Exercise in flat lights

[bloodhound31]

I think everyone can benefit from this....

I have been having huge problems with vignetting and the theory of taking flat lights. (I am a simple man)

Tonight I had a bit of a go using Jim Solomon's astrophotography cookbook, trying to use IRIS.

I got lost and confused in the three hours I tried...

In the end, I just switched on the light box, kept the camera on bulb, took three or four pictures at ISO 100 for about 2 seconds each.

I Took one two minute exposure of the jewel box at ISO 400 and stacked this with the four flats in Deep sky stacker.

Here is the result. As you can see, there is still a little bit of something going on in the corners, but I havent used darks. Overall, the huge dark corners have all dissapeared!

I think I can work with this simplistic approach. I hope this helps someone.

Image one is the original unstacked 2 minute frame, image 2 is the flat light, image three is the stacked and adjusted result.

[Terry B]

Interesting way to approach the vignetting.
Flats are usually used by dividing your image by the flat rather than adding it. It is pretty easy to do using Iris and is well explained at http://astro.ai-software.com/article...dslr_iris.html

[bloodhound31]

Any flat is obviously better than none at all. All of my latest images have been severely cropped to get rid of the vignetting. THis has the effect of losing a potentially lovely wider field, and stretches the image and all the artifacts to shocking noticability.

I guess my point to this whole thread, without getting into the complications, was to show that a much better result can be achieved fairly easily.

There are many great tutorials out there that explain everything but I feel most of them get into the details too heavily. I like to crawl before I run.

Thats why most of my tutorials use the theme, "Like this-do that."

............Point the camera, turn this knob to this position, press and hold the button for two minutes. blah blah blah............

If us noobs can just get to the guts of it and produce some nice pics, then we can develop the finer skills as we go along.