Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Asteroid Eunomia

  • Please log in to reply
10 replies to this topic

#1 ssagerian

ssagerian

    Maker Uranographer

  • *****
  • topic starter
  • Posts: 352
  • Joined: 30 Nov 2013

Posted 04 September 2019 - 12:40 PM

Hello,

any tips on both visually observing asteroids and capturing astro images of them? (keep it basic as I am slow).

Tonight is going to be fantastic (finally, and with the exception of that waxing crescent moon)  so I am going out to my dark site and try to have some fun with finding Eunomia, Amphitrite and possibly Ceres.

I ve never done this before, my expectation is that if I update the orbital elements of carts du ceil and the do a reasonable job of polar aligning my mount/scope as well as doing a 3 star alignment on the mount's pointing model, I should be able to get within in1-2 degrees of the objects. Once there, what should I look for? Ive observed comets before, will these asteroids vary in brightness, have a distinct color, twinkle more?

I am also hoping that if I select a guide star where the mount says the object is and then guide for a bit I should be able to get a light track of the asteroid using my DLSR T3i?

Really looking forward to tonight, and hoping to see all three objects, thanks for any visual or imaging tips..

Steve


  • Zorbathegeek likes this

#2 Gary Z

Gary Z

    Apollo

  • *****
  • Posts: 1416
  • Joined: 26 Jan 2012
  • Loc: New Mexico

Posted 04 September 2019 - 01:19 PM

Hello Steve,

 

Look, I wish you a lot of fun under a dark sky at your dark site.  But what we don't know is what equipment you'll be using to track your objects.  I'm assuming your using an Equatorial mount.  Granted Eunomia is large as far as asteroids go.  I take it you mean 15 Eunomia.  Supposedly this asteroid contains 1 % of the material in the inner asteroid belt.  What settings will you be using for your T3I? 

 

Gary



#3 Dan Crowson

Dan Crowson

    Vanguard

  • *****
  • Moderators
  • Posts: 2211
  • Joined: 08 Oct 2010
  • Loc: Dardenne Prairie, MO

Posted 04 September 2019 - 01:47 PM

Steve,

I think you have it down to what you need. I would just find where it will be in the planetarium program and the slew to a star that is in the controller (this would probably be easiest). Without knowing your equipment, it would be hard to give specifics but this one looks to be big and bright so you'll see it in a short exposure for sure.

 

Ideas:
 

1. Take an exposure every 15 minutes or more to show it moving between them.

2. Take exposures every minute, five minutes, etc. You could stack these to get a trail or use a program to combine images to make a movie.

3. Being that this one is big and bright, I bet you could find it in your autoguider and guide on it. You would take the exposures and combine to make a movie showing a stationary asteroid with stars moving.

 

Example of #2

 

Trail - https://www.flickr.c...son/12999673195

Movie - https://www.flickr.c...son/13000065034

 

(2 Pallas was near the satellite junk zone for me and that's the lines running across the top).

 

Example of #3 - https://www.flickr.c...son/34006328492

 

More examples in my Asteroids album here - https://www.flickr.c...157632773671313

 

Dan


  • Dartguy likes this

#4 ssagerian

ssagerian

    Maker Uranographer

  • *****
  • topic starter
  • Posts: 352
  • Joined: 30 Nov 2013

Posted 04 September 2019 - 01:48 PM

Hello Gary,
You sound sad Gary, arent you having clear skies there in New Mexico? Its hard to tell, reading forums but I wish you a lot of fun whatever your doing too!

Yes I am using a modest setup, a 120mm f4.9 refractor on a orion atlas EQ-G mount. Not sure about the settings for the camera, probably do a 4-10 minute guide with ISO 800, maybe a bit higher !S) 1600. I will probably switch between visually trying to watch them and trying to capture them with the camera.



#5 ssagerian

ssagerian

    Maker Uranographer

  • *****
  • topic starter
  • Posts: 352
  • Joined: 30 Nov 2013

Posted 04 September 2019 - 01:52 PM

Dan, thanks for the exposure times, and the images to use an example, that is helpful.



#6 Codbear

Codbear

    Viking 1

  • -----
  • Posts: 838
  • Joined: 23 Jan 2016
  • Loc: Novato, CA

Posted 04 September 2019 - 01:56 PM

Visual Strategies:

 

For Ceres and Amphitrite, you shouldn't have too much trouble identifying them with a good star chart.

 

Eunomia I think varies quite a bit by magnitude and is fainter than the other two so, if you don't have a star chart that goes deep enough, you may need to do the trusty method of sketching the field and returning the next night or at a minimum a few hours later to see what's moved. All of the objects will appear as points of light.

 

When a new asteroid that buzzes Earth is discovered (almost weekly now it seems) I go to the JPL Horizons website to generate an Ephemeris, which tells me the asteroid's  magnitude and angular motion against the stars. You can set time intervals from days all the way down to minutes to see how many seconds/minutes/degrees it's moving in a given time period.

 

My holy grail is to be able to see an object move in the field of view over a few minutes of constant observing. I have been foiled by various equipment difficulties/inadequacies, as well as a healthy dose of stupidity, in the past, but now have learned quite a few lessons and can go fainter than 16th magnitude, so it's only a matter of time til a candidate will be in the right part of the sky at the right time of night.

 

Good luck!


Edited by Codbear, 04 September 2019 - 01:57 PM.


#7 ssagerian

ssagerian

    Maker Uranographer

  • *****
  • topic starter
  • Posts: 352
  • Joined: 30 Nov 2013

Posted 04 September 2019 - 02:18 PM

Dan,

question, you took 80 exposures at 90 seconds and stacked them..to get the image in your link thats 2 hours of time, and Pallas moved just that much in the two hours..correct?



#8 Zorbathegeek

Zorbathegeek

    Sputnik

  • -----
  • Posts: 32
  • Joined: 19 Jul 2019

Posted 04 September 2019 - 06:10 PM

Hi Steve, I love finding and tracking asteroids. I use Stellarium and star-hopping. I located (135) Hertha a few days ago at magnitude 10 from urban skies with 6" Dobsonian. Lutetia, Amphitrite and Metis are next on the list. I read up on each asteroid as I find it and log date and time of observation and size of each rock in my asteroid log book. For now I'm sticking to 10th magnitude and brighter. It's quite an addictive pastime.

 

Have fun

 

Ray.



#9 Dan Crowson

Dan Crowson

    Vanguard

  • *****
  • Moderators
  • Posts: 2211
  • Joined: 08 Oct 2010
  • Loc: Dardenne Prairie, MO

Posted 05 September 2019 - 01:50 AM

Dan,

question, you took 80 exposures at 90 seconds and stacked them..to get the image in your link thats 2 hours of time, and Pallas moved just that much in the two hours..correct?

Correct. I image a lot so sometimes I just let the scope go. Looking at this another way, asteroids move at different speeds, especially based on distance. I tend to use a formula with the RA or Dec rate (whichever is quickest) to determine how long I can expose before I get streaks in single exposures. Not a big deal for making an image with a line but if I want to submit data to the Minor Planet Center, I don't want them.

 

Dan



#10 ssagerian

ssagerian

    Maker Uranographer

  • *****
  • topic starter
  • Posts: 352
  • Joined: 30 Nov 2013

Posted 05 September 2019 - 08:58 AM

After all that, stepping out of work at 5pm yesterday the chicago area sky looked like 70%+ cloud cover, despite the Astrospheric App telling me that it was less than 5%, when I got home my wife was looking up puzzled..you are still going?? Now the sky was definitely 100% clouded, again, the Astrospheric App was saying little if any clouds, above average seeing and above average transparency. At 6:30PM, it looked like we might get a thunderstorm or worse.. As you can guess, I decided to call it a "no go". Frustrated but always hopeful, tonight looks good..Astrosheric is reporting average seeing, average transparency, if it holds true..I ll take it.

Thanks for everyones advice, I can see how hunting asteroids might become addictive.

Steve



#11 Dan Crowson

Dan Crowson

    Vanguard

  • *****
  • Moderators
  • Posts: 2211
  • Joined: 08 Oct 2010
  • Loc: Dardenne Prairie, MO

Posted 05 September 2019 - 10:52 AM

We had a clear night (near Saint Louis) so I went ahead and pointed at this one since I really didn't have anything else to image. Here's the result of a couple of hours - https://www.flickr.c...3267613/sizes/l.

 

If you're in the Astro League, they have an asteroid program and you can definitely image them if you want - https://www.astrolea...d/astrclub.html.

 

Dan




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics