I’m directing this post at anybody who uses plate solve images to facilitate accurate pointing for the purpose of astrophotography.
I use Sequence Generator Pro for all of my imaging now. One of the best features of SGP is that it includes the ability to import an image. By having a local install of the Astrometry.net engine, SGP plate solves the image and knows the exact center of the image. Then, out in the field, I can make sure that it slews to that precise location – multiple nights if necessary, such as when I do a night of RGB and several nights of narrowband imaging. It means I don’t have to throw away edges because my slews weren’t consistent from night to night.
To get these plate solve images, I’ve been using an online service called Wikisky.org (also known as Sky-Map.org). Among other things, it has a great database of object coordinates, and the complete image from the SDSS2 survey. Best yet, it allows one to export an image of the current view – allowing you to customize it with your own field of view and other parameters. In other words, I’m able to export an image of EXACTLY how an object will be framed in my telescope, with my camera oriented a specific way.
Unfortunately, Wikisky’s servers go down fairly often, and I’ve never been able to open up a dialogue about what it would take to improve the service, or perhaps even develop a local version that people can purchase and download (thus helping to fund their project). And wouldn’t you know it - they’re down now, and I plan to go out to the lake to do some imaging tonight.
Now, granted – I certainly can do things the old-fashioned way (slew, take a test photo, adjust, repeat) – and I might have to do that tonight for the Cocoon Nebula that I plan to image this evening – but I have to wonder if there are other services or programs out there that can do the same thing as I described above – either web-based or available for Microsoft Windows.
If anybody knows of anything, I would appreciate hearing about it. Thank you!
Ok, I’m playing with it right now. I can see how it works and it seems to be working pretty well. Thanks to an existing plate solve frame of a different object, I’ve even been able to match up my camera orientation so I know how to orient the camera for the object.
So for a couple comments - is there any way to display the image in color? Also, is there any way to customize the brightness/contrast adjustment being done to the fetched image? It’s pretty washed out and difficult to really get a good look at some of the fainter features, such as the dust lane coming from the Cocoon.
Also, is it generating this image from the internet, or from a local install? It would sure be nice to be able to use this feature when not connected to the internet as well. I have no problem paying $39 to add this feature for some piece of mind, but if something happens in the future and the image database disappears, this feature becomes useless. Plus, there are many times when I decide on a whim to image a particular object while I’m already at the lake, with no internet access.
Yes, use the image histogram stretching controls (just like any other image. Drag the black to the start of the data and you’ll have a much better view of the canvas.
The internet
It sure would. Unfortunately, the DB is huge. So… you have 2 options:
Fetch the image while on the internet and don’t do anything with it. SGPro will cache this image. Next time you fetch it, SGPro will not access the internet and you can create a sequence from it.
Make full mosaic sequence while online, save the SGF file and run it later.
If this happens (we are certainly aware that it can), we will make every effort to find a viable substitute. There are other options out there (including hosting our own server that we control).
Well, at least SGP does cache the images. However, I must wonder how huge is “huge”. When installing Ansvr for plate solving, the download files are many gigabytes in size. Some of the games I purchase and download on my PC or XBox One are over 30GB in size. The concept of what is “too big to download” has changed significantly in the past few years.