APOD: Announcing Comet Catalina (2015 Aug 18)

Comments and questions about the APOD on the main view screen.
User avatar
APOD Robot
Otto Posterman
Posts: 3548
Joined: Fri Dec 04, 2009 3:27 am

APOD: Announcing Comet Catalina (2015 Aug 18)

Post by APOD Robot » Tue Aug 18, 2015 4:09 am

Image Announcing Comet Catalina

Explanation: Will Comet Catalina become visible to the unaided eye? Given the unpredictability of comets, no one can say for sure, but it seems like a good bet. The comet was discovered in 2013 by observations of the Catalina Sky Survey. Since then, Comet C/2013 US10 (Catalina) has steadily brightened and is currently brighter than 8th magnitude, making it visible with binoculars and long-duration camera images. As the comet further approaches the inner Solar System it will surely continue to intensify, possibly becoming a naked eye object sometime in October and peaking sometime in late November. The comet will reside primarily in the skies of the southern hemisphere until mid-December, at which time its highly inclined orbit will bring it quickly into northern skies. Featured above, Comet Catalina was imaged last week sporting a green coma and two growing tails.

<< Previous APOD This Day in APOD Next APOD >>
[/b]

Boomer12k
:---[===] *
Posts: 2485
Joined: Sun Apr 22, 2007 12:07 am

Re: APOD: Announcing Comet Catalina (2015 Aug 18)

Post by Boomer12k » Tue Aug 18, 2015 1:54 pm

"Catalina, Catalina....you look so fine...."....hmmmm...something, something.....trying to write a song here....
WELCOME CATALINA!!!!!! Have a pleasant visit!!!!!

:---[===] *

Boomer12k
:---[===] *
Posts: 2485
Joined: Sun Apr 22, 2007 12:07 am

Re: APOD: Announcing Comet Catalina (2015 Aug 18)

Post by Boomer12k » Tue Aug 18, 2015 2:04 pm

Kirk: "Spock, analysis"
Spock: "A Comet...Catalina, by the analysis, I am picking up an energy never before encountered..."
Uhura: "Captain....We are being hailed...it is from the Comet!!!!!"
Kirk: "Put it on the speaker."
Voice: "CATHLEEN....ONE MORE TIME!!!!!"
CREW at same time: "OH, NO, NOT HIM AGAIN!!!!!!!"
Kirk: "Sulu, plot a course away from the comet. Warp NINE!!!"
Sulu: "Aye, that, Captain..."


:---[===] *

User avatar
Chris Peterson
Abominable Snowman
Posts: 14357
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: Announcing Comet Catalina (2015 Aug 18)

Post by Chris Peterson » Tue Aug 18, 2015 2:10 pm

Boomer12k wrote:"Catalina, Catalina....you look so fine...."....hmmmm...something, something.....trying to write a song here....
Just an A.U. across the sky,
Comet Catalina is flying by...


Set to the tune of... well, you know.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

retrogalax

Re: APOD: Announcing Comet Catalina (2015 Aug 18)

Post by retrogalax » Tue Aug 18, 2015 3:26 pm

This picture is (again) really a nice idea of how the space is.

Sawngrighter

Re: APOD: Announcing Comet Catalina (2015 Aug 18)

Post by Sawngrighter » Tue Aug 18, 2015 9:22 pm

Boomer12k wrote:"Catalina, Catalina....you look so fine...."....hmmmm...something, something.....trying to write a song here....
WELCOME CATALINA!!!!!! Have a pleasant visit!!!!!

:---[===] *
She was a 50s Catalina with fins on her rear .. she sung a song of flashing when she drank her beer .. she was a Mermaid from Pluto with sparkly lights .. cosmologists lost their focus when she put on tights .. Go Cata Go Cata Go Cata Go. (Applause?)

User avatar
Beyond
500 Gigaderps
Posts: 6889
Joined: Tue Aug 04, 2009 11:09 am
Location: BEYONDER LAND

Re: APOD: Announcing Comet Catalina (2015 Aug 18)

Post by Beyond » Tue Aug 18, 2015 10:28 pm

Sawngrighter wrote:
Boomer12k wrote:"Catalina, Catalina....you look so fine...."....hmmmm...something, something.....trying to write a song here....
WELCOME CATALINA!!!!!! Have a pleasant visit!!!!!

:---[===] *
She was a 50s Catalina with fins on her rear .. she sung a song of flashing when she drank her beer .. she was a Mermaid from Pluto with sparkly lights .. cosmologists lost their focus when she put on tights .. Go Cata Go Cata Go Cata Go. (Applause?)
:clap: :clap: :clap:
To find the Truth, you must go Beyond.

User avatar
DavidLeodis
Perceptatron
Posts: 1169
Joined: Mon May 01, 2006 1:00 pm

Re: APOD: Announcing Comet Catalina (2015 Aug 18)

Post by DavidLeodis » Wed Aug 19, 2015 1:43 pm

I would be grateful if someone could please inform me what the "2015 Aug 11.544" means on the image? I'm guessing that the .544 means 54.4% of the way through August 11 2015 and thus shortly after 12:30 p.m., but if so that would be daylight unless the decimal time is equivalent to such as Universal Time so Australia would then be dark under its local time. I'm :?.

User avatar
Joe Stieber
Science Officer
Posts: 157
Joined: Tue Aug 18, 2009 1:41 pm
Location: Maple Shade, NJ

Re: APOD: Announcing Comet Catalina (2015 Aug 18)

Post by Joe Stieber » Wed Aug 19, 2015 4:58 pm

DavidLeodis wrote:I would be grateful if someone could please inform me what the "2015 Aug 11.544" means on the image? I'm guessing that the .544 means 54.4% of the way through August 11 2015 and thus shortly after 12:30 p.m., but if so that would be daylight unless the decimal time is equivalent to such as Universal Time so Australia would then be dark under its local time. I'm :?.
Yes, that would be Universal Time as a fraction of the day, a common way of expressing the date/time in comet observing. Therefore, we have...

0.544 x 24 = 13.056 hours
0.056 x 60 = 3.36 minutes
0.360 x 60 = 22 seconds

So, it would be 2015 August 11, 13:03:22 UT. Indeed, it would be mid-day at the Prime Meridian, but half way around the globe in Australia, it would be the middle of the night.

Edit: Calculating the time to the second is probably overly precise, since this is likely a relatively long-duration exposure (unless it marks a specific start or finish time). There were no exposure details for this picture at the photographer's web site. The web site also indicates he lives in the UK, so I'm guessing he was using a remote telescope in Australia (a common technique these days). There were no details about the equipment used.
Last edited by Joe Stieber on Thu Aug 20, 2015 7:57 am, edited 1 time in total.

User avatar
DavidLeodis
Perceptatron
Posts: 1169
Joined: Mon May 01, 2006 1:00 pm

Re: APOD: Announcing Comet Catalina (2015 Aug 18)

Post by DavidLeodis » Wed Aug 19, 2015 8:51 pm

Joe Stieber wrote:
DavidLeodis wrote:I would be grateful if someone could please inform me what the "2015 Aug 11.544" means on the image? I'm guessing that the .544 means 54.4% of the way through August 11 2015 and thus shortly after 12:30 p.m., but if so that would be daylight unless the decimal time is equivalent to such as Universal Time so Australia would then be dark under its local time. I'm :?.
Yes, that would be Universal Time as a fraction of the day, a common way of expressing the date/time in comet observing. Therefore, we have...

0.544 x 24 = 13.056 hours
0.056 x 60 = 3.36 minutes
0.360 x 60 = 22 seconds

So, it would be 2015 August 11, 13:03:22 UT. Indeed, it would be mid-day at the Prime Meridian, but half way around the globe in Australia, it would be the middle of the night.
Thanks Joe for that explanation, which is very helpful :). Without your help I doubt I would have figured out that .544 would be 13:03:22 UT.