Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: Fay on Mar 08, 2011, 17:46:38

Title: Binned flats
Post by: Fay on Mar 08, 2011, 17:46:38
If Flats are binned, do they have to brought up to 1x1 before stacking or does the program take care of it?

Thanks
Title: Re: Binned flats
Post by: Mac on Mar 08, 2011, 18:16:38
Why are you binning flats?
its not as if they take long to take.

Mac.
Title: Re: Binned flats
Post by: MarkS on Mar 08, 2011, 19:14:28
Quote from: Mac
Why are you binning flats?

Sometimes they don't work out right - they're just rubbish and need to be thrown away.
Title: Re: Binned flats
Post by: Fay on Mar 08, 2011, 19:48:00
Well Mac, 1x1 takes an age, 20 take around 20 mins. with QSI
Title: Re: Binned flats
Post by: Whitters on Mar 09, 2011, 00:29:16
Your calibration images must be taken at the same bin level as your images. Flats, darks and bias.
If your camera is temperature controlled then you can take calibration files one night and reuse them on another. But you should refresh your calibration images regularly.
Title: Re: Binned flats
Post by: Mac on Mar 09, 2011, 00:37:30
Quote
Well Mac, 1x1 takes an age,


I always though you took a flat against a white background,
and the flat would only be fractions of a second.

so that the sensors are just over half full.

so why are they taking so long.

Mac.
Title: Re: Binned flats
Post by: Ian on Mar 09, 2011, 07:06:56
Fay, the camera was plugged into a usb 2 port on it's own wasn't it?
Title: Re: Binned flats
Post by: Whitters on Mar 09, 2011, 07:09:22
I guess that would depend on the illumination source. Fay, how do you take your flats?
Title: Re: Binned flats
Post by: Fay on Mar 09, 2011, 07:44:57
With the Atik or Canon, they are very fast, with the QSI they take 20 sec to download each sub. Same time as downloading a long exposure sub. It takes the image in the given time & then takes 20 secs to finish off.
 I use a light panel
Title: Re: Binned flats
Post by: Mike on Mar 09, 2011, 08:00:48
Fay, do you have the latest firmware?

http://www.qsimaging.com/firmware_updates_beta.html

They claim download times with it should be 1 or 2 seconds.
Title: Re: Binned flats
Post by: Fay on Mar 09, 2011, 08:04:50
Yes, the camera came with 5.5  updated
Title: Re: Binned flats
Post by: Fay on Mar 09, 2011, 08:14:59
From QSi Forum



Re: [QSI-ccd] Just purchased a 583WS

Fay,

You're running the latest software and firmware. 

It will take about 20 seconds to download a full-frame bin 1x1 image, or about 2 seconds for a small subframe for focusing.

Regards,
Kevin

On Mon, Mar 7, 2011 at 2:51 PM
Title: Re: Binned flats
Post by: Mike on Mar 09, 2011, 08:20:08
Oh dear.  :(
Title: Re: Binned flats
Post by: mickw on Mar 09, 2011, 08:29:48
Are you connecting the QSI to a USB2 port ?
How many USB leads go to the QSI ? Only the download cable needs USB, the control should only need 1.1

If you don't know if a port is USB2, download this - USBView, it's the 7th one down - make sure you download the Microsoft one
http://www.ftdichip.com/Support/Utilities.htm (http://www.ftdichip.com/Support/Utilities.htm)

*Correction*
The above will tell you what the device is, not the port/controller
The USB host controller (Control Panel, System, Hardware, Device Manager) should be listed as Enhanced for USB2
Title: Re: Binned flats
Post by: Fay on Mar 09, 2011, 08:31:14
Well I am ok with the main lights taking that long, but the flats are a nuisance. I am glad that I can frame a subject in 7 secs doing 4x4, and as long as I can get a star in the focus box, I am happy.
Title: Re: Binned flats
Post by: MarkS on Mar 09, 2011, 08:55:13
583WS

WS = Weally Slow?
Title: Re: Binned flats
Post by: RobertM on Mar 09, 2011, 09:16:49
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
Title: Re: Binned flats
Post by: Rocket Pooch on Mar 09, 2011, 09:24:10
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
Title: Re: Binned flats
Post by: RobertM on Mar 09, 2011, 09:24:46
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.

Title: Re: Binned flats
Post by: Rocket Pooch on Mar 09, 2011, 09:29:18
Also, and I forgot to add, the flats should be the same size as the subs.
Title: Re: Binned flats
Post by: Fay on Mar 09, 2011, 12:13:20
Robert, what do you mean, "that means a low light level"? I am doing then at around 33,000 adu
Title: Re: Binned flats
Post by: Fay on Mar 09, 2011, 12:14:49
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. 
Title: Re: Binned flats
Post by: RobertM on Mar 09, 2011, 12:30:48
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
Title: Re: Binned flats
Post by: Fay on Mar 09, 2011, 12:38:31
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
Title: Re: Binned flats
Post by: Rocket Pooch on Mar 09, 2011, 12:42:43
Fay,

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

Chris
Title: Re: Binned flats
Post by: Fay on Mar 09, 2011, 12:49:38
no, direct connection, I do have to bring it out quite a way for focus
Title: Re: Binned flats
Post by: Rocket Pooch on Mar 09, 2011, 13:11:06
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.

(http://farm5.static.flickr.com/4050/4522207372_e3c467ec83_z.jpg) (http://www.flickr.com/photos/13007140@N05/4522207372/)
Testing the Telescope Service OAG (http://www.flickr.com/photos/13007140@N05/4522207372/) by chrissuddell (http://www.flickr.com/people/13007140@N05/), on Flickr

Chris
Title: Re: Binned flats
Post by: Fay on Mar 09, 2011, 13:46:27
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!
Title: Re: Binned flats
Post by: mickw on Mar 09, 2011, 14:06:08
Chris has the OAG in there as well.

Did Ian suggest the 19mm adapter to fit all your stuff together ?
Title: Re: Binned flats
Post by: Fay on Mar 09, 2011, 14:07:42
Well Chris said to get the 19mm, but I am wondering if it is a different distance to his.
Chris where are you?
Title: Re: Binned flats
Post by: The Thing on Mar 09, 2011, 15:17:43
He's out earning a crust!

If I read the description right you should have camera, 19mm extension then flattener i.e the distance from the front of the camera to the back of the flattener must be 19mm.
How far out the draw tube needs to be to focus is dependent on your scope. How far the flattener is from the camera chip does not, its a function of the flattener.

Hope that helps.
Title: Re: Binned flats
Post by: mickw on Mar 09, 2011, 15:35:33
So does that mean that the camera just needs 19mm of assorted bits and bobs (preferably one bit or bob) between it and something "optical"", either the scope or a flattener ?
Title: Re: Binned flats
Post by: The Thing on Mar 09, 2011, 15:40:47
Hi Mick,

This distance applies to this particular flattener. You need to know how far back the CCD is from the front of its housing. The Canon 350D is 44mm if I remeber correctly.

If you just have your Canon on the back of your Burgess you don't need to worry as long as you can get focus. I have similar issues with my Baader Alan Gee II Telecompressor (horrendous name), the trouble with that one is there are no published figures for distances that I can find. Alan Gee is/was a 'famous' optical designer, shame he could write a spec sheet!

Duncan

Title: Re: Binned flats
Post by: mickw on Mar 09, 2011, 15:51:40
Thanks Dunc, got it now (should have read Chris' post properly as well) - This means that Fay is still in the poop because she has now got a 19mm adapter and the skinny "sticking" adapter which is about 3mm.  That could account for the vignetting.

Fay, must you use the skinny adapter as well ?
Title: Re: Binned flats
Post by: Mac on Mar 09, 2011, 16:24:44
Quote
Fay, must you use the skinny adapter as well ?

Probably as she cant get the Stilsons on to it to remove it. :lol:

Mac
Title: Re: Binned flats
Post by: Fay on Mar 09, 2011, 16:39:19
Yes, I have already got it off the QSI twice with the tool that gets lids off!!!!!!!!!!!!!!   sweat sweat sweat