Jump to content



Cosmic Geoff

Recommended Posts

I wanted to observe some asteroids as I had not done it for a while, and the easiest way to spot and identify them seemed to be to use my EEVA rig.  Identifying an asteroid visually can be difficult unless one is sure to look in the right place and has a star chart that matches the eyepiece field size and the magnitudes of the visible objects. And the image reversal in a star diagonal makes it much more difficult.

On 18 Feb I imaged four asteroids using: 102mm f5 achro, ASI224MC camera and SLT GoTo mount.  Vesta, Melpomene, Echo and Amphitrite.  I plate-solved the images the next day, to find that I had got Melpomene and Echo but missed the other two.

On 22 Feb I imaged Vesta, Amphritite, Eunomia and Irene, using live-stacking, with 102mm f5 achro, ASI224MC camera and EQ5 Synacan GoTo mount.  I plate-solved the images at the telescope, to find that I had three of them but needed to change the aim and repeat to get Irene.   With this setup, a mag 9 to mag 10 asteroid shows up clearly on the laptop screen as a bright dot with a 5 second exposure.

Platesolver 2 highlights any non-catalog items in the field and one can check the co-ordinates of any object in the solved field. The image reversal in a star diagonal does not trouble it at all.

I have had the EQ5 Synscan upgrade for around 10 months but this is the first time I have managed to do anything really useful with it.

It would be interesting to observe asteroid movement over a period of time but with the current rotten weather it is good to have a method that only requires one image or stack to positively identify the asteroid.

One of the images appeared to have two bright non-catalog objects on it, which is something I may investigate later.

  • Like 6
Link to comment
Share on other sites

I like asteroids but with one thing or another I've not got round to capturing many.

A week or so ago I did make an effort with Hygiea. I confirmed it visually by it's position in the field stars but my plan to make a gif showing movement was thwarted no end of issues. 

A program I use a lot is ASTAP and it will plate solve then annotate DSO and/or Comets and Asteroids. You just have to download a couple of files from the Minor Planet Center. Here is what is what it does:


Ignore the trailing; mount problems! But it's got Hygiea spot on! There are about 10 other asteroids in that field but all greater than mag 18 and not visible in this 30 sec sub. I've got the annotation tool set for max mag of 16.

Results are better if a full FITS header is available it saves entering image details and makes solving almost instantaneous.

  • Like 1
Link to comment
Share on other sites

26/02/21. With the moon blazing away I thought I would try my hand at finding some bright asteroids. 

I used the 15"Dob/ultrastar camera. The moonlight is a pain but these asteroids at around mag 12 are easily picked up, even in a 2 second sub.

Psyche: a 200 km wide nickel-iron main belt asteroid. Take a look at https://3d-asteroids.space/asteroids/16-Psyche



Asteroid Nemausa - 140 km diameter. Take a look at https://3d-asteroids.space/asteroids/51-Nemausa for its likely shape. Made up of nickel, iron, cobalt, water, nitrogen and ammonia.



Asteroid Eurynome -  diameter 64 km. Take a look at  https://3d-asteroids.space/asteroids/79-Eurynome  for 3D model . A siicate asteroid




  • Like 3
Link to comment
Share on other sites

27/02/21 - I  tracked down a few more asteroids last night for an hour.

Asteroid Daphne - I offset the view so has to pick up NGC 2186 (bottom left). Daphne is about 200 km across and is made of  nickel, iron, cobalt, water, nitrogen, ammonia.


























Asteroid Nephthy -about 60 km across, The blue lines point to mag 17 LEDA galaxies.



  • Like 2
Link to comment
Share on other sites

Nephthys -- what a great field, Mike. There seems to be a whole load of faint galaxies to the north too. Lovely round stars too!

This asteroid hunting sounds like a fun idea Geoff.

I took a look at the data from the MPC, all 650M of it. It would be interesting to incorporate it into the platesolving routine at some point.


Link to comment
Share on other sites

28/02/21 - Approx 24 hrs since I looked at Nephthys. The shot below shows how far it has travelled in those 24 hrs. Last night's position is marked by the red dot. I have also marked on the 3 LEDA galaxies from last night and also the other 2 LEDA galaxies that Martin indicated.  Conditions were better tonight as the moon was still below the horizon, hence a darker background.



  • Like 2
Link to comment
Share on other sites

I finally made a GIF of my time with Felicitas the other night.

This is 33 x 60 sec. There is a jump caused by me not realising I set APT to take 10 frames instead of the intended 100. Ran into the trees way before then anyway. This is about an hour of motion.

I Aligned the subs in DSS then loaded into the animation utility in Photoshop. I thought I'd find a simple way to batch stretch them and correct the green colour. There are a lot of fuzzies being lost here in the GIF. Turns out my brain cell couldn't fathom that task so here it is, a bit raw. I ended up converting to grey scale to remove the green tinge.



Edited by Paul M
  • Like 5
Link to comment
Share on other sites

  • 2 weeks later...

I've been doing a bit of asteroid spotting prompted by the close approach of Vesta. My first shot is from 25 February so there was a bright Moon around. Rather pointlessly I put it through astrometry.net and then ASTAP to annotate it. My reason was that I wanted to try the asteroid annotation feature in ASTAP.


Vesta is the second largest asteroid (although the biggest, Ceres, is classed as dwarf planet). Vesta is said to have about 9% of the total mass of the asteroid belt and is about 525 km across.


Well that worked OK so I had a look at some others. Several were so close to the Moon that I got a lot of gradient in the captures but astrometry.net coped well.




Siri would be only about magnitude 11 because it's about 40 km across.




Almalthea is a bit bigger at 50 km and would be about magnitude 11 too. It was found to have a 5 km satellite in 2017. It's described as a Florian asteroid. These are similar stony asteroids in the inner asteroid belt named after the asteroid Flora.

See: https://en.wikipedia.org/wiki/Flora_family



Frigga's snapshot was less affected by the Moonlight. It's about 69 km and is classed as an M-type. M-type means that it is largely metallic (real metals not astrophysicist's anything except hydrogen and helium metals). Lots of nickel-iron and M-types are likely to a source of metallic meteorites.




Amphitrite is a bigger asteroid at about 200 km and quite bright at magnitude about 9.3. It's an S-type so mainly rocky siliceous material.


Returning to Vesta a few days ago I decided to see if I could show it moving against the background stars. Some captures about 10 minutes apart over about 70 minutes were put together and made into a gif using the feature in Jocular.





Happy viewing.


Bill S

  • Like 4
Link to comment
Share on other sites

Great animations, Paul & Bill. Every time I think about doing something similar, I ask myself whether I have the patience to return the scope to exactly the same position every 10 minutes so as not to waste the intervening session. Once I have the Pi controlling the mount maybe I will set up some kind of automated sequencing...


Link to comment
Share on other sites

  • 3 weeks later...
  • 2 months later...

Just by chance I noticed that tonight 3 Juno is passing the outer reaches of M10.

I've currently got the 127 Mak and ASI178 taking as many 30 sec subs as possible before either cloud or dawn gets in the way. Potential for a nice animation!


Edit to add a quic live stack with ASTAP of progress so far. not a lot of motion showing.image.thumb.png.93ee486c69f4f064a38a1ab284fb0d8c.png


Edited by Paul M
  • Like 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.