Hi all, I'm John a newbie to this caper and I am trying to set up a 5 inch Heritage 130p mini-Dob SkyWatcher for my son. we have been given a 3x Saxon achro Barlow recently and we attempted to marry the Barlow with the mini-dob with very limited results. While we had good views of the moon with both the 10mm and 25mm eyepieces as soon as we put the Barlow between the eyepiece and the telescope the lunar image became blurry and no amount of focusing helped. The same problem was noted with stars. Am I doing something wrong? Should I be using a 3x Barlow with this device? I was told it would be fine to use.
The advice I have been given is that it is possible to get 50x mag for each inch of aperture, so we should have an upper limit of 250x before losing resolution through the eyepiece. Using the 10mm eyepiece with a scope with a focal length of 650mm I have a mag of 65x, add to this the 3x Barlow and that brings us up to about 195x mag, below the recommended threshold. Am I missing something or doing something wrong? Please note that it was a fairly light sky last night and also we were about 15 metres from a small light, so there was a fair bit of pollution. Your guidance on this would be very much appreciated.
