Unable to Plate Solve using Astrotortilla

[Bigfoot 9907]

Hi All,

I am having difficulties plate solving images taken using the Starshoot G3 camera and Astrotortilla. I am using 'File open dialogue' and selecting the fits file. I have downloaded 18GB worth of Index files, so I don't think any are missing. It say No solution in xxx seconds.

The same  fits file is solved almost immediately by Astrometry.net.

I have attached a screenshot of the AT settings. If anyone can check them over that would be appreciated. I have messed around with the settings but to no avail. I have also followed the Light Vortex tutorial to the letter.

The images taken with my Canon 1000D are solved without any issues by AT. Not sure why the G3 starshoot fits files are causing problems.

The image file is here

https://drive.google.com/file/d/0B-Afq_Dv8HerUk53VklOUzN0bTA/view?usp=sharing

The FOV for the G3 is 21.97 X 17.01 arc minutes

Any help would be greatly appreciated.

Surinder

[Gib007]

Hi Surinder,

I saw your post on my AstroTortilla tutorial thread so here I am to help you with your astrometric index files. I would indeed run the AstroTortilla installation again (do not uninstall what you have at the moment though!). Simply select "Install additional astrometric index files" from the list of components to install and proceed. I have calculated your FOV for your DSLR as well, plus the one you gave me, so:

Skywatcher Explorer 200P + Canon EOS 1000D = 1.27° x 0.85°

Skywatcher Explorer 200P + Orion StarShoot G3 = 21.97' x 17.01'

We will select the astrometric index files needed for the entire range of FOV there. We will use the 1.27° to decide our Widest level astrometric index file. For the Narrowest level astrometric index file, AstroTortilla recommends you use 20% of your minimum FOV. Since your minimum is 17.01', 20% of this is 3.402'. There should be no problem rounding this up to 4', to prevent downloading a HUGE file. I would therefore select the following in the installation:

Narrowest level = index 4202, 4.7GB, 4-5.6 arcmin

Widest level = index 4211, 7.7MB, 1.42-2 deg (85-120 arcmin)

The installation will download those two plus all the ones in-between, so this will take a while. Thankfully it will skip the ones you already have! That covers you for your astrometric index files. 

I would also make some minor adjustments to your Scale minimum and Scale maximum values entered in AstroTortilla. Your maximum scale is actually 0.3661666...° so round this up to a simple 0.4°. For the minimum scale, you have 0.2835° so 0.28° seems fine to me. You can go down a little beyond that, maybe 0.25° to be more sure. Therefore, enter:

Scale minimum = 0.25

Scale maximum = 0.4

Search radius = 45

I only advise raising Search radius as you're having issues with it. You can probably lower it to 30 or 15 if it's working well. Also, you can remove the -H and -L operators in your Custom options since these are the Scale maximum and Scale minimum parameters, respectively, and they have already been entered correctly. I would therefore have:

Custom options = --sigma 70 --no-plots -N none -r --objs 100

I will give my tutorial a quick update in the next few days, just to be in line with my above advice. I hope this works out for you!

Best Regards,

Kayron

[Bigfoot 9907]

Many Thanks Kayron, I shall give your suggestions a try when I get home this evening

Cheers

Surinder

[Bigfoot 9907]

Hi Kayron,

Good news. The image solved .  Bad news. It took 984 seconds. I'm still happy that it solved though .  I shall re read your tutorial section on optimizing plate solving speed.

I have 18.4 GB worth of Index files in the data folder. I don't think I will be needing all of them. How would I know which ones to remove and which ones to keep?

Once again many thanks for your help.

Surinder

[Bigfoot 9907]

Ignore my last question. The answer is in the tutorial . However, what exactly does an Index file show?  A certain section of sky? if so, then I need to be careful as to which files to remove.

Cheers

[Bigfoot 9907]

I have got the solving down to 6.4 seconds. The image was solved with index file 4203-13. I have only kept two index files either side of that and moved the rest to a folder called 'Not Used'.

The question I have is that will the five remaining index files cover the entire night sky with the camera/telescope combination that I use?

Cheers

Surinder