A comet, some asteroids, some star clusters

Periodic comet 12P/Pons-Brooks is appearing on news sites because of the expectation that it will be visible during next month's solar eclipse.  It is currently heading toward perihelion on its 71-y orbit.  It is difficult to catch in the early evening twilight, especially from my site in urban Santa Fe.  I was just able to get a few images before it set into the neighbor's trees behind the backyard fence.

For this image I chose a Sigma 56mm f/1.4 lens with an Olympus E-M5iii camera.  The intent was to use a field-of-view (FOV) wide enough to show the comet and the Andromeda galaxy in the same frame.  The galaxy is circled in the upper right, the comet in the lower left.  The image is tilted because the camera was riding on the ZWO AM3 equatorial mount rather than being leveled to the horizon.

E-M5iii  + Sigma 56mm f/1.4.  ISO 800, 30 s.

 

Here is a close up of the comet, same image file, just processed differently:

comet 12P/Pons-Brooks, 05 Mar 2024.

The comet shows the typical green glow from diatomic carbon and cyanogen.  It is just possible to see a faint tail extending upward to the right for about 1°.

After twilight faded and it got as dark as it gets here (sqml=19.55), I turned the camera to a few other objects.

Aldebaran and the Hyades.  E-M5iii + Sigma 56mm f/1.4 + softon filter.  ISO 800, 30 s.

The region just north of Orion is interesting, with two star clusters (Cr 65 and Cr 69) and the asteroid (4) Vesta passing through:

E-M5iii + Sigma 56mm f/1.4 + softon filter.  ISO 800, 30 s.

Here is a close-up of Cr 65 (Collinder 65):

Collinder 65

A little bit farther north in the sky it was possible to frame three of the major asteroids: (4) Vesta, (5) Astraea, and (9) Metis.   The best way to view this image is to click on it and zoom-in on the full-size version (as usual).

Vesta was discovered in 1807 and is currently at magnitude of 8.1. Astraea was discovered in 1845 and is at magnitude 10.9.  Metis was discovered in 1848, and is at magnitude 10.4. 

Two evenings later (07 Mar) I set up a different lens: a Tokina 400mm SD f/5.6 manual focus telephoto. I don't know the exact age of the lens because I bought it used, but it probably dates back to the late 80's or early 90's.  For these exposures I also used a Metabones Speedbooster 0.71x reducer.  This combination yields a focal length of 284mm at f/4.  The Speedbooster required some tweaking to achieve infinity focus.  Focus was confirmed with a Bahtinov mask.

Collinder 69, 2° FOV..  E-M5iii + Tokina 400mm SD + 0.7 Speedbooster.  ISO 1600, 30 s.

M35, 1° FOV.  Same settings as previous image.

There is chromatic fringing with this lens, which manifests as bloated pink stars in this image of the Orion Nebula.  Even so, I like some of the results.  The last time I used this lens was during the annular eclipse last October. I look forward to trying it under the dark skies of Creede.