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.
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?
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.
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.
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.
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.
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.
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
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)
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?
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.
