Help with guider focusing

[Dadek]

Hello people, I recently got my AP gear and 2 days ago I managed to setup everything and see how it goes. I couldn't find a guide star in PHD2, tried to figure it out alone and I wasted 2 nights already so I need your help.

I am having issues with guiding in PHD2 because no matter where in the sky I point the telescope I cannot get a star to guide. I usually get heavy TV static and it seems it is related to focusing. HERE is my guiding setup (TS Optics 50mm guider + ZWO ASI 120mm mini). As you can see from the first picture I have tried to move the camera away completely from the guider but I still don't get any stars. Reducing gain to a value of 5 or 10 reduces the static drastically but still no stars. Just a bit of static. Any ideas what else could I try? Since we are at it, a more general (beginner) question... does the guide star have to be in FOV of the object I am trying to photograph?

Cheers!

[michael8554]

This image might be a good starting point for the relative distance of the camera from the scope, yours look too far away compared to this.

Michael

[Dadek]

Hi Michael, thanks for the reply!

I also tried removing the extensions of the guide camera and retracting the guide focuser, but I still get only white pictures.

[almcl]

Try focussing your guider on a distant object during the day.  You will need to reduce the exposure to milliseconds and the focus won't be quite right for stars, but it should get you in the ball park.  

[michael8554]

13 hours ago, Dadek said:

does the guide star have to be in FOV of the object I am trying to photograph?

In theory, no. 

With modern mono guidecam you should always be able to find guidestars when pointed at the target, so it helps to have the guidescope centralised to the imaging field of view. For instance, upping the exposure to 5 secs or so should show your target galaxy. 

As almcl says try during the day, with PHD2 or with Sharp Cap in video mode. 

Which camera driver are you using in PHD2? 

Did you ever try burning paper with the Sun and magnifying glass as a youngster? 

Try it with the guidecam (no camera attached ! ).

Where it focuses the sun is where the sensor should be, will give you a starting position. 

Michael 

[Dadek]

Hi Michael! Thanks for the great tip!

I have tried the focusing with the paper and it seems to achieve focus I have to expand my guide scope for extra 2.5cm, I did it with the helical focuser. I finally got the chimney focused with 0 gain and exposure around 700 micro seconds! 

Thank you very very much! I have learned a lot today

 

with this focusing I can now start PHD2 in the evening and try to fine tune it for stars?

[michael8554]

Well done.! 

Before trying tonight on a star, try focusing on a slightly nearer distant object. 

Then reset on your furthest object. 

Now you will know which way to turn the focuser to focus on even more distant objects, such as stars. 

Michael 

[Dadek]

Great advice!

Thank you again Michael, I've spent 2 days trying to figure it out