Horsehead nebula 27.11.10

[Carole]

Desperate to try to sort out my guiding problems I went out last night minus 4 degrees, then found the skies were clear and how often does that happen?

It became hazy and so the stars are really bloated (must learn the tricks to try to suppress this in photoshop).

Anyway, on the 2nd try I managed to get guiding working again - THANK GOODNESS FOR THAT!!! Been a right PITA to sort out.  (Must have been moisture in the guide camera which has been in the airing cupboard for 2 weeks).

Just over 2 hours of 5 min subs, darks, flats and bias.
Modified DSLR Canon EOS 450D CLS filter guided.

(Note to myself, must remember to take the Bahtinhov mask off BEFORE I start imaging!!)

[Rocket Pooch]

Thats quite good Carole.

[The Thing]

I'm impressed.

[Carole]

Thanks Chris and Duncan.  Shame about the bloated stars, but very pleased to have got what I did as it's my first proper Horsehead, especially after all the problems I've been having.

Carole

[Mac]

See what persistence can do.
Nice capture.

so did you make a not of exactly what you did.
All you need to do now is to refine it.

Mac

[Carole]

so did you make a not of exactly what you did.
All you need to do now is to refine it.

Hi Mac, are you referring to what I did to image, or what I did to sort my guiding out?

I think the only thing I did differently this time to previous images was more subs (I normally only manage 1 1/2 hours), and I didn't go mad with the processing which I think I have overdone in the past.  I only used the Bahtinhov mask for focus and did not use Bahtinhov grabber as it looked to be spot on without.

Oh and of course I have done my flats properly this time. 

Carole

[RobertM]

Nice capture Carole.

[Carole]

Thanks Mac and Robert.

Carole

[MarkS]

Carole,

That really is surprisingly good!  You must be really pleased with this one. The subject is well chosen - filling the field of view.  Lovely horsie.

Two hours of solid imaging - is that a record for you?

The background noise is nice and even - it is caused by the light pollution - take the same image from a dark sky site and you would notice a dramatic improvement.

This must be your best image to date - well done!

Mark

[Jim]

That's really nice, well done Carole.

[Carole]

Thanks Jim and Mark,

Two hours of solid imaging - is that a record for you?

Yes, normally the clouds roll in or something and I have to stop.  This time I only stopped because the haze was getting so bad.  

The background noise is nice and even - it is caused by the light pollution

I'm glad to hear that as I was wondering what the cause was.  Some-one suggested doing longer subs, but I am not sure what a DSLR will go up to as my images look very washed out after 5 mins.  I think getting my flats right has also helped.  

The subject is well chosen - filling the field of view.

I'd be lying if I didn't say this was a crop.  Full frame below. There is a bit of shift as I bumped into the guide scope, whilst checking the objective lenses were not misted up (I had the dew heaters on), but wanted to be sure as I have never worked in such frosty temperatures before.  So had to stop guiding and re-start.  Might have shifted the whole set up slightly as well.  

This is the full frame.

[MarkS]

Some-one suggested doing longer subs

Longer subs are only useful when CCD read noise is the dominating factor.  But in this image the dominating factor is certainly the light pollution (even using a CLS filter).

Mark

[Fay]

That has come out ok Carole, at least you have seen the horse!

[Mike]

Very good considering the poor conditions. Well done.

[Carole]

Thanks Fay and Mike.

Some-one has shown me a neat trick to reduce the stars, however it doesn't reduce the halo.  I am not sure if this is acceptable.  Comments appreciated.