June Imaging Challenge - M8 (Lagoon)

[iceman]

Hi all.

We'd love you to take part in the June Imaging Challenge (http://www.iceinspace.com.au/index.php?id=69,207,0,0,1,0). Please post your deep-space images of M8 in this thread. Discussions about the images can also be in this thread.

Please ensure the image obeys the image posting guidelines when you attach them.

While it would be nice if the image were taken in the month of June, it's not essential so feel free to post older images if you're unable to take some new ones.

For observation reports and sketches of the object, see the "Space & Astronomy Talk" forum.

[beren]

Its a few weeks old and a roughie , first attempt at using a guide scope manually while imaging through a SCT , made a error near the end of the exposure with a overcorrection and came out in the shot.

[iceman]

Nice shot Stuart, do you have a higher res version? That's just a tease! :D

[Robby]

Last night the skies cleared, and I thought I'd have ago at M8. Last years shot needed topping!
Canon 300D, C9.25@f/6.3, 10x3mins ISO1600.
Cheers
Rob

[gbeal]

Me too,
but in the spirit of things elected to use the wee 80mm refractor instead of the beast.
I also took a little artistic license and shot both M8, and M20, and got the guru to stictch them together. Each was 4x3 minutes at ISO1600, Nikon D100, Zeiss ED80/840, with a Tak .75x focal reducer. StarMate of course.

[Robby]

Very nice Gary. Long time no hear! Where have you been hiding...!

[iceman]

Stunning shots, Robby and Gary! Really nice!
I love the spikes on your shot Robby - did you tie some string across the front?

[Robby]

Hi Mike,
Yep you guessed it. Tied two pieces of 1mm wire across the front, just to see what difference it would make. I was happy with the result from it. I may do it again.
Also tis shot was the my first focussed with DSLRFocus. Pig to use, but I think it was worth it. The SCT's don't snap focus too well due to the large central obstruction, but the 9.25 is better than the C8 due to faster primary mirror. f/2.5 as opposed to f/2.
Cheers

[h0ughy]

great shot you guys.

[atalas]

Very nice work Beren,Robby and Gary ! I enjoy looking at your work It inspires me.

Louie :eyepop: :2thumbs:

[EddieT]

Hi all,
Terrible weather were having! I stayed up until 4am this morning just to get 30 minutes of M8 in between the cloud banks. I was really after something else, but the gaps were only big enough for 1 minute exposures so I thought I'd try something bright that was in a cloud hole :)

This is 15 minutes unfiltered with 5 minutes each of RGB. i'd like to go really deep with this, it turned out pretty good for such short exposures.

[[1ponders]]

WOW Eddie,:eyepop: I was just looking at the pictures of "The Tower" taken by the Hubble in the latest AS&T and here you go and get a "backyard" picture of it. Damn that's good :2thumbs:

[EddieT]

Thanks Paul! It's so frustrating, I was watching the images come out and could see so much detail in there but just couldn't get enough images to clean it up. I reckon a lot of the low-contrast stuff in there would jump out with another 45 minutes of exposures. I spent a lot of time standing in my backyard cursing the clouds last night :)

[[1ponders]]

I'll come down and join you. I know its good for the farmers and the dams, but boy it gets frustrating. I can see I'm going to have to look at a permanent set up. By the time I lug everything outside and get up it, its often to late and the cloud has beaten me.

[Robby]

Welcome to my world!! Nice image Eddie. Intersting to see the blue bias of the DSLR vs. your CCD. Not actually sure which colour bias I prefer. The purist would go for the red, but is terms of asthetics they are both nice. In some ways I prefer the Blue, but that could just becuase I'm used to it!!

Cheers

[[1ponders]]

Hey Robby I'm working on a little trick using DSLR that might allow us to take reds like that. It may take a few weeks but I'll let you know how I go.

[EddieT]

if it rained it would be ok, but it's not even doing that up here. just clouds!

[Robby]

Standing by!!! :D :xmas:

[[1ponders]]

Same here Eddie. With just the occasional teasing sprinkle. Maybe it'll take pitty on us tonight.

[iceman]

Stunning as usual Eddie. I can see that it would've benefited from more exposures, it's a little less smooth (a bit noisier) than your usual highest quality shots.

But the depth even in that short time is amazing, great job!

[EddieT]

Actually, I've been here for several years, just don't get out much :)



There should be no bias in my image. It's red because the nebula is predominantly Hydrogen. My images are colour calibrated using filter ratios determined by photometry on a G2V star and extinction would be minimal because M8 was near zenith when I imaged it. The colour is not entirely accurate though because I used LRGB which results in slight desaturation. The RGB is a bit more of the traditional purple/pink colour but has nowhere near the detail of the final image.

[ving]

to draw?

*hides*
:scared3:

[atalas]

Wow and what a 30minutes that was! :2thumbs: to be expected from you Eddie.

Louie :D

[EddieT]

Thanks Mike.

Yes it's frustrating, but I keep saying that! :) I told myself years ago that I was going to stop wasting time waiting for clouds, but i just keep on doing it.

This may be one of those images that takes several nights to finish at half an hour a night. Forecast for tonight is much like last night so I might get it done. One things for sure...it's not finished! :)

[EddieT]

Thanks to you Louie!

[ving]

oh and brilliant shots people!
Love yours eddie. such a pro!
and stuart, those 2 are great and contrasty!
I dont know which i like the best! :)

[tornado33]

Hi all
Heres my M8 effort. It was taken a few months ago when I got xtra keen and got up at 3 am to take it. Also, it was before I got my off axis guider for the 10 inch, was instead taken with my 6 inch F3.6 Schmidt Newtonian
http://www.iceinspace.com.au/forum/attachment.php?attachmentid=2320&stc=1
I used Curves to tweak up the red to mimic the modified DSLR cameras
Its two 5 min shots ISO 200 at F3.6
Scott

[atalas]

Hey scott,the links no good!can you fix?I wanna see your pic.

Louie :confused:

[Robby]

There is bias in every image. No CCD can accurately measure the entire spectrum of light. What is bias anyway? Surely we need a reference to measure it against? CCD detects more red releative to the eye. The key here is relative. And CCD will capture light that is outside the visible spectrum. Which is great!!! But I often ask, What would my eye see if a particular nebula was bright enough to register colour in the eye? It probably wouldn't be as red as Eddie's image, but it probably wouldn't be as blue as my image.
Somewhere in between I suspect. However I would say "relative" to the eye Eddie's image is red biased, which shows up more details in HA. This is great because the nebula is HA dominant. It's all abour perspective really.

Cheers

[tornado33]

Hi
Thanks, odd it was working last night, oh well.
Instead, I uploaded to my ISP provided page, here it is
http://www.users.on.net/~josiah/temp/lagoon6inch.jpg
Scott

[EddieT]

Robby,



There are references. That's why we do a G2V star calibration. These stars are white. You do photometry on them through each of the RGB filters to get the correct ratio to give the correct colour balance. This reveals the response curves of both the CCD and filters allowing the ratios to be adjusted when the final RGB image is combined. There may still be some bias caused by atmospheric extinction, but even these quantities can be calculated based on the altitude of the target and can be adjusted-for. The final result and the reason for doing it all in the first place is to acheive true-colour.

[JohnH]

I have a problem getting decent prime focus shots (ETX90) so I hope you do not mind if I put in my wide shot of M8 - it is in the middle of this....

[Robby]

Hi Eddie,
Thanks for your reply. I am curious as to the origin of "true colour". One would presume that true colour is what the eye would see... But I know this is not the "true colour" you are referring too. I guess you could take the visible light spectrum and normalise it. Therefore creating a a constant value for each wavelength. This is not how the eye would see colour though. The eye reduces intensity at each end. Sort of a band base filter on the visible spectrum.
However I must admit the human eye is probably not a good reference as everyone's if slightly different!
Therefore normalising the colour spectrum (as you have done) is probably the best "standard" that we can adhere to for consistency. Also to capture the most detail in an astro image we need to normalise the light curve, otherwise we may miss something.
I have been somewhat reluctant to remove the HA filter from the 300D due to the fact that the filter is put there so that the image reproduced from the camera is as close to as possible to what one would expect from the eye.
It's a bit of a non-standard view of astro-imaging and definately goes against the norm, but I have never been much of one for following the rules anyway!!!
Does this sort of hold any water with you?

PS. Just had a scout throguh your website. Stunning images!! Definately need to get me one of those CCD cameras to play with one day. Maybe once I've paid off the house :).

Cheers

[EddieT]

Hi Robby,


Emission nebula are red not because of eyeballs, cameras or filters, but because hot hydrogen glows brightest in the red part of the spectrum. That is it's true-colour in the visible frequency spectrum.

The visible light frequencies in the colour spectrum are known and there are specific frequencies being emitted by objects. Filters are designed pass a specific range of visible frequencies and the ccd chip has varying sensitivity across these frequencies. So doing the calibration I mentioned earlier matches it all up in order to accurately represent the colours of the object within the visible spectrum. Eyballs or no eyeballs.


This camera is designed for daylight use where ambient light is all over and contrast differences are great. The rules change in the absence of all-pervading sunlight. I've had a quick look at the response curves of the 300D. The IR filter is only passing 40% of the light at around 650nm (roughly where Red starts in the spectrum) and drops off even more below that. So it is attenuating Red significantly. Taking into account the higher sensitivity of CCD chips in the Red than blue would compensate for this somewhat, but at a guess I'd say the 300D could be up to 50% Red-deficient.



Yes and no. If you want to accurately represent the colours of objects, then the answer is no. The 300d's filter system was not designed for low light-level imaging in the absence of sunlight. Without colour adjustment of the resulting images to compensate for the attenuated Red frequencies you just cannot get accurate colour in astrophotos with the standard camera.



Thanks Robby. I still think dedicated astronomical ccd cameras are the way to go, but consumer digital cameras are getting better and better by the day. The day will come when they will replace dedicated astro ccd cameras, but that day is not today :)

[EddieT]

Robby and all,
I just discovered this http://www.canon-europe.com/For_Home/Product_Finder/Cameras/Digital_SLR/eos20da/

Canon has released an astronomy version of the EOS20D with modified Ir filter specifically for astronomy use.

[EddieT]

Scott,
That's a great image! I almost missed it among the "true color" discussion. Probably should have moved that one to another thread...

[Robby]

Hi Eddie,
Thanks for taking the time to explain above. It is appreciated. Certainly food for thought.
That ST-10 of yours is truely something special, but I just can't afford a 2nd mortgage at the moment :) The DSLR is great for honing skills and at the same time getting some very satisfactory images. I'll be all sorted when I do eventually move to dedicated CCD.
Cheers

[[1ponders]]

I don't mind at all JohnH. Here's mine. Close ups are great, but widefield just adds something to the image :)

[EddieT]

No worries Robby.

Absolutely! My first astro camera was a homemade Cookbook 245 and I learned a lot with it and don't regret any of it for a second. But the 300d's capabilities are eons beyond the cookbook camera!!

[CometGuy]

This is actually a reprocessed effort from 2 separate nights last June from my backyard at Thornlands (bayside suburb of Brisbane). I used a Takahashi E160 (530mm FL f3.3) + 300D with standard filter removed and replaced with baader IR/UV filter. 30 x 90sec ISO exposures (45 minutes combined) were processed in IRIS 4.37 and then final processing in Adobe Elements 2.0. Image has been cropped and reduced. All the exposures were unguided, and I picked the best onces that had the least guiding error.

Just a correction H-Alpha sensitivity is improved over 4x when removing the filter in the 300D. :D

Terry

[h0ughy]

very nice :2thumbs:

[[1ponders]]

Hmmm, its tempting to get that thing taken off.....Nice one Terry :thumbsup:

[iceman]

Fantastic Lagoon shots guys! Very very nice!

[fringe_dweller]

Did someone say widefield! :) hey Paul *SNAP* (insert twilight zone music) :eyepop: one of hundreds of our rejects sitting in drawers still - taken May 2003 - 135mm lens - 11 min - fuji 800 film - found a use for it yay :)
Kearn
EDIT: forgot! tacuma f2.8 135mm lens - one and only time we used this lens - to much CA and to soft/slow (dark)

[[1ponders]]

Hey! That looks just like mine :eyepop: Nice Shot Kearn:D

[fringe_dweller]

great minds think alike Paul :) and thankyou - its like looking in a mirror! - tho Stew actually guided this shot (we do hand guiding tag team style in turns - while the other becomes the assistant/secetary and gets a breather {and straightens their spine} - doing the shutter release start stop [running start on guiding heheh works a treat! and can use the super short shutter release's] /times & paperwork/ on plane and satellite watch - and we both set up the scope/mount - I do the first rough polar alignment with stews help lifting and turning the scope/tripod - and double/triple check each others work/framing every detail - freaks really - so thats why all our guided stuff has two names on it - first one is always the guiders name)
Kearn

[[1ponders]]

Sounds pretty complicated to me :). That's why I have a laptop. It does my thinking and back breaking for me. Though it would be nice to have someone to chat to while the computers doing the guiding.:thumbsup:

[fringe_dweller]

hehehe 'why do things the easy way?' is our motto lol - we havent arrived in the 21st century yet! although we did get a 350D recently - I now have foot seriuosly in the dark side - scaarryyyy :scared: hope i still go to heaven :prey2: :innocent:
Kearn
PS I do all the scanning website ect. Stewart takes the pics into developers (mostly)

[fringe_dweller]

Though it would be nice to have someone to chat to while the computers doing the guiding.:thumbsup:[/QUOTE]

Paul - yes the other one becomes the motivational coach as well - I trick stew into guiding longer sometimes - he'll say (in agony) is that 10 minutes up yet? - me: nah, just keep going mate - plenty to go :D and then he always gets the best shots LOL (hope he doesnt read this heheh) but since he smashed his last cheap PC computer (probably after reading one of my crazy posts) he hasnt bought another one yet - :) so i am safe for now
Kearn

[[1ponders]]

This is why I'm looking forward to getting my new scopes. So I can set one up for imaging, walk away and then casually view the heavens till its finished (its not that simple really but i can dream:P ). But then it'd still be nice to have someone to go "Hey! Check this out ! :eyepop:" to. :D

[fringe_dweller]

we are lucky i admit, and dreams keeps us all going i guess :) -
we do photography as a group/pair for strength in numbers sort of thing, as well as being good friends with a shared interest - never know what can happen out on your own in the middle of nowhere - like when we got bogged one night in the extreme middle of nowhere and had to walk 30 klms to get help - then your glad of company for sure!
(btw that pic wasnt taken from a truly dark sky :) - but we only do a handful of nights a year of guiding usually atm - fortunately for our spines/postures - but we plan on getting G11 full monty goto or something similar maybe by next year sometime? eventually anyway - and maybe even try widefield medium format film :) (to heavy for our present set up)
Kearn

[CometGuy]

Another, reprocessing effort on M8/M20. Same raw data as before, but actually including exposures just from 1 night (19 x 90 seconds). I like the wider field of view better with this one.

800 x 533 version:

http://www.pbase.com/terrylovejoy/image/30050101/large

1280 x 852 version:

http://www.pbase.com/terrylovejoy/image/30050101/original

By the way here is a 5-minute wide angle shot of the same area (50mm lens + 300D ):

http://www.pbase.com/terrylovejoy/image/42120189/large

Boy am I happy with that 50mm lens...purchased from the trading post as part of complete Canon EOS650 film camera setup.

Terry

[rumples riot]

Here's my version

[[1ponders]]

Hey Paul. How are you ? Nice shot:cool2: Registax stacked? Or photoshop? You know me Paul. Not happy unless I'm getting the intimate details.

And you too Terry. Love that wide field. Seeing as I'm expecting a 50mm sometime this or next week, care to share a few more capture details. Speed, simple 5 min or stacK, your engineer who removed your filter. :lol:

[rumples riot]

Paul, I am well thankyou.

The image is 41 minutes of subexposures, stacked in registax3 and processed in photoshop 5.

[atalas]

Yeah top shot Paul !keep em coming.

Louie :2thumbs:

[iceman]

wb Paul!

[CometGuy]

Its a single 5 minute exposure unguided, ISO400 at f4.0.

[seeker372011]

ok, heres my go.

ED 80, CG5 GT mount, Canon 300D (Unmodded), 4x80s images stacked in IRIS (Kappa-sigma) from Sydney


It would be nice to try this again through the ED-80 from a dark site and get some more exposure on it.

[atalas]

Nice shot Narayan, you must be happy with that shot! and yes It will be good to see this shot from you from a dark site.

Louie :2thumbs:

[[1ponders]]

Wow! I'm really looking forward to getting my 80 ED now if that's the sort of shot I can hope to take. Nice one Narayan

[tornado33]

Nice pics folks. Heres a reprocessed closeup taken with my 10 inch scope, last year. Iths three 5 min ISO 400 images stacked and processed in Phtoshop. EOS 300d camera.
http://www.users.on.net/~josiah/temp/lagoon%20final.jpg
A shot taken with my 400mm F6.3 lens http://www.users.on.net/~josiah/temp/lagoontriffid400mm.jpg
Its two 5 min ISO 800 shots.
Scott

[tornado33]

I forgot to mention I sort of cheated, by using Curves in Photoshop, a mate showed me how to enhance the lack of red that unmodified DSLR's have, to make it more natural looking. :)
Scott

[atalas]

Looks great Scott well done! using curves in photoshop is not cheating .

Louie :2thumbs:

[[1ponders]]

Nice shot Scott. Yep "curves" come in very handy for "bringing out" that missing red. :)

[fringe_dweller]

Scott - if the information wasnt buried in the shot, you wouldnt be able to bring it out in the first place - so in no way is that cheating - if thats cheating, that would mean all of NASA's shots were cheating, as they use all sorts of trickery to bring details out. That would mean stacking dozens/hundreds of webcam/digital shots was cheating ect. :)
Kearn

[Brendan]

heck. thats a greay shot seeker. love your work.

[EddieT]

Very nice Scott!

I fourth or fifth (lost track) the notions that using curves is not cheating. If curves is cheating then Masking is outright fraud! (Please don't ask, I don't have time to write another article just now :)

I'm slowly writing an article on image processing ethics, but to quote the bottom line, "There is no law that says we cannot correct the abberations introduced by our imaging systems."

Besides, curves as a tool, is used in all signal processing, not just imaging.