I set up my Starlapse on the fence with the neighbouring farmer's 100 acre grazing paddock in daylight at about 530pm local time. The paddock wraps around my property and I positioned as far north as possible to the corner to allow a view of the comet through a gap in trees on the horizon. To move any further would have necessitated climbing over the barbed wire fence.
Astronomical twilight was at 6:50pm local time. The comet first became visible in binoculars at 6:20pm local with the sun at -12o at the end of nautical twilight. I realised I had partly fluffed it. I hadn't allowed enough and it wasn't gong to align with the gap in the trees and would drift into the trees. I only had minutes before it was going to vanish into the trees on the horizon.
As it got darker, it drifted to the dead tree just left of centre of frame before the end of astronomical twilight. The fence is barbed wire so rather than climb it, I should have driven my gear to another spot that has an ideal western horizon.
The photo below was taken at 6:28pm local 22 mins before the end of astronomical twilight with the Sun at -14o.
Dust tail to the right, ion tail extending upwards.
Exposure: 9x10s @ ISO400 at 20240501.77 UT with a 300mm f4 EDIF lens tracked with a Losmandy Starlapse tracker.
Visual observations
The comet became visible in binoculars 6:20pm, I realised I really needed to go up the road but it was too late to relocate. I started the camera intervalometer running 10s sequential exposures.
Once running I concentrated on visual observations. Using the in-out method, I estimated the nucleus and
It was obviously fainter than the Mv 3.90 reference star and similar to but slightly brighter than the two 5.31. 5.34 and 5.37 mag stars. The twilight background made the estimate process difficult as I don't do these estimates very often and a out of practice. Just before the comet moved behind the dead tree, I could see perhaps a half degree of tail. I followed the comet as it passed through the branches as it got darker. I thought the tail perhaps extended a little farther that a half degree through the branches but this may just be "averted imagination." I suspect had I been able to observe the comet for the remaining 30 minutes before setting, I may have caught a little more tail as my pupils dilated further and I could have used more of the
All my gear is now packed in the car. If I get another clear night, I’ll head to one of two spots, the first 1km up the road with a low horizon and another high ridge 5km up the road to a spot I know where I have a clear zero west horizon.
Joe
