Comet 38P (Stephan-Oterma) and Kappa Geminorum on Nov 17, 2018, 09:00 UT. 40×120 sec @ ISO 3200, IDAS-LPS, Canon T3, Televue TV-85 at F/5.6.
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:
Comet 38P (Stephan-Oterma) on Nov 17, 2018, 09:00 UT. 40×120 sec @ ISO 3200, IDAS-LPS, Canon T3, TV-85 at F/5.6.
Here is a more tightly cropped star freeze version:
Comet 38P (Stephan-Oterma) on Nov 17, 2018, 09:00 UT. 40×120 sec @ ISO 3200, IDAS-LPS, Canon T3, Televue TV-85 at F/5.6.
And, one more with Kappa Gem:
Comet 38P (Stephan-Oterma) and Kappa Geminorum on Nov 17, 2018, 09:00 UT. 40×120 sec @ ISO 3200, IDAS-LPS, Canon T3, Televue TV-85 at F/5.6.
Comet 38P on Nov 3, 2018, 10:45 UT. 6×30 sec, Sony IMX224, TV-85 at F/5.6. ToupSky Live Capture.
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!
24P/Schuamasse and NGC 3489. 27×180 sec @ ISO 3200, IDAS-LPS, TV-85 at F/5.6, Canon T3.
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. 😉
62P/Tsuchinshan on Oct 29, 2017, 09:17 UT. 8×180 sec @ ISO 3200, TV-85 at F/5.6, Canon T3, IDAS-LPS. Star-Freeze version. Close-crop at 100% resolution.62P/Tsuchinshan on Oct 29, 2017, 09:17 UT. 8×180 sec @ ISO 3200, TV-85 at F/5.6, Canon T3, IDAS-LPS. Star-Streaks version. Cropped.
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:
62P_Tsuchinshan Star Streaks version negative view.
I also have a full-field, star-freeze view at 100% resolution. It is more “pristine” than the other images with only minimal processing :
62P/Tsuchinshan on Oct 29, 2017, 09:17 UT. 8×180 sec @ ISO 3200, TV-85 at F/5.6, Canon T3, IDAS-LPS.
C/2017 O1 ( ASASSN ) on Oct 29, 2017, 05:40 UT. 21×180 sec @ ISO 1600, IDAS-LPS, Canon T4, TV-85 at F/5.6.
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:
Comet Asassn. 36×180 sec @ ISO 3200 and 21×180 sec @ ISO 1600. TV-85 at F/5.6, Canon T3, IDAS-LPS filter. Cropped version.
Here is the full-field version of the above with a slightly different color balance and saturation level:
Comet Asassn. 36×180 sec @ ISO 3200 and 21×180 sec @ ISO 1600. TV-85 at F/5.6, Canon T3, IDAS-LPS filter.
Comet 24P/Schaumasse on Oct 24, 2017. 38×120 sec @ ISO 200, TV-85 at F/5.6, Canon T3.
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.
Comet Asassn on Oct 18, 2017. 60×180 sec @ ISO 200, IDAS-LPS, Lumicon Deep Sky, Canon XS (modified,) Canon 200mm F/2.8 lens.
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.
Comet Asassn on Oct 18, 2017. 60×180 sec @ ISO 200, IDAS-LPS, Lumicon Deep Sky, Canon XS (modified,) Canon 200mm F/2.8 lens. Star-Streaks version.
Comet Johnson, May 15, 2017, 02:00 UT. 28×180 sec @ ISO 3200, Canon T3, Televue TV-85 at F/5.6. Star-Freeze version.Comet Johnson, May 15, 2017, 02:00 UT. 28×180 sec @ ISO 3200, Canon T3, Televue TV-85 at F/5.6. Star-Streaks version.
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.
Comet Johnson, May 15, 2017, 02:00 UT. 28×180 sec @ ISO 3200, Canon T3, Televue TV-85 at F/5.6. Close-Cropped Star-Streaks version.Comet Johnson, May 15, 2017, 02:00 UT. 28×180 sec @ ISO 3200, Canon T3, Televue TV-85 at F/5.6. Close-Cropped Star-Freeze version.
Comet Johnson, May 14, 2017, 02:05 UT. 58×180 sec @ ISO 400, IDAS-LPS, mod Canon XS, TV-85 at F/5.6.
Here is another go at Comet Johnson from the city with my older Canon XS camera. The light pollution was at a minimum with above average transparency and low humidity levels this night. Still, being limited by the LP in exposure time made getting the ultra-dim ion tail and the full extent of the dust tail almost impossible.
Comet Johnson, May 14, 2017, 02:05 UT. 58×180 sec @ ISO 400, IDAS-LPS, mod Canon XS, TV-85 at F/5.6. Star-Freeze version.
I wanted to go to my dark sky location and shoot this, but the conditions were so iffy that I stayed in town. Clouds plagued the area all afternoon and it was just before twilight ended that the skies became clear enough to image. So, I probably could have done good away from the city, but the risk of it not clearing and wasting my time waiting for the clouds to leave was just too high.
Comet Johnson, May 13, 2017, 01:52 UT. 11×300 sec @ ISO 200, IDAS-LPS, Canon XS (modified,) TV-85 at F/5.6.
Here is another Comet Johnson image from my Bortle red zone location. I used my older, modified Canon XS camera and ISO 200. I had read somewhere that ISO 200 on the XS series was close to unity gain and I wanted to see for myself how sensitive it was shooting in the red zone LP at this setting.
I went with 5 minute subs with tracking on the comet enabled and got 11 before moonrise. I probably could have gone 8 minutes in these conditions with ISO 200 to hit mid-histogram, but I stuck with 5 minutes since the histogram hump was still well away from the left hand side. Plus, it was about 70 degrees this night and the camera showed lots of hot pixels even using ISO 200. It would have just gotten worse with longer subs.
The comet was at a low altitude starting out, so the LP and atmospheric extinction hindered me getting the really dim ion tail and the more subtle parts of the dust tail. With moonrise coming so soon, I couldn’t wait until it got any higher, unfortunately.
It is not a great image but not too bad, either. At least I tested the XS and verified what it can do. It is more suited for shooting nebula, since it is a modified camera, but I haven’t used it in so long that I forgot how it performed on comets.
Images of Comets, Nebulae, Galaxies and Star Clusters