Annular eclipse at the Albuquerque Balloon Fiesta 10/14/23 part II: Ring of Fire

a few clouds and a lazy contrail on the horizon made for an interesting sunrise, but didn't impact the rest of the eclipse (click on image for full size):

sunrise balloon fiesta park
abluquerque, NM
8/14/23 06:37:27

first contact:

first contact (upper right)
09:13:22

partial phase:

09:30:12

bye sunspots:

10:14:12

The announcer called out annularity and all the grounded burners in the field fired up.  note the annular reflections below the sun:

annularity, balloon fiesta park
abluquerque, NM
8/14/23 10:36:11

RING OF FIRE: there was a lot of talk about a "ring of fire" eclipse, but no images really show it.  here's my attempt, I digitally overexposed this image to simulate an unfiltered image of the sun (which would melt my camera sensor) to portray an actual "ring of fire"

ring of fire

here's a more conventional portrayal.  bullseye with the camera--my location was dead center eclipse path:

annular solar eclipse
balloon fiesta park
abluquerque, NM
10/14/23 ~10:36:32

cellphone:

filtered

broken ring:

image rotated horns up
10:39:09

Next up: animation and montage

Imaging details:

10/14/23

Albuquerque, NM

nikon D850

AF-S NIKKOR 300mm f/4E PF ED VR

Baader solar film, Fotga IR/UV cut filter

iso 100 1/1250-1/2000 sec exposure

Vello Shutterboss Version II Timer Remote Switch

skywatcher star adventurer tracking mount

Samsung galaxy S22 ultra

for field shot and filtered cellphone image

filter

eclipse image shot with solar filter at 30x

processed in photoshop

    Arriving early for the pre-dawn activities allowed me to dial in my polar alignment for my tracking mount, only adjusted my alignment once.

    While i tested my exposures repeatedly at home, to be sure my images were not clipped, as the sun rose higher in the thin albuequerque air the face of the sun became slightly clipped, losing the subtle surface granulation. fortunately, i caught it relatively early and decreased the exposures from 1/1250 s to 1/2000.  if you look closely at the partial phase above, you'll note a lack of subtle granulation across the bright face of the disk (09:30:12), which can be seen in the subsequent image (10:14:12)

    The nikon D850 has a built in intervalometer which is great for meteor showers and overnight sequences, but awkward to adjust on the fly.  there is software to connect a smart phone via bluetooth or wifi, but it disconnects every time you switch apps and takes >30sec to reconnect.  less than ideal for the eclipse experience unless you use a dedicated tablet.  

    I chose to used the vello shutterboss version II timer remote switch, a wired solution that can trigger the shutter manually without shaking the camera and be used as an intervalometer that can be rapidly adjusted.  i chose 4 minute intervals for the partial phases and 1 second intervals for annularity.  for the 3rd contact i held the manual trigger down with the camera set for continuous low speed shots, having determined 4 fps is the fastest my camera will write full frame raw files (8288x5520 ~53 meg) to the chip.  it can do bursts much faster but only for a few seconds.  

    I found these an excellent focus aid -o-o-

    In terms of processing, the auto color balance with the IR filter and baader film was all over the place.  By trial and error, I came up with something close to white by setting the temperature to 7100 and tint to -40 for raw conversion.  this still gave a slightly non-uniform color white in the center and slightly red red at the edges which was acceptable, though I desaturated the white images above.  not sure why the color was not uniform.  either the camera sensor is non-linear or the solar color is non-uniform.  here's the "natural color"

10:14:12

    for images with a substantial amount of the central solar disk showing, i applied a high pass filter at 1.5 radius soft light, then again at 2.5 radius hard light 50% blend (excluding the solar and lunar edges). this brought out the sunspots and surface granulation.  color images colorized at 25 hue, 100% saturation, -20 lightness