces to come to focus. I have seen this issue mentioned somewhere else recently with regard to the Bresser dobsonians.

 

 

[John]

Here is a photo of the scope with the extension tube in place (from the First Light Optics website):

[Cuto100200]

Thank you Kev and John, I was wondering what that black ring was lol