Namid Observatory - Day 8

Figure out the default temperature of the camera:

• The ML50100 can cool 45 C below ambient
• At night, it's maximum 20 C here (most nights it's 15 C or below)
• So, we'll use -20 C as our operating temperature

We noticed that the shroud was still tending to slip into the tube. Rich had the idea to screw in some bolts to the front of the scope to prevent this:

Mounted the flat panel box:

And finally, we mounted the little webcam that Rich brought:

And are streaming live to YouTube :-)

Cleaned everything up.

And we are done!!!

... well we still have to polar align tonight...

Luckily at midnight it cleared up and the wind calmed down. So, we could finally do our polar alignment.

I talked to Tolga about this and he recommended to do the polar alignment on a star straight south and very low. Do the Azimuth alignment first. Lock down the Azimuth lock screws. Because the scope points straight south, the only movement that should happen when tightening the Azimuth screws is in Altitude (the mount will be front- or back-heavy). Then adjust Altitude and lock down the Altitude screws (these shouldn't affect the alignment of the mount).

We still had the model from 3 nights ago in the mount and used that to polar align. By now, Rich was a pro and he centered the star (Antares would have been perfect, but it was behind clouds. So, we used Zuben Al Genubi instead).

We then ran another model to measure the remaining polar alignment.

First, we noticed that most plate solves failed. Which was puzzling as ASTAP was so reliable a few nights ago. When we checked everything we noticed two things:

• The clock in the mount was 1 hour behind(!!!) We had no idea how that happened as we set the clock exact. We corrected this, but were uneasy if this will happen again.
• Then we noticed that the mount was not tracking anymore. I had this issue with my 10Micron mounts too - I suspect TSX to sometimes do that ... We enabled tracking again.

Now, we ran the model and all platesolves worked!!! While the model was built, I installed the TimeSync tool from 10Micron that will sync the mount time from the PC time.

But the polar alignment error was still 1'30" !!!

With all the issues, we resigned ourselves that our alignment wasn't correct and that we'd have to do it again. But when we wanted to do a polar alignment, the mount pointed exactly at the target stars (tried several). It seems as if we couldn't trust the model building and/or polar alignment routine.

We decided to use the drift measurement/alignment from PHD2 - it doesn't rely on location or time but just checks how a star drifts.

We first measured near Deneb and got a VERY small polar alignment error (0.1"). We then measured deep south where the star movement would be fastest and got the same result. Seems as if our polar alignment was correct after all. We called it a night - but need to figure out what went wrong with the model...

Next: Day 9