M20 taken at SPSP14

[Retrograde (Pete)]

Hi All - it has taken me a while to finish processing this as I've been busy with other things. I struggled badly with the colour-balance in this image so I tried stacking raw subs (rather than converting them to tifs first) & it seems to be a big improvement.
This is my first attempt at this object (since a failed effort back in the film days) & probably my best deep-sky image so far.

14 x 1 min unguided subs at ISO 1600 through a Pentax K-5 attached to an ED102 on a Vixen SP mount.

[bobbyf (Bob)]

Well done Pete
Thats really nice mate

I wish i could get 1 min unguided! Will try again tonight, now that i've upgraded the mount software
Cheers
Bob

[cometcatcher (Kevin)]

Looks good Pete.

[Retrograde (Pete)]

Thanks guys

Originally Posted by bobbyf

I wish i could get 1 min unguided! Will try again tonight, now that i've upgraded the mount software
Cheers
Bob

Well that was my first attempt at 1 min and there is a smidgen of tracking error if you look closely. I might try leaving out a couple of the worst subs & re-stacking or try & fix the stars in post-processing if I can work out how.
Good luck with your own efforts bob I'm sure it can be done

I was previously able to get perfectly round stars on 30 sec subs but I had a few power issues on the night at SPSP (I tried a new 12v-9v adapter which was actually putting out 10.6v causing the drive motor to run fast which meant I had to fall back to using 9v batteries) all of which affected my drift-alignment.
Frankly I'm amazed that my old Vixen mount performs so well. 28 years old - unused for around 20 of those years - and never serviced or re-greased or anything

[ncorreia (Nelson)]

Really nice M20! I gotta start trying for 1min unguided

[SimmoW (SIMON)]

Yes that's a goodie, and well done getting to one min....try 2 next!

[Retrograde (Pete)]

Thanks Nelson and Simon.
If and when I get 1 min subs with perfect tracking then I might try going longer.

[BruceG (Bruce)]

Very nice image Pete, I take it that's a cropped image from the 102? It's pretty small in the field of view of my Megrez 90.
I think the colours you have a just right. I don't seem to get the same sensitivity to blue that you and others have succeeded with.
Anyways, a fine result and I look forward to seeing more from you.
Cheers, Bruce.

[Retrograde (Pete)]

Thanks Bruce

Originally Posted by BruceG

Very nice image Pete, I take it that's a cropped image from the 102? It's pretty small in the field of view of my Megrez 90

Yes the image a crop of around 55% on each axis.

My ED is 714mm focal length & I have a FF but no reducer. Think the Megrez might be a bit faster f-ratio than F7? The K-5 is also a crop-sensor camera so multiply all that by 1.5. Nevertheless the Trifid was a smaller and more difficult object than I'd imagined.

Originally Posted by BruceG

I don't seem to get the same sensitivity to blue that you and others have succeeded with.

When I initially stacked tifs (that I'd converted from the RAW files prior to stacking) the resulting DSS tif had less colour differentiation between the two parts of the nebula. With decent colour in the magenta section I could only get mauve in the 'blue' section.
When I stacked the RAW files (Pentax DNG format) the resulting DSS tif had better colour immediately & was much easier to post process into something acceptable. I'm still on a steep learning curve so I was probably doing it all wrong to begin with