Astroart Forum

Hello, a new minor version of Astroart 8 is available:

Version 8.0 SP3 - January 3, 2023
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* New feature. Astrometry with optical distortions.
* New feature. Reading and writing of FITS SIP distortions.
* New feature. Three modes for "follow minor planet".
* New feature. Camera control for the 64 bit version.
* New feature. Several script commands.
* Improved. Plate solving is 5% faster.
* Improved. More options for plate solving.
* Improved. Telescope automatic centering up to 10 degrees.
* Improved. Remove Gradient updates in real-time when changing points.
* Improved. Blink full screen with option for fractional alignment.
* Improved. Star atlas, the last searched minor planet is highlited.
* Improved. Star atlas, constellations can be searched.
* Improved. Finer zoom levels.
* Bug fix. Menu "Select coordinates" did not work sometimes.
* Bug fix. Minor corrections in the user interface.

Web site: https://www.msb-astroart.com/

futher information from the updated documentation:

"Follow minor planet" in Preprocessing:
... an extra offset is added to the auto-alignment to track a minor planet, for example for astrometry or photometry. Two modes are possible: Arcseconds per minute. The required parameter is the motion of the minor planet. It can be calculated from the "Find" button if an updated MPCORB file is available, or it can be manually taken from the MPC ephemeris page. The first image of the sequence must be astrometrically calibrated (see Plate solve and WCS), otherwise the scale and the orientation of the camera must be entered as well, for example from the settings of the Observatory.

Pixels per minute. Here the motion does not require any information about the minor planet, it's calculated from any two images of the sequence. For example, before launching Preprocessing open the first and the last image of the sequence and select the minor planet on both images.

Plate solving at beginning of a session
If no approximate coordinates are available, it's now possible to suggest a constellation (e.g. ORI, LEO, VIR, etc.) or a bright star (Vega, Rigel, etc.) and quickly set a wide search zone (30 degrees, 60 degrees) using the new buttons, see below.

Plate solving tutorial with the N6824 image:
... open the image N6824.fit, the field of view is unknown. We could write something like 30 arcminutes +- 70% to cover most typical fields (i.e. from 15 to 50 arcminutes), but we know the CCD size and the telescope focal length, so we can make a better estimation. Click the "Estimate..." button. Write 2000 as focal length and 10.2 as CCD size and click OK. A field of view of 17.5 +- 20% will be selected. Set "N6824" as Search Zone, 3° x 3° as Size and click OK to plate solve.

The procedure will be done correctly, but for the future we still need to know the exact field of view of our system. Open the Statistics window and note that the actual field of view is 20.9 arcminutes. Open again the Plate Solve window and write 20.9 +- 2% then click "Save parameters". Let's suppose now that the object and the approximate coordinates are unknown, but we were pointing the telescope just above the summer triangle. Set 60° x 60° as Size, then "Vega" or "Deneb" or "CYG" or "LYR" as search region, verify that plate solving works as well.

Astrometry, optical distortions
... for a quick check of the calibration, take a look at the O-C (Observed - Calculated) in the list: this is the difference between the known position of the star (from the catalog) and the calculated position. If some stars have a very high O-C they can be excluded reducing the O-C max value (here it's 0.9 arcseconds and one star got excluded). But be careful, don't exclude more than 10% of the stars, otherwise you are actually "cheating" in obtaining a better result. Try to enable the option "Optical distortions": if all O-C decrease, then the image is actually distorted (this is common with fields larger than 30 arcminutes) and this option should be always used.

Camera control 64 bits
64 bit plugins are included for ASCOM and Starlight-Xpress. Actually the 64 bit version is able to control any legacy 32 bit driver, in this case a proxy 32 bit process is launched and controlled by interprocess communication.

New script commands Set a custom tracking speed, can be useful for satellites. About the speed see:
https://ascom-standards.org/Help/Platfo ... onRate.htm
return the field of view in degrees for a calibrated image.
Checks if a file exists on disk.

In SP3's chart display, SP2 displayed comet and asteroid numbers, but SP3 no longer displays them.

Hi, verify if the button "ABC" is selected: and the Name Format in the options:

Hello Fabio,
Thanks a lot for this new Service Pack. I tried directly the new plate solving and astrometry functions. Very helpful for large field deep sky photos.

Here is a somewhat extreme example for Astrometry (M38 5x60secs on Celestron EHD Hyperstar V4 w. Lacerta DS2600C pro:
1. optical distortions OFF: only about half the image area can be solved (with this precision of 0.8')
2. optical distortions ON (Same settings for O-C max!): Very good IMHO.
This directly gives me further ideas: is there a possible way (in AstroArt?) to transform the image with the SIP information to CORRECT for the determined optical corrections? I use a raw processor software for DSLR nightscape images.
Any thoughts/ experiences from the community?
Sincerely
Bernd

Hello Bernd,
thanks, that's very interesting. OK it will be added immediately for SP4. Please write me by email next week to receive the pre-release.

P.S. I forgot to write that to update the language ("Optical distortions" is not translated in the screenshot) it's required to download the updated language files from the web site.
Fabio.

I also tried astrometry.
My equipment is a 1.22”/pixel 4kx4K CCD camera and a D400mmf.l.1510mm astrophotography telescope. Initially processed without optical distortion correction. The number of detected stars is set to 500 stars. There are 196 reference stars, and 163 of them are sky blue. Does it make sense? The second photo is taken with Astrometry opened and optical distortion turned on. Then it becomes only the reference star 180. The third one is the result of automatically searching for stars again with this setting from the beginning. It was reference star 163/196.

Hello Hidenori,
If I calculated well, Your setup covers about 90arcminutes of the sky AND your CCD is rather large (40mm), so there could well be optical distortion effects, even in a good optical setup. So, it makes sense to me to use or compare with the optical distortions ON.
A word of caution: With your resolution of 1.22"/pix, the estimated precision is close (1.3") or well below your setup's resolution (case 2: 0.6"). Keep that in mind.
If I look at your first screen shot, more "blue" crosses (stars that were successfully solved) are closer to the image center, the edges only have white (unsolved, O-C too large) stars. That does make sense to me.
When you turn on "optical distortions" (with O-C set to automatic!!), your maximum error decreases to about half the size (from 1,3" to 0,6"). Therefor, you end up with a LOWER number of solved (blue crosses) stars. That is also an indication that you have some optical distortion in your system.
Not sure if this helps
Sincerely
Bernd

Hello AstroBernd,

I use Astrometrica for position measurement. The reason is that the recorded time is a problem on my system, but with AA, the value that is 30 seconds behind is returned in the MPC report with a 1 minute exposure stack. For some reason, the value described in OBS DATE TIME of FITS is not entered.
As for the optical correction function this time, if we use ASTROMETICA's high-order correction function, O-C is usually within 0.6 seconds.
However, celestial objects with large motion have not been improved at all as in the previous example. We found that O-C shows a small value when the motion is small. AA8 or earlier versions can't measure well from images stacked with motion.

Hello Fabio,

I checked the new SP3 with all my Pegasus equipment, Powerbox, Switches and Sensors Temp, Humidity and so on.

In tested all my QHYCCD Cams my Filterwheel and my 10Micron equipment. All was working well with the 64 bit version.

Thanks for the update.

Peter