Serenity Imaging Day 4
Still commissioning. Another hour last night from when the stars came out until the fog and dew stopped the work.
The 90 degree diagonal came off the scope. Why?
It is good to have when using an eyepiece (less bending over wayyyy to low) but for imaging it is better off off.
1) It extends the optical path and longer is not necessarily better.
2) You gain photons by eliminating the loss caused by the optical mirror surface, in general maybe a 10% gain.
3) You eliminate another optical flip in the image (from bouncing off a mirror)
4) This one is huge and I never thought of it until the diagonal came off… eliminating another source of dust and dirt in the image from the dust and dirt on the mirror. Holy cow Batman! It was dirty!

Schmidt Cassegrain reflector will produce an image that is upside down (flipY in firecapture parlance) when used without a diagonal. When a diagonal is used the image will be corrected right side up, but backwards from left to right (flipX in firecapture parlance)
Will confirm this with the moon next session.

Walking out to the Observatory was bad last night with high temperatures and high humidity… ground fog to a large degree and lots of dew.
Turned on the scope from the park position, went to Mars, then back and forth trying to achieve a new coarse focus of the primary mirror and actually having mars in the field of view of the camera. Removing the diagonal changed the coarse focus. After a few minutes, Mars was in the FOV and was coarsely focussed.
Fine microfocusing was next then some sample images, 30 seconds without firecapture alignment, 30 seconds with firecapture alignment and 60 seconds with alignment.

Goto Saturn next, still near its transit point almost due south. It was not quite in the FOV but was within the 1/2 degree telrad inner circle. A little bit of searching found it and four more images were taken: 30, 30, 60, and 90 seconds. By this time the telrad was dewed over, the primary mirror (still without a heater or shield) was dewing and it was time to go in.

So tonights session was: no diagonal, zwo asi120mc camera, no barlow, no focal reducer, no dew shield, no dew heater.
Oh! Here are the three mars images and the three saturn images:

Mars was the best 10% of the frames taken used to stack as seeing was poor, transparency was poor and Mars was still low in the Southeast. The south Polar Cap is showing as well as some dark features in the southern hemisphere.

30 sec no align

30 sec with align

60 sec with align

Saturn was the best 50% and only the 90 second image run is shown here. The Cassini division is finally showing!