Cocoon Nebula - an update

[joecoyle]

Hi

So, here is my updated Cocoon Nebula from 15th Sep. Lots of light pollution which didn't help. 

I seem to be limited to guiding at only 2 min 30sec. I don't know why? Can anybody shed any light on why? I don't understand the settings, they are all default. Is it a case of messing until you find what works? 3 minute - they go slightly egg shaped, and 4 minute is even worse...

Comments appreciated as always. 

Stats:

10 x 2.5 min LRGB subs each binned 1x1 - 100 minutes total (didn't help that i get up for work at 6.30!).

Let me know what you think...

Cheers

Joe

[red dwalf]

That's a good start, but that target shows up better in narrowband especially Ha.

As for guiding, is your mount well polar aligned.

[Davey-T]

Nice star colours, can you work out which axis the eggy stars are moving in ?

Dave

[joecoyle]

Hi

According to my crude knowledge yes it is well polar aligned -

Polaris visible in little circle in polar scope.

0"0"0" on polar alignment error on hand controller.

I'm not sure what else I can do to polar align it ?

I have not checked the axis. Up is down, down is up! Etc etc

I'm going to invest in some narrow band filters at some point.

Cheers

Joe

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[Davey-T]

If you image something distinctive like the Pleiades so that you can identify N S E W in the image you can then see which axis is causing your eggy stars.

Dave

[joecoyle]

I'll try thanks Dave. I need to learn what the graph means in PhD. The bold likes that move and the little dim rectangles must mean different things

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[Davey-T]

I think the little dim rectangles show a guide pulse has been sent.

It will help if you can identify the dodgy axis.

Dave

[Stardust]

I assume the scopes are bolted down tight. You are guiding a long focal length with a very short one, it might just be a case of settings in PHD, other finder guiders folk should be able to help.

Definitely get a Baader Narrow band filter set, will go well with your camera  

[joecoyle]

Hi

Yeah it's the settings I don't understand do I just increase the ms of each pulse?

I should mention that I have a f/6.3 focal reducer on my scope if that makes a difference.

Baader filters are on my Christmas list!

Cheers

Joe

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[Davey-T]

How many steps does it take to calibrate ?

Dave

[joecoyle]

Usually between 20 and 30.

Joe

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[Davey-T]

Usually between 20 and 30.

Joe

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Sounds OK you could probably get away with less, AFAIK  the max length of pulse doesn't matter as it won't send a max length one any way, what it will do if the length doesn't correct it it will ramp up the length and send a longer ones until maxes out.

Dave

Dave