Pressure tuning correct?

[zicklurky]

Hiya,

I recently bought a second-hand Lunt LS50THa B600PT to image with an ASI178MM, and I'm struggling getting the whole disc to show detail at the same time. I've not used a pressure tuner before, so I'm not sure if this is normal or not. I made a couple videos to show what I mean. In the first video I centered the sun in the frame and tune from all the way out to all the way in, and back out again (sorry for the shake!). In the second video I tuned for the sun in the center of the frame and then move the sun around the frame. Would you mind having a look?

First video: 

Second video: https://youtu.be/DqUZrfFHNuI

Thanks

[Davey-T]

Looks normal to me, much like my LS60 with the ASI178., maybe try rotating the BF in the focuser and the camera.

You can take flats as per normal night time Imaging which helps somewhat or take two images and stich them together.

Dave

 

[zicklurky]

Thanks Dave!

[Carbon Brush]

Not wishing to hijack the thread.

My (used) LS60 PT came with the air pump.

What sort of pressure do others find gives a good response?

Thanks, David.

[Highburymark]

To the OP - it looks fairly normal to me too - virtually all scopes display contrasting surface detail as you move the image around - also the sun is very inactive at the moment, so difficult to really test the scope's potential.

4 hours ago, Carbon Brush said:

Not wishing to hijack the thread.

My (used) LS60 PT came with the air pump.

What sort of pressure do others find gives a good response?

Thanks, David.

I have the pump as well - because my original pressure tuner had to be screwed right to the end of the brass thread it was difficult to know whether it had reached the required pressure to expose maximum detail - with the pump I usually take it up to 19-22psi - it has definitely improved the performance of the scope.

 

[Pete Presland]

Looks pretty normal to me as well, not unusual to see an unevenly illuminated disc. Even tricky when you double stack it. I have rotated the blocking filter diagonal with limited success to try and achieve a more even illumination.

[zicklurky]

Great, thanks for the replies. Good to know that's just how it works and I need to get better at tuning!