Some Progress - looking for help on next stage.

[Spacehead]

Hi All,

I'm using the sw200p on an EQ5 with motors and a cannon eos 400d (so quite old that cam).

I am confident now about getting a good polar alignment and can do it in about 10 mins - if that.  On a good level too.  So that and my fitting and use of the motors is complete.

The other night I went out and took some pics.  I have attached these for you - so you can see where I am up to.

I am fairly confident the level of drift is low enough that I can get 30 second subs - with (to my untrained eye) very little egging.   60 is pushing it - but I think I can get something workable - not to NASA level or you guys - but at least something I can start stacking with.

First pic of the Pleiades is a single shot at 30 seconds.  Probably 800 ISO (although not sure as I was rushing to get as much in as poss).
I am fairly pleased with this one.  My question is with x number of shots like that stacked, will I EVER get the cloud swirls I see on other more expert photos?
What is x?  Given my 30 seconds.

Second pic is m31 - I am over the moon with this - because I couldnt even see it with the naked eye and it took a while to find.  Again though,  whilst I can "just about" see a dust lane there - how many subs will I need at 30 seconds to get anything worthwhile to look at once stacked? (looking at it I suspect I did 1600 ISO on that one)

I read a lot about "lights" "darks" "flats" "bias".

As well as helping me with the above two questions about the 30 seconds and x number of shots - could anyone tell me if my understanding below is "accurate" and that my statements are true or false (just me trying to explain my learning).

Statement - My "lights" are all the photos I take of the target object.  Am I correct?

Statement - For "darks", I need 20, these are taken by putting the cover over the end of my telescope thus blocking ALL light, and taking 20 photos after taking all my "light" photos.  If all of the "lights" in my set are taken at 30 seconds ISO 800, then my 20 darks MUST also be taken at this setting.  Is this correct?

For "flats", I have no idea - please help!!!

Statement - For "bias", upon completing my "lights" during the night, and in the same manner as I do for "darks", I place the cover over the end of my telescope and shoot 20 photos with the ISO set to the same as my "lights" and the exposure time set to be as short as my camera allows.  Is this right?

Any advice appreciate - Cheers all.





 

 

[bottletopburly]

 All explained here  http://deepskystacker.free.fr/english/faq.htm#lightdarkflatoffset

[swag72]

This is also a good link http://www.rawastrodata.com/pages/typesofimages.html

[Garethr]

Sara

Great link.  Never heard of dark flats though, do you use these when you use a dslr.

 

Gareth