NGC6888 Ha, OIII & L

[Rocket Pooch]

Hi,

I can do some more tweaking with this but considering it was taken on a full moon today and Sunday its quite good.

5x15min Ha
10x10 min L
6x15min O3

LRGB L&R=Ha G=OIII & B=L

[Ian]

Looking good there Chris. I'm interested in the blue/green haloes around some stars, is that a processing artifact or scattering or are they really that colour? Whatever that is, they're good and round

[Rocket Pooch]

Hi Ian,

The image was taken three days appart and its nearly improssible to get exactly the same focus (manually) on the stars hence little halo's on the bright stars.  The colours are not representative of the actual colour of the stars or nebula because of the colours I chose for each channel,

its like this

L which should be RG&B is actually Ha or Red
Red is Red
Blue is OIII which is actually Blue Green
Green is actually RGB

I did it this way round because the target is very Ha rich and also the Red was taken on the best nights exposures, I will fiddle (reduce noise and being out the nebula more) a little when I get time to get the image a bit better, but for now after nearly three months on non-imaging I was just happy to get out there again.  Any boy was it cloudy last night as well, with the moon out I was suprised I got what I did.

Just need to home that my trip to france next week does not coincide with their monsoon season.

[Mike]

Nice focus you have on that image Chris. What kit was used to acquire this one ?

[Rocket Pooch]

Hi Mike,

The ED80 at prime and HX as usual.

Chris

[Fay]

Chris,

well worth your effort, really fantastic. You should be really pleased, after such a long time of bad weather as well. You got right back into the swing.



Fay

[Whitters]

Superb image Chris. You mentioned cooling the Starlight and mentioned the freezer. Do you realy dump it in the freezer or do you have another method?

[Rocket Pooch]

Hi Paul,

Actually I resorted to turning the thing on at least two hours before imaging to get the temprature cool and stanble.  I resorted to longer exposures.

The issue with the SE HX Camerai is the dark current is high at high tempratures and when I was taking 2 minute exposure with this non-flat chip I really was getting some bad thermal effects.  This has been cured by cranking up the exposure to get better signal/noise.   

The other thing is the ED80 @ F7.5 is slow so I have been looking for a 600mm or 800mm F4 scope to get the exposures down by 75% so 5 minute subs are required and not 20 minute subs with the same ADU's and S/N ratio, this will cure the need for 6 hours of signal for a good image and bring it down to 1h 15m

This means a new fast short scope 8" F4 and also a 10" or 12" F4 scope as well at some point.

Chris

[Mike]

I'd be interested in what you find for a fast scope as I am after something similar myself. I fancy splashing out on something decent like a Tak or a TMB or maybe one of the WO Megrez's. Takahashi do a nice 90mm at F5.6

[Rocket Pooch]

Hi Mike,

I was thinking if £400?  GSO 8", I just need to get some more feedback on it.  Also I'm trying to find a .5 FR for the Vixen, that will give 900mm at F4.5, uba fast then.

Would love a TMB but thats going into the £2k price range, but if you get one can I borrow it?

Chris

[Whitters]

I see what you mean cooling the camera, does improve things a lot. Just need to remember to get it plugged in.