No stars found with ASI 120 as Off-Axis-Guider

martin_voelkel

Hello!

Sorry first: I am from Germany and my english is not very good.....

I have a Problem: I can find no stars when I use my ASI 120 mm on an OAG (Celestron SC 8").

The Main camera is an ASI 1600 MCC.

I tested the System in daylight: A tree that is about one Kilometer away made no Problem to get in Focus with both cameras (i tested it with sharpCap).

In the night, i tried about one hour to find a star in several regions in the sky.

The System is well focussed with bhatinov.

I turned the axis with 360°, put the prism more in and out - all that in very small steps and tried to set more gain in PHD - no stars.

Could it be that the ASI 120 is not sensibel enough to find stars?

I use a Celestron 0,63 Reducer, so the focal length is 1300 mm and F 6.3.

I use the newest Drivers for my ASI's.

Also, I do not know exactly what I must choose in PHD for camera (Windows wdm style...?) and Telescope (ASI ST4 telescope Driver?) when I have connected the ASI 120 via ST4 cable with ST4 Port of my advanced VX.

Can anyone help me?

Thanks a lot and clear skies

Martin

Support@ZWO

I think maybe you should try 3-5s explosure of ASI120 to find a star.

And you can try to focus moon firstly before you turn to take photo of deepsky target.

martin_voelkel

Thanks for proposing this Thing with the moon. I will try soon!

But isn't it problematic with exposure times longer than 2 seconds?

Does this not lead to drifts in guiding and stars formed like eggs?

I use an Celestron Advanced VX with Starsense, so I think to guide with more than 2 seconds will make me do the polar alignmnet very well. Isn' it?

james_screech

martin_voelkel wrote:
Thanks for proposing this Thing with the moon. I will try soon!

But isn't it problematic with exposure times longer than 2 seconds?

Does this not lead to drifts in guiding and stars formed like eggs?

I use an Celestron Advanced VX with Starsense, so I think to guide with more than 2 seconds will make me do the polar alignmnet very well. Isn' it?

2 seconds is not long for guiding, I sometimes use 4-5 on my AVX. The PHD2 best practice guide recommends 2-4 sec. anything too short and you will be just chasing the seeing.

James

X1m

Hello! I am here as i have a at6rc “f/9” and at 1322 focal length. I am useing a asi120 with zwo oag and having trouble aswell. Did you get yours to work perfectly?