Lee, I was in the exact same position as you. I have been imaging with a RC8 on an EQ6. The problem is that my mount isn't GoTo compatible. I currently use settings circles but I wanted a more accurate way to find faint fuzzies. Plate solving was the way to go.
After doing some reading, I downloaded Astrotortilla
http://sourceforge.net/p/astrotortilla/home/Home/ and it does exactly what I need.
You need to download star catalogues, which is what AstroTortilla will look through to match star patterns when it comes to plate solving. The amount of catalogues you need will depend on your image scale. The smaller the scale, the more catalogues (larger download required). See the manual on the home page to guide you.
When you install AstroTortilla, it will ask you which index files (star maps) to download. It's generally pretty slow but you can download index files directly from
here. For my image scale, I had to download 4004, 4005, 4006, 4007, 4008 and 4009 series. Each series covers the entire sky. However, 4008-4019 has only one file to download and each covers the full sky. 4005-4007 are made up of 12 tiles (see the hp.png in
this directory to show you what regions of the sky each tile covers). Series 4000-4004 are made up of 48 tiles (see the hp2.png in
this directory to show you what regions of the sky each tile covers). So, you can reduce your download by only getting the tiles that cover what is visible in your sky. Let me know if this is confusing!
So once it's all installed, this is my workflow:
- Polar align
- "Sync" my setting circles to a star
- Look up object of interest
- Move scope and match setting circles RA and DEC based on RA and DEC of object
- Connect camera
- Take a 5 sec shot at ISO1600 (only need a 5 sec shot). I use jpeg files.
- Go into AstroTortilla and connect to my mount via ASCOM*
- Click Tools and then GoTo Image. This allows me to load my 5 sec image.
- It should start to plate solve. It generally takes 30-60secs but can take up to 2 mins depending on how many index files it needs to solve. Once solved, I move the mount in RA and DEC and plate solve again until I'm happy the object of interest is centred.
A few things that will affect solving time:
- Scale Minimum and Scale Maximum. I generally set this to +/- 10% of my maximum image scale (based on the longest dimension of my sensor)
- Sigma. This is how many objects it detects. When it starts plate solving, it should give a number of how many objects it detects. Aim for about 20-200. Anymore, and it will take a long time to plate solve. Any less, and it may not solve at all. Increasing the sigma, reduces the number of objects identified.
*You can use AstroTortilla to move you mount after plate solving to the correct RA and DEC. My ASCOM driver is old (no updates since 2006) and it doesn't really work so I just manually move the mount, plate solve, move the mount, plate solve etc until I'm happy.
I hope this helps!
Dan