focuser problem?

[joshyouarebaker]

I've been getting some nice views of Saturn recently. I've been using 108X mag (650/6mm) and its looking great. I tried using a 2X barlow with this last night and i could not get Saturn in focus (not even close). Given, my aperture is only 130mm, but i thought it would be able to focus an object at 216X mag. Any thoughts on this? Could i have a focusing issue? I do not need to collimate as everything is looking good, i just have such a narrow focus window for anything over 108X. 

[TiTanecd]

Hi joshyouarebaker

I have the same scope and the kit as you. I can confirm that using the 6mm without the Barlow is much clearer than adding the Barlow.

I made a 15:1 focuser gearing attachment (temporarily out of Lego) and I can get much much finer focus on objects, even with this at 216x a few millimetres takes it out of focus. Its still not as sharp as without the Barlow.

[joshyouarebaker]

wow. can i see a pic of this please?

[TiTanecd]

Kk, don't know if I'll be able tonight as I'm working but will soon.

[ronin]

Suspect you do not have a problem, the barlow and a 6mm is likely too much for the scope.

Just because something says 2x diameter it means little in reality, I have seen 3x, 4x and others.

2x diameter delivers a 0.5mm exit pupil which is the minimum for the eye, not for the capabilities of the scope. The scope capabilities likely fail around 1mm or a bit less, however it depends on the scope and the barlow and the eyepiece. Is it a top of the range £200 barlow?

[joshyouarebaker]

ha. no. it's not. It came with the Celestron eyepiece kit. I agree, i think its too much for my scope.

thanks for your response