Astrophoto matching
From WikiSky
Below is short and rough description and tips for astro photo matching process. Feel free to edit this page to improve the document.
Start with wider angle images. It's easier to match.
The best practice is to identify object on image, preferably closer to the center of the image. Find it on SKY-MAP using search, click on object to open info page, under list of images section click on "Add new image". Provide http location of the image (or upload it from local hard drive, but http usually works faster, as it uses fast server-to-server connections) After the upload a matching window will open up. (Sometimes uploaded image does not appear at first, try to click zoom-out button ("-") RA and Dec will be preset to position of the object you clicked on. By default mouse mode is set to "Stretch/rotate", use mouse click-and-drag in image area to find close resolution and rotation. It helpful to compare your image with outer images of the area. If there are no good images, look at SDSS or DSS survey images. Check if image is reversed. If it's the case - check out the "reverse" checkbox and click "Update" button. (Use "Update" button it you change parameters in text fields) You might want to change size of reference (matching) stars and change number. Those two parameters are for helping in matching process only and do not saved. I usually trying to get reference stars sizes close to stars on images, then when match found I decrease size and increase number of stars for fine-tuning.
Please provide short but informative description, like "Andromeda galaxy by John Smith (10-Jan-2008)" Also don't forget to provide link on page with the description of the photo. We have plans to significantly improve astro photo section with much more details and extensive categorization and link to description page of the image is critical here.
When you done set status to "Active" and click "Save", wait for notification with new image Id pops up. If you wasn't able to match image, you can still save it but leave the status as "Inactive". Add comments to description what the problem is, i.e. "(can't match - aspect ratio problem)". Another thing - if image has borders or does not fill full area, match it, save it leaving it inactive and send us email with following data: ImageId, type of area (rectangle/custom area), for rectangle provide pixel positions of left,right,top,bottom edges of useful area; for custom area provide list of pixel points that will rescribe the area in format x1,y1,x2,y2,x3,y3,... , where x1,y1 pixel position of point1, and so on. If you successfuly matched and activated new image, you would need to wait for few minutes before pre-viewing just matched image on SKY-MAP to let new image replicated across all sky-map servers. Also first preview will be slower, especially for large images as servers will pre-process the image for fast real-time rendering.
