suttonrog I will try your proposition to see if it help.
Thx

Plate solving requires sharp round stars.. With such long focal lengths the stars can get bloated and cover many pixels. The software then rejects them as stars (DSS will also reject them). By binning, the star size is reduced and made sharper and any noise wont be mistaken as a star,
I notice that you are using full gain. Try dropping it to cut down on noise and false stars.

Rog

suttonrog oh good idea, didn't try that, an other option to try out.
Thx

The object I try to get is located at 12h26' +12°33'
So you will understand why I need native equipment.

kellimtai The object I try to get is located at 12h26' +12°33'
So you will understand why I need native equipment.

Yeah, the skies near NGC4388 has few stars to use for plate solving. Lots of small, dim galaxies in that region, but they cannot be used for plate solving (they are not even in star databases).

As a last resort, GOTO a part of the sky nearby that has more stars and do a plate solve there, then sync your mount before doing a blind goto to your final target. With good mounts, good polar alignment, and good leveling of the mount, you should end up quite close to your target.

As a really, really last resort, take an image and submit to astrometry.net to plate solve after doing an initial GOTO with ASIAIR. Then apply the difference in RA and Declination that is obtained from astrometry.net to the ASIAIR for a blind GOTO.

Good luck,
Chen

w7ay yes it was the idea to do it that way but unfortunately the wather conditions changed fir tonight so will have to do it a other day. In case I couldn't catch it with the RC I got the option to use my newton 200/1000 and try it with that it do open twice the size of opening.

Have you tried the Detect Star option to find out how many stars Asiair it is detecting?

Maybe Chen could explain to us how many and of what magnitude are necessary to be able to make a correct platesolve (or a correct stack, too)

elpajare hi
I shared 2 pics just above to show how many stars it get if I put my gain at max and the exposition time at 10sec.
In average I get in that configuration 180 stars if it is at a right place with a lot of stars but due of the little window i get with the RC it shrinks to get enough stars in a combination but what's strange is, it's before I got the possibility to catch the PA without problems still using the first gen Asiair.
But if the VW Asiair is more capable with a more little window of course it will be my next investment. But also consider I need ZWO to investigate in a little camera like the asi174 but with integrated GPS to do my work in asteroid ocultation. It need to be very precise at the frame per integrated time.
Well this is of course not for the RC it's more for a fast newton.
Actually I will test some proposition tonight the sky is a bit shitty but should be enough for testing.
If it runs well tomorrow I will get a good weather condition to try it again and do my work elsewhere I have to use the 200/1000 newton.

Thx to Chen and the other, I will replay my test later.

I am more concerned with the magnitude than the number of stars. It would be interesting to know what the limiting magnitude is for Asiair to take them into account.
I also have problems with platesolving and stacking.

To better understand each other, I am using an RC 203/1824 with the ASI294MC and my preview is 5 seconds with maximum gain.

StevenEvan These are the plate solving files included in the ASIAIR Pro

Interesting that ASIAIR includes the 4204 through 4206 files from the 42xx series, while the 42xx series at astrometry.net goes from 4201 (smallest asterisms) to 4207 (largest asterisms).

I wonder if ASIAIR will automatically scan the folder for other series 4200 files (e.g., 4203 to support smaller FOV for example) if we add them to the folder.

The total size of the 4203 files is about 2.5 GB.

Chen

Nice work both.
A quick way to check you image is to download ASTAP onto your PC with its reference files and use this to check your image. I find that this works most of the time.
https://www.hnsky.org/astap.htm
Rog

StevenEvan The AAP installed index files are a total of 2.47GB in size and ZWO load all of these into memory and search "in parallel" to speed up the search. However, if you add another 2.5GB for the 4203 index files you don't have room in the RPI and you need to change the config file for sequential search on the SD card. This is much slower and can take many minutes to find a match.

Ah, so this is what prevents the FOVs in the original ASIAIR to be expanded for the long focal lengths.

Also, searching in parallel must mean that it is an I/O and memory bound problem and not a processor bound problem. A future release of Raspberry Pi might fix that.

This also explains why some of the plate solve threads stay around. Often, even after you abort a plate solve, it would, a few seconds later flash a window up to announce that plate solve has succeeded. All sorts of threads in ASIAIR not properly killed. (Not just in plate solving but especially noticeable in the Focus window; or when you switch cameras.)

One possibility with file size limitation to actually remove the files that you will not ever need (not for the faint hearted). If you are far enough in the northern hemisphere, you will never need too plate solve stars in the south. Ditto when you add the higher resolution files -- only add the files with the asterisms that you ever need. Even better, preprocess the files from astrometry.net to throw the unneeded asterisms away.

And the way to mitigate the memory size limitation is perhaps to edit the index files to remove unneeded stuff too.

I see a fun side project coming up -- a program to filter the asterisms from astrometry.net to produce files that matches a latitude (should speed up searches too, not that we really need any speedup when the plate scale is known), ha ha.

Chen

StevenEvan So I changed this in the binaries to 20 degrees and that was an nice speed improvement.

+/- 180º is insane, and only useful for circumpolar stars and people using DSLR lenses.

ASIAIR should just be working with just the database that are in the hemisphere which contains the Zenith. This could speed up solves by a factor of two (not quite your factor of 9 speed improvement).

That being said, the Raspberry Pi 4 version of ASIAIR is already quite fast when the focal length is known. With my mount simulator (which can draw stars at very good signal to noise ratio for the camera that is pointed at the computer monitor), ASIAIR often solves in 0.3 seconds with an equivalent focal length of 210mm with an ASI174 sensor.

Chen

w7ay That being said, the Raspberry Pi 4 version of ASIAIR is already quite fast when the focal length is known. With my mount simulator (which can draw stars at very good signal to noise ratio for the camera that is pointed at the computer monitor), ASIAIR often solves in 0.3 seconds with an equivalent focal length of 210mm with an ASI174 sensor.

Chen

You're right. If you stay within the recommended FOV it works well.

At the time I investigated this I was doing planetary imaging with an ASI224 on a 8" SCT at FL 2030mm.
My FOV was half the minimum that was recommended by ZWO for the AAP.
I added all the available index files (4200-4203, around 30GB) and reduced the search radius to +/-20 degrees.
I could get plate solves in around 5-10 seconds in good condition with a known FL.

It's not really a practical solution for most people, considering the work involved.

Steve

Ciao Steven, questo processo può essere applicato anche ad Asiair PLUS, che non ha scheda micro SD?
Se fattibile, si potrebbero avere istruzioni più dettagliate su cosa e come modificare i file per aggiungere gli indici 4200-4203 e ridurre il raggio di ricerca a +/- 20 gradi?
Grazie mille