HFG1 + Abel6, another old shot on the waiting list

[jimao22]

In 2015 I tried to imagine this elusive nebula, HFG1, using my MN190 and the old ATIK 314L+mono, but the result was rather poor and totally unsatisfying me. So shortly after, I give another try to this nebula, this time using another set-up, to increase the luminosity along with the increasing the total exposure time. The picture was made using the Equinox 80x500 telescope, with a focal reducer which reduce the focal ratio from 6.25 to 5.375, with a total exposure of 13 hours in Ha and 14.16 hours in OIII (more than 27 hours). Most of the exposures was 900 sec, using the EQ6/EQMOD mount and Baader filters. Shots were made in 2016 and "developed" yesterday. The result is better than the first try (see there the second and the third pictures - the first one is just a better result of someone else - https://astrodata.wordpress.com/2015/12/28/hfg-1/ ).

 

 

I should re-try process this shot with a better accent on the noise, which is obvious here on the sky background. When I will have time and patience... 

[Shibby]

Very nice. Great effort with all that data captured! I don't think I've ever heard of or seen this pair, but they must be extremely faint. As you say, the background does need some work - could you just drop it back a bit in the meantime?

[jimao22]

Sorry, I am not a native English speaker, can you explain me what "drop it back a bit" mean actually?

I will re-do the processing work if that it mean, because I want to participate to ATIK 2018 competition and I cannot do it with such an image, with a lot of noise. But I was very keen to show you the result because excepting the noise - the result was pretty good. 

[wimvb]

1 hour ago, jimao22 said:

Sorry, I am not a native English speaker, can you explain me what "drop it back a bit" mean actually?

It's an interesting object. If you make the background darker, the image will be better. This is what @Shibby means.

[jimao22]

Oh, yes, I totally agree with both of you!

I will do it for sure!

[jimao22]

I managed to re-do the process for this nebula (I did it 3 times actually) and this is what I have got. Is not the best shot but is the best I could do.

If someone else want to try re-process the raw files, I can send them to him. The only condition is to put the result here, on this topic. 

[wimvb]

This seems a very difficult target. The best image using amateur equipment, that I have seen is from Rick Stevenson:

https://www.flickr.com/photos/114789817@N06/40095589491

He invested 55 hours at a dark site to capture this target.

It seems that the brown areas in your image coincide with the Ha regions in Rick's image. To improve your result, you will need to collect more data, I think.

I downloaded your jpeg and decreased the intensity and saturation of the background a bit in GIMP:

(click for larger version)

If you PM a link to the (unprocessed) integrated image (fits or xisf format), I can have a look at it.

[jimao22]

I can send the .fit images, already calibrated with flats, darks and biases.

I cannot make other exposures because I do not have this camera anymore (ATIK 314L+). My sky is a suburban sky, 10 km away of the center of Ploiesti city (population almost 200,000). I am surounded by orchards and the street (where some f...g led lamps are located) is 100 m away. 

Tell me how to send you the files.

 

L.E. - I can send the files by wetransfer, but I need your mail address. You can send me the mail by pm, here.

[wimvb]

It's an interesting target, but weak, so it needs a lot of integration time.

I did a quick process in PixInsight:

- star align with H as reference (btw, you can star align all subs in one go. Just select the best in terms of fwhm, eccentricity, etc as the reference. As long a you have filter information for the subs, you don't need to align one filter at a time. Even if you do, use one and the same sub for all star alignment. This way, all your masters will already be aligned.

- channel combination (HOO -> RGB, and HHO -> RGB)

-DBE with only few samples. No normalization. This will also neutralise the background. For nb imaging, you don't need colour calibration.

-TGV Denoise  (HOO only)

-Historgram transformation

-CurvesTransformation to tweak the background.

An attempt at a pseudo Hubble palette (HHO)

[jimao22]

Yes, much better than mine, but you have absolutely right. I need much more integration time. Perhaps I will try it one more time with my new camera, which is more sensitive anyway. And of course, I will put at leas 10 more hours for each channel. But now I am looking for something else. 

Thank you very much for your try - I have an answer now for my doubts.

[gorann]

Very nice and interesting. Don't think I have seen this one before. I particularly like the very distinct blue bubble near the right edge. A planetary nebula?

[jimao22]

Yes, that's Abel 6...

[ollypenrice]

A very difficult processing challenge, I'm sure. Very well done on the capture. Wim's processing has shown what the data can do.

Not many people would try this from an imperfect site so well done.

Olly

[jimao22]

Coming from you, Olly, this is a very encouraging. Thank you for the appreciation and thank to Wim for the effort spent to show me a better version of my job.  

[wimvb]

The beauty of astrophotography is that once you've collected the data, you can process which ever way you like, and redo as many times as you like. Data has no best before date. In this case, I just pushed the background less than you did.

The target is a very interesting one, and deserves to be imaged more often.