WordPress Appliance - Powered by TurnKey Linux

Category: Comets


C/2014 Q2 (Lovejoy) on Jan 29, 2015, 00:43 UT.  17x180 sec @ ISO 1600, TV-85 at F/5.6, IDAS-LPS, Lumicon Deep Sky filter, Canon T3 DSLR.

C/2014 Q2 (Lovejoy) on Jan 29, 2015, 00:43 UT. 17×180 sec @ ISO 1600, TV-85 at F/5.6, IDAS-LPS, Lumicon Deep Sky filter, Canon T3 DSLR.

Click here to see an extra-large version of the above.

StarFreeze Processed Version

StarFreeze Processed Version

Here’s the StarStreaks version:

q2-150129-0043-17x180-1600-85f5_6-ss

StarStreaks Processed Version

I don’t shoot very many deep sky images with a moon past first quarter, but with comets I can make an exception.  Lovejoy is a really photogenic comet and it even looks good in poor conditions.   Clouds came in and I had to stop imaging after shooting less than 20 sub-images.   But, with this comet, 51 minutes of integration was enough to show it without blurring due to the tail rotation that is evident in my previous animated GIF images.

C/2014 Q2 (Lovejoy) on Jan 28, 2015, 03:00 UT.   12x180 sec @ ISO 1600, TV-85 at F/5.6, IDAS-LPS & Lumicon Deep Sky filters, Canon T3 DSLR.

C/2014 Q2 (Lovejoy) on Jan 28, 2015, 03:00 UT. 12×180 sec @ ISO 1600, TV-85 at F/5.6, IDAS-LPS & Lumicon Deep Sky filters, Canon T3 DSLR.

Comparison with image taken the day before to see what the tail has done in 24 hrs time.

Comparison with image taken the day before to see what the tail has done in 24 hrs time.

My prediction that the tail of Comet Lovejoy would display a structure seen 9 days before the date of this image has failed.  There is no resemblance to the appearance of the comet from 9 days before and the comet actually exhibits features I have not seen before.

Very strong moonlight hindered getting good images.  The moon was just past first quarter and was right below the comet.  I guess I’m lucky to get what I got.  I’m still investigating the rotation aspect of the tail structures and why it appears to take 9 days to complete one revolution.

C/2014 Q2 (Lovejoy) on Jan 27, 2015, 01:17 UT. 31x120 sec @ ISO 3200, TV-85 at F/5.6, IDAS-LPS, Lumicon Deep Sky filter, Canon T3 DSLR.

C/2014 Q2 (Lovejoy) on Jan 27, 2015, 01:17 UT. 31×120 sec @ ISO 3200, TV-85 at F/5.6, IDAS-LPS, Lumicon Deep Sky filter, Canon T3 DSLR.

With the moon only a few degrees away in the sky and just past 1st quarter, imaging Comet Lovejoy Q2 was iffy at best.  Well, I did it anyway and here are the results.  Since the comet is relatively bright, it can be imaged with the right filters and exposure.

Comet Lovejoy Q2 on Jan 25, 2015, 00:43 UT to 03:49 UT.   3 frame animation shows how the angle that the tail subtends is closing as the comet rotates and the incidence angle of our line of sight changes.

Comet Lovejoy Q2 on Jan 25, 2015, 00:43 UT to 03:49 UT. 3 frame animation shows how the angle that the tail subtends is closing as the comet rotates and the incidence angle of our line of sight changes.

More evidence that the comet is rotating or spinning around an axis.   This is just over 3 hrs of time and the angle of rotation in that time looks to be about 5 degrees.  So, if we take 360 degrees and divide by 5 degrees we get 72, which is how many 3 hr periods to total one rotation.    72 times 3 hrs = 216 hours total time for 1 rotation.  216 divided by 24 hrs = 9 days.    Bingo!

Comet Lovejoy, Jan 25, 2015, 02:25 UT.  34x120 sec @ ISO 3200 and 6x480 sec @ ISO 800, TV-85 at F/5.6, IDAS-LPS, Canon T3.

Comet Lovejoy, Jan 25, 2015, 02:25 UT. 34×120 sec @ ISO 3200 and 6×480 sec @ ISO 800, TV-85 at F/5.6, IDAS-LPS, Canon T3.

Comet Lovejoy, Jan 25, 2015, 01:00 UT. 31x120 sec @ ISO 3200, TV-85 at F/5.6, IDAS-LPS, Canon T3.  (Version 2)

Comet Lovejoy, Jan 25, 2015, 01:00 UT. 31×120 sec @ ISO 3200, TV-85 at F/5.6, IDAS-LPS, Canon T3. (Version 2)

This image should correspond to my image from Jan 16th, 2015 (UT.)   The resemblance is striking, especially the head area.  However, it does look like this one has just a little less width and therefore is turned at slightly more of an angle than the one from Jan 16th.

q2-jan19-20-21_2015-l

Comet Lovejoy Rotation – Jan 19th, 20th and 21st, 2015. Images are roughly 24 hrs apart. It appears to go through about a third of a revolution in 3 days. So, is it roughly 9 days for it to return to the same orientation?

Well, well… the comet is spinning.  Possible revolution of about 9 days.  Then, the same features should show up again and again in a repeating pattern every 9 days.   Well, let’s take a look, then:

If we go back in time 9 days to January 10th, 2015 UT, images of the comet should look similar to the 1st image in my animation.  So, I went to Spaceweather’s Comet Gallery and found these images from the day in question.   Here is a partial list:

Taken by Adriano Valvasori

Taken by Norbert Mrozek

Taken by Knut Schäffner

Taken by Gianni Cerrato (xamad)

There you go.  Almost exact matches.   The comet changes but it also doesn’t.  It repeats a pattern because it is rotating.  We see the same tail structures every 9 days, at least in this part of the apparition.   On Tuesday, Jan 27th, 2015 CST (Wed Jan 28th, UT, ) the comet should present the same structures again as in my 1st image.

Unfortunately, the Moon will be just past 1st quarter and just to the southeast of Comet Lovejoy, so getting enough detail of the dim tail features will be difficult.  I might try my Lumicon Deep Sky filter on it with the Canon 200mm F/2.8 telephoto to see if that blocks some of the moonlight.

Comet Lovejoy on Jan 21, 2015, 01:36 UT.  63x120 sec @ ISO 3200, TV-85 at F/5.6, IDAS-LPS, Canon T3 (StarFreeze Version.)

Comet Lovejoy on Jan 21, 2015, 01:36 UT. 63×120 sec @ ISO 3200, TV-85 at F/5.6, IDAS-LPS, Canon T3 (StarFreeze Version.)

Comet Lovejoy on Jan 21, 2015, 01:36 UT.  63x120 sec @ ISO 3200, TV-85 at F/5.6, IDAS-LPS, Canon T3.

Comet Lovejoy on Jan 21, 2015, 01:36 UT. 63×120 sec @ ISO 3200, TV-85 at F/5.6, IDAS-LPS, Canon T3.

The last image I took of Comet Lovejoy before the weather changed and it clouded up and rained.   There is a moon out now and the window to image Comet Lovejoy will get smaller and smaller as the rest of the month progresses.

WordPress Appliance - Powered by TurnKey Linux