lights darks flats?

[iwols]

just about ready for taking some images(prob m42 orion  neb to begin with) with my heq5 mount ed80 and d750 camera ,but not sure what i should be taking ,was looking at say 20 lights at 90 secs ,10 darks at 90 secs,but not sure what else,not sure what flats are to be truthful

[MARS1960]

I'm going to do that in about 2hrs with a very similar set up, unguided.

I'm all set up outside, first thing i'm going to do is get focus on Rigel then slew to M42, take a 30sec exposure at ISO 1600 and check the histogram, if all is good i have my intervalometer set for 50 exposures of 30secs, then i will take 10 darks and run them all through DSS and see what i get, fingers crossed for attempt No'5 .

[iwols]

let us see the final pic cheers

[Starlight 1]

3 hours ago, MARS1960 said:

I'm going to do that in about 2hrs with a very similar set up, unguided.

I'm all set up outside, first thing i'm going to do is get focus on Rigel then slew to M42, take a 30sec exposure at ISO 1600 and check the histogram, if all is good i have my intervalometer set for 50 exposures of 30secs, then i will take 10 darks and run them all through DSS and see what i get, fingers crossed for attempt No'5 .

Looking at you plan? 49x30s 11x10s 16x5s  33 Darks at 30s  I only use with odd numbers .

[Pompey Monkey]

14 hours ago, Starlight 1 said:

Looking at you plan? 49x30s 11x10s 16x5s  33 Darks at 30s  I only use with odd numbers .

Why only odd numbers?

[Physicist13]

Due to individual sensor differences (pixel to pixel) and optical distortions, if you imaged a perfectly uniform light source (even intensity at every point) the you would record a non-uniform image. To correct for this, you take a "flat" image (simulate a uniform source as much as possible...eg white T shirt, or poss an illuminated screen..has to be uniform!) and expose your sensor to this source. it is VITAL you use exactly the same optical train as when your lights were taken!! ie setup has to be idential..including sensor orientation!! The you can use this information to "correct" the light images. Can make a big difference to the final image.

Note M42 is partic hard to image, due to v large dynamic range (range of bright to dark features). Hence range of exp times required and careful combination of results (often HDR combination).

P