Markarian's chain 10th and 20th April

[Carole]

Started this on 10th April (pre new mount) and continued on 20th still on CG5 GT as wanted to compare my experience with the NEQ6 and CG5 GT.  I think I've finally nailed the PHD calibration problem with the CG5 GT, but the graph was not all that good.  

Anyway, total of 18 x 6mins, + darks flats and bias
Bromley back garden
Usual Modified DSLR 450D + CLS filter
SW Pro ED120

I think this is probably the best I will get out of this object in my light polluted garden.  
Just a first time experiment really and one for DSC.

[Fay]

Well that is one of your best Carole

[Carole]

Do you think so Fay, I thought every-one was going to tell me it was a waste of time trying to do it in Bromley.

I do like to attempt some of these from home so I get some idea for the next time I do them.

Carole

[Mac]

very nice capture,

Its not a waste of time from bromley, just a very hard challenge due to the light pollution,
the more subs you add, the better the image will become, (up to a point)

Just look at the other images produced from london,

It just means that people from a dark site will be able to get better data quicker,
which you can add to your own images anyway.

If you want to challenge yourself then go down the route of narrow band imaging
Light pollution becomes irrelevant then, but your image times go up 10 fold.

so that you need to nail your guiding first.

Mac.

[Carole]

It just means that people from a dark site will be able to get better data quicker,
which you can add to your own images anyway

so it's worth adding data I get from home to data I acquire at DSC then?

Carole

[Carole]

If you want to challenge yourself then go down the route of narrow band imaging

Can you do narrow band with DSLR?

Carole

[MarkS]

Carole,

That's a good result from a light polluted location - I would never have tried it from Sidcup.  The acquisition and guiding looks good and you've done a very good job of processing it.

My PDH graph was not good last night either - the sky conditions were quite poor - this can hjave a big effect on guiding.

Mark

[RobertM]

That's quite a difficult subject from here Carole so you've done well to remove any gradients and get the result you have.  The version posted is a bit small though, were the warts that bad

[Carole]

Thanks Mark.

The version posted is a bit small though, were the warts that bad

Hi Robert, good point, larger version shows up the noise more and the poor guiding.

This is a slighlty larger version

[Mac]

Have you only got the DSLR and the philips webcam?

Mac.

[Carole]

Have you only got the DSLR and the philips webcam?

Yes that's the only imaging cameras I have Mac. 

Carole

[Whitters]

Very nice image Carole, The noise will go with more subs, even from Bromley. Go for it it is a fantastic subject and looks great in a wide field shot like this. Have you thought of taking more shots arround and getting a realy wide field of the galaxy strewn area?

[Carole]

Have you thought of taking more shots arround and getting a realy wide field of the galaxy strewn area?

and do a moziac do you mean?  I should have positioned the "eyes" a bit lower and a bit more to the right and might have got more in. 

Instead of a mozaic though I think it might be simpler to use the Megrez which has a wider field of view.

I am hoping to do this at DSC so this was just a "practice run", so not sure if I'll add any more subs to it in Bromley, will have to see.

Carole

[Whitters]

By mosaic I mean take the image you have already then re-position the camera so that you overlap the origional image but capture a biit of sky you didn't in the first. Then you can overlay the two sets to get a wider view.
See below for an example, and you should be able to do better than this.

[Carole]

Did another 2 1/2 hours on this last night.  It's improved the noise but made no difference whatsoever to the amount of nebulosity visible, so not going to spend any more time on this subject until I get to some dark skies.

In total 4hours 18mins my longest to date.  Spent a lot of time making sure I got sufficent darks last night, was really shocked at the amount of noise in the darks at last nights temperatures, but I guess this is DSLRs. 

Carole