It was a bit of a spur of the moment late night decision last week to test out the autorun function on the ASIAIR Pro while I went to bed. Needed a small target I could get with the l-extreme since it was a 90% moon…
Bunch of firsts for this one:
First time capturing ngc3132
First time autorun AAP (worked perfectly btw)
First time processing a full image- used Startools (stacked dss)
C14 with the 0.63 reducer and l-extreme
Eq8 with the ASIAIR pro for capture
3hrs of 1min exposures culled to 153subs
Stacked DSS
Processed Startools and a big crop
I’ve had a few goes at Startools before without much luck but decided to give it another go on the trial before deciding to buy the licence. After using Martins (startrek) procedure as a starting point I spent a crazy amount of time flicking a heap of different sliders and every so often finding one that made a good improvement. I was certainly able to extract a lot of detail that was completely impossible with gimp/ps so I reckon it’s going to become something I spend a bit more time with. Still pretty noisy, I’m sure I’ll be able to do better with practice (stuffed up the colour balance I think) and would certainly appreciate any comments for improvement.
Great job there, David. This planetary is not often photographed, mainly because of it's small size. What was the reason for using a reducer on the C14 for this object? Would it have been too hard with a longer focal length to centre the object in the frame? Planetaries are always interesting objects, thanks for showing us this one.
Thanks Mick- yes it’s tiny and I’m really enjoying exploring the deep sky with the c14 even though I mainly got it for visual and planetary. I just got into the habit with my non edge scts leaving the reducer in for dso imaging. Guess I just figured the faster speed and flatter field might be an advantage but you’re right for something like this it’s be better without it.
Raymo- yes you’re right - but this was a 1.9mb upload auto scaled down by IIS to 42kb . But also since this was done in the trial version of startools it’s a screen shot which is going to lose resolution immediately anyways. I’m in the process of buying the licence but I think that might be the best quality I can upload for now till the licence comes through… but here’s a link to the 1.9mb version:
nah that doesn't look out of focus, it looks the opposite. Stars are very nice and small, considering this looks like a heavy crop. I've plugged in the FOV of that scope into Stellarium and this object is tiny. The image is just pixelated because of the likely? crop.
I’m pretty confident the focus is ok but certainly my processing skills aren’t doing me any favours. Bear in mind its a mag10 40” x 60” object!
Yes it received a huge crop because:
1) the surrounding star field wasn’t really the centre of attention. Most of the time I’ve seen pn’s presented they receive a similar crop
2) I’m still waiting for the new el panel to arrive so the flats are not adequate. As soon as I started processing I had all kind of artefacts around the edges so needed to do a big crop otherwise the startools algorithms were going nuts trying to flatten the image.
In addition, I binned my asi294mc pro 2x2 on capture to achieve a better pixel ratio, and I think that’s upset some things in startools algorithms again. It all got very blocky very quickly. Not sure if that’s a thing with startools or something wrong I did…
Next time I’ll do it at the native f11 and unbinned to see what happens. But in the meantime I’m happy to get a result!
Very much would appreciate any additional constructive critiques to help with future processing.
I don't know what everyone else is looking at, but in both the high res and the little 42kb versions the target itself is far from sharp, and the stars are blobs even when I take the screen down to 25%.
raymo
Last edited by raymo; 24-02-2022 at 06:06 PM.
Reason: more text
That's because it's a super high res crop
I'd imagine that this would be a near +150% crop of the original image, easily. That's what heavy crops look like.
I don't know if David binned the image; it would have been beneficial for SNR , but it's definitely not unfocussed IMO, it's just heavily cropped in.
David are you able to post the original image as well prior to cropping? It would also help with advice about processing. I'd be interested to see why you've got that black artefact around the object.
Hey Adam yes I’m not too sure what that is. I did have a lot of problems doing the “wipe” due to unsatisfactory flats so maybe something there. I don’t know how to get you an uncropped version as I needed to crop it before I processed it (as per startools requirements). But I’ve attached an uncropped stack that has had some stretching / curves in gimp. Maybe that will yield some clues. And yes- it was a 2x2 bin and then binned again in startools as per the module procedure.
Regarding focus- it is possible you’re both right. I think it is not as unfocused as it seems due to the big crop and inexperienced processing. But common sense tells me there must have been at least a small amount of focus shift with shifting temperature as I haven’t hooked up an eaf yet and had it running unattended for 3hrs. So thanks for the heads up on this one Raymo I’ll need to work on a solution for this.
Dave,
Ive read your thread with some interest
Taking on such a tiny dim planetary nebula under an almost full moon in bortle 7 with a massive light bucket is a “HUGE” challenge, however I admire the fact you decided to go for it and did salvage an image.
I’m only a few km away from you ( when I’m in Sydney) and my yard borders on Bortle 8 as I have Las Vegas neighbours either side of me most nights
My observations
Firstly the L Extreme does not act as a bonifide light pollution filter like I thought it did a while back. Yes it helps but you still need to mitigate the LP and moon glare noise floor with calibration frames , dithering and processing.
Secondly, 2.5 hrs seems a bit shy for optimum SNR on such a tiny dim object with that 294MC. More like + 4 hrs would yield improved SNR under those sky conditions that evening ( obviously its not always possible )
I capture all my images with my 2600MC bin 1x1 and let Startools work it’s magic with binning for optimum SNR and resolution ( 90% of time the default Bin 50% works really well as I’m oversampled at around 0.70 arc sec per pixel )
Under your sky conditions that night good calibration frames are a must. I don’t really know what works with the 294MC ( my 2600MC uses Flats and Bias which works well under all conditions)
Startools requires clean linear data from the stacker ( no intervention after stacking )
Big crops in Startools before Wipe through to the final noise reduction is a big no no . By massive cropping before processing in Startools your effectively taking away usable data which has a negative effect on the softwares ability
Perform your initial stretch using AutoDev, Bin 50% then use Crop to trim the edges for stacking artifacts , then Wipe and on to your final stretch in Autodev
Leave your massive crop for the final saved image.
As far as stretching is concerned some folk use Filmdev which is not the recommended way as Filmdev applies a stretch across the whole image at a uniform way whereas Autodev stretches the image to apply dynamic range where its needed to highlight structures and other details
The only 2 tools I use in Autodev which yields good results is ROI ( I use the mouse a draw a ROI ) and the “Ignore fine detail” slider. The rest of the settings I leave as default
Another advantage of using AutoDev is that it’s almost impossible to black clip your data which is sometimes too easy to do with other software programs
Anyway enough for now , I could blabber on forever
Hope the above offers some practical advice
Again well done on your capture of NGC3132 I’m sure a re process in Startools would yield some improvements
Clear Skies
Martin
Hi Martin thanks for those tips. I’ve been wanting to have a go at proper post-processing (as opposed to livestacking and stretch) - for about 6 months now - and have had almost zero clear nights to get any data that would be useful. Hence the less than optimal conditions to test things out. But then I love a challenge!! The goal was to get some kind of output as a starting point and get some feedback for a second / third etc go at it. So I’m very appreciative for the feedback that’s come back so far.
I think you’ve probably nailed the biggest issues with the processing. I did have darks and bias (calibrated as dark flats for the asi294) and flat calibrations. The problem was the flats were not good. As a matter of fact I’ve only last week upgraded to the asi2600mc so this may well be the final shots I get with the 294mc. I should also get my new flat panel for next week.
Thanks for the startools tips. I can immediately see about 3 things I did totally wrong so yes I’ll do a repeat… More data and getting the eaf up and running will also be essential too I believe.
Dave,
Glad to offer some assistance ( personal experiences) where I can
Startools is powerful post processing software and is designed for typical long exposure AP. There are more suitable programs other than using Startools if your staying with the Live stacking and EAA pathway.
Congratulations on the 2600MC , man what a camera , other than the issue I had and as with many others with the thermal grease smear on the sensor early last year , the camera never ceases to amaze me with performance. I’m into DSO and planetary imaging with Newts between 900mm and soon to be 1250mm , sort of an all rounder focal length.
Both the 2600MC and 2600MM do require a dedicated 12v power supply for cooling , relying on just USB doesn’t cut it. Cooling to -10C seems to be adequate as these cameras are super low noise especially dark current.
I run mine via Ascom with APT and mostly use Highest Dynamic Range Gain 0 but have also tried lucky imaging ( short subs in Sydney) with Lowest Read Noise Gain 100. Gain 100 does reduce your noise a tad but at the sacrifice of under half well capacity for dynamic range
I’m pretty much set on Gain 0 in Sydney and down at my dark site South Coast
. But also since this was done in the trial version of startools it’s a screen shot which is going to lose resolution immediately anyways. I’m in the process of buying the licence but I think that might be the best quality I can upload for now till the licence comes through… but here’s a link to the 1.9mb version:
