Norris Adams

Thanks for you advice Elp.

The workflow you describe is pretty much exactly the pattern I have tried to follow. I only move between the three light settings to help me settle on the best histogram shape. But I sometimes find that when I try to replicate the best profile a little later, I sometimes get a completely different outcome (which seems ridiculous I know)!

I even wondered if I'd left the end cap on after taking the darks!!

And you are right of course that for EAA it is best to take Darks and Flats at the start of the session. This is what I normally do. I decided  to do these trials during the day only because I wanted to get the process right and to try and find out why I'm not getting a consistent outcome.

Still scratching my head here!!?!

By the way, am I right in saying that I cannot build a Flats 'library' (unlike Darks) because the camera's position will vary (even if only by a few degrees) with each imaging session?

Norris

I have recently been trying to improve my EAA images with the subtraction of Flat frames in SharpCap.

I have made use of a light box (with three different light settings) which has enabled me on occasion to create an averaged Flat with the right kind of histogram profile.

So far so good.

What is puzzling me is that when trialling optimal Flat Field Illumination set-ups (using light box & stretched white T-shirt etc) I sometimes seem to get very different profiles from the histogram even though I don''t think I have changed anything or I have simply recopied earlier successful settings. 

I have attached a couple of examples using nominally the same physical set up (see also below) and SharpCap settings.

What am I missing? Why such big differences when nothing seems to have been altered?

Secondly, should I be seeing the histogram itself vary in real-time, when for example I alter the light levels in the box or increase the exposure time? At present it only changes when I do a full reset - usually by clicking 'Live Stack' twice and then changing the relevant parameters (e.g. using a different Light Level settings or increasing exposure time to seek out the best profile)

I wonder sometimes if my laptop simply lacks processing power to do this in real time - or is there something else I should be thinking about?

Finally, I should add that I also take some darks prior to acquiring flats, but I can't see how this should make any difference. Nor I think should reattaching the camera in a slightly different angular position.

Any help or guidance gratefully received!

Thanks,

Norris

Skywatcher P1501 / ZWO ASI183MC 

I definitely get it Chaz.

Ever since I rolled into EAA I've been hooked. 

I also had a couple of cataracts removed two years ago and I'm off to the opticians for an eye test again this week - I'm pretty sure my sight has deteriorated quite a bit over the last six months.

EAA allows me to take every advantage I can get, so I will continue to exploit it to the full!

Norris

Whenever I feel that the summer nights are a no-go, I remind myself that the first time I saw Polaris B - not too difficult a target I know - was June 21 in 2021.

There's always something out there when the clouds part!

Norris

On 26/04/2024 at 00:18, Paul M said:

In a land far, far away, Cumbria to be exact, there is a pristine clear sky.

I'm not there to witness it, but the Paulsky Camera is!

While flicking through the images, I spotted a nice meteor. So here is that frame. It'll be lost as a sub-second flash in the overnight time-lapse.

Cloud and moonlight have been blighting the Allsky Camera recently but it's improving again, maybe a window of opportunity before the all-night-twilight sets in.

The Great Glowing Cheesball is just starting  to affect the camera now. So, it's downhill for the rest of the night...

 

In other news, emboldened by @Skipper Billy's Allsky camera linked to above, I've ordered a lens that will fit the whole image circle on the ASI 178 sensor. So a full 180deg view. That and I've ordered a much bigger dome. Again, Skipper Billy suggested that on his website as it allows ventilation holes to be drilled around the camera, allowing the very warm air from the RasPi to circulate in the dome, hopefully keeping it condensation free.

There is a newly released firmware (EEPROM) for the Raspi, which allows even greater overclocking. I can't dream of taking the enclosed Pi to the max but I still had the original firmware on my Pi 4B which limited the CPU to 1.5 MHz, I've now set it to 2.0 Mhz. It might, and probably will cook in the summer. So I'll likely stop recording daytime images and just let it idle in the heat of the day. I'm looking to swap the Pi4 for my Pi5 to limit some of the issues with image handling. I tried at the weekend but it balked at boot-up, complaining of voltage drop. Thinking about it, the PoE splitter is only rated at 2A, so I've got a higher rated one on order. The PoE injector is a big 8 channel PoE switch rated at 85w total load. It is also running 2 x PoE surveillance cameras, but I'm confident that total load will be compliant.

That'll be an ongoing project into the summer, due to my limited opportunities to get up there once the parts arrive.

Beautiful image!

Competing with Hubble?

Somebody likes a challenge!

Amazing work - great achievement!

Regards,

Norris

On 13/06/2024 at 12:52, Tony Acorn said:

Welcome Martyn from a fellow newbie who lives in a significantly mpore polluted area. I suggest that you get a flexible clamp to secure on the focus knob and extemd th eleverage - that gives you much finer control of your focus. HTH
Tony

Hi Tony,

I'd been looking for something to give me a better focusing ratio for some time. Not being able to find an over-the-counter solution I'd tried various home-made ideas with limited success.

Your chance remark (regarding a clamp) made me think of a small, retail clothes 'grip' that I had thrown into my tool box just the other day. I felt sure it would be useful for something...!

I've just tried it and it works great! Rigid, secure and light to control and move! Because I'm only using it at the point of fine focus (for EAA work), it will never have to move more than a few degrees., so there's no interference issue. But trying to achieve those few degrees (or even sub-degree movement) when using a small wheel is mighty difficult!!

Thanks again!!!

Norris

Here's my first go at a DSO.

Bode's after seven minutes!

It was taken a couple of years ago. 

Even though it's smeared and grimy, it still delighted me at the time. Without a camera, I'd spent many nights 'wobbling' the scope to try to catch a glimpse of something that the star maps told me was definitely there, but I'd never been able to see it.

Here at last was proof they weren't lying!!!

Norris

Hi Ed - I guess with the task of sketching particular targets you probably observe much more than the average astronomer.

Your work reminds me of a conversation between Dr Watson and Sherlock Holmes in "A Scandal in Bohemia".

"When I hear you give your reasons," I (Watson) remarked, "the thing always appears to me to be so ridiculously simple that I could easily do it myself, though at each successive instance of your reasoning, I am baffled until you explain your process.

And yet I believe that my eyes are as good as yours.""Quite so," he (Holmes) answered, lighting a cigarette, and throwing himself down into an armchair. "You see, but you do not observe. The distinction is clear. For example, you have frequently seen the steps which lead up from the hall to this room.

"Frequently."

"How often?"

"Well, some hundreds of times."

"Then how many are there?"

"How many? I don't know.""Quite so! You have not observed. And yet you have seen. That is just my point. Now, I know that there are seventeen steps, because I have both seen and observed."

Well done Sherlock!

I suspect you (and your peers) see a lot more than the rest of us - imagers and visual astronomers alike!

Norris

58 minutes ago, Recretos said:

Whirpool Galaxy M51, with 22h of integration (8020*10s), stacked and processed in Pixinsight. I did not push the sharpening and denoising all the way in these images, as it does start to degrade fast, and denoise tends to remove detail and deform the galaxy. However, I must say I never dreamed of capturing such images with a small device like the Seestar. I live in Bortle 3 at 1050m (3500ft) above sea level, so the conditions likely help the outcome. One image has a bit more saturation, as I just tried two different approaches and couldn't decide which is better.

I got my Seestar S50 in mid-February, and I also bought Pixinsight at that time. So, being only 4 months into this hobby, I welcome constructive feedback and criticism from the more (or less) experienced folk, as that is probably the best way to grow your skills. Thanks for watching.

 

Hi Recretos - Stunning captures from such a remarkably compact piece of kit.

Great work indeed!!

Regards,

Norris

You must be delighted Aditya!!

Amazing!

Regards,

Norris

16 hours ago, DaveS said:

Nope, not for me. EEA lacks both the organic immediacy of eyeball to eyepiece and the ability to go deep, especially on faint galaxies, that true Deep Sky imaging provides.

Each to his own Dave!

Maybe one day I'll dip in to the deep-end!

Clear skies!

16 hours ago, Elp said:

To me, EAA is pretty much AP without the post processing. You're still taking subs and stacking them but in real time. I sometimes do it to check what's around, then set it to run an imaging session to process later. You do remember visual experiences more but I think that's more to do with a biological response, looking at a screen doesn't elicit the same (emotional) feeling hence why people prefer "analogue" visual experiences, you can't fight with thousands of years of biological evolution.

I do think where applicable a camera can be "better" because a camera sees over time rather than at the time, so visually you'll never match what a camera can see especially in light polluted areas. I'll take a ten second image of M13 over a incredibly faint (is it there?) smudge visually any day in my LP zone, in fact it's why I image, I can't see anything of significance DSO wise from a Bortle 7 even with six inch aperture.

But I do agree when you do get moments of good seeing, visual does astound at times.

A very succinct summary Elp!

As you say, sometimes features emerge that you hadn't expected. I shot my regular five minute exposure  (10.7s subs) of a reflection nebula (NGC 6914) in Cygnus a few nights ago. After the allotted time, I was beginning to see something that I hadn't expected, so I let the camera run for another 15 minutes. The result is attached.

It's far from perfect but it kept me happy!

Norris

18 hours ago, carastro said:

I have been watchig the Smart Telescope images being posted by my local group and they are quite impressive, and certainly make getting an image more accessible to many.  

However if you are already imaging with traditional kit  - Smart telescopes would not bring enough satisfaction as they do not do long enough exposures.  

Paradoxically Carastro, Smart telescopes seem a bit 'too easy' to me!

Not that I have ever used one, but I have tried subscribing to remote telescopes and processing the images they deliver. Even though the quality is much better than anything I can produce with my own kit, the finished output didn't feel like I owned it....since I hadn't put the effort in the acquire the image - I'd done it through a middle-man. 

Maybe I'm just too 'old-school'! 

Perhaps, to misquote an advert on TV - "maybe one day all telescopes will be made like this".

Norris

8 hours ago, Roy Foreman said:

It's not only up north that gets the cloud. I'm in west somerset and six months into 2024 and I've only had three cloud free nights. Shooting through or between clouds is a way of life. I have plenty of patience but it's wearing a bit thin.

Well done for defying the elements and producing an acceptable result.

Hi Roy,

It's certainly been a difficult year.  With so few clear skies, I can understand why people crave a permanent housing for their kit (just to snatch a few images when the opportunity arises).

Norris

7 hours ago, Coco said:

Swap your cameras for an eyepiece, I did and never looked back

Thanks Coco - For all its frustrations (and there are plenty!) I'll stick with my trusty CMOS camera!

I understand what you're saying though. Visual astronomy is a very different experience. 

I think you 'live in the moment' more looking down an eyepiece - if that makes sense?

Norris

17 hours ago, Vroobel said:

 

I live in Merseyside which is called 'a cloud generator'. I think the only thing which differentiates us is patience.  

 

Hi Vroobel - I guess that'll be all the wet Atlantic weather squeezing up towards the Pennines!

Well done on the perseverance front!

Norris

I am blown away by many of the images that serious astrophotographers show on this site and other comparable astronomy portals. I cannot (and do not) expect to achieve similar results. My equipment, my patience and the Yorkshire weather place stringent limits on what I can realistically hope to do!

But I can acquire an image in around five minutes - and sometimes it's out of all proportion to what I was expecting!

Here's one I did of C12 earlier (a few nights ago). It was stacked in SharpCap and incorporated both Darks and Flats (the latter for the first time). I also did a little stretching and final touch up in GIMP.

Of course it still takes 30-45 minutes to set up, but I can usually beat the clouds and get a few captures in before they come back!

EAA allows me to cut through light pollution, to see objects five or six magnitudes fainter than with the scope alone and finally, it gives me a permanent record of what I have observed.

I recommend it to the house!

Norris 

SkyWatcher P150i / ZWO ASI 183MC

Hi Ardsley - You've got to be well pleased with these early attempts!

I started with open clusters because they were 'easy'.

You've jumped in nearer to the deep end!

Also, I used to write a list of the things I felt I'd gotten wrong or needed to fix to before my next shoot.

(Actually, what do I mean...used to)?

Norris

Nice work!

The galaxy appears almost annular and the clarity of the concentric rings is impressive.

Norris

Hi Ben - Welcome to the learning curve (which never seems to stop)!

Finding your way round the constellations (using identified stars) is a great way to start. It's like scouting the lie of the land. Plus, there's a host of deeper space objects lying in wait for when you're ready.

Arkansas? I bet you'll enjoy lots of warm nights and clear skies in deep South! 

Spare a thought for us 'Northerner's'...two pairs of socks and two pairs of trousers / pants are essential here from October onwards.!

Norris

13 hours ago, Repasustem said:

Hey Norris, I feel you on the scientific notation struggle! It's like decoding hieroglyphics sometimes, right? How did you juggle coursework with your hobbies? Thinking about a university course myself, but kinda scared of the workload.

Well, the OU course is easy to dip into and out of, and its nominally only 20 hours, but it whetted my appetite for more.

I did think some time ago about doing a Certificate in Astronomy & Planetary Science (also OU) but that was a lot more work (600 hours) and I worried I'd be losing valuable imaging time trying to achieve the goal! It's still being run (Course S10).

I guess you've just got to decide what fits best with the other commitments you already have.

Norris

Yes Pat, I noticed the motes, but I guess they'd disappear with the application of Flats.

Funnily enough, I tried my first Flats last night (in SharpCap). I had previously used only Darks, but my daughter bought me a Light Box and I set it up properly for the first time last night. (I'd noticed an increased degree of vignetting recently so I felt it was time)!

It was a bit of a faff, but it seemed to work well. I have yet to process the images to see the full effect, but they looked good on screen during the wee small hours.

I know you can take Flats at the end of a shoot, but since I'm not really post-processing I've got to do it before I take the Lights.

Norris

From one Irishman to another...!

I've previously found Bode's to be a challenge (it always appears to be slightly diffuse and ethereal), but I see you have also managed to capture Holmberg IX into the bargain!

I had a quick look in my last image of the same target but there's nothing comparable there!

It's an accomplishment to be able to pick up these targets so close to the solstice.

Norris

Hi Trated - Scientific notation is relatively simple when you're dealing in squares and cubes, but 10 to the power of minus 28 divided or multiplied by a similar quantity (which might be provided in nano, micro or 'milli' units) can get a bit trickier! It caught me out a few times.!

Also, because the numbers used in astronomy and astrophysics are so large (or so small!), it's sometimes hard to get an intuitive grasp of the data you are manipulating! 

Norris

10 hours ago, Trated said:

As an amateur stargazer, cloudy nights pushed me into the academic side of astronomy, particularly galaxy evolution. OU's course was a challenge, especially with my rusty math skills, but it's been worth every moment.