My tutorial for installing, setting up and using AstroTortilla

[Thalestris24]

As I know that my images are exactly 2.44 degrees wide, I wanted to explicitly clamp the scale to as close to that value as I could. After all why search scales from 1.22 to 4.88 when I know that the scale will be exactly 2.44. It solves faster with 2.4 to 2.5 than with 1.22 to 4.88, but I got fed up with resetting the values.

The bottleneck on plate solving is now waiting for Backyard EOS, and converting the 22mp jpeg to a ppm and extracting the stars. So I am not too worried.

Well, if that works then no problem!

[Gina]

I now have AT working very well and solving in 5-8 seconds.  I'll post my settings later when I have my observatory laptop running if anyone would like to know them.

[julian489289]

Hi, I am trying to get my AT set up parameters maximised for my set up.  Currently it takes AT about 70-90 secs to solve.

I use an Explore Scientific 102 mm Triplet APO, 714mm Focal Length, Canon 650D DSLR which I understand has a FoV of 1.79 deg x 1.2 deg and a resolution of 1.24"/pixel. 

I set the exposure to 10 secs and currently I have set my Solver settings as follows;

Downscainlg            0

Scale minimum        0.6

Scale Maximum       2.685

Scale Units              degwidth

Scale refinement     0.1

Search radius         15

Custom options       --sigma 70 --no-plots -N none -H 2.685 -L 0.6 -r -- objs 100

Could anyone please advise as to whether these are the correct settings and how I can reduce the time it takes AT to solve??

[frugal]

Julian,

Which index files are you using?

[Thalestris24]

Hi

You might find the faq useful: http://sourceforge.net/p/astrotortilla/home/FAQ/

Not sure if it's a typo but there shouldn't be a space with the --objs 100. I usually run it with --objs 50 and the -r sort. Also, you don't need the --H and --L parameters.

Hope that helps

Louise

[julian489289]

Thanks Guys

I have not altered any index files so I assume all of them.  Not really sure what to do or how to tell which ones I don't need??

Yes Louise that was a typo, oops!!  What difference would dropping 100 to 50 make?  Also what do you mean by running with the -r sort

What should my custom line read rather than what I have?

Sorry not much knowledge of this area,

Thanks again

[Thalestris24]

Hi

The sort does what it says on the tin - sorts the stars in order of brightness so quicker. If you do the first 50 brightest then I think it's slightly quicker than doing the first 100. As it says in the faq: "-r to re-sort the discovered objects calibrated by the background flux, and -c 0.02 or higher value to relax the star pattern accuracy from the default 0.01"

Louise

[julian489289]

Thanks Louise, How do I know if I am using the 4000-series indexes and where would I add the -c 0.02 in the string?

Also you state that I can remove the -H & -L but I thought that I had read in the tutorial that these figures re the FoV needed to be in the string?

--sigma 70 --no-plots -N none -H 2.685 -L 0.6 -r --objs 50

Also should I reduce the 10 second exposure time that I use, would that speed up my solve?

Sorry for a million and one questions

[Thalestris24]

Hi Julian

If you followed the normal AT installation you would have downloaded the 4200 series which are fine. I don't use the -H and -L parameters and it works ok. I wouldn't say using them or not using them makes any difference to speed. You can just put the -c param at the end of the list but if you're solving ok without it then you probably don't need it. Again, I don't think it will add anything to speed. Adding the -r switch should help speed things up, as should reducing the number of objects to 50. If you turn on the log viewer in Tools tab you'll be able to monitor the solve process which should help to see where it's taking most of the time. Reducing the exposure to 3-5s might be a good idea. Also, try setting sigma to 30 or 40 in order to detect more stars.

Hope that helps

Louise

[frugal]

I have not altered any index files so I assume all of them. Not really sure what to do or how to tell which ones I don't need??

If you have all of the index files then it will be slowing tour matches right down. You should just need to install a few indexes based on the camera and scope combination you have. Thee is a section in the original post

[julian489289]

With a FoV of 1.79 deg x 1.2 deg how do I work out what indexes I would need?

[Gib007]

With a FoV of 1.79 deg x 1.2 deg how do I work out what indexes I would need?

Hi Julian,

You can take 1.79° to be your "maximum FOV" and 1.20° to be your "minimum FOV". To give some leeway both ways, you can choose the following astrometric index files:

Narrowest level: Index 4206, 313MB, 16-22 arcmin

Widest level: Index 4212, 4.0MB, 2-2.83 deg (120-170 arcmin)

That will download those two plus all the astrometric index files in-between them. It will have everything it needs to work!

Best Regards,

Kayron

[julian489289]

Thanks Kayron.  Is there a tutorial or instruction page for how to remove the unwanted index files?  I assume that you should not delete them.

Kind Regards

Julian

[julian489289]

Where are these index files kept on my computer when I downloaded them?

[Thalestris24]

Hi

On a win7 system they are in: c:\cygwin\usr\share\astrometry\data

You can just create a sub-folder in the same directory and move any unwanted index files into there.

Louise

[julian489289]

Thanks Louise.  I have windows 8, will that be the same location?  Sorry not too computer savvy.

Do I have to set up a sub directory for the files not required in that same data directory and leave the ones required as they are?

[julian489289]

Sorry Louise ignore my last I did not read you full reply.

I have checked this data folder and 4212 & 4213 are not there??  Is this right?

[julian489289]

I also note that 4203 - 4207 all have a number of additional files connected but after 4208 to 4219 there are no additional files.

4203 47 extra files

4204  47 extra files

4205  11 extra files

4206 11 extra files

4207  11 extra files

[Thalestris24]

Sorry Louise ignore my last I did not read you full reply.

I have checked this data folder and 4212 & 4213 are not there??  Is this right?

Hi

It depends on which index files you downloaded.... If you want any that you haven't already got then just re-install Astrotortilla and it has options for just downloading index files. It's worth spending time with the tutorial so you can be methodical about it.

Louise

[Thalestris24]

I also note that 4203 - 4207 all have a number of additional files connected but after 4208 to 4219 there are no additional files.

4203 47 extra files

4204  47 extra files

4205  11 extra files

4206 11 extra files

4207  11 extra files

That's correct!

[frugal]

I also note that 4203 - 4207 all have a number of additional files connected but after 4208 to 4219 there are no additional files.

4203 47 extra files

4204  47 extra files

4205  11 extra files

4206 11 extra files

4207  11 extra files

It is not so much that those indexes have additional files, but more that the index is so big that it needs to be broken up into multiple parts to be usable.

[julian489289]

Thanks for your patience everyone.     As you have probably guessed I have no idea re computers etc!!

However, with everyone's kind help and time, hopefully I am getting there!!

I have now reinstalled 4212 missing from  my data file and put all of the others in a separate sub directory within the data file. 

I will let you all know how I get on on the next clear night with AT.  Oh no i hear you all gasp!

[Gib007]

Thanks for your patience everyone.     As you have probably guessed I have no idea re computers etc!!

However, with everyone's kind help and time, hopefully I am getting there!!

I have now reinstalled 4212 missing from  my data file and put all of the others in a separate sub directory within the data file. 

I will let you all know how I get on on the next clear night with AT.  Oh no i hear you all gasp!

Hi Julian,

I've replied to you on my tutorial comments. I hope it helps you out - I feel it will fix your re-centering failure issue!

Best Regards,

Kayron

[julian489289]

Thank You every one for your great advice. 

I then followed guidance from Kayron as to the sequence for opening the different programs.  However, this still failed and AT did not re centre after solving until I changed  the append on sync command to dialogue based on Eqmod, then it solved and re-centred!! 

Thanks again

[Gib007]

Thank You every one for your great advice. 

I then followed guidance from Kayron as to the sequence for opening the different programs.  However, this still failed and AT did not re centre after solving until I changed  the append on sync command to dialogue based on Eqmod, then it solved and re-centred!! 

Thanks again

Hi Julian,

It's great to hear you fixed it and with something so simple as well. Having changed EQMod to work "Dialog Based" means Sync commands are not adding alignment points and therefore do not function as star alignment. It's not really an issue at all. After all, you go to your target, you plate solve on it and you're 100% centred on your target. You then just guide and image. No need to do star alignment at all and so having EQMod in "Dialog Based" mode is not a disadvantage. 

Best Regards,

Kayron

Edited March 25, 2015 by Gib007