STEP BY STEP
STEP 1
Wide-field images can be taken with a tracking or non-tracking mount. For non-tracking, you need a medium-high ISO and a wide lens (stop down slightly if edge distortion occurs). Set exposure according to the ‘500 rule’; divide 500 by the focal length of the lens you’re using to get the maximum exposure possible before trailing becomes evident.
STEP 2
For the comet’s Pleiades and Hyades encounter a lens shorter than 50mm will comfortably fit all three in shot. For just the Pleiades and comet, 120mm or shorter is ideal. For the close pass of the California Nebula, try 60mm or shorter. The pass of Capella is close enough for a telescope with a focal length less than 1,000mm to be used.
STEP 3
Close-ups on the head of the comet will show any structure present. A DSLR attached to a telescope is ideal. For equatorially driven telescopes, a time limit will apply before the relative motion of the comet blurs the image. Set your camera to a medium-high ISO and try a 30” exposure. Call up the result and examine it on the camera’s review screen.
STEP 4
If there’s no motion blur on the comet, repeat Step 3 adding 10” each time. Once you have an optimal exposure setting, take numerous sequential images. Stack these using the comet as a reference (stars will trail). Software such as DeepSkyStacker and PixInsight have routines to assist in combining stacked stars with a stacked comet.
STEP 5
If you collect many images of the comet over an extended period, software such as PIPP (sites.google.com/site/astropipp) can be used to combine them into an animated sequence. The resulting movie will reveal how fast the comet appears to be moving against the background stars. Any faint detail in its head or tail will also stand out well.
STEP 6
If the comet is relatively bright, it may be possible to use a planetary imaging setup to take sequential images of its core region using a high-frame-rate planetary camera. Captured images can be stacked in software such as AutoStakkert! (www.autostakkert.com). This techniques is good for revealing faint dust jets close to the comet’s pseudo-nucleus.