"Comet Neowise" photographed from Lady Lake, Harbour Grace, July 19th 2020. Took a whole whack of 30s exposures of the comet last night after it got
dark. One sequence of 25 frames I co-added and attached after
largely-derotating. Why rotated? I'd
brought out my tripod, venerable Canon T2i and Tamron 18-270 lens (which
I managed to stay focused), star tracker pro, shutter cable.... but NOT
the tripod head to mount to the tracker, so I could aim the camera!! So
I was forced to mount the camera directly to the polar axis of the
tracked (which also had a 1/4-20 tripod thread).
While rotating about the polar axis to "aim upwards just a bit" took
care of altitude, and rotating the whole tracker took care of azimuth,
the polar axis was not point at the NCP and initially I didn't use the
tracker. I turned it on a bit into it just the same, and about half the
tracking error went away... enough for usable 30s exposures.
I should've saved RAWs instead of JPGs, though... there are curious
horizontal (pre-derotation) artifact/streaks present.
Canon T2i at ISO 800, 30s,
Tamron 18-270 superzoom at 39mm "quasi-tracked"
Click on image for full original photo. |