Sites providing details on comets
Visual comets | astro.vanbuitenen.nl
Using polar-aligned tracking, take a series of exposures of about 300 to 900 seconds. Longer exposures tend to be counterproductive, burning out the detail of the comet’s nucleus. Setting the telescope and camera to track a chosen star keeps the stars in the image focused and round and exaggerates the comet’s speed and power by slightly blurring and elongating it. Alternatively, track the comet and let the stars trail in the background. From Sky&Telescope.
COBS - Comet OBServation database