I have a new iOptron CEM60 and tri-pier on order and they may be arriving within a week. I plan to use it mainly for astrophotography. I am relatively new to astrophotography (been doing it for about 5 months using an iOptron skyguider pro; and have a very small amount of experience with guiding). I read the forum posts and internet articles on the CEM60, and would like to make sure I test the important aspects of the mount within the 30 day return window. I collected the following tips/tricks/testing procedures:
- Read manuals before receiving mount
- Order second counterweight to balance 8" SCT
- Practice using magnetic clutches/switches
- Put teflon tape under mount to ease azimuth adjusments
- Order computer control cable: Ioptron Equatorial Telescope Upgrade Control Console Cable Coding Line Ieq30pro RS232 to 4P4C RJ9 (6FT, for Ioptron) - this seems less bulky/complicated and Amazon reviews say it works with the CEM60
- Alternatively, could order the USB2.0 to Serial (9-pin) DB-9 RS-232 adapter cable (FTDI chipset) for computer control - may just order the iOptron one
- Possible sideways balance fix: https://www.cloudyni...fix-for-cem-60/
Regarding testing, my current thinking is:
Testing (indoor/daytime testing possible):
- Listen for any grinding or stalling sounds when slewing, with different loads attached
- Check whether polar scope is coaxial with RA axis and fix if not (http://www.ioptron.c...e_Alignment.pdf)
- Can I test computer control by slewing to a target and checking it's pointing approximately in the right direction (pretending it's polar aligned)?
Testing (clear skies needed):
Set PhD2 guide rate to 0.80 and calibration step to 3000 (I read that this is what works for the CEM60)UPDATE: removed this - does not seem accurate based on users' experience
- Test RMS error (I have a ZWO ASI224MC which I am planning to use as a guide cam, with a Nikon d5300 as the imaging cam):
- I assume it makes sense to test both with and without guiding. Is this right?
- Is it possible to measure RMS error in PhD2 without sending guiding signals to the scope? If so, how?
- I assume it should be tested with different loads - I have an 8" SCT (Celestron non-Edge HD) and 72mm refractor. I know the non-Edge HD SCT is suboptimal for astrophotography but I'm only planning to use it for testing at this point
- When testing guided performance, does the focal length of the guide scope matter for the purposes of testing? (I realize there is a separate consideration about matching the guide scope/camera to the imaging scope/camera, but here I'm asking about testing the mount's performance.) I have 50mm aperture/190mm focal length and 72mm aperture/430mm focal length scopes that could be used as guide scopes (for the 72mm scope and the 8" SCT respectively)
- What RMS RA/Dec error is acceptable?
Is there anything else I should test or should have thought of? Or any other tips/tricks to be prepared when the mount/tri-pier arrive? Thanks.
Edited by Ragnar1, 16 February 2020 - 10:04 PM.