Imaging comets with a OSC CCD?

[Helen Usher]

Hello all,

I’m new to gathering my own data for astrometry and photometry analysis in Astrometrica.  

I have a OSC camera on my main scope (a William Optics123FLT refractor) and so was wondering the best way to use it.  Can I use it unbinned and if so do I de-bayer and then load into Astrometrica?  And what filter setting should I use in Astrometrica?  Or would I be better binning and just using the mono output?

Or should I just use a mono camera instead??

Thanks

Helen (currently gathering unbinned data on 64P ) 

[David Swan]

This is a good question – to which I can’t offer you a good answer! You might want to submit your question to the comet discussion list and Nick James or another will likely pick it up quicker.

I would say that if your plate scale is around 1 arcsec / pixel or below then you might as well 2×2 bin and use the mono pics for astrometry. I’m not sure what you should do if you are correctly sampling or are undersampling.

I look forward to seeing your colour pics of Wirtanen! I’ve just bought a Hyperstar (Christmas brought forward) to give me a wide field of view for the close approach.

Good to hear you are imaging 64P – it’s nice isn’t it? And 38P is moving to a better position.

David

[Nick James]

Hi Helen,

David’s advice is pretty much spot on.

I would de-bayer and use the green layer in Astrometrica as pseudo-V, i.e. set Astrometrica to use V band or the Gaia G band. You can then do astrometry and photometry. Have a look at the comphot page if you want to have a go at photometry. Depending on your pixel scale you can do the de-bayering by linear interpolation or simply by binning the two green pixels in each set of four. The latter is probably more photometrically correct. I have done photometry and astrometry using an ASI294MC camera and get good results.

Let me know if you need more detail on this. I hope that you decide to submit images and data to the section.

Nick.

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