Astrophotography diagnosis of M 92: Sensor tilt

Moon at 5%: ideal dark-sky conditions, no lunar gradient expected, confirmed by the background map (plane at 1% amplitude, R²=0.01). With the LP filter (broadband anti-pollution) on a globular cluster, a quintessential stellar target, you are limited neither by the moon nor by a gradient. The background is nicely neutral and symmetrical. The real constraint is not the sky but integration time: 30x60s i.e. 0.5h on a faint surface-brightness target leaves a modest SNR, visible in the slightly short background/black-point margin (e_margin 2.38). Stacking more subs would be the main lever.

The Askar 65PHQ (416mm focal length) paired with the ASI585MC gives roughly 1.4"/px sampling, comfortable and well suited to typical seeing: the measured central FWHM (2.0px, ~2.8") confirms correct sampling, neither over- nor under-sampled. The wide field places M92 comfortably at center with plenty of margin, maybe even a touch tight given the cluster's small size, but framing is clean. The AM3 mount holds 60s exposures perfectly (no drift or oscillation on the PSF panel). The LP filter is a sensible choice in decent skies. For this target, longer exposures (120-180s) would boost background SNR without saturating the cluster core further.