Another M42

[DanWebster]

On Tuesday the skies were wonderfully clear, so despite it being below freezing I had to go out.

I initially started on M81, but as that got lower in the sky I switched to M42, and while I wasn't going to go crazy as it was already getting fairly late, I ended up getting 120 subs at 30 seconds each.

The final image uses 112 subs which is by far the most total time I've used in an image.

While the stars are not entirely round, and the core is slightly over blown I can still see that I'm making progress so I'm happy with that.

The scope and the camera were covered in frost by the time I was done, and I thought the mirror would be too, but it seemed fine when I got inside.

So I guess the softness of the image is due to the focus not being as good as it could have been, so I'll have to work on that next time.

Thanks for looking

Dan

[Jessun]

Hi Dan, you should be very happy with that, and you'll find that you'll keep breaking that record of total exposure. Keep adding to this!

/Jesper

[Gina]

I agree - you're coming on nicely

[DanWebster]

Thanks for the kind comments

I suppose I should setup PEC, but as I can't drift align from the back garden I've not done it.

Do you think it would be a good idea to set it up any way, but with just a polar scope alignment? Or could this create more problems than it solves.

I also have to take the scope in at the end of the night, so it will always be slightly different from the previous setup.

Cheers

Dan

[Jessun]

Do you guide Dan?

You may find looking through your subs that a few are 'below par', as in affected by wind or seeing. You can chose not to add these to the stack, and a Sigma reject routine can do some more good for the final stack.

I can't see any immediate tracking problems in your image, it's really quite good.

M42 is a funny one as 30 seconds is probably the least useful sub length. The core - Trapezium - is too bright already at this short time and the rest of the nebula benefits from longer subs, several minutes if that can be achieved. So it's common to take two sets of exposures, plenty of longer ones and perhaps not that many short ones, maybe 10 second long or shorter. These will then make up two different stacks that you combine to your taste in some software that can handle layers.

If you guide or not plays a big part in what people will advice you on here for the next step.

/Jesper

[DanWebster]

I'm not guided at the moment. I'm on an EQ5, so from what I read I'm at the weight limit already.

I tried making a lightweight finder guider with a logitech webcam. It had good focus on Jupiter, but failed when I tried to point it at a star so it didn't get used on this image.

I'll give it another go next time and see if I can get it working, but I'm probably going to be unguided for a while.

[Pete Presland]

coming on nicely

[Jessun]

For unguided that is excellent!

I had a HEQ5 for a while, but since I guided I never tried the PEC training routine, so I cannot really advice on that. I'm sure someone else will come in here with their view on that.

I used a few versions of MS Lifecam for guiding since they were easy to fit inside an old eyepiece or extension tube. It's vital that this little unit is rock solid and doesn't move the slightest as you slew across the skies.

PS you can chuck some info about your current setup in your signature so everyone can see what scope etc you use

/Jesper