The "No EQ" DSO Challenge!

[parallaxerr]

19 minutes ago, The Admiral said:

Thanks Jon.

It's getting a bit frenetic on this thread, and what with sorting out my own images I'll have to catch up later!

Ian

Agreed, I for one am going to attempt to stop opening cans of worms and stick to posting my results, as per the original thread intent!

[The Admiral]

That's where a new forum topic would help!

I'll get me coat!

Ian

[The Admiral]

6 hours ago, parallaxerr said:

Here's the result of a quick manual Dev, loading the FITS up again for AutoDev now, but it takes about an hour to load in ST @550mb

Haven't we been down this avenue before? Your FITS shouldn't be that big. Have you got something switched on in DSS that shouldn't be, like drizzle or mosaic?

4 hours ago, parallaxerr said:

And here's the AutoDev'd version. Struggling with colour a bit and as you can see, there's more noise...

There's plenty of data there to play with. Have you tried using the RGB Max button in the colour module? That can get you near the correct colour balance.

I must admit I generally use the manual develop mode, despite Ivo extolling the virtues of the auto dev. I found it quite sensitive to the placement of the 'region of interest' box if that is used.

If it was me I think I'd crop it some more, but each to their own. Bear in mind that this isn't the easiest of targets, and even in the best images it somehow takes on a somewhat fuzzy appearance to me.

Ian

[The Admiral]

4 hours ago, Nigel G said:

Jon, I know what you mean about low alt objects and LP, I took 120 sub's on NGC 253 last night, it's max altitude was around 18 degrees, it was just above the houses to my south.

Really hard to get any detail at all, no colour. Pushing my luck, but you don't know until you try.

This was ISO 1600. with LP filter mixed subs 30s 45s and 60s total 1 hour 10 minutes, flats and bias, no dark. When I done the first auto dev I have never seen anything like it before  a bright burnt image with a multi coloured cigar shaped smudge. Its amazing what processing programs can do with a stack of rubbish

I'm stacking a different amount of subs atm 60 % to see if that changes and adding darks.

Nige.

 

I think that's come out rather well Nige, especially as you must have been imaging through a load of dirty atmosphere. And as you say, I too find it amazing what can be pulled out of something you'd regard as noise if you didn't know better! It'll be interesting to see what you get with your other stack.

Ian

[parallaxerr]

24 minutes ago, The Admiral said:

Haven't we been down this avenue before? Your FITS shouldn't be that big. Have you got something switched on in DSS that shouldn't be, like drizzle or mosaic?

No drizzle, but, to be fair that was a mosaic. I wanted to see the extent of the field rotation and have as much area as possible to crop from.

EDIT: How strange, I just loaded a standard (not mosaic) stack of the same image, but X2 drizzle @ 1.08Gb into ST in just a few seconds?

Edited November 29, 2016 by parallaxerr

[The Admiral]

2 minutes ago, parallaxerr said:

No drizzle, but, to be fair that was a mosaic. I wanted to see the extent of the field rotation and have as much area as possible to crop from.

Fair point, but given that ST needs you to crop out the artefacts anyway you might as well go with the standard or intersection mode, and not lose anything.

Ian

[SteveNickolls]

2 hours ago, The Admiral said:

That's where a new forum topic would help!

Well I have posted on the thread asking when Admin are going to do/say anything. And I was polite and everything yet still no reply. Are we being ignored?

[Nigel G]

I think maybe we are Steve.

A comparison, first the original then 60% with darks. For some reason I don't know DSS left 2 jet trails in the image which were removed in life & isolate, the only setting I changed was to up the hot and cold pixel removal....

Not much in it at all, about the same to process .

Nige.

[Filroden]

Just started imaging. My main aim tonight is to experiment with a lower gain (ISO) to see if I can keep most stars properly exposed and also to add more data to the four targets I did on Friday. So far the initial subs are much fainter (as you'd expect before integration and stretch) but I'm worried that they won't process as easily. Initial histogram measurements show most stars are within the new dynamic range and it's only the cores of the very brightest that are just exceeding it.

[parallaxerr]

I thought lowering the gain would free up more DR as with DSLRs?

[Filroden]

Just now, parallaxerr said:

I thought lowering the gain would free up more DR as with DSLRs?

It does but it means the fainter stuff is compressed into the left side of the histogram. Amplification at higher gain stretches that further to the right so it appears brighter. Hopefully with the extra range, lower noise (but higher read noise) it should stretch okay in processing.

[Filroden]

One think I'm noticing more tonight is how badly the focus drifts as the temperature drops. After only 15 frames I'm going to have to pause and tighten up the focus more.

[parallaxerr]

1 minute ago, Filroden said:

One think I'm noticing more tonight is how badly the focus drifts as the temperature drops. After only 15 frames I'm going to have to pause and tighten up the focus more.

Something I've not considered. I set the camera going on M33 an hour ago, better go check I suppose. Will have to goto a bright star which I'm reluctant to do because it's tracking so well, but no point tracking a blur!

[Filroden]

I can just about focus on my target but it's a slow process as I have to do 1s exposures. I'm going to have to investigate automatic focusing!

[parallaxerr]

Of course, no live view for you. Just slewed to Mirach and saw a tiny focus shift. Longest time then spent taking 30s exposures to ensure M33's centered.

Are triplets more prone to focus shift? I've heard of the pinched optics problem.

Edited November 29, 2016 by parallaxerr

[Filroden]

I don't know. I know refractors take longer to settle and I guess I hadn't had the scope outside for long enough before starting my first sequence. It's held steady for the last 20 frames so hoping it's okay now.

[The Admiral]

My triplet seems fairly focus robust, but I guess Ken that your software control allows you to monitor what comes out fairly quantitatively and you'd be fairly sensitive to change. I just look at my camera LCD and eye-ball it . Perhaps I'm just a slovenly operator, but I don't really need to re-focus. Mind you, it's darned cold out there tonight so I ought to check.

Ian

[Filroden]

Yes. I get a HFR reading for every image and it's tracked on a graph so it's not noticeable by eye but you can see the trend. It also plots number of stars in the frame which is useful for spotting faint clouds.

Edited November 29, 2016 by Filroden

[Filroden]

Focus is now oscillating suggesting either tracking, seeing or wind.

[happy-kat]

I can say that the goto handset worked fine and went to. I can't say tracking worked I think not. Interesting with a 50mm lens I only good good star shape at 4 seconds...! Problems I can't see any stars south or east to align on. Vega and polaris was good enough for goto. So looks like I'm not going to actually be able to contribute and I'm gutted. I had hoped it would be the handset that would set/control tracking but now I'm not so sure, it was on side real rate I will check the skywatcher align chart to see what other northern star might be available. The handset if on rate 9 would move the mount, if on any other number I couldn't discern any movement, wonder if the mount was controlling that. 

[Filroden]

You should still here the motors engage at slower slew speeds. I know at speed 4 I have to press it for a good second to see marginal movement but I can hear the motors very quietly.

[Stub Mandrel]

Right Ken, I'm having a pop at your favourite - NGC1333 - to see what a DSLR can do - wish me luck, although teh results will be in the EQ3 challenge thread, not here (or I would get lynched by Nigel's bloodthirsty Ninja Clangers!)

[Filroden]

Good luck. I'm up to my third hour of luminance data and I still think it needs at least twice that much to see the dust. However, the good thing is the central nebula shows quite well even in single 45s subs.

[Stub Mandrel]

I can just see the nebula on the preview screen (which shows what a jpeg version would look like although I only save RAWs). I'm not holding my breath for dust, but it would be nice to get a trace of some, hoping for 3 hours subs at least.

[Filroden]

Well, I think my night might be drawing to a close. Just been checking my subs of the HH and Flame and just noticed I can see a very clear binary to Alnitak in the iimages...just stepped outside and there looks to be a growing haze coming up from the horizon