This Flat cant be right....

[Earl]

this looks very wrong any ideas?

[shaunster]

A few questions..

Exposure details?

What was the ADU reading?

How many flat subs is this? and did you use bias frames as well?

[Earl]

Its 1 second

No idea on ADU ......

1 single sub taken with a t-shirt over the scope, if you stretch it it looks very odd

[Paxo]

You might have overcooked it. What was OTA pointed at?

Steve

[Earl]

its pointing at a lovely cloud formation where polaris is LOL

[Paxo]

It shouldn't matter what it's pointed at as long as you have an evenly illuminated surface, in this case the T shirt. The conversion to JPG has lost the ADU information, only registering as 160 (I've converted one of my own flats from FIT to JPG and it has done the same).

When stretched, the lined area that appears looks as if there wasn't an even illumination. Try different exposure lengths to get 20,000 to 26,000 ADU values average. This info can be found usually in your imaging software.

Steve

[adamsp123]

looks over exposed to me.

[shaunster]

No idea on ADU ......

Your imaging software should tell you this, aim for about an average of 20,000 ADU and see what happens.

BTW for a nice light source I use a netbook screen + sheets of paper, creates a nice flat evenly illuminated light panel for taking flats and should be much more reliable than the t shirt method.

[todd8137]

hi there the old t shirt method is great it does work i use a school shirt of my daughter and point at the morning skies and it works out well for me failing that get some leds from maplins strips of 4 are cheap

pat

[Earl]

Your imaging software should tell you this, aim for about an average of 20,000 ADU and see what happens.

BTW for a nice light source I use a netbook screen + sheets of paper, creates a nice flat evenly illuminated light panel for taking flats and should be much more reliable than the t shirt method.

Cheers i have found that now, all these little things do add up, its a long check list LOL

[Earl]

hi there the old t shirt method is great it does work i use a school shirt of my daughter and point at the morning skies and it works out well for me failing that get some leds from maplins strips of 4 are cheap

pat

Morning skies...... what are those