By ERHAD on Friday, 22 July 2022
Posted in Imaging Tips
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Hi, new member here, just signed up, I am currently awaiting a dataset from Pier4 and in checking and downloading the calibration frames I realised there are no dark flats. I typically calibrate my flats with those so was wondering how you guys go about this process.  I calibrate and integrate with Astro Pixel Processor, by the way.

 

Thanks!

Erik

Hello Erik,

Welcome to Roboscopes.

You can use the Bias frames. 

Bias frames are similar to dark flats.

 

Regards

Darius

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1 year ago
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Hello Erik, 

Welcome to Roboscopes.

To keep things simple for everyone we provide a full set Bias, Darks and Flats for all piers.

Due to the speed at which the flats are taken generally we don't need them on the Cmos cameras a simple Bias calibration is enough. 

We would only provide darks for the flats if the exposures for the flat exceed 5s and then we try to keep the exposure for the flats inline with our standard dark frames.

Hope this helps

Regards

Peter Shah

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1 year ago
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Hi and thanks for the kind replies. Excuse my ignorance, never really used Bias, I've always used DF since I started this hobby. So do you suggest that I should load the Bias frames in APP as if they were Dark Flats? I'm afraid that if I load them as Bias, when it does its full run of calibration and integration it will also apply Bias frames to the Light frames...

Thanks again for your patience and assistance.

Regards,

Erik

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1 year ago
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Hi Erik, 

Its better to create a master Bias first. Then remove the master Bias from the darks and flats, essentially calibrating the flats and darks. Then do a full calibration of your lights. Then you can continue with your stack etc...

Regards

Peter

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1 year ago
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OK, understood. Thanks again!

 

Erik

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1 year ago
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OK, understood. Thanks again!

 

Erik

Hi Erik and Welcome

When you placed your order on Pier 4 you asked about camera angle so I have run Pinpoint on a recent sub for you

Solving using 6166 image and 353 catalog stars
Matched 240 of 6166 image and 353 catalog stars;
Average residual 1.8 arcsec; order 4
RA 15h 40m 19.5s,  Dec -19° 00' 06.5"
Pos Angle +00° 00.5', FL 101.9 mm, 7.61"/Pixel

I hope that helps

Steve

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1 year ago
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OK, understood. Thanks again!

 

Erik

Hi Erik and Welcome

When you placed your order on Pier 4 you asked about camera angle so I have run Pinpoint on a recent sub for you

Solving using 6166 image and 353 catalog stars
Matched 240 of 6166 image and 353 catalog stars;
Average residual 1.8 arcsec; order 4
RA 15h 40m 19.5s,  Dec -19° 00' 06.5"
Pos Angle +00° 00.5', FL 101.9 mm, 7.61"/Pixel

I hope that helps

Steve

 

 

Hi Steve,

 

Thanks so much, that is really kind of you, really appreciated.

 

Best,

Erik

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1 year ago
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Hello Erik

 

I also use APP.
I used to ask a question about dark flat on the APP forum and got an answer.

See the answer in the URL below.

https://www.astropixelprocessor.com/community/main-forum/if-the-calibration-frames-are-not-in-principle/

The thread is a long sentence, but the answer to your question is the following sentence.


”You simply take darks that have the same gain, offset, temperature and exposure time as the flats. Then in APP instead of loading them as darks you load them as dark flats and you're done.”

I am very happy if it helps.

 

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1 year ago
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