guiding

dbradf

I am considering buying the AM5, but I noticed a statement in one of the retailers that ZWO does not recommend using the AM5 for deep sky photography with greater than 900mm focal length scopes. Does that mean that the AM5 has some limitation as compared to traditional mounts (insofar as the guiding limitations with long focal length telescopes)?

enaiman

Lots of people are using it with great success at FL way above 900 mm; plenty of photos from them on Facebook - you can ask them directly if you want a first hand experience.

dbradf

The ZWO note seems to be predicated on a limitation of the mount to go below 1"/pixel. However, that does not make sense as a limitation on a specific mount to deliver good guiding. Image resolution is a limitation related to seeing, etc. and should be applicable to all mounts. The ZWO note repeated by retailers sounds like ZWO is inferior to other mounts to deliver good guiding at longer focal lengths. Is there something about the AM5 (or other harmonic drives) that makes it inferior to traditional mounts to deliver good guiding at longer focal lengths?

dbradf

Put differently: It looks like harmonic drives are lighter and have less backlash and more torque, but in general have more PE than traditional mounts in the comparable price range. I currently have a traditional mount rated at 28 pounds for astrophotography. If I can correct the PE of the AM5 with good auto guiding, can I safely say that I can handle longer focal length (heavier) telescopes at least as well as a traditional mount in the under $3,000 category? Or am I missing some other important shortfall of the AM5?

enaiman

dbradf Facebook AM5 user group - just ask your questions there.
Excellent images at 1500 and 2000 mm FL - if the images don't speak enough I don't know what else does.