Binned flats

[MarkS]

583WS

WS = Weally Slow?

[RobertM]

Fay, I have the same problem.  The issue is that because the sensor is full frame it needs a mechanical shutter.  The shutters used on these cameras are not focal plane like the Canon so if you need to take flats then they have to be at a low light level to prevent any shadowing on the image and that means longer integration times.

Robert

[Rocket Pooch]

Hi Fay,

I'm not really sure what you expecting, the QSI is a completely different camera than the ATIK, the flats and subs sound a little slow, maybe the laptop, but the 2 second focus is the same as mine.  I thought DSLR took a while to download as well and you seem happy with that.

Anyway, did you ask Jim about Nebulocity, he seemed to get on with it really well, no issues focusing etc.

Chris

[RobertM]

sorry that last sentance should have read:

if you need to take flats then they have to be at longer integration times to prevent any shutter shadowing and that means a low light level to prevent saturation.

[Rocket Pooch]

Also, and I forgot to add, the flats should be the same size as the subs.

[Fay]

Robert, what do you mean, "that means a low light level"? I am doing then at around 33,000 adu

[Fay]

Chris, I am getting the hang of it. At the moment, it is just the slow flat download, that is a bind, everything else is gradually falling into place. 

[RobertM]

I mean that the subs for the flats need to have a longer exposure so whatever you're doing the flats against will need to be dimmer so you reach the same ADU level.  Does that make sense?

Also as I've mentioned in a previous posting you should ideally be using 2/3rds well depth for better s/n so that's 65000 *2/3 = 40,000 (I'd better not get any more technical or the post shifters will move in).  Though that shouldn't matter very much if the optics produce a fairly flat field to start with.

Robert

[Fay]

Using the QSI with ED80 & flattener, does produce vignetting. With the 7nm ha filter, I had to do 20sec subs to get to 33,000 adu.

Never done that long before, never over 4 sec

[Rocket Pooch]

Fay,

Your not putting a 2" nose piece on the front of the flattener and then onto the scope are you?

Chris

[Fay]

no, direct connection, I do have to bring it out quite a way for focus

[Rocket Pooch]

Fay,

Look at the picture below, from the back of the reducer to the chip it has to be 55mm, there is 36mm from the front of the QSI to the chip, this means you need 19mm from the back of the reducer to the front of the camera, if you do not have these dimensions right you may get issues, I do not get any Vignetting with mine so I can only assume something is up.


Testing the Telescope Service OAG by chrissuddell, on Flickr

Chris

[Fay]

I have just received 19mm from Ian. I have to connect it to my other adapter as well, or it does not fit on the flattener. Is that right? Have you got 2 adpators into the camera, to make it 19mm?

Looking at your picture, my drawtube is out another 3 times more than yours!

[mickw]

Chris has the OAG in there as well.

Did Ian suggest the 19mm adapter to fit all your stuff together ?

[Fay]

Well Chris said to get the 19mm, but I am wondering if it is a different distance to his.
Chris where are you?