Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: Fay on Mar 05, 2011, 12:57:57

Title: QSI artifacts
Post by: Fay on Mar 05, 2011, 12:57:57
It was a bad sky last night, & I could only save 8x600 subs

I have not processed much so you can see the problems

ED80/ dedicated flattener, 7nm ha filter, flats, darks taken

Astroart struggled to stack the large subs but DSS was fine

It is a very noisy image, but not a lot of subs

There are thin vertical lines

Top left are strange effects

Also I have flared stars

I had about 1000 hot pixels as well

Was QSI ok with being plugged into

all the flats are lighter on the left, & have a curving light pattern that could be the edge of the filter, not sure.

I will check that Astroart puts the cooling on, I think I saw a checked box, but will make sure


Any suggestions welcome

a beyond stressed Fay

(http://farm6.static.flickr.com/5014/5498820127_5d422c48e9_b.jpg)
Title: Re: QSI artifacts
Post by: Fay on Mar 05, 2011, 13:29:04
Just checked Astroart and cooling on box was checked.............but I had not put a temperature in there!!!!!!!!! One problem solved, probably why I had 1000 hot pixels
Title: Re: QSI artifacts
Post by: mickw on Mar 05, 2011, 13:59:37
You haven't cropped it have you ?

Did you only have the Ha filter in the wheel ?
Can you have just 1 filter in the wheel or must it be fully loaded ?
The curved artifact could be a reflection from a filter hole in the wheel.

The straight artifact looks like light

When you fitted the filter did you check you put the case back together properly ?

QuoteWas QSI ok with being plugged into
Meaning.......... ?
Title: Re: QSI artifacts
Post by: Fay on Mar 05, 2011, 16:33:40
Wondered if electrics could up set it, if plugged into the same hub as, say, the mount

Filter wheel is full

I think there is a star somewhere top left, but surely not that amount of light

well filter wheel is revolving, also I checked it with the case off, to see how it was doing
Title: Re: QSI artifacts
Post by: Carole on Mar 05, 2011, 16:59:18
Isn't that top left artifact a bit like the one Mark got on his horsehead.  though in his case I think it was Alnitak causing it.  Might be worth speaking to mark.

Carole
Title: Re: QSI artifacts
Post by: Fay on Mar 05, 2011, 17:28:12
Yes it seems it is Alnitak, I will have a look at Mark's
Title: Re: QSI artifacts
Post by: Rocket Pooch on Mar 05, 2011, 20:17:40
Hi Fay,

This camera is completely different from the old one, mine has 100's of hot pixels, but they are not saturated, its comon on Kodak chips, the bright star has caused the stuff in the top left.

With Astro Art you have to click on Dark on the main tab to shut the shutter, if you did not do this then the bias and darks are not valid.

Give me a call and we can have a chat about the image.

This looks ok to me for a 1st try.

Chris
Title: Re: QSI artifacts
Post by: RobertM on Mar 05, 2011, 23:33:23
There's nothing much wrong there Fay.  Alnitak is a devil and causes all sorts of problems just like that.

I think you need to get used to the camera so pick Chris's brains before he withdraws the offer...

Robert
Title: Re: QSI artifacts
Post by: Fay on Mar 06, 2011, 08:17:10
Chris's brains have already been picked!!!  There were a lot of things I did not do correctly. I was treating it in the same was as the Atik, whereas it is completely different.

If the conditions are ok tonight, I will be out there putting Chris's tips into operation. I will do HH again, as it is only a practice run & hopefully things will be better.   
Title: Re: QSI artifacts
Post by: Rocket Pooch on Mar 06, 2011, 11:29:32
eMail on the way Fay.....

Chris
Title: Re: QSI artifacts
Post by: MarkS on Mar 06, 2011, 17:08:12

Fay,

Imagine taking a photo, with a standard lens, on a Summer's day - the old fashioned kind of Summer, where the sun shines.
Imagine the sun is just inside or just outside the field of view.
Loads of artifacts will appear because the sun is so incredibly brighter than everything else in the image.
Well that is what happens when you take an image of the Horsehead with the stars in Orion's belt just inside or outside the field of view.
They are so incredibly brighter than everything else in the image that they can cause artifacts everywhere.
The more complex your imaging train (mirrors, lenses, filters etc.) the worse it is.
You can tell what is causing the artifact by taking a series of 10 quick images, say about 10' apart for your field of view.  The change in position of the artifacts will provide valuable info.

Mark
Title: Re: QSI artifacts
Post by: Fay on Mar 06, 2011, 17:20:19
Thanks for that Mark, I had never seen that effect before