Leo Triplet mono

[DaveS]

My first, and for this year, last Leo Triplet. 18 x 300 sec subs, binned 1x1. 130 PDS, Baader MPCC III, Astronomik CLS filter Baader L filter (From LRGB set) Trius 694. Guiding ST 80, QHY 5 II, PHD2.

2 rounds of gradient and vignette removal, 2 rounds of histogram stretch, crop, another vignette removal, and finally a slight low-pass filter.

I don't intend to do anything more with it for this year, but will keep the data for next year to go with, hopefully, some RGB data.

[sologuitarist61]

Excellent capture - well done!

[DaveS]

Thanks Richard.

Looking at it again, I'm seeing some more inhomogeneity in the background than I thought. The big dark triangle out of the central star is, I think, the shadow of the focuser intruding into the light path.

[lensman57]

That is a beautiful image.

A.G

[ollypenrice]

Very nice cores indeed.  You don't mention flats but these would, I'm sure, really help to separate the faint stuff from the bacground and further flatten the sky.

Olly

[DaveS]

Thanks Olly.

No, I didn't take any flats, a mistake on my part mainly due to concern about matching them up. However I now have my 'scope covered by 4 layers of white T-shirt so I'll bash off a few, hope I can match them up.

[DaveS]

Here we go:

18 x 6 sec flats. After stacking there was still some vignetting (Possibly negative) so I did a remove gradient and vignetting, two histogram stretches and a final gradient and vignetting after a slight crop.

[strutsinaction]

Background certainly looks more even but I think you've lost some detail in the galaxies. I prefer the first image 

Regards

John

[DaveS]

I think you're right, bother.

OK, back to processing.

[ollypenrice]

Did you dark-subtract the flats? This is vital. The good news is that you don't need to shoot dedicated darks for your flats (ie darks of the same duration and at the same temp.) All you need is a master bias and that will make a perfect dark for any flat.

Thd second image has the potential to ba far better than the first but the black point is still very high and you'd get more contrast by cutting it back a bit. Keep working with the second dataset. Trust me, it is far better than the first.

Olly

[DaveS]

I have 20 bias frames that I used for both the lights and flats in AA5.

[DaveS]

Well, this is where I am now. When I did a process with flats I had an inverse vignette, so I did a weighted average with one without flats, that gave me a reasonably flat background, I then did two histogram stretches and a slight crop.

I do need darks, but as I want an early night and it will take a couple of hours to do them I'll wait til tomorrow.

I'm actually quite worried about the cooling of my camera, I think it's not working as it should as I've never seen better than -11 c, even in mid winter when I had ice on the laptop. these were no better than -1.5 c

[DaveS]

Well, I did 24 5 min dark frames to add to my flat and bias frames.

Gradient and vignette removal, 2 histogram stretches, the second with two curve points and a mild low-pass filter. I think this is about as far as I can take this data, and given the time of year it's now on hold until next March-April.

Roll on the narrow-band targets!