Beginnings of my August new moon projects.

[AlexN]

These are the beginnings of my August projects.

I'm on leave from work for the next 10 days so the mount is set up in the yard and staying that way until I go back to work. Hopefully in 10 days I can amass a decent amount of data for each of these.

In any case..

M16:
This one is only 8x 300s exposures at this point. 40 darks, -15c

NGC-253:
Currently at 30x 300s. 40 darks, -15c

I had hoped to get more of 253 before I packed it in at 3:50am but I saw orion enter the sky for the first time since I got back into astrophotography. I've not pointed a scope at orion since 2009. So I simply had to run 30 minutes of data on the trap before bed.

I had a bit of a late start last night. Helped getting kids to bed before setting up, then deciding to change scopes before starting imaging, then discovering that my camera won't come to focus in the 8" newt with adaptive optics fitted, so I had to do some quick surgery on the camera prior to commencing.

I'll be cutting down the 8" today and reinstalling the AO-7 unit prior to imaging tonight.


Hoping to get an earlier start tonight and hoping to hit 10hrs per target by Friday. I have no western view from my yard. So I can only image to about 1hr past the meridian.



EDITS :
Added image of NGC-253 with added data captured with AO and rejected 5.4hrs of data affected by skyglow and poor seeing.
Added final image of M16 with 5hrs 20m exposure.

[codemonkey]

Nice start Alex! :-) And how perfect are these nights at the moment? Perfect time to take some leave. Any time I take leave it clouds up, it's like the new gear curse.

Anyway, as I said, nice start; I look forward to seeing the final results! 253 is looking a bit red/magenta, I'd probably adjust the colour a bit. What are you using for processing?

[AlexN]

Stacking in deep sky stacker then moving the tiff files into photoshop cs6.

I am actually colour blind so getting the colours right for me is a bit hit and miss.

[AlexN]

And yeah as you say, perfect nights. Seeing has been quite good too. The only thing that could make the nights better here would be a slingshot to take out the street lights to the NE and SE.. The sky is reasonably dark here but for those streetlights. It's dark enough to clearly see the milky way at 1/4 moon.

[Rex]

Nice start Alex, hope it all comes together for you for your time off mate. watching and waiting for the final results.

[Atmos]

Going to be watching this space, I am so envious of anyone with clear skies. Melbourne has been a killer this year :/

[Slawomir]

I am looking forward to the fruits of your leave from work :)

[AlexN]

After last night I'm at 5.6Hrs on 253 and 3.3on M16.. The detail in the arms of 253 is becoming apparent and the outer edge dust lane detail is looking much tighter.. I've now got quite a collection of background galaxies coming through... The detail is still hidden a little by noise.. I'm not sure where the noise is coming from with 67 subs.. The M16 image is looking quite clean and probably only an hour or two from complete.

[Stevec35]

Promising stuff there Alex although NGC 253 is a bit too red/magenta. M16 looks very good.

Cheers

Steve

[AlexN]

Here they are with added data for comparison

[strongmanmike]

Yeah these latest ones look good Alex :thumbsup:

How is the leave treating you, night sky wise, so far?

Mike

[AlexN]

Had 5 solid nights of crystal clear skies so far. 8 nights to go. Going to dedicate as much time to ngc253 as I can muster although I have been tempted to point north and get a few hours on M33 too. My FOV makes for a very intimate M33.

[strongmanmike]

Wow, QLD usually puts out this time of year huh? :thumbsup:

Mike

[AlexN]

Yeah mate. This time of year the only thing we contend with in Brisbane is seeing and dew. Couple of fans and a heater here and there and you are set.

[tilbrook@rbe.ne]

Nice work Alex!

Your 253 is coming along nicely, the second image is looking good.
I'm a little confused about the amount of noise for the time.
Is the camera inherently noisy?

I've only used an LP filter once and didn't like it, certainly gave some weird cast to the image.
Kevin ( Cometcatcher) seems to have processing down when it comes to filtered images, might pay to PM him.

Cheers,

Justin.

[AlexN]

This camera isnt particularly noisy..I'm considering re-doing darks to see if perhaps they are not working properly however they are less than a few months old. According to the specifications it's one of the lower noise sbig cameras... It could be because I'm having to squeeze the data to pull the objects through the light pollution although it could be my processing skill (or lack there of) causing the noise too

[AlexN]

Should note. The camera is an SBIG ST2000XCM, scope is an 8"f/5 Newtonian

[AlexN]

Not understanding why the image still presented fairly noisy even after 9hrs exposure, I went through the subs one by one to gauge what was going on. It seems in my over zealous nature, I began imaging NGC253 at about 30~35° elevation..

The subs taken early on each night all displayed 3 distinct differences from the ones taken later in the night/early in the morning.

A - FWHMs were above 5 as opposed to 3.0~3.4
B - Sky background was measured much higher
C - Colour balance was severely skewed...

What have I learned.. In suburbia, dont image until the subject hits 45° and is clear from the surrounding skyglow.

In any case I got 15 more subs last night with the AO unit bolted to the front of the SBIG this time... the FWHM's on those subs is far superior to the ones previously captured.

Guiding at 5Hz I found I was easily able to get guide stars everywhere I pointed the scope (advantage of OSC camera rather than guiding with filters)

Here is 6hrs worth of the 11.4hrs data I have, I rejected the rest due to sky sky background and high fwhms. This is still not perfect, and there is still noise present (Im capturing new darks at present)

[codemonkey]

Hey Alex,

First off, nice work mate! Your mention of the AO unit making a big difference in FWHM almost makes me want to fork out some money.... must resist. Actually, not that hard to resist right now because they're all well outside the budget.

I had a quick look at the specs on your cam and it looks like it'll produce a reasonable amount of noise, but this is coming from someone who's only ever used low noise Sony sensors so my perspective might be skewed.

Given you've got 6hrs worth of data with an F5 newt and 7.4 micron pixels, I'd expect less noise in the resulting image.

What length exposures are you using? You need to ensure you get your target sufficiently separated from the read noise.

Would you consider making an integrated but otherwise unprocessed image available for me to have a play with?

Cheers,
Lee

[AlexN]

All 5 minute subs Lee. I find here any longer and the skyglow gets out of control.

I've had a lot of Astro ccds in my time. A Lot. This is perhaps the noisiest thus far. Going on calibrated frames that is. I'm keen to get an ST-10xme for shooting lum and narrowband from home and keep the osc st2000 for collecting colour data from dark skies.

I can give you the 16bit tiff to play with. Send me your email in a pm. It's only 11mb.

[AlexN]

Possibly the past update. Here is 253 with12hrs total and 37 fresh darks taken with the cooling operating at 45% to reach -15c vs the old ones with the cooling at 83% to hit -15c

Much cleaner overall result. It's probably obvious from this image but I am pushing to reveal the dark dusty regions of 253 with this.

In some deeper images of 253 that I have seen the core of the galaxy seems to have dusty tendrils being ejected outwards (more likely dust being drawn inwards) around the core. I've done my best to show these, and I can see them in there however I feel to be really effective I would need to visit dark skies to run 10+ minute exposures.

[Slawomir]

Hi Alex,

You must be pleased with result of your perseverance with this project :thumbsup:

As I understand it, dark skies is a must for imaging galaxies, so it would be interesting to compare what difference would it make to your photo.

I feel that processing of the latest version has been a tad too hard - I think it might pay off to reprocess this image one day.

[codemonkey]

Nice work Alex! I think you could pull a bit more out of that with some more work.



Having seen the raw data Alex is working with, it was enough for me to declare that I'd never move back to suburbia. I've only ever imaged in what I estimate to be Bortle 3 skies and the gradients he's dealing with here blew me away, not to mention the impact of light pollution on the signal.

So while dark skies might not be an absolute must, it's going to make it much, much more difficult for sure.

[Slawomir]

That's why I really admire Alex's perseverance and results he is getting.
I only ever imaged at what I estimate to be Bortle 7 at best, thus 3nm filters are the only way for me to enjoy this hobby...