About questions on fits images alignment

[njua...@gmail.com]

Hi!

I'm an undergraduate now doing reduction and alignment of raw fits images in a project about low surface luminosity galaxies. 

The raw images are taken one by one for the same galaxy. But due to some technical problem, there are some minor shifts and even rotations between each picture. Therefore I want to align them first before combining and stacking them. 

Here's my problem:

In alignment, using "imalign" in iraf, I have to select stars and generate coordinate and shifts manually. It takes me hours to align one series of images. 

While using commercial softwares like PixInsight and Deep Sky Stacker, I don't know how they works and we are afraid of getting some false data.

Do you have any suggestions on alignment?  Is there any pipeline using "imalign" in iraf and how can I generate coordinates and shifts automatically? Or if there are some codes that just do the translation and rotation and preserve the original counts?

Sincerely,

Weiguang

[Matt Craig]

I'd use astrometry.net to add WCS and then use reproject (a python program, see: http://reproject.readthedocs.io/en/stable/). 

That won't work if you can't add a WCS, though...

Matt Craig

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[njua...@gmail.com]

Yes, I have used the "reproject" code and it's very nice! However, adding WCS became a tough work. Because I have to upload those images one by one to http://nova.astrometry.net  and wait and download one by one. Is there any convenient way to add WCS to plenty of fits files?

Sincerely,

Weiguang 

在 2017年7月11日星期二 UTC+8上午11:25:57，Matt Craig写道：

[Dustin Lang]

You could use the client.py program (in astromemtry/net/client/client.py):

python client.py --newfits new.fits --upload M63-HST-Subaru-LL.jpg  --apikey $API_KEY_NOVA

(which uploads to nova.astrometry.net, waits for the solution, and downloads the new.fits file)

cheers,
--dustin