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Re: Lunar observation engraving c.1871
From: Peter Monta
Date: 2022 Jun 28, 18:40 +0000
From: Peter Monta
Date: 2022 Jun 28, 18:40 +0000
Here's my (doubtless incomplete) list.
- octant rather than sextant
- missing index arm
- if it's a telescope: optical axis not aligned to horizon mirror
- if it's a peep sight: unit magnification not enough for lunars
- eye too far away from telescope eyepiece or peep sight
- star shining through the moon
- chosen star has low sensitivity to lunar motion
- upper dotted line goes to center of moon (or perhaps some random point on the limb) rather than the limb's nearest point to the star
- upper dotted line should intersect the sextant at the index mirror
- lower dotted line should intersect the sextant at the horizon mirror
- odd-looking back-sight assembly
- deck watch not shown
- lunar elongation is very low, making for a challenging (or impossible) sight
Cheers,
Peter
