Comet Wirtanen is looking to be the best comet this season.  It is a short-period comet that comes around every 5.6 years.  It should be at it’s best as it passes closest to Earth:

• Occurs Dec 16, 2018
• Less than 4 days after perihelion
• The comet is near its brightest

• Geocentric Distance 0.0775 AU
• 30 Lunar distances
• 11.5 million km
• 7.1 million miles

So, it has 2 more weeks until that happens and look at the size of that thing already.   It is huge!  See the comparison with the moon taken with the same scope below:

BTW, the above image appeared on the home page of SpaceWeather.com on Dec 4th and 5th, 2018  and is also featured in an article on the Televue Optics blog, which are the guys that make my scope and focal reducer/flattener.   🙂

I re-vamped the above image with the better version star-freeze image (and also with both the comet and the moon oriented north) and that is here:

I shot two sets of data for this comet.  Both were 40 sub-images.  The first image and the image below are from the first set.  The moon/comet comparison image above was done from the second set.

Taking another crack at processing the first data set, I made this version below that has a slightly different comet position, is a little lighter and shows more coma, but less tail:

Here’s the second set of data with a star streaks and star freeze version of the comet with extra processing plus a red boost on the former and minimal processing for the latter:

Finally, here are both sets of the comet together, but with the background stars from only one set of 40 x 2 min subs:

Lots more coma is visible, plus the tail from the fist set of subs shows as well.  I think here we have a coma that is so bright it is blowing out the faint tail as seen in the second set above.   Not as much coma was picked up when it was lower in the sky muck, but the wavelengths from the tail got through and made it more obvious, as seen in the first set of subs.

So, it is possible that shorter “core” sub-images mixed in with longer exposures to get the coma might be a way to tame this comet and get a good final image with DSLR equipment.   I will try that the next time I get to image this beast.

Edit Dec 23 2018:  Reprocess of 2nd set of 120 sec ISO 3200 shots and added in all other data taken that night.

I just knew there was more there.   I just had to strive for the right stretch and do selective red channel boosting.   The tail was mostly in the red channel and that gets clipped a bit with the removal of LP and background noise.   So, I had to leave as much as possible of the red in the tail area but suppress it everywhere else.  Some selective masks for various saturation and color balance adjustments did the trick.

Edit Dec 27, 2018:

I had a chance to take another crack at the star-streaks version of the image with the above data and considerations and also added Larson Sekanina filtering for the tail:

New comet Machholz-Fujikawa-Iwamoto (C/2018 V1) showing two tails.  I took this right at the end of the best time for observations before the moon interfered.   Unfortunately, I did not have much time to shoot it, since it didn’t rise out of the low-elevation muck until after astronomical twilight started.   Oh, well… I did my best.   28 subs is not too bad.

I was at my “dark” site shooting this.   Could have gone better.   I had equipment problems and other issues and wasted lots of time trying to get the mount calibrated.  To top it off, my dead-end road spot was invaded by duck hunters arriving before dawn to hunt.   I lost about 10 subs from their vehicle headlights.

Wide-field view of Comet 38P near Kappa Geminorum.  Small comet, but it has a tail and a nice extended coma.  You can see this better in this cropped star-streaks version below:

Here is a more tightly cropped star freeze version:

And, one more with Kappa Gem:

Comet 38P along with comet 46P are both peaking this fall/winter.   38P will stay relatively dim, but at least it has a tail.  This image of it was just a test of the Sony IMX224 on a half-decent comet.

I really wanted to shoot it with my DSLR and I was going to, but the weather changed abruptly Saturday night late and Sunday morning was clouded out.  Heck, it even rained before sunrise.   I had to tear down the rig before the comet was out with the fast change in weather.  Darn the bad luck!

Not much detail for periodic comet 24P/Schaumasse, which was low to the horizon over a stronger LP dome when I started taking the sub-images for this shot.   I thought it might have a discernible tail that my camera might pick up since Cartes du Ceil showed it with one.  LoL!   Unfortunately, no software (or humans) can predict exactly what comets will do, which is why they make such good astrophotography targets.   😉

Here is a quickie of 62P/Tsuchinshan.  Only 8 sub-images, but it went deep enough to pick up a few faint fuzzies.   The comet was predicted to be dim, so I was not expecting much from it.   My main target this night was another comet just a few degrees away, which is why I did not spend much time on this guy.   But, it looks promising and I might try for it again soon.

There is something weird about this stack, though.   Some sort of artifact, maybe?   It looks like two tails, but I can’t be sure.   Its more apparent in a negative view of the star-streaks image:

I also have a full-field, star-freeze view at 100% resolution.  It is more “pristine” than the other images with only minimal processing :

On this night, I drove out of the city to a semi-dark spot about 30 minutes away.  It was forecast to be very transparent, according to ClearkDarkSky.com.   Moonset was near 1:00 AM on Sunday morning, Oct 29, 2017, so I setup and took advantage of the dark time that was left and managed to shoot 3 comets before sunrise.

The first one was Comet Asassn.  I processed it and created an initial star-streaks version, since it is the easiest to do.  I still had a set of ISO 3200 sub-images to add in, but it looked fine to me with just the ISO 1600 data, so I left it as is.  Plus, the two data sets did not mesh well with so many stars and the differing exposure times.

For the star-freeze version, I did add in the ISO 3200 data, which was 36×180 sec.   Check it out:

Here is the full-field version of the above with a slightly different color balance and saturation level:

This is one of those early morning comets that are low to the horizon at dawn and very dim.   Consequently, 2 minute sub-images at ISO 200 barely picked it up from the Bortle Red Zone glow I was shooting in.

I could easily see two 11th magnitude galaxies nearby in the sub-images, but this guy was barely visible.   I think it is supposed to get brighter before too long.   I will try again for it if and when it does.

I tried for Comet Asassn and even with 60 subs, I did not get much.   The Canon 200mm F/2.8 lens was just too small of an image scale to do it justice.  Bortle Red Zone conditions did not help.  Plus, the parking lot lights from the nearby theater were still on for most of the imaging session.   When they go off at 2:30 am, I can see about a mag to a mag and a half dimmer stars in the sky.   I can do 5 minutes exposure instead of just 3 with them off and it makes a difference in the final outcome.

I made it out to my dark sky site again on Mother’s Day, 2017.  Mom’s house was on the way there, so I managed to visit with her before my imaging session, which worked out pretty well.

Comet Johnson was my only target on this evening.   I used my Canon T3 with no LP filter at ISO 3200 with 3 minute sub-images.   That was about max for this particular night in that area of the sky.   A few high clouds interrupted me after about 8 shots, but I was able to continue shooting after they moved on.

I was hoping to catch a glimpse of the ion tail with a single exposure, but no luck in that department.   The LP dome to my northeast that the comet was embedded in was the limiting factor here.   Maybe the LP filter would have let me use longer exposures and I might have been able to detect the ion tail like that.

The 3 minute subs let me track the stars with only minimal pseudo-nucleus smearing, but anything longer and I would have had to track the comet.   That makes it harder to do star-freeze processing if the stars are trailed, however.   I either have to fix the trailing in post-processing or shoot a set of star-tracked sub-images.