Comet 156P/Russell-LINEAR (17 Jan 2021)

 Comet, Solar System  No Responses »
Jan 182021
 

The list of observable comets issued by the MPC yesterday has 953 entries. One of them is 156P/Russell-LINEAR. The comet was initially discovered by K.S. Russell in September 1986 at Siding Spring Observatory, Australia.

The following animation is made of 99 sixty second exposures. You may see a satellite pass through the field of view and there is also some low altitude haze that passed overhead.

The ‘P’ indicates the comet is in a periodic orbit. 156P takes 6.7 years to orbit the Sun and its orbit comes just inside Mars’ orbit at perihelion and just outside Jupiter’s at aphelion. Right now, the comet is above the ecliptic and heading back out into the solar system after close approach on the 17th of November last year. Right now it is visible in the constellation Triangulum.

I measured the magnitude of the nucleus at 15.0 so it will take a fairly large telescope to view visually but would be visible photographically in a small scope.

156P’s orbit viewed from above the solar system.
Graphic courtesy of the JPL Small-Body Database Browser.

156P’s orbit in an oblique view of the solar system.
Graphic courtesy of the JPL Small-Body Database Browser.
 Posted by at 15:28

C/2020 F3 (NEOWISE) (17 Jul 2020)

 Comet, Solar System  No Responses »
Aug 012020
 

The skies finally cleared enough to try to see the comet. We headed north to an area just south of I-10 off of Hwy 285. It is a large field cleared of trees and has an excellent western horizon. Unfortunately, it also has a surprising amount of nighttime traffic.

We set up just before sunset and waited. The setting Sun was pretty enough to take a shot. The camera I was using does not have a live view capability so I just pointed it using a compass and a guess as to altitude and hoped the comet was in the FOV. One of the first shots during dusk was lucky. If you click on the image on the right it will display full size. The comet is just visible to the lower right of the two stars. Although the picture shows blue skies it was taken after the sunset picture but at a 6 second exposure.

For the rest of the evening I took images using the guess method, but after processing, 10 of the 22 images contained the comet in some way.

During the evening Donna and I were joined by a NWFAA club member Walter Dunn. None of us saw the comet naked eye but each of us was able to find and view it in binoculars. Ultimately, clouds and haze moved in and hindered viewing the comet. We left just before the comet set.

 Posted by at 13:32

Going to pieces – C/2019 Y4 (ATLAS)

 Comet, General Commentary, Solar System  No Responses »
Apr 172020
 

This image shows comet C/2019 Y4 (ATLAS) as it continues to break up the closer it gets to the Sun. This is a single 600 second exposure with the mount’s movement matching the comet’s motion. Two primary fragments are obvious but I have convinced myself I can see at least one more bright spot trailing the other two in the comet’s tail.

C/2019 Y4 (ATLAS) [CV:1x600s]

I took advantage of a software capability I hadn’t used before to take this image. APCC (Astro-Physics Command Center) is software that sits in between the user and the AP mount, in this case an AP1600. It has the capability of using data generated by the JPL HORIZONS web based tool. That tool takes the orbital elements of an object and generates an ephemeris of the desired solar system object based on user specific parameters.

I use the tool due to its extreme accuracy. It is also convenient since JPL lists the PTO in its list of observatories. I had always used the output ephemeris manually before, printing out the table of data, reading the objects location at the current time and manually sending the mount to that location. This is the first time I had the software read the data directly and adjust the mounts tracking rates to match the comet. I am pretty sure this will not be the last time I use HORIZONS.

 Posted by at 16:34

Going, going, …

 Comet, Solar System  No Responses »
Apr 142020
 

Comet C/2019 Y4 (ATLAS) continues to fade after its apparent fracturing sometime during the early days of April. This animation shows 30 minutes of motion on the morning of 12 April. The brightness near the center of the coma is elongated and there is no central condensation indicating the nucleus is losing structure.

 
The still image is the first of the 60 images that I used to create the animation.

C/2019 Y4 (ATLAS) [M: 1x30s]

The comet is still well above the plane of the solar system but is just about to cross the orbit of the Earth.
 

C/2019 Y4 orbit diagram (side view) courtesy of JPL Small-Body Database

C/2019 Y4 orbit diagram (top view) courtesy JPL Small-Body Database
 Posted by at 21:58

C/2019 Y4 (ATLAS) 31 Mar 2020

 Comet, Solar System  No Responses »
Apr 012020
 

Comet ATLAS is still heading toward the Sun for a perihelion inside Mercury’s orbit on the 31st of May. It is currently above the plane of the solar system a little less than half way between the orbit’s of Mars and the Earth. It is now visible in the northern constellation Camelopardalis (the giraffe).

C/2019 Y4 (ATLAS) [CV: 28x30s]


The image is a stack of twenty-eight 30 second exposures registered to the comet. The tail appears to be a little more defined and the outer coma fills nearly all the FOV.
 Posted by at 17:44
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