Back to forums

Tilt

ZWO ASI1600MM COOL Equipment Tilt Troubleshooting Help Needed
8 replies•130 views
Rodd Dryfoos avatar
Rodd Dryfoos avatar
After much work I think I have determined that I have sensor tilt (or some other type of tilt).  I am shooting with the FSQ 106 with .6x reducer with the ASI 1600.  I imaged IC-443–the Jellyfish that has 2 bright stars–one about 1/4 the way from the right hand edge and one 1/4 the way from the left hand edge.  There are diffraction spikes due to the stars brightness, and the diffraction spike on the right hand star is noticeably off center–and the stars on teh right side look pushed.  The diffraction spike on the left star is dead center, and the stars look round.

How does one address tilt in the ASI 1600?  Shims?  How does one ensure the shims are properly positioned with thread on connections?  Do they make shims that are round that are different thicknesses on different sides?

This problem has frustrated me for a long time.  I lived with it for as long as I could.  I can't any longer.  I have switched to F5 (no reducer) and see the same effect–though less pronounced.

Any input would be very welcome
Thanks,
Rodd
Helpful Engaging
Luca Marinelli avatar
Luca Marinelli avatar
Rodd,

I noticed this classified on Cloudy Nights yesterday with a simple tilt-adjustment shims solution that may be what you are looking for:

https://www.cloudynights.com/classifieds/item/240677-rotating-tilt-adjuster-for-m42m48m54m68-etc-including-zwo-eosnikon/

Tilt adjustment units are more flexible but also take up quite a bit of backfocus, which with the 0.6x reducer you don't necessarily have.

Cheers,

Luca
Well Written Helpful Respectful Concise
Rodd Dryfoos avatar
Rodd Dryfoos avatar
Luca Marinelli:
Rodd,

I noticed this classified on Cloudy Nights yesterday with a simple tilt-adjustment shims solution that may be what you are looking for:

https://www.cloudynights.com/classifieds/item/240677-rotating-tilt-adjuster-for-m42m48m54m68-etc-including-zwo-eosnikon/

Tilt adjustment units are more flexible but also take up quite a bit of backfocus, which with the 0.6x reducer you don't necessarily have.

Cheers,

Luca

Thanks luca--I will have a look
andrea tasselli avatar
andrea tasselli avatar
When I had the need I used hand made shims (of prescribed thickness) cut to size (about 45deg in angular extent) and positioned between the flange of the camera and the focuser mating flange. You press it tight and at the same time you clamp it in place to enforce the prescribed tilt. Used brass sheet of different thickness.
Rodd Dryfoos avatar
Rodd Dryfoos avatar
andrea tasselli:
When I had the need I used hand made shims (of prescribed thickness) cut to size (about 45deg in angular extent) and positioned between the flange of the camera and the focuser mating flange. You press it tight and at the same time you clamp it in place to enforce the prescribed tilt. Used brass sheet of different thickness.

*Sounds beyond me.  Not sure I get it when you say between the flange of the camera and focuser flange.  Do you mean between the filter wheel and the spacer that connects to the focuser?  That would be easy--I don't want to put it between the filter when and camera for  reasons--1) I have the dew controller strip (ZWO) and that might interfere  2) The filters and the sensor should be parallel--but what if the tilt is the camera--not the filter wheel?  what it its just the sensor?
andrea tasselli avatar
andrea tasselli avatar
I used to have a filter wheel + camera combo. The shim was placed between the flange of the 2" adaptor of the filter wheel (toward the focuser) and the push-fit adaptor on the focuser, so flat against flat. It only works on push-fit connection because you need a bit of gap to make it work (in order for that adaptor to fit tilted within the focuser tube).
Helpful
Rodd Dryfoos avatar
Rodd Dryfoos avatar
andrea tasselli:
I used to have a filter wheel + camera combo. The shim was placed between the flange of the 2" adaptor of the filter wheel (toward the focuser) and the push-fit adaptor on the focuser, so flat against flat. It only works on push-fit connection because you need a bit of gap to make it work (in order for that adaptor to fit tilted within the focuser tube).

*Ah-I have all threaded connections.....and I hate them.  they are sometimes impossible to unthread, especially in the cold.
andrea tasselli avatar
andrea tasselli avatar
If all the image train is threaded either: 1. you have a tilted lens/objective (but then you'd be able to see un-symmetric extra and intra-focal diffraction pattern) or 2. the tilt is in the sensor. Don't ZWO sell a tilt adaptor, BTW? Note that in case 1 you could re-tilt the lens to get rid of the tilt in the image plane.
Concise
Rodd Dryfoos avatar
Rodd Dryfoos avatar
andrea tasselli:
If all the image train is threaded either: 1. you have a tilted lens/objective (but then you'd be able to see un-symmetric extra and intra-focal diffraction pattern) or 2. the tilt is in the sensor. Don't ZWO sell a tilt adaptor, BTW? Note that in case 1 you could re-tilt the lens to get rid of the tilt in the image plane.

*I won't be fiddle with the FSQ 106 objective, that's for sure.  I will inquire, however, if that is likely....thanks