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Seriously, if an amateur did this they would be crucified although at least we are trusted to post discoveries on TNS. We are not allowed to post to The Astronomer’s Telegram since we can’t be trusted to get things right on our own. I’d be interested to know what checking the MASTER team do before posting their discoveries. Checking for moving objects like asteroids and planets is pretty basic stuff. It would be nice to see a comment on TNS from one of the authors explaining what went wrong but so far nothing.
Possibly. It could have been an aircraft I suppose but the faint residual image in the next frame looks like a decaying train.
Well done them. You’d have thought that one of that almost infinitely long list of authors might have checked…
That sounds like a fun thing to do although recovering your expensive kit might be challenging. There are rules about launching high altitude met balloons in the UK and a useful FAQ here in case anyone wants to have a go.
Rotten weather here in Chelmsford although my cameras caught a few meteors last night during short gaps in the cloud. There were only small gaps in the cloud at the predicted time of the storm and nothing was picked up then.
Lots of showers this morning and a load of clouds around. The seeing is awful and it is blowing a gale but I was lucky at first contact here in Chelmsford. Here is a frame from my video taken at 2019-11-11T12:37:33.
Here’s the animated GIF of first and second contact.
Here’s a quick animation I obtained tonight while waiting for it to get dark. These are 10s exposures. 33×22 arcmin field, N up.
Thanks. Here’s a short movie taken a little later when it had cleared up. Still a very bright Moon in the sky.
Thanks for the reminder. That’s a great movie. It is cloudy here in Chelmsford at the moment but I did have a few gaps earlier and caught the trail. It is currently around mag 15.3 moving at 7 arcsec/min.
https://openphdguiding.org/man-dev/Tools.htm#Comet_Tracking
Although I have never used this myself…
Well, given the position, it is possibly Leda but I don’t think you could be sure unless you had multiple stacks which showed the blob moving at the correct rate. If you try this in future you will want to get a long enough series of subs that you can make two separate stacks, each of which have enough SNR to get astrometry of the object. Once you have confirmed it by its motion you can always stack the whole set to get a higher SNR. That’s what I did with this faint comet which was about the same magnitude as Leda.
Good try Paul but that’s the trouble with faint objects in busy starfields! When you say it is “in about the right place” could you quantify in terms of arcsec? Leda’s ephemeris will be very good. Normally, in cases like this, you would produce two stacks at different times and check that the object’s motion is consistent with the ephemeris. You may not have enough subs to do this in which case the identification will always be iffy.
Try this:
http://www.nickdjames.com/astrolinux/utils_ubuntu18.tgz
The tools are all dynamically linked so you will need the libraries but they are all available for Ubuntu. I think the following should get them all:
apt install libcfitsio-dev
apt install libgd-dev
apt install libnetpbm10-dev
apt install wcslib-devNick.
Paul,
I have a VM running Ubuntu 18.04 LTS. I’ll build you a version of the tools in that. Hopefully that will work on your system. If not I’ll have a look at linking the libs statically and, failing all that I’ll give you the source (with an NDA!).
Nick.
Paul,
If you don’t mind command line software I have written a set of tools which I use as part of my image calibration and processing pipeline. They are based on the cfitsio library so should read any format supported by that library. You can download them from here:
http://www.nickdjames.com/astrolinux/utils.tgz
The stacking tool is called fcombine. The normal syntax to use it is:
fcombine -N -a 611,713 -A 0 -o 0.368,236.7,1.42 200p_ofs FLI*200P*FITThis says:Normalise the median level of each image before stacking, track on a guide star at position 611,713 in the first image, PA of the image is 0 deg (i.e. north up), Offset at 0.368 arcsec/sec in PA 236.7 deg, Pixel scale is 1.42 arcsec/pix. Output file is 200p_ofs and the input files are all files which match FLI*200P*FIT. You can add -F to write as a float fits and -s to do a true average rather than a statistically clipped average. You can also use -v to get a lot of stuff about what it is doing during teh stack (otherwise it is silent). Note that the position for the guide star assumes (1,1) is the top left corner of the image (the convention most amateur software uses) rather than the bottom left (which is what pros tend to use). The FITS standard doesn’t say which is right.
Typing the command with no arguments gives a list of what it can do. For fcombine you get:
fcombine [opts] outfile infiles
By default combines images using mean with outlier rejection
-a x,y[,d] Align on guidestar
-A n[,M] Position angle of image with optional mirroring
-C Cometstack
-c n Crop to image of size nxn
-d n Resample and drizzle by a factor of n
-F Write float format rather than int16
-f file Take alignment offsets from file
-g n Apply gain of n to output
-h Do not use FITS header
-m Minimum pixels
-M Maximum pixels
-n Normalize mean levels by scaling
-N Normalize mean levels by offset
-v Verbose
-V Version
-r n Tracking and PSF radius to use (default = 5.0)
-I Scale to a FITS that IRIS can handle
-R Write output mirror reversed
-o rate,pa,pix Offset (arcsec/min)
-O rate,pa,pix Offset (arcsec/frame)
-p n Add pedestal of n
-P n Reject for PSF > n
-D n Shift step size (default is 1)
-s No outlier rejection
-S n Stacksize (all images by default
-t Align on target
