saac

Now if Takahashi made premium lager , it would probably be the best in the world  

Jim 

20 minutes ago, John said:

The thought of those lucky enough to be able to observe with a 20 inch scope under really dark skies makes me go a tinge of green as well 

To mis quote William    "those few, those happy few , those band of brothers with large aperture dobs "   

Jim 

I think you got some great answers there too Bongo.  Some people think they see some very faint colour; my teenage daughter thinks she can detect faint colour in the Orion nebula. Sadly my eyes will only ever see the whisphy ghost like structure you have also seen.  But that alone is amazing so keep enjoying it . Regrettably , no matter what aperture you have you will not see the deep sky objects as they are presented in astrophotography.  Our eyes just don't work that way - they cannot take long exposures.  Are the colours real - well yes they are , remember a colour is a particular frequency of light and the cameras are capable of detecting those frequencies (wavelengths) over a certain range.  As for how representative the colours are in all astrophotographs well that get's very technical very quickly - check out the excellent and thorough contribution vlaiv made in the the post about "authenticity of images". It is a very technical thread but very informative especially if you looking to get into the  higher end of image processing.

Jim  

" ultimate benefit from such collaboration is less than that of the pro how can anyone NOT see the inequality inherit to such relationships?"

I think we all measure inequality differently . More so when as an amateur we have freely entered into such a relationship with no obligation, coercion nor promise of reward.  If it is "credit" we seek then indeed should we be amateurs?  As non amateurs are we ready to forgo the loss of reputation potentially income  when we next publish our latest great work only to find we left the lens cap on 🤣 I don't begrudge the professionals anything, but if they give me some insight to their world I would be both interested and grateful; when I've had enough I can walk away without carrying the pressures of their work - I have my own  :) 

Jim  

What sort of projects would you use it for ?

Jim

9 minutes ago, blinky said:

Never had that before - everything has dewed over, Primary of my Newt, even with a dew shield attached,  the filters in the filter wheel, the Coma Corrector and even the front cover slip of the ASI1600! All covered in dew.  Was calling it a night as it clouded over anyway, but Ive never had a Newt primary dew over (actually been out twice with the hairdryer tonight!), never mind everything else.....  Was cold though, around minus 3 and everywhere is covered in frost/snow. 

Same here in Fife  , gave up after 2230, started off so well. Inside of the obsy looks like a winter wonderland  

Jim 

Looking good   I over tightened and stripped one of the threaded sockets on my ADM saddle plate - so easy as it's just aluminium.  I made a repair using a helicoil insert but I'm still cautious about it. Lesson learned   

Jim  

On 05/06/2020 at 18:22, George said:

https://www.facebook.com/groups/345004195931930/?ref=share

Thought the 3D printing brigade would like this 😉

Good spot, thanks for sharing, just joined. 

Jim 

On 31/12/2020 at 21:56, tooth_dr said:

Can ask what is the main concern over threads? I’m a newbie to 3D printing (few weeks with printer) but so far have printed some (what appear to be to me) decent treads - 0.75mm pitch in varying diameters M28 M42 M48 M54 M60 M72 both male and female.  Is it structural failure?  I’ve tried to break/strip the threads by over tightening but to no avail.

Thanks in advance

Adam  

 

 

I agree Adam, I think it tends to be one of those urban legends that just gains traction. I have the Ender 5 and have had little problem printing fine metric threads for extension tubes and adaptors - particularly using Paul Gerlach's Fusion 360 add on for M42 T adaptor threads (see low Spec Spectroscope thread) .  I have a number of very successful adaptors together with some other non astronomy related threaded components using PLA and yet to experience any problems.  Just give it a go and experiment. 

Jim 

Just now, John said:

Can't compete with this entry

 

I bet that would still get more points than us  

Jim 

14 minutes ago, johninderby said:

Nooooooo say it isn’t so.................still a member of Eurovision. 🙀🙀🙀

Yep afraid so , it has nothing to do with EU . 

Jim 

24 minutes ago, gorann said:

Thanks! I did not want to spread salt in the Brexit wounds - just wanted people to see this amazing video😉

Not a problem I really enjoyed that .  Anyway we are still a member of the Eurovision Song Contest , unfortunately - but that is another story 

Jim 

20 minutes ago, gorann said:

I cannot imagine NASA would be this creative! Is the UK still a member?

 

Gorann thanks for sharing that, fantastic  and what talented people . 2021 now has a lot to live up to, the bar has been set high 

Jim 

"Ok launch time has come " from Flight Ops Director  at 2:27

love it

Jim 

I'm pretty sure ESA is wholly independent of EU so I suspect UK membership is unaffected.  

Cool video  

Jim 

In aviation terms Situational Awareness is defined as:

" ^{is the perception of environmental elements and events with respect to time or space, the comprehension of their meaning, and the projection of their future status"}   

It features as a key part of Crew Resource Management  and pilots are well schooled in the dangers of loss or compromise of situational awareness. In the early days of aviation and,  even today it is  still a recurring feature in accident investigations where pilots have been unable to reconcile what their instruments are telling them and what they are experiencing.  It would appear that when the brain has set itself on a certain course of action/belief  then it can in some circumstances be difficult if not impossible to change that. I've only ever experienced the feeling once where my senses were presenting me with conflicting information and it was scary to say the least.  I was caught in a heavy snow drift travelling up the A9 heading back to RAF Lossiemouth . The snow was falling at such a angle that I was convinced the car itself was drifting across the dual carriageway.  I pulled over into the layby quite shaken at this stage but again as the snow was driving horizontally across the windscreen I was convinced the car was still moving !  No matter how many times I checked the handbrake or looked at the speedometer I eventually had to turn the engine off and get out of the car.  I still get a shiver thinking about it !!  Imagine the stress and confusion something like that can cause a pilot  - no layby at 30,000 ft!! 

Jim 

1 minute ago, andrew s said:

Yes even us amateur spectroscpists aim to get as close as possible to the arrival rate of photon per resolution unit above the atmosphere.  This involves careful calibration of the instruments and images using well known methods and more often than not working differentially using standard or secondary spectroscopic standard stars. Similarly with photometry it is done mainly differentially as few of us have photometric skies. 

I am currently trying to improve the way this is done for slitless spectra which have particular issues with flat fielding as the response is wavelength dependent.

Regards Andrew 

Andrew what is meant by "photometric skies" 

Jim 

That is a good summation vlaiv.  So here is a different but related question.  I think we would agree that professional astronomers/cosmologist are more concerned with the integrity of the data in their images and less with the aesthetic.  I'm guessing that for the likes of their spectroscopy analysis then instrument response, spectral range, resolution etc are the important concerns. What else is important , what are the main data streams that they are looking for - position, velocity, rotation ?  How do they ensure that what they are recording is "authentic" ?  I'm guessing careful and constant calibration of instruments  and use of clever mathematics to reduce uncertainty errors.  Are aesthetically pleasing photographs ever of scientific merit beyond say publicity and outreach?

Jim

2 hours ago, andrew s said:

I feel @vlaiv proposal is as authentic as it can get but the artist still chooses the framing and exposure etc. However, I like @saac I see astro images as acts of creation albeit from  "nature" .

Regards Andrew 

Actually Andrew I think you are right; was it not yourself that described the discussion as a false dichotomy.  We are being presented with too narrow an option field to properly explore.   Anyway, be our images artistically presented or records of the authentic I'm just happy that we have the means to capture and enjoy them.  I am also grateful that some clever people are really skilled at the capture and processing as my efforts could never be mistaken for either artistic nor authentic ! 

Jim 

2 hours ago, andrew s said:

I feel @vlaiv proposal is as authentic as it can get but the artist still chooses the framing and exposure etc. However, I like @saac I see astro images as acts of creation albeit from  "nature" .

Regards Andrew 

Isn't this the problem with the term artistic I guess, it is so loosely defined and without any common agreement.  I accept also that CCD/CMOS and displays can be matched to the broad spectral response of the human eye. I still have difficulty accepting that our wonderfully richly saturated astro photographs can be considered representative of "authentic" - or at least we need to define what we mean by authentic for this to hold true. Are we defining  authentic in terms of how closely the image replicates our own visual response or does authentic refer to replication of what is actually there.  I think the later is more in the realm of science/cosmology than astrophotography as it will look for a more quantitative outcome covering the whole of the EM spectrum. Looking at the former definition  I'm sure a past thread somewhere contains a discussion on how we would visually perceive a nebula were we closer or indeed inside.  Our cameras would continue to register the deep saturated colours but would our eyes, with shorter integration time,  remain unable to discern the feint color?

Jim

17 minutes ago, vlaiv said:

Actually no, or at least not in sense that algorithm used is not left to designer discretion but is rather well defined.

There is standard developed to assign certain values based on frequency response of recorded light. That is CieXYZ value of each color and corresponding spectrum. Since whole spectrum is compressed into three values this is by definition lossy transform, but it is closely modeled on human vision and human sensory response will be the same for all spectra that give the same XYZ values. Contrary to popular belief - each color does not have unique spectrum but rather infinite set of different spectra can and do produce same color in human vision.

Knowing these three values and having light sources that produce each of these three spectra:

 

I think we will differ on this one vlaiv.  The algorithm has been "designed" therefore it responds to a particular prescription, the image it produces will also be subject to the particular instrument response. No two sensor and certainly not between different manufacturers will produce identical images. As for artistic classification then I consider that is the prerogative of the person presenting the image - hence my reference to the modern art efforts of Tracey Emin. I see a messy unmade bed of no artistic value but the artist considers otherwise. The value judgement of what is artistic is not easily defined if it is at all possible to define, it is afterall something that provokes a personal response in the viewer. The mere act of presenting an image is considered by some as artistic. 

Jim 

42 minutes ago, vlaiv said:

Would you characterize following scenario as "authentic" or "artistic":

You take DSLR camera, set it to faithful color reproduction and take an image of a scene and transfer it to computer without any further processing.

 

The "faithful" colour reproduction setting of the camera will be an algorithm chosen/designed by the camera's engineers - it will no doubt have incorporated some image processing.  The final output conforming to what the designers define as "faithful " will therefore produce an image influenced by the internal algorithm and instrument response.  When transferred to a computer and rendered on the display, the colour reproduction will again be subject to further interpretation based on the monitor's response.  You could argue then the image has been "authentically" reproduced  - but you would qualify authentic in this case based on the response characteristics of the instrument train.   At the same time you could equally argue that the image has been presented artistically; here you have chosen how the image is to be presented and viewed. Therefore, you have made (consciously or not) an artistic value judgment of your work.  So artistic and authentic in superposition   

Now ask me what I think of Tracey Emin's bed  or the formaldehyde shark!

https://www.tate.org.uk/art/artworks/emin-my-bed-l03662

Jim 

11 hours ago, andrew s said:

On a more serious note, as a non imager, it's about the craft of rendering what the processor (artist) wants to draw from the data and its relationship to the intended impact on the viewer.

Regards Andrew 

 

Agreed and in this respect there is no "authentic" because it is very much an artistic judgement.

Jim  

On 29/12/2020 at 10:40, DaveL59 said:

I'd wonder what the effect of any adhesives they use burning off in the upper atmosphere, having had recent close up experience of these particulate boards burning and the awful smell. Nothing like injecting chemical agents directly into the ionosphere and affecting the ozone layer etc.

I'd be surprised if it would be any worse than the residues from the electronics. I guess the volume would be sufficiently low anyway as to have any material impact - hopefully !  

Jim 

I had been meaning to make a Bahtinov mask for ages but just never got around to it. Lots of 3d print options available on thingiverse but the print times are overly long.  So in the end I made a laser cut  version - 3mm ply.  Looks ok, edges are really nice and clean, probably better than I would get on a 3d printer and it took about 10 minutes to cut.  Just need 2021 to bring some clear nights and I'll be able to test it.    Should anybody want the svg files I can upload them  - sized for my SW 80 ED.

Jim