Pre made calibration frames

[Calzune]

Is it a good option to do sets of Darks, Flats and bias frames with different ISO and exposures  in different outdoor temperaturea to save time while the day comes to do astrophotography? 

Now I spend maybe 2h doing lights and 1h of the other frames which is not very fun to loose 1h of extra  possible light data.. 

 

I know that the dust on censor and outdoor temperatures are important. I have seen some people have pre-made folders for these frames to save time, but what are your thoughts on this? 

I only have a Canon eos 1100d so I know that the temperature frames is alittle harder than a ccd camera. 

Edited October 5, 2019 by Calzune

[Ronclarke]

If you use PHD for guiding, you can Dither and then you won't need Darks. Saves a lot of time, I have a library of Flats that I use also.

 

Ron

[Calzune]

1 minute ago, Ronclarke said:

If you use PHD for guiding, you can Dither and then you won't need Darks. Saves a lot of time, I have a library of Flats that I use also.

 

Ron

I just bought a guide cam and scope but haven't used it yet. But are you sure that I won't need Darks when dithering? I have seen people dither and use Darks.. 

[Ronclarke]

That's a decision you must make, try just dithering and process the image. Then add Darks and see if there's any improvement??

I find Flats more beneficial than Darks for my imaging although I'm just changing from a DSLR to a CCD cam!

Ron

 

[Calzune]

Just now, Ronclarke said:

That's a decision you must make, try just dithering and process the image. Then add Darks and see if there's any improvement??

I find Flats more beneficial than Darks for my imaging although I'm just changing from a DSLR to a CCD cam!

Ron

 

Okey thanks 👍🏼 

[Fraunhoffer]

I do my darks with the camera off the rig when I start clearing down and when Im setting up so not to lose time and whilst its at the same sort of temperature as everything else.
Im experimenting with artificial flats at the moment as I got some very strange gradients earlier in the year no matter where I pointed the scope - sky/clouds/ fence/indoor wall - that were different to those on the lights.
So what I do now is to quickly stack the lights using DSS at 100% and manually weed out any with low scores then do a stretch in DSS, save the stretched TIFF file and load it into PaintShop. In PaintShop I clone out the brightest stars and the general area of interest if a bright nebula. Then I do a massive gaussian blur at 90 or 100 pixels and save the file as my 'flat'.
Then I either re-stack using my blurred image as a flat or take the original saved file and blend it with the blurred image (layer) using difference (Subtract) mode at 80-90% to remove the gradients. It can be quite severe so have to play about with the settings a bit, but saves me a load of time in taking flats with a screen etc. Its not perfect and had its downsides but in the limited time I have it usually works as 'good enough' for me. 
 

[Star101]

I find dithering makes a HUGE difference to quality of image. Darks need to be the same temp and time length. If you have any dust bunnies or vignetting, then flats are needed. But try dithering, for me, it does make a big difference to the outcome

[Calzune]

What's the best settings for dithering? I use apt

[Calzune]

On 05/10/2019 at 10:57, Star101 said:

How about just Bias and Flats? Can I shoot those two frames pre-made? Just having the same ISO and outdoor temperatures and put them in separate folders and use then in my different sessions? So when I'm doing my photography I just have to focus on lights and Darks.. What do you think? 

 

Edited October 6, 2019 by Calzune

[Star101]

For Dithering, i would try the medium and go from there. 

Darks and Bias ( or short Darks of 2 seconds as I use ) can be created anytime. Just try to keep them the same temperature as your lights are taken. If there are no marks on the image, no dust bunnies, vignetting or dew then yes, you could create and use a library light, but beware than if you setup and tear down there is a tendency for dust to get on the lens or sensor that new flats can remove. It depends how particular one is about imaging  

I am not sure about using Bias with CMOS as it does make my ZWO ASI183mm pro images worse. Instead I use short darks as bias ( 2 second exposure ) and this helps. I know some create Dark Flats but that implies darks being shot at the same level as the flats....My flats can sometimes be 0.01s. Which is almost a BIAS. If I use 2 seconds DARKS instead. I get better results.

You will need to experiment to find what works for you.

Hope this helps. 

Edited October 6, 2019 by Star101
speelin missteak.