Ocal Collimator used on TS-Optics Newtonian

Thanks  again, Andrea!

Thanks Brian!

Mine has a built in tilt adjustment. So i will get to work!

CS Haakon

Hallo Georg,

you could shim the base, like Brian says above. I will do that on my telescope, because the adjustment screws does not really function.

CS Haakon

Hallo Emil, 

do you mean the sensor of the Ocal camera?

CS Haakon

If you're testing it using the scope then you are not doing it right. You need an independent test (rig). Same applies to the Ocal. Conversely, if by other means the scope could be guranteed to be collimated it could be used to collimate the laser (not sure the Ocal can, though).

andrea tasselli:
If you're testing it using the scope then you are not doing it right. You need an independent test (rig). Same applies to the Ocal. Conversely, if by other means the scope could be guranteed to be collimated it could be used to collimate the laser (not sure the Ocal can, though).

I made a testing rig a while ago to test my laser and used it for the ocal too. I just attached a few M42 extension tubes to the camera so I can rotate it without changing its position. 

Emil

Haakon Rasmussen:
Hallo Emil,

sensortilt would explain the problems i have getting good collimation using my IMX571 camera. My collimation was much better when i had the ASI294 McPro camera. Smaller sensor and bigger pixel. I do not have a test-rig, so i guess for me i would sell the Ocal and buy me an Autocollimator from Farpoint to be able to achieve better collimation. What do you think?

CS Haakon

It seems the Farpoint Autocollimator are hard to come by at the moment ?

Yes the Farpoint Autocollimator is sold out at the moment.

What type of focuser is mounted on your ONTC?

Hello colleagues, hello @Haakon Rasmussen 

I am sorry but I don't fully agree with some statements here above, especially the statement that says that a newtonian colimation needs a tilt ajustment for the focuser :
- either the colimation is done with primary and secondary adjustments
- either a sensor tilt is managed with a tilt device at the camera level

I have a Lacerta also and it took me some time and some understanding of "what is colimation with a newtonian" to understand that tilt adjustement at the focuser is not necessary, I thanks Towny Nawratil, Vic Mesnard and Jason Khadder for the time they took via mail or PM to explain me that.

The Ocal is for me the most precise tool that you can get for a daytime colimation, but you must use it for what it can give you and you must understand what it gives you: it gives you a very precise geometrical reference that you will use for the alignment of others axis.

For me, it is very unlikely that the screenshot of @Emil Andronic comes from a sensor tilt, the most propable cause is that the Ocal is not properly calibrated 

It is like when you use a chesire : you need a reference for the axis of the focuser and the center of the sensor is not precise enough.

First : the Ocal comes with a serial number that need to be used for getting seetings that are when the software is launched, did you use the right values ?
Second: if you want to get a better tuning of the "ocal center" you can use insert a M42 tube end use this a reference for the calibration of the center of the OCAL with the "Center Offset" feature

in the screen shot here under, I found that with -4 Vertical and 3 Horizontal, the rings are properly and better  centered, you can see the internal thread of the M42 tube :


The OCAL is so accurate that you can see the differences that comes when you change something at the focuser level, the main reason for that is the accuracy of the "focuser axis", it is normal to see a difference after a rotation,
here after the difference that comes by changing the coma corrector with another :


the other reason is the flexion that you may have, here under is an animated GIF that shows a difference with and  without a weight of 2 kg added on the focuser :



My advice would be to first check that you have a good and valid reference for the "center" that you will use for the axis of the focuser

all the best and clear skies

Jean-Baptiste

Hello Haakon

Personally, I think that the closer you are to your "astrophoto configuration" the better it is.
In addition, with the 55mm your sensor will be closer to the focal point.

In my case with  the coma corrector , the image is a little blury, so I may make the tuning without any CC ;-)

in all the case, the final steps is at night with stars : star test and if necessary final adjustment with Hocus FOcus that comes with NINA : the sensor analysis is a must for the last steps, be it colimation adjustments or tilt adjustments

CS
Jean-Baptiste