Testing a new ASI 178MM Cool

jays_ct

All,

Just got my ASI 178mm Cool.. Unfortunately mother nature isn't going to cooperate anytime soon. Is there a way to "test imaging" with it in the house? I'm not sure the all sky lens (although it fits) from my 120 and 224 works with these. Can't seem to get to a focus point. Would appreciate any thoughts..

Jay S.

jays_ct

Anyone? Would greatly appreciate it.

Thanks in advance.

Support@ZWO

lens from 224 will be OK for 178.

jays_ct

Sean,

Thanks. How far away would something have to be for the all sky lens to come into focus? I tried the 178 with my auto tracking scope on some trees toward the back of my house and it worked fine.. I never was able to get the 224/120 lens to come into focus indoors when I had it on the 178, yet both the 120 and 224 worked on very close objects inside.. I realize there's an extra 5mm added to the distance between the lens and the sensor..

Jay S.

Support@ZWO

120, 224 have same back focal length with 178. I'm sure the lens can be used on all of them.

jays_ct

Sean.Wang wrote:

120, 224 have same back focal length with 178. I'm sure the lens can be used on all of them.

Sean,

According to the specs online the 120 and 224 are 12.5 backfocus and the 178 MM Cool is 17.5 backfocus. The screw in all sky lens doesn't seem to work, at least not at close range objects with the 178 MM Cool but does focus (I'm talking a coupe of feet away) with the 120 and 224. I just double checked the specs here on the site. The 178 worked fine when I connected it to my 60mm guide scope and focused on a more distant object.

Are you saying that the small All Sky lens should also focus with the 178 at an object a couple of feet away?

Thanks in advance..

Jay S.

Support@ZWO

OH, yes. the cooled version can't use CS lens, but C mount lens will be work.

jays_ct

Sean.Wang wrote:

OH, yes. the cooled version can't use CS lens, but C mount lens will be work.

Sean,

By "C" Mount, do you mean Canon mount? I have that. Is CS, the small screw in all sky lens that comes with the 120 and 224?

Jay S.

Support@ZWO

No, C-mount is just like CS-mount, the threads are same, but back focus of C-mount is 5mm longer than CS-mount.