Another try at the Orion nebula

[Carole]

The seeing was awful tonight and clouds rolling in all the time, however having gone to the trouble of setting everything up and doing an accurate alignment I wanted to get something.  At my stage of things I need all the practice I can get.

However still having problems with K3.  I did 46 x 4secs LX followed by 72 x 5 secs, unguided.  This was about as much as I could get before it disappeared behind both the clouds and the trees.  I could not see Orion let alone the nebula at all, but somehow the camera found it, but obviously conditions were pretty bad.

However when I went into the AVIs that K3 had captured there were 7 files.  Two of which had nothing on them at all.  2 had  about 3 frames.  1 had 12 frames, 1 had 36 frames and one had 71 frames.  So where did all the rest go? So in the end I only managed to stack around 85 frames by the time Registax had chucked out the rest.

I think this is a slight improvement on my first image of the Trapezium.  Captured more nebulosity despite the poor conditions.   I don't know why the image is so pixelated.



Carole

[Mike]

Isn't that camera modded? Shouldn't you be able to do long exposures with it? WHy not go for like 30 seconds?

[Carole]

Wasn't sure how far I dare go without guiding.  I'll give it a go next time.

Carole

[Ian]

you'll have no problem imaging the orion nebula without guiding. I would put all thoughts of guiding to one side until you've got the hang of the main camera.

For LX imaging at the start, you need to concentrate on getting your mount polar aligned properly and then target bright objects, star clusters, bright nebulae and galaxies first. Move on to the dim ones later. There's quite an apprenticeship to pass through before you'll be imaging the Veil. Ask Chris, Fay, John, Robert or any other active imager how much time they've put it imaging to get to where they are. With a reasonable mount, which you have, and a short focal length scope, which you have, you should be able to get up to around 30s or maybe even longer without trails as long as you set everything up well. 30 Seconds on the orion nebula will burn out the trapezium...

[JohnP]

Carole,

It still doesn't look to me like you have the serial port controlling long exposure correctly. I think for 4 secs with Max Gain set you should see a lot more than you show in your picture. If you have got AVI files that have nothing in or strange numbers of frames etc. it sounds like you are dropping frames or have communication errors. You need to ensure that when you have it looping doing long exposure in K3 all the frames displayed look the same - if you suddenly have 1/2 frames or black frames etc. something is wrong...

If you want I can borrow your camera sometime & try & set it up on my laptop... This will at least isolate your laptop or K3 settings as a 'cause for concern' - there is still something not right somewhere...

John

[Carole]

Many thanks every-one.  As I am sure you will appreciate I am going through a new big learning curve.  John's kindly had a look at my camera settings and thinks things are not working as they should be (see the last posting).

If you want I can borrow your camera sometime & try & set it up on my laptop... This will at least isolate your laptop or K3 settings as a 'cause for concern' - there is still something not right somewhere...

Many thanks John, I'd appreciate that?
I can drop it over if you send me your address by PM and let me know when it is convenient.

you need to concentrate on getting your mount polar aligned properly

So far I have been quite pleased with my alignments, as far as I can see they have been very accurate (unlike the very "approximate" alignment that was possible with an ETX, and now I have an Equatorial Mount with a polar scope, I can see what was missing on an ETX which does not have this facility at all).  Quite a luxury for me because when I was doing planetary with the ETX I normally had very little time to play around with the controls before the planet would drift away.  I think only once did I ever manage to get it as accurate as my new mount, so I am well pleased with that.  However I know this is something that needs to be practiced over and over again so not going to be complacent just because I have done it pretty well twice.

30 Seconds on the orion nebula will burn out the trapezium...

Great thanks.

Carole

[JohnP]

Carole,

Look at this old image on my website - taken with same camera as you i.e. modified Toucam with SC3 chip. This was 2 sec exposures... you can see why I don't think your LX is working...

http://homepage.ntlworld.com/john.punnett/graphics/archive%20images/latest_10.html

John

[Fay]

That was a good image John

[Carole]

I agree with you John. 
If you took 100 x 2secs and got that and I took 72 x 5 and 46 x 4 then there's definitely something not working right.

Just what you need when you're a beginner to not have your kit working properly, and esepcially when you don't know what to expect.

Many thanks for your continuing help.

Carole

[JohnP]

I will try & find the original avi file in my archive storage & email it to you so you can get an idea of what the avi looks like - will also give you something you can practise processing with.....

[Carole]

Thanks John.

Carole

[Ian]

Carole, when you stack, use difference alignment and raise the threshold to above about 30. The reason your image has diagonal stripes is that K3 is aligning on the inherent bias of the chip which appears a diagonal striping and doesn't move. If there is a little movement, which there will inevitably be, then with some luck that bias can be averaged out.

FYI, the threshold is a pixel filter that makes K3 ignore very low value pixels, such as background noise and faint nebulosity, which you don't want to align on. It only affects the alignment, and not the final stacked image.

[Ian]

oh, and when you get longer exposures, the image will be brighter so you won't need to stretch the histogram so much and the background noise will be much less visible.

[Carole]

Thanks Ian for that. 

I did give it another go at stacking in K3 (I did it is registax before). 

difference alignment and raise the threshold to above about 30

, Did this but it didn't really improve the final image.  I guess the raw material is too crappy in the first place.  Not sure about doing things to histograms, saw some-one do it once, but long before I started imaging, so don't remember what to do.

I am however keeping a copy of all this useful information so I can refer to it as need be. 

I am going to wait until John checks my camera before I try anything else with it. 

Carole