Exposure calculator?

[Jeffr86]

I use a color ccd camera. Or will be, new enough that I might as well say "will use"(I have a revolution imager)

Is there a calculator/program that  might ask

CCD camera info,

Telescope info (such as Focal length, aperture, etc)

Ask me the approximate magnitude of an object. (Lets say a magnitude of 5.5)

and then compute it, and give me a suggestion such as "you might consider a exposure of x250 or 1/500"? or a cheat sheet of some sort?

[Demonperformer]

I'm no expert, but I don' think there is, but it is not really necessary.

For bright objects, it only takes a couple of minutes to experiment with short exposures to select the one that looks ok (not burning out the bright bits is most important - you can often bring out faint details by processing - you can't recover information that is burnt out).

For faint objects, the rule of thumb would be take exposures that are as long as your mount can bear without tracking the stars. For these, you will almost certainly need to take lots of exposures (subs) to reduce noise. You can get an idea of what sort of total time will be needed by finding images on the web and seeing what others have used. The important equipment figure is the F/ratio, like a camera lens.

You will no doubt get better replies from more experienced people, but hope this helps.

Thanks.

[Tinker1947]

I would run off some images the first @ 60 second then double up until your light pollution causes problems, you will also need to consider the Moon my CCD will exceed 20 minutes with no Moon, but only 3 minutes with a full Moon.....

[Jeffr86]

Ah,  I just ask becauseI ran across a similar cheat sheet for a specific dslr.  Was a chart "magnitude of ___ =recommend iso___"  so I figured there might be one ccds

[Freddie]

Is this what you are looking for?

https://starizona.com/acb/ccd/calc_ideal.aspx

 

[Jeffr86]

Something along this line: WHat Im working on is establishing some sort of baseline (just to start). As I "perfect" each picture, Ill record specific settings for that picture seperately.. THis is just to get things sort of visible..  So, for example I have seen both saturn and jupiter present on screen with exposure set at 1/500.  I would like to think to myself "Hmm, Saturn has a mag of +1, I saw it starting to show up at 1/500 exposure. Therefore, I should be able to get any object with a magnitude of +1 to begin to show up."  Again, just general, just trying to deal with these two factors  things like gain, gamma, stacking,  brightness all are important too......

 

Exposure time	Magnitude of object	Example objects
1/x Fraction second	-25 to  +5	Saturn +1 mag 1/500 exp Jupter -2 mag 1/500 exp
X2 .04 or 1/25
X4 .08 or 1/12
X6 .16 or 1/16
X8 .32 or 1/3
X16 .64 or 1/2
X64 1.2 seconds
X128 2.56 seconds
X256 5.12 seconds
X512  10.24 seconds
X1024 20.48 seconds	+12  and up