Flaming Star and Tadpoles - first attempt at guiding

[Filroden]

Having just about managed to polar align my new AVX mount I was still disappointed at the unguided exposures I could achieve. I was lucky to get up to 50% retention at 2 minutes largely (I think) down to my PA accuracy and uncorrected PEC. There was no avoiding learning how to guide so I took the plunge last night setting everything up.

PHD2 really was designed for dummies! I had it up and running so quickly including calibration and a quick drift align to improve my PA (good in az but I need finer controls over my alt adjustments). I even managed to get it linked into SGPro so I could control everything from a single interface. The only snag I had was trying to reach focus with the OAG camera (my ASI224MC). In the end I accepted slightly out of focus and elongated stars but PHD didn't seem to mind.

I only managed two hours of imaging thanks to the weather. It was blowing a gale but the mount didn't seem to budge and, for the first time, every image I took had a consistent FWHM which was much lower than I'd previously achieved unguided with the AVX (regardless of exposure length) or with the Evolution mount before it.

I captured 30 x 120s Ha exposures and 20 x 60s each of RGB (all at unity gain and -20C). However, the nebulae were sinking quite low and close to a street light so my RGB data was badly affected by gradients. I could probably have pushed the exposures much longer on the Ha but I didn't have a dark library beyond 120s and I knew I'd be too impatient today to spend over 2 1/2 hours building one

Celestron AVX mount + Skywatcher Esprit 80 + ZWO ASI1600MM-C + ZWO RGB filters + Astrodon 3nm Ha filter + OAG guiding with ZWO ASI224MC

Here's the Ha result:

I tried combining this with the RGB data but there were uneven colour gradients as you can see in the 'tail' of the Flaming Star showing more purple than red. As this is over a Ha luminance there is also nothing for the blue reflection data to hang over, so the actual 'flaming' part of the nebula is left more as a tint rather than the lovely ?Manx? shape I should have got if I'd also captured some L data. Still, it's nice to see some colour.

Anyway, comments/criticism always welcome! Thank you for looking.

Edit: Final colour version

[Nigel G]

Excellent first guided image.

Good detail and depth.

Well done  

Nige.

 

[Filroden]

7 minutes ago, Nigel G said:

Excellent first guided image.

Thanks Nige. You really helped with the set up. And it's so nice to not have to crop anything more than a few pixels down the sides! Two hours of imaging and no noticeable movement from first to last sub. Now I just have to work out dithering in SGPro to get rid of the few hot pixels that my darks didn't catch.

[Allinthehead]

Nice result Ken.

[Filroden]

Another attempt at the RGB element of the above image. This time I did a masked stretch, took it into PS for some levels work on the red (boost) and blue (reduce) channels, and then back into PI for the HaRGB combine. This time I did a blend (lighten) on the two resulting images (66% of Ha into R, and 33% of R into Ha). Overall this I think this is a better result, with more 'life' and contrast in the nebula and a lot less purple. Some of the stars look better too.

EDIT: see below for final colour version

[andyo]

Great shot 

[Filroden]

1 hour ago, Allinthehead said:

Nice result Ken.

Thank you. I'm pleased with it. I'm so surprised at how easy (and forgiving) guiding is!

14 minutes ago, andyo said:

Great shot 

Thank you. I've been trying for both targets for almost 6 months but they couldn't fit within the same frame with the alt/az mount because of field rotation. I prefer them like this - together, almost like musical notes.

[Filroden]

Final reprocess of RGB (I promise) applying a second background extraction to the RGB channels using many large points to remove the remaining, more complex gradients (particularly in blue).

Edit: breaking my promise and adding once final version on page 2 (and included in first post)

[wxsatuser]

Background looks green on my Lenovo at work.

Will wait to see it on my better HP at home.

[wxsatuser]

Never before noticed that dark bar eating into the yellow star, interesting.

[Filroden]

1 hour ago, wxsatuser said:

Never before noticed that dark bar eating into the yellow star, interesting.

I think it's micro lensing. In the RGB image it appears clearly on three sides and very faintly on the fourth. I'll check green. I had run a 80% SNCR but I may have let it sneak back when I reprocessed. 

[The Admiral]

Nice one Ken. A step change from AZ eh?

Ian

[Filroden]

2 hours ago, wxsatuser said:

Never before noticed that dark bar eating into the yellow star, interesting.

Here's the star in it's component channels: B, G, R, RGB and Ha:

The effect is clear in all channels and I've just notices it is faintly visible in one of the other bright stars. However, the angle of the effect is different in B compared to R and Ha.

[Filroden]

38 minutes ago, The Admiral said:

Nice one Ken. A step change from AZ eh?

Ian

I'd like to say no, but it's been a huge change. Guiding makes all the different. I've gone from subs with average FWHM varying from 4.5 at best up to 6 down in a single run down to subs which ranged from 1.9 to 2.0 in R and Ha (Ha had double the exposure time), and even smaller in B and G. It's made the image so much sharper in detail. I also only lost a slither of image down the sides when I cropped. Almost no noticeable image rotation. So much so that I'm going to have to learn to dither as the hot pixels stacked, something I've not seen in AltAz.

The one downside is that it took me 2 hours to set up and start imaging for this run. To be fair, I did a number of firsts, including controlling the mount from the laptop, drift aligning, guiding and making SGPro work with PHD2. I also ran the all-star polar alignment routine twice before drifting and there was probably a good 25 minutes lost as a large cloud passed overhead before I even starting aligning. I hope to get this to below an hour next time and eventually down to about 40 minutes once practices.

I now have two more things to practice: drifting and using SGPro to re-centre the scope based on a previous image.

[Filroden]

3 hours ago, wxsatuser said:

Background looks green on my Lenovo at work.

Will wait to see it on my better HP at home.

There was a definite green tint by about 5 points! I tried both SNCR and background neutralisation and the latter worked best. 

[wxsatuser]

4 hours ago, Filroden said:

There was a definite green tint by about 5 points! I tried both SNCR and background neutralisation and the latter worked best. 

Have now looked on my better laptop and the green is not there, think it was my Lenovo screen, it's not a good colour screen.

[ollypenrice]

This is a serious image. And a darned good one.

Autoguiding is (as I have opined many times before) the life blood of DS astrophotography.

Green? Yes, a bit, but just use the eyedropper in Ps set to Colour Sampler, 3X3 average, and tweak as neessary.

As for the 'light house beam' artefacts, 'Am I bovvered?'  Personally, not in the slightest. Stellar artefacts abound in this game. Check out the Hubble site.

Olly

[happy-kat]

That's gorgeous.

[Filroden]

45 minutes ago, ollypenrice said:

This is a serious image. And a darned good one.

 

11 minutes ago, happy-kat said:

That's gorgeous.

Thank you both. I'm really pleased with it. My first serious attempt with the new mount and guiding so I didn't know what to expect. I think the thought of guiding put me off, but I don't think it could have been simpler. Click three icons in sequence...job done  I struggle to 'picture' a process when it's written down. I wish more guides would include flowcharts with graphics.

47 minutes ago, ollypenrice said:

Green? Yes, a bit, but just use the eyedropper in Ps set to Colour Sampler, 3X3 average, and tweak as neessary.

It's another area where I think PS is easier to use than PI: the eyedropper makes much more sense. In PI I'd be seeing numbers like 0.0627, 0.0814, etc whereas PS tells me the background is 23, 24 or 30. They mean the same thing but whole numbers are much simpler to process! PI's background neutralisation did a good job after a new application so I didn't need to adjust it manually in curves. I also applied a little bit of "healing" around the lighthouse beams. Now I've seen them I can't unsee them so they need to go! I won't post it as the current version is still good, even with a slight green tint. I'd rather wait now until I've had chance to capture some more data.

[ollypenrice]

Well, you'll find 'light house beams' abounding in my images!

Olly

[Rodd]

Wonderful and SO LITTLE TIME!  You are very close to convincing me pull the trigger on the ASI 1600mmcool.  Who needs 20 hours of exposure time over a month when you can do 2 hours in 1 night and get results like this.  Is there an OAG that works with the camera?

Rodd

[Filroden]

18 minutes ago, Rodd said:

Wonderful and SO LITTLE TIME!  You are very close to convincing me pull the trigger on the ASI 1600mmcool.  Who needs 20 hours of exposure time over a month when you can do 2 hours in 1 night and get results like this.  Is there an OAG that works with the camera?

Rodd

Thank you  The camera has its downsides (file processing time/storage being the biggest) but when you can get presentable data in an hour or two from a suburban backyard it's nothing short of a miracle camera!

ZWO make an OAG and a filter wheel which all work nicely together (16mm and 20mm respectively from memory) but I've seen others use other manufacturers successfully. The main thing is to get the filters as close to the sensor so you can get away with 1.25".

[Nigel G]

Awesome Ken  

Nige.

[Allinthehead]

9 hours ago, Filroden said:

using SGPro to re-centre the scope based on a previous image.

Using platesolve 2 with sgpro is unbelievably simple, and gets me within a handful of pixels in minutes. Well worth the effort.

http://mainsequencesoftware.com/Content/SGPHelp/SequenceGeneratorPro.html?PlateSolvers.html

[Filroden]

14 hours ago, Allinthehead said:

Using platesolve 2 with sgpro is unbelievably simple, and gets me within a handful of pixels in minutes. Well worth the effort.

http://mainsequencesoftware.com/Content/SGPHelp/SequenceGeneratorPro.html?PlateSolvers.html

I have plate solving working so I just need to tick the right boxes to activate it. Now I know how everything links together and that the mount responds correctly I will use it on my next session to get back on target.