Well, we had a good run of clear night skies last week, and here we are heading toward the new moon, and it's going to rain for three or four days. Anyway, it was great while it lasted. Taking very long exposure images with a telescope, and by long exposure I'm talking the shutter open 5 minutes for each frame. Every image I captured over the last five clear nights has been through this 8 inch Newtonian scope (8 inch primary mirror (203mm) inside the tube where the gold foil cap covers the end, the secondary mirror is where the camera connects to the focuser, toward the top of the scope). And I ran every night's imaging session with the ZWO ASIAir controller.
Trying something new tonight. So far, I've only used the ZWO ASIAir Plus with the AM5 mount and my William Optics scopes. So, I'm setting up the Sky-Watcher EQ6R-Pro and the 800mm Newtonian for narrowband, and decided to try out the ASIAir with this combination of gear. It has every feature I use with NINA (my normal astro controller system), that's polar alignment, plate solving, sequenced capture, guiding, so should work well!
I'm hoping for some clear skies tonight, enough to test out the #ZWOAM5 with my trusty William Optics GT81 and the ZWO ASI071 cooled color camera. It's a beautiful fall day out there right now, at quarter after 5pm, but I don't think this is going to last into the evening.
Just wanted to document the spacing and backfocus distance for the ZWO ASI1600MM-Pro with the electronic filter wheel and OAG. The William Optics SpaceCat 51 allows a maximum distance of 57.9mm to achieve minimum focus, so I like to be somewhere close to 50mm when everything is totaled up--and looking good:
I am using a fanless Windows 10 machine and a Pegasus Astro Pocket Powerbox to run my ZWO AM5 mount. Both of these are mounted to a SmallRig cheese plate with 3M Command Strips (I like these better than Velcro).
MeLE Quieter2Q Fanless Windows 10 PC with J4125 CPU, 8GB RSM 128GB Storage
Pegasus Pocket Powerbox
SmallRig Multi-Functional Cheese Plate
Sprig Cable Management Device
SVBONY Dovetail Base 32mm wide
Actually, I'm just taking pictures of my gear because the evening weather is foul. But if it was clear, this is what I would be using to capture the night sky.
If I'm calculating this correctly, the theoretical best performance for my particular ZWO AM5 mount with a maximum period error of 23.6" is 0.136 arc-second error for a 1 second guide duration. So, 0.136" error is what's possible with perfect seeing, no atmosphere, in Earth's orbit somewhere. Here on the ground, ZWO has specified that all AM5 mounts should perform with 0.5" to 0.8" total error or better, given average seeing and atmospheric disturbance. And that seems to be exactly what I am experiencing.
For a detailed walk-through of the periodic error report values and calculations see 10 things you need to know about the custom AM5’s PE Test Report provided by ZWO
The weather doesn't look like it's going to cooperate in the next four to five days, and at the same time, the moon is seriously imposing its reflective properties on the night sky. So, not the best time to try out a new filter—even a narrowband one. I recently bought the Optolong L-eXtreme dual-band filter, specifically for my ZWO ASI071 color camera, which has an APS-C sized sensor. The L-eXtreme filters out everything except two narrow (7nm) bands along the Oxygen III line and Hydrogen-alpha line. I am anxious to try this out with the 8" f/4 Newtonian on the Veil Nebula.