I have placed this in imaging because I have never used a dedicated camera before, as you can see I have the ZWO ASI 178MM
I have always been happy with DSLRs but want to use the ASI for solar but have NO idea and happy to admit that, unfortunately having Autism does not help meaning lost tempers and giving up
Is there any form of diagram that shows me some idea of the imaging train please.
I have most of what is needed but no matter what I do I can't image trees in the distance, or over 50' away
The ONLY way to image the trees 1/4 mile away is with a barlow and extension image 1
Just camera nothing
Many thanks
Last edited by Ukastronomer; 12-02-2019 at 07:21 PM.
For starters, I suspect that the flip mirror adds too much length to the imaging train. The simplest way to find out where the focal plane is in the system is to remove the camera and put in an eyepiece and bring that to focus. If focus can't be achieved with an eyepiece with the flip mirror in place, no matter how much the focuser is racked in or out, remove the flip mirror assembly.
With the eyepiece inserted directly into the drawtube again rack the focuser in or out until focus is achieved. once you have focus with an eyepiece, then your ZWO camera will require about another 12 / 15mm of in travel of the drawtube for the camera sensor to reach the focal plane.
Using an barlow will move the focal plane further out, maybe not by much, my 2.5X Powermate when added to the imaging set up requires the drawtube to be racked out an extra 10 / 12mm approx. That is why you can just reach focus with an barlow in place and therefore without an barlow in place you you need some extra in travel of the drawtube to reach focus.
When you racked the focusser out with the cam direct in it, were the star images getting smaller? I assume that was a night time test?
It might be risky to assume that if you cant focus on something relatively nearby in daytime that it won't focus on the stars. There is a big focus difference in mine between daytime objects and the sky. You might need an extension tube to put the camera somewhere in between those two distances (Flip mirror in and out of the train) the best way to tell will be to see if you can get any kind of star image with just the camera in the focusser and if they are getting smaller when you run out of travel or not.
Are you trying to use the camera in the ED72 , then maybe with the flip mirror in place you then can't focus in far enough and without the flip mirror you maybe can't move the focuser out far enough. There may not be a long enough drawtube travel. Without the flip mirror in place you may need a short extension tube as well.
A friend of mine has an ED72, I will ask him tomorrow what configuration he uses with his cameras and if he has drawtube travel restrictions.
You need to find where the focal point is. Initially remove all the stuff you have connected to the rear of the scope, simplify in other words. now connect the zwo to your computer to see whats the image looks like.
now with the rear of the scope still open hold the zwo to the scope and slowly move it back watching the screen and stop when you get a sharp image. You need to measure the distance between the scope and zwo and find an appropriate extension tube (or set of) to get the two physically attached together. Then you can fine tune using the focuser to add or remove spacers to get the zwo at a distance where the focuser can be comfortably used.
Once you have that set you can move on to stuff like barlows if you want, but get the basics right first, you have to figure that out yourself, unless someone with the same combo can let you know the distance.
With my ed100 + asi224, if I have the diagonal attached before the camera I find that I just can’t get focus racked all way in.
If I stick the camera straight in the spout i get focus racked out about 12 turns of knob.
That’s with the 1.5in adapter nose screwed on cam. Not sure if it makes an appreciable difference or not?
Also go slow when trying for focus and check whatever software your running is set to a quick exposure. Otherwise you might miss focus if racking too quick.
All mistakes I’ve made lately too