Mr niall

Can you post a picture of the eyepiece / your focusser please?

What do you mean when you say: "the benefits of such are dubious"? 40mm eyepieces are absolutely brilliant, but often much maligned sadly. When you say 1.5" eyepiece - do you mean 1.25"? I will assume you do. The problem with 40mm eyepieces is that the field stop of a 1.25" eyepiece means that generally speaking a 30mm Plossl or a 25mm wide angle eyepiece will give you the widest view that your scope can accommodate - so you don't really gain any extra FOV by using a 40 over a 30 in most cases. However where they do excel is on very long focal length scopes such as Maksutov's, Shmidts and long focal length refractors - where their larger exit pupil is a real advantage over smaller eyepieces in some circumstances. I use one in my 90mm refractor most nights.

You need to do two things really:

•  compare the barrel diameter to the other eyepieces that came with your scope - if they are the same then it will fit fine BUT...
• Also check the focal length of your scope. I think they did an older version of the Skyhawk that had a built in barlow (a small lens physically fitted to the bottom of the focusser). If yours really is a 1145P then it wont have that but probably worth checking. Your scope should be around 500mm I think, with the Barlow's ones being about 900mm. Although I'd still be surprised if that were he culprit even if it were one of those.
•  Dont bother trying to focus on anything closer than about 50 feet away. Telescopes aren't designed for that, many wont come into focus much closer than that.

Having said that if you do have the standard 500mm one then a 40mm eyepiece wont be the perfect choice for widefield viewing due to the large exit pupil, but still one I would hang on to. 40mm have their place! All 1.25" eyepieces will fit in all 1.25" focussers (general rule, there are subtleties regarding focusser travel etc but don't worry about it).

1 hour ago, LottJT said:

Hope it went well. I'd be very interested to see how you got on.

I’m not very good so it may not be very inspiring! Was really windy last night too. Lost quite a few subs, but I’ll share what I end up with for reference if nothing else.

33 minutes ago, LottJT said:

Thanks for the recommendation. Good to read of someone using a similar set up to what I'm proposing. I know it's more suited to wide angle Milky Way images but have you managed to capture any DSOs with it?

Yes I’m doing an M51 / M101 widefield as we speak!

I use that exact tripod (except its branded as Rollei) with my LX3 and a Canon 250d. Its rock solid cant recommend it enough. Mine is only the aluminium one too not the carbon version so you should be fine.

31 minutes ago, alacant said:

Hi

No, but take them as soon after (or before) your imaging session to cater for the -albeit rare- occasion where dust settles on the sensor.

Camera on tripod. Screen in fixed position (a table? Wall?) at a fixed distance. Set the camera to Av and press the shutter to get the exposure. Adjust the distance or screen brightness to get a minimum of 1s. Switch to M and enter the same exposure. Don't change the aperture or focus. Fire 20 or so frames.

DSLR: dark frames will usually introduce more noise. Use bias frames, flat frames and dither between each light frame.

HTH

Ok that may help - I've been doing that apart from the "fixed" bit. I may need to work out some way of getting the laptop and camera fixed in a relative position. I notice nobody has mentioned anything about how important getting it perfectly perpendicular is. I suppose my point is that if you compare the two images below - both were an attempt to get as perpendicular as possible but you can see if you can compare them that they produce ever so slightly a different pattern as the camera lens was obviously pointing fractionally in a different direction.

I was worried that I wasn't getting a proper flat as I cant work out a way to tell whether I am 100% completely square to my screen, I'm always going to be off by a degree or two no matter how hard I try - but as long as they're all from the exact same position it doesn't matter too much? Everything else was the same in both pictures.

Thanks again

Hello there

I could do with some advice on taking flats if at all possible? At the moment I'm using a Canon 18-55mm standard kit lens. Trying to take flats with this lens is quite tough because the focus is changed by rotating the whole element at the front of the unit (which moves it back and forth at the same time). Its quite delicate - so stretching a T-shirt or anything else over the front is a no-go as it only takes the slightest pressure to move it off-focus.

I've therefore tried pointing it at a laptop scree but I'm not sure I'm doing it quite right; as the vignette across the frames is visibly very different depending on how perfectly perpendicular the screen is to the camera. So I end up sort of wiggling the camera around to try and get the vignette evenly distributed into the corners but I don't think that is really the point is it!?

Do flats absolutely have to be taken at the same time as darks, or could I get away with making a stash of them for various focal lengths (as it is becoming a bit of a pain!). Many thanks

15 minutes ago, alacant said:

Hi. OK, to help us, next I'd suggest posting a flat frame.

 

I think I may have just had some success - tried a couple of flats and darks with the existing memory card and a shiny new one - shiny new one removed all banding. So it appears that problem is solved. Thanks both that was a great help 👍

Just now, alacant said:

Hi again. @Mr niall. Just to clarify... On this thread, there are now two clean images of the data. One of those has details of how it can be processed. Are we perhaps now more concerned about doing better next time? IOW we're not now trying to rescue the original?

Cheers

Yes I would say that sums it up. The ability to rescue the previous data was an uplifting result; but my main aim is to try and understand what caused the specific limitations of the data that I had collected with an aim to doing better in the future if possible (or having a small camera shaped bonfire as an alternative...)

43 minutes ago, Skipper Billy said:

@Mr niall  Can we go back to basics.  Can you post a single sub straight from the camera - no processing of any kind. Then we can see if the banding is present on a single sub ie is the problem the camera or the processing. Then we can move forwards. I am no expert but will gladly help if I can.

@Skipper Billy@wimvb

Yes good thinking - I decided to cut out the middle man and stretch the master dark. The results show the banding. I'll try some darks with another SD card. Added a raw raw too.

darkstretch.bmp P1080921.RW2

1 hour ago, jager945 said:

I sincerely hope you will re-read my post. It was made in good faith and answers many of your questions and concerns directly or through concise information behind the links.

To recap my post; a great deal of your issues can likely be alleviated by flats, by dithering (giving your camera a slight push perpendicular to the tracking direction between every x frames will do) and using a rejection method in your stacker.

If that is not something that you wish to do or research, then that is, of course, entirely your prerogative. Given your post above, it's probably not productive I engage with you any further at this time.

Yes I'm sure your info probably was well intentioned. My results do actually suggest a 9 year old with a polaroid took them, the fact they were taken by someone with hundreds of hours of reading and practice under their belt doesn't change the fact that they are total garbage. I will review thanks.

2 minutes ago, wimvb said:

 

I think you pretty much summed it up:

You tried to shoot with a non-modified dslr in a light polluted area, near a full moon. That's a sure recipe for imaging an overexposed star field. I think that if you try the same two weeks from now (no moon), with a light pollution filter, you will get better results. Just make sure you point your 42 mm lens at the Milky Way. And take many exposures. It's the total integration time that counts. 

Thanks Wim, yeah I did have concerns about the moon! I don't think I can get a light pollution filter for my old lumix though? Because it uses MFT lenses I think the screw thread at the front is a weird diameter. Having said that I think maybe putting the money towards investing in a new camera might be the smarter choice! 

2 hours ago, jager945 said:

I would highly recommend doing as suggested in step 1 of the quick start tutorial, which is perusing the "starting with a good dataset" section.

Yep did that, not sure what your point is there. With the exception of flats, which I didn't believe I needed at 40mm, everything else was done (including a restack with intersection selected on DSS) I would be amazed if they transformed the situation.

If you'd like to explain to me a good dithering procedure for a 15 year old DSLR with a wide angle lens mounted on a clockwork timer then I'm all ears.

2 hours ago, jager945 said:

Your dataset is not really usable in its current state.

That was literally the point of my post; if it isn't any good then I was hoping for advice on perhaps what was causing the issues I was experiencing. The post is even called "Help a Niall" for goodness sake.

2 hours ago, jager945 said:

Apologies in advance, as  I'm about to give some tough love....

2 hours ago, jager945 said:

There are three important parts of astrophotography that need to work in unison. These three things are acquisition, pre-processing, and post-processing. Each step is dependent on the other in that sequence. Bad acquisition will lead to issues during pre-processing and post-processing.

Thanks for being both patronising and condescending. Believe it or not I've been trying to do this for nearly three years with little success. But it is reassuring to know that one quick look at my work is enough for you to make an assessment along the lines of "they've never done this before / or they've no idea what they're doing". Cheers for that. If the solution is to chuck a couple of thousand pounds at mounts at camera's then I'm not really any better off than I was to start with.

Working with good data is easy. I cant get good data. I don't know how to get good data. I don't know why my data isn't good. That's why I'm asking for help. If you'd read my post then you'd see that.

2 hours ago, jager945 said:

The best advice I can give you right now, is to spend some time researching how to produce a clean dataset (not deep - just clean!)

Again - that was literally the point of my post. If I knew what the problem was, I wouldn't be asking for help. That was the point of my post.

2 hours ago, jager945 said:

I'm sorry for, perhaps, being somewhat blunt, but I just want to make sure you get great enjoyment out of our wonderful hobby and not endless frustration

Yeah… not sure you how you think you achieved that. Patronising comments aside you haven't actually said anything other than "your data is rubbish". I'm already at "endless frustration", and I'm following the guidance, repeatedly.

2 hours ago, jager945 said:

I processed it, just to show there is at least a star field in there, but, per the above advice, giving you the workflow would just teach you how to work around dataset-specific, easily avoidable issues...

WHAT ISSUES!!!????

BTW - I did enjoy the irony of "here's a nice version of your picture - but I'm not going to show you how to do it because you're not good enough yet to deserve it". 

Well thanks, that's me feeling like an idiot again. I'll pack the camera away and try again in another few months. If the sum total of the advice is that I'm either useless or an idiot then that advice probably would have been more useful 3 years and several hundred hours of frustrated effort ago. It's not easy asking for help when are clearly so far behind what nearly everyone else seems to be able to achieve, and believe me I doubt many are "trying harder". 

Your post is probably the most demoralising thing I've ever read. Good work.

3 hours ago, alacant said:

Hi

Yes, that's correct. That's what I got. That's just a big hammer stretch which frightens away most new users.  But you're not finished yet... The magic comes next...

In this case I think you forgot the 'banding' module before the wipe with 'vignetting' selected. Then call wipe again at around 90% with a mask to select only the band on the top part of the image. The milder bands will by now been removed as a result of the first call to banding. Finally call AutoDev a second time and adjust the 'ignore fine detail' slider with a roi over the fat star on the right of frame. Use the gamma slider to make it look realistic.

From there I used decon and colour before switching off database tracking and denoise. Then made it look nice in DarkTable. It sounds a lot but takes less than 5 minutes. Or significantly longer using other software... (...takes cover!)

HTH

 

Nope still ended up with a crazy colour explosion! Or a hideously clipped black image with three white dots. Will have another go tomorrow! Many thanks

1 hour ago, alacant said:

Sorry. Missed this bit. 

Which bit of it? The banding maybe? I'll try to help if I can.

Cheers

 

Ok I was inspired so I had another go on star-tools and followed the tutorial on the star tools website; https://www.startools.org/modules/introduction/quick-start

I'm clearly experiencing a failure of intelligence here though because at the end of step 4 I did the second autodev as, I think, I was supposed to and ended up with the below pic. Now - I'm no Pete Lawrence, but I'm not sure that is quite correct... Especially  considering that step 5 is dedicated to "the teasing out of finer details".

hmmm...

19 minutes ago, Skipper Billy said:

Back ground extraction shows the true extent of the strange banding and the vignetting.

The banding is the first thing I would try to address - dodgy USB lead maybe ??

Thankyou - yes it is a bit of "70s wallpaper disaster" type effect. I don't have any USB's in the train though. Although I could try a different memory card maybe... 

Thanks for having a look really appreciate it.

34 minutes ago, alacant said:

Sorry. Missed this bit. 

Which bit of it? The banding maybe? I'll try to help if I can.

Cheers

 

Well I remember following a tutorial that said something like auto-dev then wiping various things like gradients and such. But  every time I ran anything it just created a crazy stretched mess with colours everywhere. Maybe I didn’t understand it. Do you know if there are any good tutorials out there - particularly for low quality noisy stuff like mine?

thanks again!

Thanks for taking the time to look at this everyone. It is massively reassuring to know that I'm not going massively wrong. I feel like my underlying acquisition and editing maybe weren't too terrible its just that my expectations of what was realisable with the given data were much too optimistic. 

But with that in mind - where do you recommend I go from here? Apart from obviously picking a better target, the end result is still pretty... underwhelming. I would guess my editing workflow will need some development but I am struggling to find tutorials that I can readily transpose to Gimp. I have had a go at Startools but I just don't understand it. Within seconds I'm looking at a technicolor explosion of vomit.... 🙃

Here is my result below - I now see that I have stretched this much much too far to try and attempt to get data from it but looks like continuously stretching will only get me so far. And hopefully you can see what I thought was amp glow. And those dreaded lines of misery are even more evident.

1 hour ago, alacant said:

Hi

None really. Some nice star shapes and colours.

You could improve by taking flat frames and use a stacking method which includes the intersection of all frames.

HTH

 

That is amazing! How on earth did you do that?

1 minute ago, david_taurus83 said:

The bands look like the outer edges of different frames. Did you move the camera a few times?

No camera didn’t move at all - it was on my last image too...

11 minutes ago, almcl said:

You've got round, small stars; that's more than many of us manage with our first attempt, addressing any issues you dislike is now just a matter of time, research and trial and error.

Welcome to the dark side!

Thanks that’s really useful! However I must admit this isn’t a first attempt, I’ve been doing this on and off for about 3 years. Seem to be fine with the “error” bit, it’s just the subsequent improvement that’s the issue!

Hi all

All this enforced free time seems to be creating a certain amount of stress and hand wringing. Having wasted  spent much of last night shooting the Auriga region and then subsequently trying to turn rags into riches yesterday evening and this morning I thought I would just give up and call in the big guns (i.e. people on here). I wont share what I have managed at this stage it is just too embarrassing. I am following this tutorial https://www.learnastronomyhq.com/articles/easy-dslr-astrophotography.html, and it seems to be going ok (except for the results!)

My attempt at editing this seems to have the following positive aspects:

•  Round stars

And the following negative aspects:

• Worrying lack of detail
• Horrible vignetting
•  Terrible amp glow
• Crazy gradients
• An almost depressing "few white dots on a black background" result / technicolour nightmare that looks nothing like an astronomy photo.

Now in my defence I did pick a relatively bland area of sky as I'm just trying to get the hang of basic focussing and tracking and subsequent editing. The focussing and tracking are ok it seems, and DSS seems happy enough, but the results at Gimp stage are consistently that appalling that I'm wondering if it is a) the camera or b) me (more likely the latter).

If anyone would feel like having a go at turning the attached TIF into an actual usable image that doesnt frighten pets and children I would consider it a massive personal favour. I'm just trying to narrow down why I am so wide of the mark when it comes to producing something worth looking at.

Lumix G2 (MFT) 14-42 kit lens at 42mm f5.6. ISO 400*. 32x90sec light 12x90 sec dark. Stacked in DSS

I know ISO 400 seems a bit low but at ISO 800 I get a white screen that is so white I ant actually pick out any individual stars.

Many many thanks all. Any advice really appreciated. I am happy to take any sort of criticism (astronomy related of course!).

dss output.TIF

1 hour ago, lyfestyle said:

 I know all about the constellations and astronomy, 

… that puts you in the minority! 😉

Binoculars are a good choice but you shouldn't think of them as a "beginners instrument". They are often recommended to beginners because they are really easy to use, but nearly all of us own at least one pair (or many more!).

Celestron and Orion are actually the same company - but there are lots of reputable companies out there. If it were me - I would look at 8x42 or 10x50 but probably not 7x50.

Its all about "exit pupil" - the maximum that your dark adapted pupils can dilate to. The generally accepted maximum is 7mm, but in reality it decreases with age and with many people it never gets anywhere near 7mm to start with. If your pupils open to 6mm and you have a pair of binoculars with a 7mm exit pupil then you aren't utilising as much of the light as possible. That doesn't really matter that much - but what matters more is that 7x50s were amazing, 50 years ago. Now our light polluted skies deal better with a fraction smaller exit pupil (also - smaller exit pupil = higher contrast i.e. darker background sky). But then, of course - the higher the magnification, the narrower the field of view, and the more difficult it is to hold them steady. BTW - exit pupil is objective diameter / magnification so 7x50 is 7+, 10x50 is 5, 8x42 is 6.

The other big consideration is weight. I had a pair of 15x70s - they were great but too much to use handheld for any period of time. So I changed to a pair of 10x50s. In reality they're probably still a bit much. It's not a case of overall strength, but the fine motor skills required to hold something dead steady at an awkward angle for a long period of time. If it were me I'd be happier with 8x42's - but that is just me!

If you can budget a way to mount them - either a monopod or tripod, then you'll get a lot more out of them.

Hello

Following a previous post asking about whether it was worth bothering with an old MFT sensor (which got no replies which was kind of a reply in itself!), I decided to have a go anyway. The biggest caveat here is that I'm not very good at imaging and never really had much success so gave it up a while ago. But decided to have another go with what I had available (which was an omegon minitrack and an elderly MFT with a 14-42 kit lens.).

I pointed it vaguely at Auriga (hoping for m37/38 area but apparently wildly underestimating the width of field of view! Tried a few shots at ISO 800 but the screen was completely washed out so had a go at ISO 400 instead and am now wondering whether I should have stayed at ISO 800.

Anyway - I ended up with 35x60 secs lights, 15x 60 secs darks (no flats as I haven't ever really worked out how to do them well and someone told me not to bother below 50mm anyway, I don't know whether that is correct or not!) at 14mm. The big plus is the tracking seemed ok.

Stacked in DSS, edited in GiMP. I've stretched it but don't really have the skills to go attacking gradients on GIMP, and looking at the crazy vignette may have to look at flats after all. 

But - does this look right? I sort of found the finished result a bit... meh. Its just a bit "screen with white dots". It isn't clipped or blown, and I'm not convinced there is a huge amount more detail to come out of it. Would another 30 light frames bring out a whole lot more detail? I'm not sure. I've got an intervalometer coming in the post so I can hopefully go more than 60 secs but, at the moment I don't really have anywhere I can go in terms of equipment (i.e. I'm stuck with what I've got). 

Is there a way I can get more from my images without having to invest a fortune (also travelling to a dark site isn't really on the cards!)

Banding on the shot - may have to live with that! Very elderly camera!

299x60? I’m surprised you managed to get the horse to sit still for that long!

Hello all

I'm struggling. I own a Lumix G2. It is indeed a very elderly camera (bought new for £700 (ouch!) in 2009). Its a Micro 4/3 format and it is definitely my favourite camera ever ever.

But it needs upgrading. I have owned a Nikon D3400 and an EOS 1300d, which were nice but a bit too big for everyday use. I also had a EOS M10 which was amazing but with no way to attach an intervalometer and a max 30 sec exposure wasn't really much use for astronomy. They all got moved on.

I'm really considering getting a Lumix GX800 as it would be a considerable step up from my old G2, and it could use my G2 lens too. But would it be a silly idea if my biggest reason for upgrading would be to use it for imaging? I'm not a very good imager at the best of times (only widefield playing up to about 150mm) but would the move to a micro 3/4 be tantamount to shooting myself in the foot? I've had a look at sensor sizes and it is a fair bit smaller than an APS-C. But then again I've never really heard a huge amount of argument about APS-C being pointless compared to Full Frame...

I don't know... has anyone had much success with a 4/3 (I know the ASI1600 is 4/3 but that isn't really a fair comparison!)

Thanks all.