Calibration frames for Solar/Lunar imaging?

[cgarry]

Do any of the imagers out there use calibration frames (dark / flat / bias) when they image the sun or the moon?  I doubt they are of much use for the small sensors generally used for planetary imaging but guess they could be beneficial for the large sensors often used for Solar/Lunar imaging.

Cheers,

Chris

[Bizibilder]

Flat frames can be essential for solar and lunar imaging - even with a webcam.  They are useful to get rid of dust bunnies and other blemishes.  I don't normally use them with my DSLR full disc solar images unless i get a dust bunny - when I do, I take "sky flats" and use them to help clean up the image (and then have a session cleaning the sensor!!)

[cgarry]

You make a good point about dust bunnies on webcams which I had not thought of.  I often find myself using my mount handset when planetary imaging to keep the planet from drifting onto an area of the sensor with a dust bunny.

[Uplooker]

What you can do for solar flats is  put a very thin plastic fruit bag that you get from the supermarket over the front of the scope and up the gain and shutter speed to match the histogram, then get 200 frames for a flat. You can then load this into Registax as a flat. Might / should solve your problem.

Ian

[Ibbo!]

I have used the plastic bag method with some sucess

also find a blank bit of sun and defocus and capture with without altering exp or gain and use as above

[cgarry]

This is all good to hear as I have been busy adding support for calibration frames to PIPP.

It looks to be working well so far, but I do not have much of my own suitable test data.  So, at some point I will be on the look out for some test images that I can run through PIPP, or somebody willing to do some pre-release testing!

Cheers,

Chris

[Luke]

I use flat frames with my Quark and ED120 for solar imaging, to remove dust bunnies and also because the Grasshopper 3 camera I use gives two bands when imaging the Sun in hydrogen-alpha, one at the top and one at the bottom, that the flats remove (there are no bands with the Grasshopper when doing white light).

[cgarry]

Sky flats and similar seem easy enough if you are using solar film as you can easily remove the filter to take the flats.  But how would you go about taking flats when using a herschel wedge?

Cheers,

Chris

[JB80]

I have just started using flats for Ha solar, primarily for the gradient but having it kill dust bunnies and newtons rings too is a bonus.