The "No EQ" DSO Challenge!

[Nigel G]

I'll have to continue this tomorrow,  need a large whisky 

[The Admiral]

1 hour ago, SteveNickolls said:

That is absolutely gorgeous, the colours are brilliant and the image has a glass like quality-very well done. Splendid. Will see if the main monitor shows even better detail (I'm on the tiny Hudl right now).

 

1 hour ago, Filroden said:

That's a lovely image. The reduced stars really makes the nebula pop. You've really captured some lovely detail in there.

 

36 minutes ago, happy-kat said:

Ian that newly tried processing approach has made your image well extrordinary, such a difference with the cleaner back drop for the main event the nebula.

Thank you all for your kind comments, and it was a rush job an' all. Mind you, I probably couldn't reproduce it! After a while I find it quite hard to be objective about one's images. I too was impressed at the extra detail visible in the nebula. That sequence of operations certainly gives a lot of power to one's elbow.

Ian

[The Admiral]

6 hours ago, Filroden said:

Here goes: my first LRGB image using 30 second subs on the ZWO ASI1600MM at -20C with a gain of 300. Processed in PixInsight.

That's a super image of M45 Ken, I love the nebulosity, which looks even better on my main PC.

1 hour ago, Filroden said:

Well, my aborted attempt at IC1848 really was a mess.... It's not pretty. There's some serious star trailing going on which I think is down to me letting PixInsight manage frame selection.

 

I think you are being too hard on yourself. I feel sure that there's a lot of detail in that image itching to be released. Are you able to do the equivalent of what we are doing in ST, with PI?

Ian

[SteveNickolls]

37 minutes ago, Nigel G said:

Hmm, somethings gone wrong , might need a new camera ? I'm seeing red but only in frustration. 

Oh my Nige, so sorry to hear that.

Cheers,
Steve

[The Admiral]

41 minutes ago, Nigel G said:

Hmm, somethings gone wrong , might need a new camera ? I'm seeing red but only in frustration. 

Oh Nige, sorry to hear that. Hope it's something simple like a wire having got detached, or at least, something that is visible to the eye and readily put right. I think you'd be wise to put it away and start again tomorrow, when you're fresh.

Ian

[Filroden]

14 minutes ago, The Admiral said:

That's a super image of M45 Ken, I love the nebulosity, which looks even better on my main PC.

Indeed and thank you. I think it loses something for being converted into a lower quality jpeg for the web but the full Tiff image on a large screen is breath taking.

I think my PixInsight processing is not too dissimilar to the StarTools processes you describe. I still have to master masking as it's vital to being able to pinpoint which elements of the image to affect. I'm also learning how to use it's preview feature which allows me to apply processes to smaller parts of the image (reduces processing time) so I can tweak the settings until I find the result I like. I could probably push the data harder but I think I need to collect more before I really push the processing.

I think what's impressed me most with this new imaging setup is that I'm finally happy with star colours. It seems to be much easier to balance the colours when you can work on each of them individually. Also the fact that SGPro makes capturing the data so automated. Once I've resolved the issue with my wifi connection to the scope and I can re-centre the scope every 5-10 minutes, I should be set for some longer imaging sessions.

Next on my "to learn" list is whether binning the colour data improves things. In theory, I trade resolution (not so important for the colour channels) for improved sensitivity so I can take shorter colour subs to achieve the same effect (and therefore allow more time to collect luminosity, improving image quality/sharpness).

[Nigel G]

22 minutes ago, The Admiral said:

Oh Nige, sorry to hear that. Hope it's something simple like a wire having got detached, or at least, something that is visible to the eye and readily put right. I think you'd be wise to put it away and start again tomorrow, when you're fresh.

Ian

It might be terminal,  but a fresh start tomorrow hopefully will sort the problem. 

I only know one way to learn and that's the hard way, I can see this costing me £s .

Oh well s#@t happens.  It's only a camera. The most annoying thing is the weather man was right.

I could use my all in one astro cam, maybe. The trouble is it only saves jpg files I think. 

Big sigh. Nother whisky .

Hope you're sky's are clear. 

Nige.

[The Admiral]

Well, bitten by the newly found workflow, I thought I'd have a bit of fun with my Pacman snap. What I really like is the ability to control how obvious the background star field appears in the image, because up 'til now they've been blasting the ol' rods and cones something chronic. And of course, being able to treat the target nebulosity without a thought about the stars getting too wayward. Hats off again to Steve fro spotting that one . The stars in this one seem larger than in my original one though, and some of the nebulosity is not coming through as well.

I'm still trying to work out how you can work on the stars as well. It seems that the stars don't respond once they've been extracted - may be that has something to do with tracking being turned off. This is where ST loses me!

Ian

Edited September 30, 2016 by The Admiral

[Nigel G]

Great looking image Ian. That tool is well worth it.

My orion as to cam can record in bmp, jpg, tif or fit, which will allow DSS to stack, any ideas.

I'm firing up the pc now to hopefully find out but someone might already know and my astro pc can take 10 minutes to get going ☺

Nige 

[The Admiral]

Thanks Nige, bit of a curate's egg that one!

Can't help with you query, I've not used an astro cam.

Ian

[Nigel G]

Sometimes you just need to walk away, I sympathised with Ken and his problems last night, tonight its all going Pete tong . 

First my camera,  now the pc just decided to go to sleep when I started using my astro cam, by the way tif, fit or jpg is ok for DSS.

I'm going to observe tonight, I don't often get the chance to just look, so I'm going to make the most I can of the clear sky's. 

Huff

Nige ??

[Filroden]

6 minutes ago, Nigel G said:

Sometimes you just need to walk away, I sympathised with Ken and his problems last night, tonight its all going Pete tong . 

First my camera,  now the pc just decided to go to sleep when I started using my astro cam, by the way tif, fit or jpg is ok for DSS.

I'm going to observe tonight, I don't often get the chance to just look, so I'm going to make the most I can of the clear sky's. 

Huff

Nige ??

Even though I had hours of frustration last night, the final result made up for it.

Here's hoping you get to see something spectacular! And aren't eyes the ultimate alt/az mounted scopes?

Edited September 30, 2016 by Filroden

[wxsatuser]

8 hours ago, Filroden said:

Here goes: my first LRGB image using 30 second subs on the ZWO ASI1600MM at -20C with a gain of 300. Processed in PixInsight.

Looks pretty good for short subs.

Been toying with getting one myself.

[Stub Mandrel]

Have you tried removing an reinserting all the ribbon cables?

I had to.

[Filroden]

I noticed my image of M45 had a gradient from the bottom (so probably light pollution). I didn't want to reprocess the image from the start (typically gradient removal is the first processing step) so I've done some crude post-processing of the image to try and minimise it. Not sure whether I'm trading gradient removal from the background for increased noise in the main image?

Still, for 15 mins of lum and 5 mins each for RGB, I'm going to call this one done until I can collect more data.

[The Admiral]

To be honest Ken, my first reaction was that if it had been my image, I'd have probably made the background darker. But then, on looking closer I reckoned that actually the top LH corner looked OK, but also came to the conclusion that the rest of was lightened due to nebulosity. The prospect of gradients hadn't entered my head. Gradients? Nebulosity? Your call! Your resulting image does look good though, but it would be a pity if you removed some of its character.

Ian

PS. Having looked here, you are probably right though! http://www.messier-objects.com/messier-45-pleiades/

PPS. But then, looking here I'm not so sure! http://dso-browser.com/picture/view/1033/deep_sky/pleiades/M/45/bright-nebula/by-reptux?0=&from=dso&dso_id=859

 

Edited October 1, 2016 by The Admiral

[Filroden]

5 hours ago, The Admiral said:

To be honest Ken, my first reaction was that if it had been my image, I'd have probably made the background darker. But then, on looking closer I reckoned that actually the top LH corner looked OK, but also came to the conclusion that the rest of was lightened due to nebulosity. The prospect of gradients hadn't entered my head. Gradients? Nebulosity? Your call! Your resulting image does look good though, but it would be a pity if you removed some of its character.

Ian

PS. Having looked here, you are probably right though! http://www.messier-objects.com/messier-45-pleiades/

PPS. But then, looking here I'm not so sure! http://dso-browser.com/picture/view/1033/deep_sky/pleiades/M/45/bright-nebula/by-reptux?0=&from=dso&dso_id=859

 

I still think there is a slight bottom to top gradient. The darkest points at the bottom give readings of over 20 in R and 40 in B, whereas at the top they go to almost zero. However, I'm not convinced it's all gradient and some of it is nebulosity so I don't want to clip it any further. I typically like to not clip shadows. Although it means noise is more visible (let's be honest, we clip because our images tend to be noisier!) the eye is great at detecting pattern out of noise. Even though signal might be too low to enhance effectively with our processing tools, the eye can still do that final stretch. So I'd rather see it and spend hours debating whether it is or isn't signal than not see it at all.

As a for instance, if you were to make an equilateral triangle, using Alycone and Merope as the base, with the point directly down, then I'm convinced there is a cross of dark nebula (close to the left of HD 23632 if you have a star atlas). Now I know there is dark nebula in the area but am I just imaging detail into my noise? That's why I love astronomy...you can dream!

Edited October 1, 2016 by Filroden

[Filroden]

Look's like I might have a clear night on Sunday. Any thoughts on which of these might be good targets?

The California Nebula would need to be a two panel mosaic so I think that might be one too many complications for me to attempt so soon with the new camera. Has anyone tried for the nebula/clusters in Auriga?

P.S. I've just found out that you can double click your images when creating your post and reduce their sizes!

[The Admiral]

30 minutes ago, Filroden said:

I still think there is a slight bottom to top gradient. The darkest points at the bottom give readings of over 20 in R and 40 in B, whereas at the top they go to almost zero. However, I'm not convinced it's all gradient and some of it is nebulosity so I don't want to clip it any further. I typically like to not clip shadows. Although it means noise is more visible (let's be honest, we clip because our images tend to be noisier!) the eye is great at detecting pattern out of noise. Even though signal might be too low to enhance effectively with our processing tools, the eye can still do that final stretch. So I'd rather see it and spend hours debating whether it is or isn't signal than not see it at all.

As a for instance, if you were to make an equilateral triangle, using Alycone and Merope as the base, with the point directly down, then I'm convinced there is a cross of dark nebula (close to the left of HD 23632 if you have a star atlas). Now I know there is dark nebula in the area but am I just imaging detail into my noise? That's why I love astronomy...you can dream!

I think Ken we might have been at cross purposes. I was referring to my first thoughts on your original offering, but I see that you are likely to be correct, a bit of both, and your revised image does look better to my eye. I just wasn't sure how much was down to gradient and how much to nebulosity. I also think the dark patch near HIP17692 is genuine, subtle, but it's there, and so I agree it's important not to push the black point too hard.

How do you find the noise levels with the ASI? It certainly seems to have taken the community by storm. I wish though that they could produce a self-contained unit, like a dslr, but with such a device as the ASI, and a processor loaded with firmware which will do the astrophotography essentials. Clearly, though, it'd need a cable for cooling.

Ian

[Filroden]

1 hour ago, The Admiral said:

How do you find the noise levels with the ASI? It certainly seems to have taken the community by storm. I wish though that they could produce a self-contained unit, like a dslr, but with such a device as the ASI, and a processor loaded with firmware which will do the astrophotography essentials. Clearly, though, it'd need a cable for cooling.

For me it was effectively a one-for-one replacement for the DSLR as I was already tethering the camera to the laptop to allow me to sequence images (and with a very long USB cable so I could do it from the warmth of the house!). The filter wheel connects to and is powered by the camera so the only additional lead I now have to manage is the power supply to the cooler. The filter wheel is fully ASCOM compliant so I just set up my sequence and let it run for 30 minutes, in which time it's captured 30 L and 10 each of RGB. (I've not yet really tested the different focal points of the four filters so I'm probably introducing some blur if they are not par focal). I can then re-centre the object (I find that helps over time - the mount can track but it eventually starts to go wayward) and then repeat the 30 minute routine. Plenty of time to sit and watch TV!

So far the noise levels have been brilliant. It was so much easier to process the images, even with such limited total integration. In fact, I could probably have skipped noise reduction entirely and still had a cleaner image than a much longer DSLR image with noise reduction!

One of the biggest immediately noticeable difference is in the colour noise. The bayer matrix on all OSC DSLR really does introduce a lot of colour noise. Particularly for us given it's constantly rotating so each pixel over time swaps from picking up R G G then B. I found my backgrounds looked like ants had crawled through the picture with paint on their feet! What noise I now see is an order of magnitude less noticeable.

So for me, I've gain a couple of huge benefits from the swap:

- I'm now imaging at the full resolution of the chip, with every pixel equally sensitive to all colours (including deeper into red) compared to the DSLR where only 1/4 of the pixels would read red and even then it was only 25% efficient at the Ha band.

- the cooling removes much of the noise and its very low read noise means I can capture signal in much shorter subs.

- I get more natural colours when I combine the RGB and it's much easier to balance.

- I don't have to worry about mirror vibrations, so I've speeded up my capture rate (6 seconds pauses between images is a lot when the sub length is only 30s to begin with).

There are some negatives:

- because of rotation and the way I'm currently sequencing, my final filter subs (B) are much rotated from the initial subs (L) - I can probably address this in two ways a) ignore it, 60 subs with OSC go through the same degree of rotation so I would be cropping anyway and b ) rather than take 30 L then 10 each of RGB I can take 10 sequences of 3 L and 1 each of RGB - I think a) is the right way for me to think about it but I will probably do b ) because it means I have some colour data if clouds come over.

- it takes a little longer to process because I have to integrate four sets of subs, crop each of them (trivial), remove gradient from each (though I could remove gradient from RGB after combination) then work on L and RGB through noise reduction and stretching before they are finally combined into a single LRGB image for final processing. That said, I've become faster with each try so other than the initial integration, the processing feels like it's taking similar times.

- I need more storage - each channel takes 32Mb.

Given we are limited in exposure, having a much more sensitive camera with lower read noise and lower noise overall, really helps reduce some of the gap we suffer from not being able to do guided long exposure subs on an EQ mount. Once I get to grips with SGPro and can align the scope quicker, I think I'll be able to capture much higher quality subs than with my DSLR. Though I think Nige has it right with modding the camera to make it more red sensitive - though even with 100% QE on red, you're still only using 1/4 of the pixels to capture it.

P.S. I also realised why my IC1848 had star trails - it was at a very high altitude so 30s was probably too long given it was more to the NE than E.

Edited October 1, 2016 by Filroden

[The Admiral]

Thanks Ken, a full and useful summary.

Ian

[The Admiral]

On 29/09/2016 at 12:00, Nigel G said:

It must be rotation or bad tracking.

Nige.

Nige, have you seen this thread re. DSS alignment? May be pertinent to your situation?

I don't wish to rub salt into the wound, but interested to know if have you managed to get your camera back up and working?

Ian

[SilverAstro]

4 hours ago, The Admiral said:

 It certainly seems to have taken the community by storm. I wish though that they could produce a self-contained unit, like a dslr,

I was about to say that there is the similar numbered cooled colour version which would be a more DSLR-like one-shot setup. But I have not seen anyone in the community using it !

But Ken and Gina are producing excellent results with the mono+filters.

I will have to go google why Luminance is being shot alongside RG&B, I think once-upon-a-time colour TV cameras shot only R,G&B and the Luminance ( for B&W compatibility) was derived electronically from the RGB ?

Edited October 1, 2016 by SilverAstro

[Filroden]

Here's a few explanations that I could find. My L integrated image is definitely more detailed than the combined RGB image.

http://www.robgendlerastropics.com/LRGB.html

http://astro-imaging.com/Tutorial/LRGB_I.html

Edited October 1, 2016 by Filroden

[SteveNickolls]

5 hours ago, Filroden said:

Look's like I might have a clear night on Sunday. Any thoughts on which of these might be good targets?

The California Nebula would need to be a two panel mosaic so I think that might be one too many complications for me to attempt so soon with the new camera. Has anyone tried for the nebula/clusters in Auriga?

P.S. I've just found out that you can double click your images when creating your post and reduce their sizes!

These all look good subjects to image Ken, the Flaming Star Nebula will be at 30 degrees Alt around midnight and 70 degrees or so in Az, well past my bedtime but maybe not yours of course. I'll try imaging later in the year. The California Nebula is higher in Alt of course and better placed to the East but a wide field shot and maybe one others will want to capture on Sunday. Thanks for these suggestions.

Cheers,
Steve