How productive are people at observing MPC NEO's?

5 years 10 months ago #103585 by albertw

I've noticed over the past while that I've managed to report astrometry on very (almost zero!) NEO's. A large part of this is down to not actually observing much thanks to a toddler at home :)

But for slow enough moving NEO's, using 10 x 30-60 second exposures stacked I have a lot of trouble getting a good S/N ratio for targets down below Mag 18. 18.5 really is my limiting magnitude on a dark night in the less light polluted bit of sky (C9.25 @f6.3 ATIK314L binned).

Most nights when I filter down the NEOCP there are no objects that are visible or bright enough for me to image. Often when they are bright enough they are too fast for me to get accurate enough astrometry.

So I was just curious to see how others are getting on with astrometry for the MPC, and whether larger scopes and less light polluted skies extend your limiting magnitude much.


Albert White MSc FRAS
Chairperson, International Dark Sky Association - Irish Section

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5 years 10 months ago #103594 by Mike
Same here Albert, between work (now on evening shifts) and family commitments it is difficult to devote time to ones passion and with the added difficulty in that the weather usually won’t cooperate just like an obstinate child, its all the more difficult!

NEOs are a challenge, especially those that are faint and fast moving. The recent 2004 BL86 flyby (which was one of the brighter of such events), its apparent motion across the sky was in the order of 159 arcsec/min around closest flyby according to the Minor Planet Ephemeris Service. Where asteroids Cherryvalley Observatory has worked on are in the order of 0.70 arcsec/min thus allowing sufficient exposure time without trailing to obtain a good SNR and thus precise astrometric and photometric measurements.

A quick calculation for my own telescope system with a pixel scale of 2.17 arcsec/pixel (field of view of 46 x 37 arcmins) indicates that a maximum exposure time of 0.8 seconds was allowable before trailing would occur of NEO 2004 BL86! However because the NEO was relatively bright, astrometric and photometric measurements was obtained by amateur astronomers using their own equipment.

Since I own a modest 8-inch SCT, faint NEOs are simply not on my radar, Cherryvalley observatory chooses instead to undertake photometric work on relatively bright asteroids that very little to nothing known about their rotation characteristics and in the process you make a new discovery and one can publish results in a PEER review publication.

Your system Albert if I am not mistaken has a field of view of around 21 x 16 arcmins and I am guessing you use x2 binning to give you an approximate pixel scale of 2 arc seconds and in that case an exposure time of 0.7 seconds would be maximum before trailing occurred on NEO 2004 BL86 as an example.

If I had a larger aperture telescope and a better mount I would like to undertake NEO observations as it is valuable and important work. I don’t know if you’re a member of the BAA, but the asteroids and remote planets section have Dr. Richard Miles and Peter Birtwhistle as section officers whom are there to help and are masters in their field. Here is a link to the asteroids and remote planets section which has much information that you may find useful...

Best wishes, clear skies and best of luck with you NEO observations, I do look forward to seeing more of your work Albert.


I83 Cherryvalley Observatory

After one look at this planet any visitor from outer space would say; "I WANT TO SEE THE MANAGER".

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5 years 10 months ago - 5 years 10 months ago #103598 by phoenix
Even with the 16" I've only managed 1 object on NEOCP so far this year. Doesn't help that my ccd only has a peak QE of 54% and then combine that with weather and other duties.......... :pinch:

My limiting mag is 19.6 on slower movers.

16" ODK (incoming), Mesu Mount 200, APM TMB 80mm, SXV H16, SXV H9
J16 An Carraig Observatory

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5 years 9 months ago #103654 by albertw
For the NEO's I filter out anything faster than 3"/min unless they are very bright. The shortest exposure that i can use while keeping noise down is 30s, so I'll typically do 10x30s and take the best of those. My pixel scale is around 1.7 "/pixel.

I'm not a member of the BAA but have come across Peter Birtwhistle before; very knowledgeable guy.

I think I may have to start looking at photometry as a possible future route. Need to get some photometric filters!

Thanks for the replies.

Albert White MSc FRAS
Chairperson, International Dark Sky Association - Irish Section

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