27 August 2013

TUTORIAL (IMAGING): Setting up and Using AstroTortilla for Plate Solving

Tutorial Type: Imaging - Setup

AstroTortilla is one of those programs that may seem overly complicated to set up and start using, hence this short tutorial for those interested. It is however a program that once you start using, you will not regret having spent the time to install it and set it up. Best of all, AstroTortilla is completely free and works wonders for plate solving. 

For those unaware, plate solving is a process by which software checks your astrophotograph for star patterns and determines what it is you are actually looking at. Why is this in any way important, though? Simple - when you tell your telescope to go to a deep space object, it will go to it but will probably miss and not have your chosen object centred in view. Of course, a decent three-star goto alignment prior to slewing to your target removes quite a lot of the error but:

1. The goto alignment will very seldom provide you with perfect goto accuracy. 
2. Why would you want to bother picking multiple stars and aligning them perfectly when you would rather spend the time actually imaging your target?

It is here that AstroTortilla excels. You set up your telescope and CCD camera, you send your telescope to your target and then tell AstroTortilla to plate solve. It will capture an image with your CCD camera, analyse it to check where you are actually aiming and then slew your telescope to remove the goto error and centre your target. It can even iterate through this process until your target is very precisely centred within a chosen margin of error (default is 1 arcminute). I tend to only need a single iteration to get my target perfectly centred. 

Interested? Well, you will need to sort out a couple of things beforehand:

1. Your mount must be controlled via a laptop and the likes of EQMod or other such ASCOM software, through an EQDirect USB interface. This is paramount as AstroTortilla needs to interface with your mount directly via ASCOM
2. Download the latest version of AstroTortilla for free from this link

With these things sorted, we proceed.


Yes, it may sound silly going through the installation process but there is a bit we need to pay close attention to. Choose to install AstroTortilla to the default directory. 


As we are installing everything from scratch, leave the default option "Install AstroTortilla, Cygwin, astrometry.net and indexes" selected with everything checked. 


If it were all installed but we simply wanted additional astrometric index files (these are the reference files that contain the star patterns to match up against your captured images and astrometric index files are different for different fields of view), we would select "Install additional astrometric index files"

It is important to install Cygwin (part of AstroTortilla's package) to its default directory. 


We now reach the important stage that we need to carefully consider. 


You may have multiple telescopes and multiple CCD cameras. Matching these up will naturally produce different fields of view and if we want to install AstroTortilla armed with all required astrometric index files to work on ALL your combinations, we will need to figure out the fields of view produced by your narrowest-field setup and your widest-field setup. For example, I have two telescopes and one CCD camera. One produces a wide-field and another a narrow-field, so it is easy to figure out the range of astrometric index files required. 

In order to calculate the fields of view, we can use the free, online Sky at Night Field of View Calculator


You may find your telescope and CCD camera listed and therefore you can simply select these (do verify the details are correct!). My CCD camera, the ATIK 383L+, was on the list but my telescopes were not. So, I selected my CCD camera from the list, verified the details were correct and then manually entered my first telescope's details. 


I note that my Borg 77EDII F4.6 with my ATIK 383L+ yields a field of view of 2.93 degrees x 2.18 degrees. Now I enter my second telescope's details. 


Finally, I note that my Altair Astro 8" RC with my ATIK 383L+ yields a field of view of 56.74 arcminutes x 42.26 arcminutes

Now we return to the AstroTortilla installation process. First I select my widest field of view. We always use the biggest number of the two. My widest field of view is 2.93 degrees x 2.18 degrees, so I take the field of view number to be 2.93 degrees (the largest). From the astrometric index files list on Widest level, I select "index 4213, 2.1MB, 2.83-4 deg (170-240 arcmin)". The range of 2.83 - 4 degrees clearly covers my 2.93 degrees. Now for the narrowest field of view. The installation suggests we select about 20% of our narrowest field of view, so let us do that. My narrowest field of view is 56.74 arcminutes x 42.26 arcminutes, so I take the field of view number to be 42.26 arcminutes (the smallest). 20% of it is 8.452 arcminutes. From the astrometric index files list on Narrowest level, I select "index 4204, 1.2GB, 8-11 arcmin". This range clearly covers 20% of my narrowest field of view, 8.452 arcminutes


Please note the installation will actually download these two astrometric index files and every other one in-between them. Checking the file sizes, the astrometric index files for narrower fields of view are quite large and the entire download probably sums up to about 2.4GB in total for my telescopes and CCD camera. Your astrometric index files may differ from mine. 

If indeed you only have one telescope and one CCD camera, then it is simpler. For example, let us say that I only have the Altair Astro 8" RC telescope and ATIK 383L+ CCD camera. We calculated the field of view to be 56.74 arcminutes x 42.26 arcminutes for this setup. We therefore take our widest field of view here to be 56.74 arcminutes and the narrowest to be 42.26 arcminutes. 20% of the narrowest is then 8.452 arcminutes and we have our numbers for selecting appropriate astrometric index files - 56.74 arcminutes for Widest level and 8.452 arcminutes for Narrowest level

Once you have adequately selected your needed astrometric index files, proceed with the installation and finish it. No doubt the downloading of astrometric index files will take a while, depending on your Internet connection with the server. 

STEP 2. Setting up AstroTortilla with optimum settings for fast plate solving

When you first run AstroTortilla, it might look intimidating and perhaps even unrefined. It is however very powerful and you need not do much to configure it and get it running. 


Let us first summarise the sections of this window. Under Telescope, we connect to the telescope mount and once connected, you are shown your current telescope position in the night sky as well as your intended target. Basically when you issue a goto command for the telescope to slew to your target, it will most assuredly miss and you will notice the difference under Current and Target

Under Camera, we connect to the CCD camera via compatible software such as Nebulosity, MaxIm DLBackyard EOS, etc. We can also ask AstroTortilla to control the CCD camera directly via ASCOM or in fact, select File Open dialog and select an image that we have taken by our own means (without asking AstroTortilla to do it itself automatically). Here we also set the desired exposure time. Unless you are currently using a narrowband filter, 10 seconds usually suffices. 

Under Solver, we can customise a couple of settings, and this is what we will do first and foremost. These settings tell AstroTortilla what field of view we are actually dealing with (to give it a head-start in plate solving and allowing it to take much less time), how many degrees off from your target you wish to look at, the noise tolerance, etc. 

Under Actions, we set off AstroTortilla to do its job. It is of utmost importance that we always check Sync scope and Re-slew to target as these will make sure AstroTortilla does the job of centering your target in view and adding a sync point to EQMod (like a goto alignment point) to correct future slewing accordingly. You could also of course check the third option Repeat until within and enter an amount of arcminute tolerance. Please note this will cause AstroTortilla to iterate through the process at least twice (first time to perform the initial error correction and second time to check resulting accuracy), with more iterations possible depending on how far off you are from your target after the first correction. The Capture and Solve button of course, sets it all off to do its magic. 

The first thing we will do is change some settings in AstroTortilla, under the Solver section. Since I have two telescopes and one CCD camera, I have two setups I can possibly use. I will therefore create two settings files, one for each setup, so that in the future I can load up the one I need and set it off quickly. 

The first settings we will change are Scale minimum and Scale maximum. These are where you tell AstroTortilla the minimum and maximum field of view possible. Let us say I am using my Altair Astro 8" RC telescope first. This provided a field of view of 56.74 arcminutes x 42.26 arcminutes with my CCD camera. We will work with degrees rather than arcminutes and therefore dividing these numbers by 60 gives us the field of view to be 0.946° x 0.704°. We note then that the maximum is 0.946° and the minimum is 0.704°. To be safe, we will calculate 50% above and below these values. So, 50% less than 0.704° is 0.352°. 50% more than 0.946° is 1.419°. We need not be 100% accurate so I will enter 0.35 in Scale minimum and 1.42 in Scale maximum


I will leave degwidth in Scale units as we are entering everything in degrees. Now we must edit Search radius. The default value of 180 is way too high. This means AstroTortilla will search 180° around your target. This is quite simply savage as though we will miss the target, we will not miss it by 180°! To be safe though, we will set 15°, so I enter 15 here. Please keep in mind this value if it turns out AstroTortilla is not successfully plate solving your images. You may want to first try increasing it to 30 or even 45 just in case. You should never need to go higher than 45


Finally, we will alter Custom options. The first option that is there by default is particularly important, --sigma 1. This defines the noise tolerance in analysing your captured image for plate solving. The default value of 1 is very, very small and pretty much any speck on your image may be considered a star. Even with a cooled CCD camera, this is certainly not the case and in fact, we do not want TOO many stars to be considered for plate solving as it would take ages. For a 10 second exposure (without a narrowband filter in place!), a much better value is something like 50 to 70. In fact, any value between 50 and 100 is good depending on the number and brightness of the stars in your field of view. This value is balanced out with exposure time, as you would imagine. I would set it to 70 and then just alter exposure time to suit. We leave the --no-plots and -N none options there but add two more. We will reiterate to AstroTortilla the field of view we expect. For this, we use the options -H and -L, which are highest field of view and lowest field of view, respectively. I will stick to the same values as with Scale minimum and Scale maximum and therefore enter -H 1.42 -L 0.35 to the end of Custom options, after adding a space.

[EDIT: There are two more Custom options that are particularly interesting, one of which I was reminded by a comment in this tutorial by Blackwater Skies and the other of which I only found out through this very same comment. My thanks to Blackwater Skies for the contributions. The two options that help speed up plate solving are in some way related to one another and are -r and --objs. The former, -r, need only be added as that. This command instructs AstroTortilla to sort the stars in order of brightest first, therefore allowing AstroTortilla to optimise the plate solving process as it starts with the brightest stars in your image. The second option to help speed up plate solving is rather to ensure that if it is going to fail, that it fails quicker rather than keeping you waiting. The --objs command must be accompanied by a number, e.g. --objs 100. What this command does is instruct AstroTortilla to use a maximum of 100 stars for the plate solving (the developers generally recommend between 100 and 200 stars). After having sorted them in brightest-first, it seems like a good idea to restrict how many AstroTortilla should use as if it fails after the first and brightest 100, for example, there is a very, very good chance it will simply fail altogether. At that point of course you would adjust other parameters such as your exposure time. Please be aware however that these options are not always best. Sometimes you may want to include more stars than 100 or you may not want to restrict the number of stars used. This could be due to persistent plate solving failures. Feel free to remove the --objs command if you feel it necessary and though the -r command tends to be a good idea to leave active, feel free to test by removing it also.]


Due to the length, you cannot see the entire Custom options line in the above screenshot. For reference, it reads:
--sigma 70 --no-plots -N none -H 1.42 -L 0.35 -r --objs 100
AstroTortilla is now customised for my Altair Astro 8" RC so I save the settings to a new file, naming it appropriately for future reference. 



Now to customise AstroTortilla to my Borg 77EDII F4.6 telescope with the ATIK 383L+ CCD camera. We note the field of view was calculated to be 2.93° x 2.18°. This will again define our values of Scale minimum and Scale maximum. 50% less than 2.18° is 1.09° and 50% more than 2.93° is 4.395°. Again, since we need not be 100% accurate here, we enter 1.09 for Scale minimum and 4.40 for Scale maximum


We will leave Search radius at 15, like before, and --sigma 70 in Custom options (for noise tolerance). I of course will alter the -H and -L options to enter the same values as Scale minimum and Scale maximum. -r and --objs 100 are added on as well. 


Due to the length, you cannot see the entire Custom options line in the above screenshot. For reference, it reads:
--sigma 70 --no-plots -N none -H 4.40 -L 1.09 -r --objs 100
Again, I save these settings to a new settings file, naming it appropriately. 



I have now customised AstroTortilla for both my telescopes and their resulting fields of view. Depending on my imaging setup on a particular night, I can load up the appropriate settings file. These settings optimise the plate solving process to make it significantly faster and always yield a solution. You may need to alter exposure time to suit if a solution is not found when plate solving or it seems to be taking too long. For reference, plate solving should normally take under 3 minutes to perform.

[EDIT: If for any reason the stars in your images are not coming out round and plate solving is therefore failing (optical defects, collimation, focus, etc), you can add another Custom option to relax AstroTortilla's restriction on what constitutes a star. The command for this is -c, which needs to be followed by a value. As a default, AstroTortilla uses -c 0.01 but if you wish to relax this a little, you can add -c 0.02 to your Custom options. If you increase it, do so by very small amounts, like -c 0.02.]

STEP 3. Using AstroTortilla for plate solving

With the appropriate settings file loaded (for the imaging setup being used), the first thing we need to do is connect to our telescope mount via ASCOM. So, we select "ASCOM Telescope" from the list at the top and then confirm via the ASCOM dialog that pops up (I am using the simulator for this tutorial!). 



Once connected to the telescope, I issued a goto command in Stellarium to slew the telescope to the Cocoon Nebula



With the telescope on target, you can gauge an idea of the error under Telescope within AstroTortilla (comparing Current to Target co-ordinates). In a real-life situation, the difference here will be much bigger (remember I am using the simulator for this tutorial!). With Tracking displayed under Target, we are ready for plate solving. 

Now we will need to connect to the CCD camera. You have a choice of what to do here. For example, I use Nebulosity for astrophotography so open your program and connect to the CCD camera within the program. Once connected to the CCD camera, select the program from the list in AstroTortilla


It is important to start the program and connect to your CCD camera beforehand as AstroTortilla will issue commands to the program itself to start capture, after which it will download the resulting image and start the plate solving. If your program is not listed on AstroTortilla or for some reason is not working as intended, you can always capture the image yourself within your program and save it somewhere. Then in AstroTortilla, select File Open dialog for Camera and later when we start plate solving, it will ask you to open the image file. This ensures AstroTortilla is very universal. You can also of course, connect to your CCD camera directly by selecting ASCOM Camera and then selecting the appropriate driver from the list, which will be installed if you have used your CCD camera in the past. If you are having AstroTortilla capture and download the image itself (and not providing one via the File Open dialog), set an appropriate exposure time as well. 10 seconds tends to be very suitable and you are advised not to make exposures too long. Under one minute is always good.

[EDIT: A good point raised by a developer of AstroTortilla (read comments at the bottom of this tutorial) is that you can employ the use of binning (if you are using a CCD camera and not a DSLR). To do this, click the Setup button and set it there. If you choose to do this, use 2x2 and not more. 2x2 makes your CCD sensor about four times more sensitive, which means you pick up more stars (and make stars brighter) with the same exposure time. An additional advantage of using 2x2 binning here is that your images become half the size in both x and y, meaning the filesize is reduced about four times. The advantage here is that the image will download much quicker from the CCD camera and AstroTortilla can start plate solving sooner. Please note that it is recommended that you use binning rather than down-scaling of the plate solving image. Binning effectively down-scales the image in resolution but at the same time, makes shorter exposures capture more stars as the CCD sensor sensitivity is increased significantly.]

To start plate solving, check Sync scope and Re-slew to target under Actions


To start plate solving, all we need to do now is click the Capture and Solve button and watch it happen. In my experience, one plate solving iteration centers my objects perfectly but if you want to be very precise about it, check the third option Repeat until within and enter a respective accuracy in arcminutes. Please note that this will cause the plate solving process to be repeated again and again until the desired accuracy is achieved. At the very minimum, two plate solving processes will occur - the first to perform the initial centering to your target and the second to check that it is within desired accuracy. 

In any case, when happy, click Capture and Solve. AstroTortilla will first capture your image, download it and start plate solving (if you chose to provide an image file yourself via File Open dialog, it will just ask you for the image file). The plate solving process starts by searching its astrometric index files (the ones you downloaded for installation) for a match, calculating how far off you are, slewing your telescope appropriately and syncing the difference as a goto alignment point in EQMod. Subsequent iterations of this process are up to you (dependent on your chosen accuracy for repetition). 

This concludes how to use AstroTortilla. It really is that easy and after having customised it for your possible telescope setups, plate solving should be a fast process. Do make sure you play around with exposure time if a solution is not yielded with a 10 second exposure but remember that under one minute is good. Too long an exposure time will basically take longer to capture and will not really be necessary for plate solving. You can of course play around with the --sigma value here as well. Decrease it to include more stars and increase it to reject dimmer stars. 

Kayron Mercieca

37 comments:

  1. Thanks for such a detailed write-up, only one minor update: the -L and -H switches are not necessary, AT will use those switches internally based on the configured scale limits, and you can further let AT automatically adjust those by setting the "Scale refinement" to a some fraction for tolerance, e.g 0.2 for 20%.

    For speeding up a bit, the camera settings dialog supports binning for almost all image sources and with MaxImDL and Nebulosity you can also force a specific filter for AstroTortilla use. Personally, I use Luminance filter, 2x2 binning, no downscaling, and a 2s exposure for all solving purposes on 550mm focal length (1.6x1.2 degrees) and 5s on 1200mm. With those I get a fast download from my camera, a 6-7 second solve time on the imaging laptop for a very quick goto correction.



    Yours,
    Antti from AstroTortilla

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    1. Thanks very much for your comment and clarification of the -H and -L switches on "Custom options". "Scale refinement" does sound like a good option for those wishing for extra tolerance on the FOV limits. 2x2 binning does sound like a good idea for plate solving given its still-high resolution, stronger signal and significantly shorter image download time!

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  2. Great write up. A few additional things that may help:

    1. If using EQMOD, make sure the 'Append on Sync' option is selected (it should be by default). This ensures that the EQMOD pointing model is updated each time AT successfully solves an image and thus improve the accuracy of subsequent gotos through the night.

    2. Two additional parameters can be used in the "Custom options" box to help speed up solving:

    -r

    This re-sorts all the identified stars, or 'sources' in astrometry.net speak, and starts solving with the brightest.

    -objs 50

    This limits the solving attempt to only use the first 50 stars or whatever number you specify. I find that if you can't get a solution from 30-50 stars then the attempt will usually fail so you might as well fail quickly and try again rather than waiting several minutes for the solver to give up. You should use -r and -objs 50 together as far as I can tell.

    3. You can use -c 0.02 (or more) to relax the star shape detection routine. The default value is 0.01 so if you are getting no stars detected try adding it and increasing the value slightly if your stars are bloated or non-round.

    4. You really shouldn't need to use a value as high as 45 degrees for the search radius. Depending on your camera field of view and the initial accuracy of your mount's gotos (before you've done any solving) you can almost certainly use a much smaller value like 5 or 10 degrees. Once you have started building a pointing model (i.e. have a few alignment points) you can usually reduce the value even more, perhaps a couple of degrees depending on your FOV. This will speed up the solving process even more.

    5. When trying to work out the image scale for selecting the index files to download, if you can't find your scope/camera in the Sky at Night (12 Dimensional String) calculator give my imaging toolbox a whirl: http://www.blackwaterskies.co.uk/p/imagingtoolbox.html It has 588 telescopes and 383 CCD and DSLR cameras plus support for focal reducers/barlows and can calculate the height and width of the field of view (in degrees) of any combination.

    6. Alternatively, if you already have a (single unstacked) image from your camera/scope you can upload it to http://nova.astrometry.net/ and have it solved online using the same back-end software as AT. Look in the 'Calibration' section once your image is solved and it will state the height and width in degrees which you can then use for the index files download.

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    1. I would like to thank you for your contributions. You reminded me of the -r command and taught me about the -objs command. I have updated the tutorial and screenshots accordingly and have credited you for it! :)

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  3. Thanks for taking the time to assemble this useful reference!

    Can you tell me, if you use AstroTortilla to set parameters in Nebulosity (like switching to 2x2 binning or specifying a filter) will AstroTortilla restore the imaging camera to the previous settings upon completion? Or is it up to the user/different software to re-establish the Nebulosity settings?

    Thanks again! Great reference!

    Craig Smith

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    1. In my experience with AstroTortilla and Nebulosity, if before using AstroTortilla I have captured an image in Nebulosity, it won't respond to AstroTortilla's commands. What I do here is close Nebulosity and re-open it quickly (to avoid the CCD sensor temperature rising too much as Nebulosity controls it).

      Once Nebulosity is "freshly opened", it responds perfectly to AstroTortilla. However, once AstroTortilla is done with it, the settings in Nebulosity are kept as what AstroTortilla set them to be. This is because AstroTortilla generates a script from your chosen settings and interfaces with Nebulosity, which opens this script and executes its commands. Once finished, Nebulosity remains configured with this script.

      So, if Nebulosity doesn't seem to be taking the exposure AstroTortilla wants, close it and re-open it. Once AstroTortilla has done its job, it's your choice whether to close Nebulosity and re-open it again or just alter the settings. Check everything - binning, exposure time, number of exposures, series name, folder where series will be stored when captured, etc. The last point (folder for storage) is important because AstroTortilla sets a really odd temporary folder to store its plate solving image so you might later be unable to find your actual images (without a search)! :)

      You are very welcome. I am glad this tutorial is helpful to you.

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    2. Thanks Kayron,

      I find the sane thing with Nebulosity, that is, if it is used for some captures, then it seems that AstroTortilla cannot access it without restarting Nebulosity,

      As a result of this work-around, I have at least superficially started learning to use scripting in Nebulosity to restore settings after restarts. Makes things easier, even if I wasn't using AstroTortilla.

      Regards,
      Craig

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    3. Nebulosity does have a few quirks from AstroTortilla point-of-view. It has no way of telling us where images are saved currently, and trying to save an image to an absolute path doesn't work either. Thus AT has to set the image saving directory in Nebulosity script to a known location (temp dir) and it the restores to another known dir you can define in AstroTortilla from the Camera Settings -dialog. The default is something like c:\Astro\\ but you can set it to your liking.

      If there's a problem accessing Nebulosity after acquiring images, this clearly needs to be investigated. Can you reproduce the problem with the (ASCOM) simulator camera? If yes, write a bug report with the steps to reproduce the error at astrotortilla.sf.net

      -Antti

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    4. I love your tutorials very clear and easy to understand thank you for putting this together. I am now using ASTRO TORTILLA and its so much easier to get my targets aligned correctly. More time imaging and less time searching around brilliant.

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  4. Without question this is the best and clearest guidance on Astrotortilla that I have found. Even though I already have gotten it to work for me this has still helped me to refine my use of the program. I only wish I'd had this in the beginning when I was trying to figure everything out for myself.

    thanks,
    Al

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    1. My thanks for your comment. I am glad it was helpful! :)

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  5. Thanks Kayron

    I'm looking to automate an alignment process and this is a great tutorial for me to do this!

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  6. Superb tutorial. Can't wait to get out there now - just waiting for the moon, clouds and fog to clear! :)

    Thanks Kayron :)

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    1. You're very welcome! I'm glad this is helpful and wish you success. Many seem to have found this tutorial useful and I can tell you that to date, I still use the exact AstroTortilla settings described here, with 100% success rate! :)

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  7. Used this for the first time the other night, during one of our increasingly rare clear nights. Gave me something to play with while the moon was fat. Absolutely brilliant. Slewed to the first target, took a snap with AT (all seamless), solved in seconds and then centred the target - spot on. Did this seven times. I could have happily played with it all night, but it was getting a bit nippy!

    One thing I did notice: I'd slewed to M1 and noticed after it took the first snap that it was more or less centred anyway. AT seemed to get a little confused here and kept shifting slightly backwards and forwards in RA. I had to close it down with task manager, but following that it was fine, I suspect it was trying to make a tiny adjustment that my EQ5 isn't capable of doing. Bless :)

    All in all, success beyond my wildest imaginings - thanks for the tute Kayron :)

    Doug

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    1. Doug, my apologies for the late reply. I am really happy to hear that using AstroTortilla after the configuration was very successful! I'm sure that you have since used it further (weather allowing! :)). AstroTortilla is by far one of the most useful programs I use in my procedures. Certainly makes mosaic work spanning several nights a hell of a joy! :)

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  8. Have you used AstroTortilla for polar alignment and if so have you any comment?

    Ian Wardlaw

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    1. Hi Ian, I have not personally used AstroTortilla for polar alignment. There was a bit of a discussion about this going on the thread I created to advertise this tutorial:

      http://stargazerslounge.com/topic/193470-my-tutorial-for-installing-setting-up-and-using-astrotortilla/

      People's general consensus seemed to be that AstroTortilla does not yet have a mature-enough polar alignment feature to really be helpful. Personally I use EQMod for polar alignment and that's it, though I have in the past used Alignmaster to refine this (Alignmaster is excellent).

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  9. Hi,

    Looks like a useful piece of software I'd like to have a go with .

    One thing though, the Index files that are loaded on install, are they available fo download separately ? I'll be installing it onto a laptop that doesn't have internet access (it's in the middle of nowhere in Spain), sop would like to have all the install files and index files ready on a memory stick for it.

    Can I do that, and will the installer take the index files from local disc instead of the internet ?

    Cheers

    S

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    1. Hi Stuart,

      Thanks for your comment. During AstroTortilla's installation on your computer here, install everything including the astrometric index files you need. Make a copy of both the "AstroTortilla" folder in your Program Files folder and the "cygwin" folder in your drive C: on a USB stick.

      For AstroTortilla's installation on your remote laptop, only select to install "AstroTortilla" (as "Cygwin and astrometry.net" and "Astrometric index files" will require an Internet connection). Once that's installed, copy-paste the "AstroTortilla" folder from your USB stick to replace your "AstroTortilla" folder on your remote laptop. Do the same with the "cygwin" folder.

      Once done, in theory the laptop will have AstroTortilla installed properly and since you copy-pasted the data from your computer, you will have all the data required including the astrometric index files. This may or may not work 100% - I have not tested it, but it seems sensible to assume it will work. Worth a try within your own computer (or another laptop) I guess.

      Best of luck!
      Kayron

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  10. aha, will give that a try, thanks !

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  12. I am wondering why for me nothing works

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    1. Hi Luca,

      What are the errors/problems you are encountering with AstroTortilla?

      Kayron

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  13. Hi Kayron
    It does not work under windows 8.1 unless everything (including installer) is run using windows7 compatibility.
    Once installed it must be run using administrative privileges otherwise it won't connect to an ascom telescope.
    Now it works great!
    Thanks for the tutorial

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  15. First of all, great tutorial, thanks for taking the effort to publish.

    I have come across an issue I hope someone can help with. When I use the file dialog box to solve a plate, AT works great. But as soon as I connect AT to my telescope with ASCOM, it becomes very unresponsive. I can't edit any text boxes without waiting an exceedingly long time, and even trying to move the AT window on my screen takes upwards of ten seconds to respond. I can press the 'solve' button butAT to snap the picture, then it takes upwards of a minute just to get to where AT starts solving. After that it starts to crawl through the index files so slow I have to give up on it.

    Anyone have any ideas? This program has such great potential! I am running a Windows 7 laptop with an Athlon A4 processor.

    Thanks!

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  16. Hi Craig,

    Thanks for your comments, I appreciate them. As for your question, I think this is a case of a problem with the laptop as opposed to the program in its own right. I don't mean to suggest a component in your laptop is faulty, but there's something going on. It could be up to very little free memory and/or a very fragmented harddisk. What I would suggest trying is first and foremost, run the program "msconfig" (just type this in Run and click OK) and under "Startup", uncheck any and all programs you don't need running. Anti-virus programs tend to take a lot of computer resources, for example. The less you have checked on the "Startup" list, the less programs will start up with Windows and take up memory. Please note doing this does not uninstall anything - it just stops the programs from starting with Windows when you boot up.

    Once that's sorted out, reboot and give it a go. If you removed a lot of programs from starting up, you will immediately notice much more responsive performance from your laptop. You can also defragment the harddisk (if your laptop does not use an SSD as for SSDs, this is not needed). When installing/uninstalling and moving stuff around, files get fragmented into pieces and shoved all over the place. This means that the harddisk head has to move around extensively to access a single file at times. Windows has a "Defragmenting Tool" that will tidy everything up and speed up accessing of files on your harddisk. To run this tool, open "Computer", right click on your harddisk drive (C:), go to "Properties" and under "Tools", click "Defragment now". This process can take minutes to an hour or so and is best you do not touch your laptop in the mean time until it is done. Reboot afterwards just in case.

    If all that does not alleviate the problem, I would investigate whether other programs also suffer from sluggish performance. It could be down to a corrupted drive. Windows can check for areas of the harddisk that are corrupted and unpartition them (remove them from being accessible, improving performance as it avoids the problematic areas). To do this, again go to "Computer", right click on your drive (C:), go to "Properties" and under "Tools", click "Check now". Check both "Automatically fix file system errors" and "Scan for and attempt recovery of bad sectors". This can also take a while (an hour and more at times) and is best you leave your laptop unattended for it. A reboot afterwards is also recommended.

    Further to that, you could try adding more RAM to your laptop if possible. Replacing the harddisk with an SSD would massively improve performance as well, whether or not your harddisk has problematic areas since SSDs are flash memory based and incredibly faster than harddisks.

    I hope this gives you ideas to look into!

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  17. Hi Kayron --

    Thanks for your response. I'll do as you suggest and see if it picks up AT's performance. Again, great tutorial.

    Best regards

    Craig.

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  18. Because I do not have an st-4 port I can only connect telescope to one program at a time. I can either connect to starry night or AT. Because of this I do not think I can use the program. Am I missing something or am I out of luck?
    Rick

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    1. Hi Richard,

      The ST-4 port on your mount is purely for autoguiding purposes and should connect to your autoguiding camera. How is your mount connected to your laptop? I use an EQDirect USB cable. These work on ASCOM, which are a set of free drivers on your laptop that connect to every astronomical device (mount, autoguider, camera, etc).

      In reality, many programs can access one single device at the same time through ASCOM. I normally have EQMod (for slewing), Stellarium (for GOTO) and AstroTortilla connected to the mount at the same time. They all interact beautifully through ASCOM, as if they're one program.

      I hope this gives you a better idea of how it all works together in software. You can read more about the software side of things here:

      http://www.gibastrosoc.org/sections/astrophotography/equipment-and-software/6-the-software

      If you wish to ask me anything else, please feel free to post here on to e-mail me at: kayron.mercieca@gibastrosoc.org

      Best Regards,
      Kayron

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    2. Just to embelish on the above, the EQDirect USB cable connects to a USB port on the laptop but on the mount, it replaces the standard Hand Controller the mount comes with. It goes into the same port the Hand Controller normally does. The ST-4 port is an extra, on which I have my autoguider camera connected.

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  19. Very well written tutorial on Astrotortilla. Much Appreciated!

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    1. Thank you for your comments. You're very welcome!

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  20. Great tutorial thanks, it's threads like this that improve our skills in the steep learning curve of AP, without which I would never improve!!

    I have just been advised about AT for plate solving. From reading the above comments, I see this is a great tool for matching the night sky to your mount accurately with alignment for gotos.

    However, I have a portable mount which I have to set up each night that I want to image the night sky. Unfortunately, in a single night session, I do not have enough time to get enough data to achieve a great final result. I have never managed to match a target from different nights to add data. Would AT be able to plate solve an image taken from a previous session to ensure that when I set up again on another night that I am exactly lined up?

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    1. Thank you for your comments, I appreciate your thoughts on the usefulness of this tutorial to your personal experience. Indeed AstroTortilla is one of those "once you use it, you won't go back" programs.

      I too have a portable setup as in Gibraltar, we live in flats compacted into a very busy and small city. I also don't generally have enough imaging time in one night to complete an image, particularly since I image in monochrome. AstroTortilla is perfect for what you want to do. Here's what I do:

      1. Go to my location and set up. Polar align and focus the optical system.
      2. Connect AstroTortilla to my mount and send my mount to the target using Stellarium or Cartes du Ciel.
      3. Let AstroTortilla plate-solve to centre the intended target.
      4. Image!

      The next night, I do exactly the same as above! I do nothing to different to ensure the target is centred because AstroTortilla always seems to get the target perfectly, perfectly centred. You can however use the menu at the top of AstroTortilla to open an image file and have it send your mount to that target (issue a GOTO command based on what is in your image). What it will do is plate-solve your image, calculate the co-ordinates and send the mount there with a GOTO command. You can then plate-solve after the mount stops slewing to ensure the target is centred well.

      In any case, I just do the same thing every single night and it always works perfectly.

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