Looking for beta testers of new Polar Alignment utility.

[Gonzo]

" Left / Right / Up / Down" add-on feature request.

I'm going to try to explain... bear with me...

EQ3-2:

Star Adventurer:

Look closely at the location of polar alignment knobs, on the EQ3-2 it's at the front, while on the Adventurer it's at the back.

I believe on the PPA, the left/right/up/down confusion comes from where the knobs are located and from where you stand.

Feature request:

Can we have an option like " polar adjustment knobs: front ~ rear"

From that option, the up/down/left/right statements would be reverse.

Also, the user should be always facing the lateral knobs.

[themos]

Hello Gonzo, the instructions left/right up/down are as if someone were to grab the celestial point at the end of the polar axis and move it. I'd really not want to start confusing people with inverting but I could put a little Notes window under the Move window that says whatever the user wants it to say , eg, "Left means tighten blue knob".

[Gonzo]

A note would be good.

[themos]

Andy, I always use arcsec per pixel myself as it's what the solve-field command displays. I am also pretty sure that downscale=0 causes problems (if the user selects value=1, I just don't pass anything). Also, you have scale explicitly set in the extra field and it is the wrong way round (-H2 -L4.5). I am also suspicious of the --sigma and --objs options so try without them. In summary I would put in the extra field "-p -B none -M none -N none -R none -U none -S none" and nothing else, set arcsec/pixel, L=1, H=120, downscale=2 and try it. Then you can start experimenting.

[visionoz]

Hi Themos

Some Queries Before a live Run using PPA please!

1) With v1.0.4 are PPA_coarse.cfg and PPA_fine.cfg still required and relevant if AstroTortilla is installed and one wishes to use the "local" solves?

2) Would it make any difference if one has the CWD (ie parked position with the mounting pointing to SCP + counterwieghts pointing down) and had the DSLR in a portrait position for the first shot and then slew in RA to the horizontal postion for the second shot or the DSLR in horizontal position with the CWD at the start for the first shot and then slew in RA to take the second shot as portrait position? Methinks it doesn't matter as long as the image used in the solve is the correct one wrt the "vertical" & "horizontal" buttons.

3) After taking the first vertical & horizontal shots would a delay of time period affect the results of the "Show Improvement" plot? ie if say one were to take the third shot intentionally 5 mins after the first two were solved?

I suppose I could experiment and find out for myself but am time-poor atm, not wishing to wait for next week but rather would like to try it out in my backyard for practice first with my EQ6!

Cheers

Bill

from Sunny Perth, DownUnder

[AndyKeogh]

Andy, I always use arcsec per pixel myself as it's what the solve-field command displays. I am also pretty sure that downscale=0 causes problems (if the user selects value=1, I just don't pass anything). Also, you have scale explicitly set in the extra field and it is the wrong way round (-H2 -L4.5). I am also suspicious of the --sigma and --objs options so try without them. In summary I would put in the extra field "-p -B none -M none -N none -R none -U none -S none" and nothing else, set arcsec/pixel, L=1, H=120, downscale=2 and try it. Then you can start experimenting.

Thanks Themos

Tried your parameters  but AT gave up after 10 mins of cpu time.  Simplexy had found over 4000 items!

My parameters came from http://lightvortexastronomy.blogspot.co.uk/2013/08/tutorial-imaging-setting-up-and-using.html and he makes the case for defining a sigma value.  I have added that back into your set of parameters.  After a bit of experimentation I am getting solves with a sigma of 16. Simplexy still finds around 1000 items which I think is a bit high. 

Solves are taking longer so I think it is now time to read up on AT's configuration parameters.

Solve for Portrait (v) image:-

Solve for landscape  (h) image This took 145 seconds!

I compared the improved polar alignment using solutions from Astrometry.net and Astrotortilla and there was only a few arc seconds  difference so that is very promising.

Astrometry.net solution :-

Local solve solution :-

Thanks again for all your efforts.

Andy

[themos]

1. No, the PPA_coarse.cfg and PPA_fine.cfg are not looked at unless you explicitly click the "Read from Astrotortilla configuration" button and point to one of them. You can make lots of different AT config files and read them in as needed (but make sure they don't have mistakes in them!).

2. Correct, it doesn't matter how the camera is set up relative to the mount. The only sensitive issue is that the image marked horizontal (or improvement) is the one where the horizon would be horizontal.

3. After a 2-image solve and determination of where the RA axis is on the image, the one thing you must not do is move the camera relative to the polar axis. You can rotate about the polar axis or move the polar axis plus camera as rigid body. Normally, a few minutes delay is not going to be important. If you had tracking on during all the time, and a few minutes have passed your improvement image will no longer be horizontal. But the difference will be small so the left/right/up/down instructions will still make sense but they will be refering to a slightly rotated set of axes. You can rotate back to a more horizontal position if the camera is noticably non-horizontal (say you had to go away for 20 minutes or so). As long as you only rotate around the polar axis, the magnitude of the error displayed will be correct but the breakdown in terms of left/up will change. 

Hi Themos

Some Queries Before a live Run using PPA please!

1) With v1.0.4 are PPA_coarse.cfg and PPA_fine.cfg still required and relevant if AstroTortilla is installed and one wishes to use the "local" solves?

2) Would it make any difference if one has the CWD (ie parked position with the mounting pointing to SCP + counterwieghts pointing down) and had the DSLR in a portrait position for the first shot and then slew in RA to the horizontal postion for the second shot or the DSLR in horizontal position with the CWD at the start for the first shot and then slew in RA to take the second shot as portrait position? Methinks it doesn't matter as long as the image used in the solve is the correct one wrt the "vertical" & "horizontal" buttons.

3) After taking the first vertical & horizontal shots would a delay of time period affect the results of the "Show Improvement" plot? ie if say one were to take the third shot intentionally 5 mins after the first two were solved?

I suppose I could experiment and find out for myself but am time-poor atm, not wishing to wait for next week but rather would like to try it out in my backyard for practice first with my EQ6!

Cheers

Bill

from Sunny Perth, DownUnder

[themos]

Andy, downscale =2 should help with cutting down on the number of sources identified. After your initial solve with scale [1,120] you find a scale of 2.57. Subsequent solves should be using a scale interval of [2.57*0.95, 2.57*1.05] if you have the "Restrict scale" setting ticked. I would be surprised if those two factors do not significantly improve your solve times. Here is what I get with one of your 2.57-scale images as a subsequent solve (downscale is 2, sigma is 16)

C:\cygwin64\bin\bash.exe --login -c "solve-field -b /usr/local/astrometry/etc/astrometry4200.cfg -u app -L 2.45 -H 2.70  -z 2 --sigma 16 -p -B none -M none  -P none -R none -U none -N none -S none -O  \"Q07A8473.JPG\""Reading input file 1 of 1: "Q07A8473.JPG"...jpegtopnm: WRITING PPM FILERead file stdin: 5760 x 3840 pixels x 1 color(s); maxval 255Using 8-bit outputExtracting sources...Downsampling by 2...simplexy: found 115 sources.Solving...Reading file "Q07A8473.axy"...Field 1 did not solve (index index-4214.fits, field objects 1-10).Field 1 did not solve (index index-4213.fits, field objects 1-10).  log-odds ratio 163.818 (1.39692e+71), 19 match, 0 conflict, 88 distractors, 25 index.  RA,Dec = (11.9382,89.7333), pixel scale 2.57482 arcsec/pix.  Hit/miss:   Hit/miss: -+-+-+--+--++--+-+-++--+----+--------+-+--+---------------------------++--+-------------------------Field 1: solved with index index-4212.fits.Field: Q07A8473.JPGField center: (RA,Dec) = (11.82, 89.73) deg.Field center: (RA H:M:S, Dec D:M:S) = (00:47:17.243, +89:44:03.824).Field size: 4.11842 x 2.74579 degreesField rotation angle: up is -90.4765 degrees E of Nlocal solve time 16.1820001602

downscale=4 and sigma=4 also produce quick solves with 100+ sources.

[AndyKeogh]

OK I have had a play around with sigma and the downscale factor to see what sort of relationship exists.  My main focus was on the first horizontal image Q07A9356.  What I noticed was that as the down sampling increased  the value of sigma had to be reduced otherwise no source objects were found and the solve failed.   The following table shows my results.

I noticed that the value of RA and Dec changed with downscaling and also with some values of sigma.  So I ran two solutions :- the first with downscaling set to 1 and sigma set to 64  I then changed downscaling  to 4 and sigma  to 4.  The results are in the notes field rows 28 and 29.   No difference except downscaling to 4 saved a whole 8 seconds. 

Caveat  this result is based on a sample size of 1.

So this is my improvement using local solve.  The Astrometry.net solution is earlier in this thread.

So it appears that whatever downscaling factor is used, as long as the number of sources found is approximately 100 or more then a local solve produces a good result.

QUESTION.  Is there any guidance available on the minimum index set required for a successful solve with PPA and Astrotortilla?

Andy

[themos]

Hello Andy, 

the place to ask detailed questions about astrometry.net solves is 

https://groups.google.com/forum/#!forum/astrometry

Yes, there are ways of figuring out which index .fits files you would need at a minimum, given your image scale and size. I don't feel qualified enough to give advice, though. 

I think the reason you see different RA/DEC centers for the solves is that the astrometry.net does not always pick the same stars to match, when you change the downscale and sigma options. I think the way it works is it tries matching a certain "quad" (a set of 4 stars) with a quad in its database and then goes to find corroborating evidence by finding database stars in the image where they are expected to be. Sometmes it uses a particularly squashed quad and then I expect the accuracy to drop off. Ideally, we would select the quad ourselves, picking 4 stars that are in the image and are "well separated". Something to think about...

Themos

[Gonzo]

Yes, there are ways of figuring out which index .fits files you would need at a minimum, given your image scale and size. I don't feel qualified enough to give advice, though. 

that link might help you out

http://astrometry.net/doc/readme.html#getting-index-files

Edited January 12, 2015 by Gonzo

[AndyKeogh]

Thanks Themos and Gonzo will have a look later.

[AndyKeogh]

Hi Themos, last night I had a problem with local solves in V1.04  all my setup data from my earlier sessions had been forgotten  My expectation was that it should remember it.  Have I missed something?

Andy

[themos]

Hello Andy, the settings should have been saved in the file PPA.ini, in the same directory as all the other installed files. You may have reinstalled in a different directory, perhaps?

[AndyKeogh]

Hello Andy, the settings should have been saved in the file PPA.ini, in the same directory as all the other installed files. You may have reinstalled in a different directory, perhaps?

Well I went back to my new build "shed" computer and it worked fine this morning.  Last night I had lots of problems  with remote logins to the existing "shed" laptop so maybe I forgot which machine I was actually on at the time.

Sorry for the false alarm.

Andy

[Gonzo]

This is strange, I am unable to get the 'local' to work on the latest version.

Set the shell to:

open -a Terminal /

configfile to:

/usr/local/astrometry/etc/astrometry.cfg

The 'local' button is still unavailable, am I missing something somewhere?

[Gonzo]

Also noticed that only the API settings are saved on restart, the Local solver settings do not get saved.

[Gonzo]

This is strange, I am unable to get the 'local' to work on the latest version.

Set the shell to:

open -a Terminal /

configfile to:

/usr/local/astrometry/etc/astrometry.cfg

The 'local' button is still unavailable, am I missing something somewhere?

managed to get the 'local' button to appear with

shell = /bin/bash -c "%s"

loading up an image, hit solve and all I get is in the terminal:

local solve time 0.0644419193268

but nothing gets solved really.

[AndyKeogh]

managed to get the 'local' button to appear with

shell = /bin/bash -c "%s"

loading up an image, hit solve and all I get is in the terminal:

local solve time 0.0644419193268

but nothing gets solved really.

have you been into File Settings ?  There is an import button to read your Astrotortilla settings.

Andy

[Gonzo]

I'm on a Mac and do not have Astrotortilla. I have also updated the PPA.ini file manually.

Could you please post your Astrotortilla config files?

My local astrometry install works fine, I can solve-field images without any issues from the command line.

[Photosbykev]

I had a play last night with a EQ3 Pro mount and Canon 5D3 and 200mm lens. I delibrately offset the PA by a few degrees and then shot a vertical and horizontal image which PPA solved using a local installation of AT in about 5 seconds/image. What threw me was the image that popped up showing the red X etc, because I was about 4 degrees off the magnification of the visual image was too large to see the X and the true NCP. I also struggled to visualise what the move instructions meant i.e. move 4 degrees right and 2 degrees down. Am I right to assume I had the mount 4 degrees left of the NCP and 2 degrees too high??

Also does the alignment of the camera relative to the axis of the mount significantly affect the results?

[StevieDvd]

I'm on a Mac and do not have Astrotortilla. I have also updated the PPA.ini file manually.

Could you please post your Astrotortilla config files?

My local astrometry install works fine, I can solve-field images without any issues from the command line.

I'm using PC windows and a local astrometry without astrotortilla and found what was needed.

If the api field is empty it does not save all settings (I guess that's a check for the new user to make initial settings) just put a number in the api key box.  Second the config file is for the location of the astrometry config (mine is /etc/astrometry/backend.cfg)

Just need to get the solve settings and local copies of the solve files all tidied up for the cameras I plan to use. Will be using the local solve for SGP too.

Hope that helps.

[AndyKeogh]

I'm on a Mac and do not have Astrotortilla. I have also updated the PPA.ini file manually.

Could you please post your Astrotortilla config files?

My local astrometry install works fine, I can solve-field images without any issues from the command line.

Here is a screenshot of my settings for a local solve. Camera is a Canon 5D mkIII in a Megrez90.

If you do not know your image scale  then untick Restrict scale  and set scale_low to 1 and scale_hi to 180 and see what comes back with the solve.  Alternatively sole with Nova and it will provide your image scale.  Themos in an earlier message gave the factor to convert the scale into a range.

HTH

Andy

[themos]

I'm on a Mac and do not have Astrotortilla. I have also updated the PPA.ini file manually.

Could you please post your Astrotortilla config files?

My local astrometry install works fine, I can solve-field images without any issues from the command line.

Hello Gonzo,

I messed up the Mac case in 1.0.4 

To treat it as a Linux machine with 1.0.4 perhaps it will work if you edit your .bashrc file to include setting the environment variable OSTYPE to linux. 

export OSTYPE=linux

[Gonzo]

Will try and report. thanks