Author Topic: Call for images - Testing new plate solving and annotation features  (Read 1507 times)

Offline Juan Conejero

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Hi all,

We are currently implementing new features in our plate solving and annotation scripts, and lack the necessary real-world data to test them thoroughly. We'd appreciate if you could provide us with images suitable for testing these features. We need images that comply with the following requisites:

- Required: Acquisition time metadata. We need to know the date the image was acquired, accurate to within one minute if possible in the case of inner planets (see below), or to within one hour or so for the rest of objects. For example, if your image has been acquired in FITS format and has a valid DATE-OBS header keyword generated by your acquisition software, that would be ideal.

- Required: Images with planets and/or asteroids. The new features that we are testing involve calculation of high-accuracy solar system ephemerides, which we must test against real data. We need images with:

- One or more of: Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto.

- One or more of the 343 most massive asteroids included in DE430's numerical integration—see the list attached to this post as a plain text file, which you can open in PixInsight's Script Editor. For example, if you have images covering relatively large areas of the Ecliptic, the probability that you have recorded one of these asteroids is high. In such case, even if you don't know whether you have one of these asteroids in the image or not, you can send it to us if it complies with the rest of requirements.

- Geodetic coordinates of the observer. It would be great if you could provide at least the approximate longitude and latitude (also height if possible) of the location where the image was acquired.

- Linear images. To perform the accurate plate solving and measurement tasks that we need to test the new features, we need unstretched (linear) images. We cannot perform valid PSF measurements on stretched images.

Thank you so much in advance!
Juan Conejero
PixInsight Development Team
http://pixinsight.com/

Offline Juan Conejero

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I forgot to mention something I thought was obvious (since we are speaking of plate solving), but maybe it is not. We need deep-sky images, not planetary images. That is, we need deep-sky images with stars and planets and/or asteroids, as described in my yesterday's post. Sorry for the potential confusion.
Juan Conejero
PixInsight Development Team
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Offline RickS

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Hi Juan,

I have some test subs at fairly short focal length (image scale a few arcsec/pixel) with Saturn near M8/M20.  Are they useful?

Cheers,
Rick.

Offline Juan Conejero

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Yes, absolutely! Thank you Rick.
Juan Conejero
PixInsight Development Team
http://pixinsight.com/

Offline RickS

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I'll upload a few to Dropbox tonight and send you a link...

Offline ngc1535

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Juan,

I can provide many high quality images across many platescales that satisfy your needs.

1. Are you looking for calibrated images? (or raw?)
2. Is there a repository you are maintaining or do we provide links from our own places?
3. Do you require temporal series of like images? In other words...I am certain some of the ecliptic data will have some of the asteroids. Do you want a series of sequential images to show moving objects for confirmation or is a single image good enough?

-adam

Offline Juan Conejero

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Hi Adam,

Thank you so much!

Quote
1. Are you looking for calibrated images? (or raw?)

Calibrated images. I have to perform accurate PSF measurements. The higher the SNR, the better.

Quote
2. Is there a repository you are maintaining or do we provide links from our own places?

Please provide a link if you can, or upload the images to some cloud storage service such as dropbox.

Quote
3. Do you require temporal series of like images?

Not necessarily, but if you have a sequence of frames with the same object(s), that is great for verification of accuracy in ephemeris calculations.

These tests are intended to verify experimentally the robustness of a new version of our plate solving script, which implements a new distortion modeling algorithm of unprecedented accuracy. I am also working on a new version of the annotation script able to identify and annotate solar system objects. These tests are a great test bench for the whole set of astrometry tools that will be available in the next version of PixInsight, including the integrated solar system ephemerides, position reduction and plate solving subsystems. In addition, the new local distortion correction modeling capabilities are essential for the astrometry-based mosaic generation tool that I plan on releasing soon. So this is indeed important :)
Juan Conejero
PixInsight Development Team
http://pixinsight.com/

Offline kkretzsch

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Hi Juan,
I have no asteroid images yet, but a confirmation how good the plate solving algorithm works (see attachment). The resolution of the image is 0.8 arc seconds per pixel.

Thanks !
Klaus

Offline pk825

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Do you still need images? I have just take some frames of 772 Tanete can I could share.
Is made with a remote personal observatory and a G2-4000 at bin2 (https://sites.google.com/view/3zobservatory).
TEL 0.30-m f/8.0 Ritchey-Chretien + CCD + f/5.8 focal reducer
COM Long. 11 33 48 E, Lat. 42 28 48 N, Alt. 150m, Google Earth

Here is a link
https://drive.google.com/file/d/11KNRYMm_vNkSw8wKyGp_bUux3VMw56NR/view?usp=sharing
of the raw data and a integration frame with dark, bias and flat.
you have only to pay attention to date time in the fits header that is not correct (Ascom driver problem), the UTC is +2h respect the real one, so you have to subtract two hours.



Offline Juan Conejero

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Thank you so much for uploading these images. Yes, of course I am always interested in good test data for our new algorithms, and these frames are excellent.

This is a quick test with one of the individual uncalibrated frames:


Click on the image for a full-size version.

I have solved the image with the ImageSolver script (latest version), with distortion correction enabled and Gaia DR2 data up to magnitude 19.

Following your instructions about the difference between UTC and the DATE-OBS value stored in the FITS files, I have generated the annotation mask with the AnnotateImage script for the UTC time point 2019-05-31 22:21:22. Note that I have added one minute to match the middle point of the 120 seconds exposure.

The observed coordinate errors are, in arcseconds:

Delta_alpha * cos(delta) = 0.13
Delta_delta = 0.01

These errors are within the expected limits imposed by image noise and acquisition time uncertainty. I'll investigate the apparently large error in right ascension.
Juan Conejero
PixInsight Development Team
http://pixinsight.com/

Offline Juan Conejero

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More on this. Here are the geometric ephemerides of 772 Tanete calculated for the starting, middle and ending times of the exposure in the measured image:

====================================================================
Target body : 772 Tanete
Ephemeris   : Spherical equatorial coordinates.
Observer    : Topocentric
Longitude   : 11°33'44".00 E
Latitude    : 42°28'45".00 N
Height      :   150 m
====================================================================
                      --------Geometric---------     True      Vis.
     Date - UTC           R.A.          Dec.       Distance    Mag.
--------------------  ------------  ------------  -----------  -----
                        h  m  s        °  '  "      au
2019 MAY 31 22:20:22  13 27 19.983  +13 35 16.51   2.04230844  12.99
2019 MAY 31 22:21:22  13 27 19.966  +13 35 15.97   2.04231510  12.99
2019 MAY 31 22:22:22  13 27 19.949  +13 35 15.43   2.04232175  12.99


The asteroid moves 0.496 arcseconds in right ascension during the 120 seconds of exposure, so the observed annotation error of 0.13 arcseconds is equivalent to an uncertainty of about 31 seconds of (combined Earth-object) orbital motion. It would be great if we had access to the unbinned images, since PSF parametrization, and hence centroid coordinates, would be more accurate with a better sampling.
« Last Edit: 2019 June 11 05:11:41 by Juan Conejero »
Juan Conejero
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Offline pk825

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I have to check if the frames have the correct date time, because I think I have fixed the synchronization time just after this acquisition. In that case I have about 30s error.
I have send you 772 because is the only one that is in the list you attach in the first post, if you want I have some frames related to other asteroids not in list with the correct date time.

You say: It would be great if we had access to the unbinned images, since PSF parametrization, and hence centroid coordinates, would be more accurate with a better sampling.
But in may case, I'm not sure it is better to acquire image in bin1 because the seeing in the observatory zone is not very good and the guide error is about RMS of 0,7'', so the bin2 with a sampling of 1.7''/pix seems the best choice. Do you suggest also in my case to use bin1?

Offline pk825

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Anyway yesterday I get some bin1 frames of 1093, the night was with high cloud and moon so the photos are terrible, but there is the asteroid and I think it is possible to do astrometry .
I share the single frames and the integration frames (star aligned and comet aligned)
https://drive.google.com/open?id=1dhF9qkS7umc00gOx57IdG7FG18SJngc1
the comet aligned one have elongated stars an I get the solving of the image only putting the sensitivity star detection to minimum.
« Last Edit: 2019 June 12 11:27:28 by pk825 »