Astrofest collection

[peter_4059]

I finally got around to processing the images I took at Astrofest. Happy with how some turned out but had a lot of issues with tracking for some reason this year.

NGC6334 (24x5mins)
NGC6357 (16x5mins)
Corona Australis (23x5mins)
M16 (17x5mins)
Rho Orphiuchus (27x5mins)
IC2948 (40x5mins)
M20 (37x5mins)
IC4628 (27x5mins)

All processed in PS but intend to go back over the data with Pixinsight when time allows.

Comments/advice welcome.

Thanks for looking.

[peter_4059]

last few

M17 (16x5mins)
NGC5128 (19x5mins)
NGC3324 (20x5mins)
Eta Carina (11x5mins)

[jjjnettie]

:bowdown:
:eyepop:
An amazing collection Bester.
I remember the Running Chicken night. The rest was a bit of a blur.
And that may indeed be the explanation for your tracking issues. :rofl:
Contratulations on a damn fine set of images. :D

[alan meehan]

Fine collection of images Peter you done better than i did,good luck on re process with pixinsight.
AL

[troypiggo]

Mate, fantastic collection! Well worth the wait!

[ozstronomer]

Great Shots Pete, that's certainly an impressive collection, they have come up really well.:thumbsup:
Be interested to see the difference if you redo any in Pixinsight.

[jase]

Awesome portfolio Peter! You're on fire! Really like NGC6357 and the composition for NGC3324 is excellent. Have not seen it framed that way before. As you suggest a few could do with a touch up, but wow there is certainly some productive imaging going on. Well done. :thumbsup:

[Ross G]

Great photos Peter.

I really llike your Centauras A.


Thanks.

Ross.

[h0ughy]

some really nice shots there Peter. did you ice up on a couple or were your flats not quite right? The trifffid looks a little green. I like the Corona Australis shot.

[glenc]

That is an amazing collection of impressive nebulae images Peter.
The one of rho is actually IC 4603. Rho (IC 4604) is 1 deg north of that.

[Dennis]

Wow Peter – that is a superb set of images. Surely, you must win the “imaging factory of the year” award at astrofest for this prodigious output!

Thanks for the views.

Dennis

[peter_4059]

Thanks JJJ. You might be on to something there.



Thanks Al. Despite the nights being cut short by cloud and/or fog I did manage 1-2 images each night. Not as productive as previous years but plenty of data to process.



Cheers Troy. This is the first time I haven't rushed the processing and actually came back to the image a couple of days later. In most cases I wasn't happy with how it looked and re-did several of the steps. I also went to the trouble of flattening, resizing and changing to 8 bit before saving for web and paid more attention to the black point in the jpeg and I think this paid off.



Thanks Geoff. It is nice to have a few keepers to show for 10 days of imaging!



Thanks Jase. I'm really pleased with how the NGC6334 and NGC6357 images worked out as I've had several attempts at these objects but have never been happy in the past.



Thanks Ross. It was quite difficult to process compared to previous attempts - I suspect there was some high cloud around while I was imaging it.



Cheers Dave - I don't think the camera iced up this year - haven't had that problem since I filled it with argon. I normally apply threshold as a first step to find the black point and this usually reveals flat issues however I don't recall seeing this in these images. I haven't viewed all the flats in detail but will have a look. Did you think the flats were not right in all images or particular ones? Had a lot of trouble getting the triffid to look right - especially the blues but was very happy with the detail in the dust, especially at the bottom left hand side.



Thanks Glen



Thanks Dennis - we missed you up there!

[CoolhandJo]

Wow. So many great shots. Production factory!

[allan gould]

Most excellent images Peter. Well composed and processed as usual.

[strongmanmike]

12 images from one star party - nice work!

Like looking at a set of holiday pics :thumbsup:

One day I'll get to an astrofest :question:

Mike

[multiweb]

Great set of pictures Peter. Excellent focus. :thumbsup: Are you flat fielding?

[RobF]

Whatever it is, this one is my fav :)
Congrats on a fantastic portolio Peter :thumbsup:

[peter_4059]

Cheers Paul. It is nice to be able to leave everything set up rather than have to cart it in and out of the house each night.



Thanks Allan. There is always more to learn about processing!



Thanks Mike - it would be good to see you up here! Maybe next year?



Thanks Marc. I am doing flats, bias, darks and dark flats in DSS. I've had a look at a few of the flats (I take a set each night as I remove the camera) and they all look similar. Histogram between 30% and 50% in PS. I've attached a typical master flat created by DSS after combining 20 raw flats.



Thanks Rob. Wish I had a wider FOV for this one though.

[multiweb]

I'm asking because you have a gradient on all your shots which is consistent with over correction with flat fielding. The center of the field goes darker and the corners lighter. This is usually caused by a flat/bias wrong combination or the flat ADU level being a tad too low. I've battled with this issue for months. Drove me nuts. It is more obvious on the very faint stuff like Rho.

[peter_4059]

Thanks for the heads up Marc - how do you tell if it is a problem with the flat or the bias? I'm taking flats to get the histogram between 30-50% and the bias at 0.001 s.

[multiweb]

If the bias is not subtracted from the flat prior to divide it into the sub then you get an over correction. If the flat ADU is too low or too high you'll get the same problem. It's hard to tell if it's one or the other but it is very easily fixed with pixel math. I'd use the Rho shot to test. Add or subtract 100ADU to start with from your master flat and divide in your sub until you get an even background. Once you got it right you can apply the values to the rest of your subs and you'll be able to push your data even further because the border will dim and bring more faint stuff while the center will brighten up slightly.

[peter_4059]

I thought DSS was subtracting the bias from the flat before dividing into the sub - that's what the DSS help calibration flow chart implys?

When you say divide in your sub until you get an even background are you saying try different adu values in the subrtaction step or perform multiple divisions?

[Alchemy]

Must have had some good nights by the look of it.

[multiweb]

You add/subtract in increment of 100ADU from your master flat then save it as another version. Then take one original uncalibrated sub and divide it in (once) with the new master flat and check how your background evens out. When you hit the sweet spot use that flat to calibrate all your other subs.

[peter_4059]

Thanks Marc - I'll give that a try