Can't get focus!!

[04Stefan07]

Currently using a Lunt50 and a ASI178MM-C camera for some solar work but I can't get the damn thing into focus! I tried with the eyepiece holder and also screwing the camera directly to the diagonal but still no luck.

Is there anything I can try??

[marktownley]

Use a low power barlow on the nosepiece of the camera? There's lots of pixels on that chip so you should get away with zooming in a bit...

[denababy]

I have the same scope but I use a zwo asi 120 mm that I screw directly onto the blocking filter after taking off the adapter, you then need to draw the blocking filter out by about 6-8 mm or 1/4 inch in old money. Which capture software do you use?

[Martin_S]

This is my setup 04Stefan07 I use a ASI120mm with a 2x barlow inside the t2 extension tube. Drop your Gain and exposure to a minimum, too bright an image will hinder your focusing.

Martin

[MapleRidge]

I’d try manually sliding the blocking filter in and out to see which way it need to go to get to focus. I’d suspect it needs to go out past the focuser travel, which can be with the blocker skid back and locked in with the set screw or use an extresion tube/T-thread spacer use up some focus travel.

Brian

[Bruce G]

I have a Lunt 80, but things should work pretty much the same with the 50. On the Lunt scopes, the drawtube attached to the blocking filter is an important part of the focus mechanism. In order to more quickly set up my equipment, I made reference marks on my draw tube using a colored pencil. First I set the focuser to about its midpoint. I then adjusted the drawtube to get close to focus and made a mark for 1) eyepiece only (in the center), 2) camera only (the mark closest to the BF), 3) Camera + 2.5x Powermate (same place as with the eyepiece) and 4) Camera + 5x Powermate (farthest from the BF). Nothing has to be perfect in these markings. Since the focuser was set at its midpoint, you have half of its range on each side of the reference marks.

Your particular locations may not be in the same places as mine, but one thing is for sure - you won't achieve focus until you pull the drawtube out at least some.

Lunt focus settings2.jpg (451.61 KiB) Viewed 1241 times

[04Stefan07]

Thank you for the replies. I will try and take the BF out and see if I can achieve focus.

Will let you know my results once the clouds have cleared!