Finally... A first image with 314L+

[AndyUK]

After one or two trials and tribulations (which turned out to be down to me checking the "pre" option within Artemis Capture ), and also fumbling around trying to align, combine and process LRGB images (I doubt I'll be able to remember next time!), I managed to capture my first true image using the 314L+ during the early hours Wednesday am.

I know I still have a huge amount to learn about setting the correct exposure on subs (I forgot to use autostretch to check saturation) and also forgot how to get the FWHM box up... and certainly I need to work on a process for taking flats (it's a bif different now that I don't have an AV mode to play with!) but I think with a fair bit more practice, I might be able to eventually get the hang of it .

Thankfully the addition of the Atik filter wheel (thanks again Anna!) into the path gave me the extra 20mm I needed to be able to achieve focus with the MN190, so hopefully next time out I'll be able to set up much quicker and get an extra hours worth of subs.

I know it's not brilliant, but it is the first one - Next time I'll pick something with a little colour in it (maybe using the Ha filter?) and possibly use the wider FOV of the Equinox 80... I think I can safely say that the camera definitely works and works very well (it's just me that doesn't )

This image of M13 was taken with 12x300s Luminance and 4x300s 2x2 binned RGB each. I did apply darks and bias to the L, but haven't taken any binned darks/bias frames yet so they were just straight. Stacked in DSS and all other processing in Photoshop

(If anyone has any advice on what I could have done to improve this, please shout - The background looks very black to me, but I can assure you it's not clipped... honest!)

[blackparticle]

There are about a million stars in M13.. I think you might have got most of them !!

[fatwoul]

Good job. And don't feel bad about the "pre" thing. I'm just getting to grips with Artemis myself.

Does this image look a bit green or cyan? It might be my stupid Mac at work, but if I had to pick out a colour cast, that's the colour I'd say it was.

[AndyUK]

Cheers both...!

Fatwoul - Hmmm, it's entirely possible that it might have a cast... Although I know I can get rid of it, I believe that what I really need to do is image a GV2 star to then work out the % of RGB to use to get a "balanced" colour(?).

Still, I just had another go at this using a different (much more complex!) tutorial and cme up with this version... I THINK it might be a bit better in colour terms (and the black isn't so "dominant")?

[Moonshane]

as an AP layman I prefer the first one, though I see what you mean about the black background. that said, how else should it look in space?

[antimorris]

2nd is definitely less clipped. I downloaded it and you still have some room on it before you hit the clipping point. I bumped it up just a hair in between what your first would have been and your 2nd.

Nice first go though with the new camera! For something with such a range, perhaps grab a set of shorter frames as well and use layers and masks to merge them so the center isn't so blown out but you still get the fainter stars.

Its a great camera isn't it? I love mine!

[AndyUK]

Thanks Anna - It seems to be very different from using and post-processing a DSLR image, but yes, I think it's a camera I could grow to like... a lot! . The thing that immediately hit me is the apparent total lack of noise... I was also quite amazed that I didn't appear to have any dust bunnies/donuts or gradient...

As you've said though, I could take some more lower exposure subs and layer / mask / merge them in, but to be honest, I think there's still a lot I need to practice with Artemis capture... specifically exposure, flats and trying to assess how many LRGB's I need to capture of an image... and then the ratio of R, G and B

And if I'm to attempt an HaLRGB-type image - (or heaven-forbid, a hubble pallete image), then whilst using PS to align / combine is okay, there HAS to be an easier way. I think I need to see if I can get another Maxim trial as a great many of the links I found with tutorials were using it and maybe then I can get a workflow process documented.

I'm now very much looking forward to having another go on the next clear night... on top of which I had a pleasant surprise this month in that I seem to have slightly more available cash than I thought, and I can hear the SII and OIII filters calling to me!

[RogerTheDodger]

Looks like you got some blue stars in there , so looking good

[swag72]

Prefer the 2nd edit - Looks like a real steep learning curve, but one you are clearly starting to climb. Well done for persevering!!

[Uranium235]

Welcome to the wonderful world of CCD image processing!

Doing a G2V is worth it becuase it will give you the particular RGB values for your setup. Though you have to find a G2V star thats quite high up, im pretty sure theres a G2V list and tutorial on the astrodon website.

Good idea to stick it on the Equinox too, the nebulae are on the way back and im itching for a co-op on M16 (when it becomes available). I already have the OIII filter and I guess I can spash out a little now and get the SII.

[AndyUK]

Cheers all!

@ Roger - There are indeed some blue ones in there somewhere... (which is a little odd, as I thought these clusters were some of the oldest objects in the Universe (12+ billion yrs old) and blue stars were young (and needed dust clouds to form?). Obviously my Cosmology knowledge is lacking somewhere!)

@ Sara - Yes, coming from "DSLR land", there certainly seems to be a different set of skills required (and software!). However, although obviously a very long way to go, I can't afford to give up - My wife would never let me hear the end of it! I'm trying to treat it as more of a challenge than a series of stumbling blocks, which is how it seemed to start out... Apparently Monday might be the next good night (fingers crossed)

PS - I prefer my 2nd edit myself too (although I like Anna's better!)

@ Uranium - Thanks... (I think!). You're also right about the existence of G2V star lists - I found this which seems to explain how to do it and also links to a list... I think I also saw a link somewhere which also had a calculation for working out how to adjust it depending on DEC (maybe on the Astrodon site as you've mentioned).

M16... Hmmm... It'll be pretty low for me unless I can venture out, and I have a LOT to learn about this, but give me a nod when you think you might want to have a crack at it. My FL will be slightly different from yours (the Equinox 80 is 500mm, whereas I think the 80ED is 600mm?) but we can have a go (I'll be using the same filters). I'm sure it also must be possible to get a trial of registar... although it's very possible that I may not be ready for you this year...

[ollypenrice]

C'mon that is a great start.

I wouldn't bin colour on an object as bright (and as full of delicate detail) as M13. You are wanting to separate red stars from blue, remember, so colour resolution matters.

No, you are flying already. Chip away.

Olly

[MikeWilson]

Wow Andy, you must be really pleased with that result! It's very clear with an awesome resolution! Imagine how close you could get into the core of that object with the focal length of your Mak 180

I'm glad that the camera is working for you

[Uranium235]

My FL will be slightly different from yours (the Equinox 80 is 500mm, whereas I think the 80ED is 600mm?) but we can have a go (I'll be using the same filters). I'm sure it also must be possible to get a trial of registar... although it's very possible that I may not be ready for you this year...

Im using the 0.85 FF/FR, so my FL is 510mm, only 10mm off the Equinox. I can handle the registering as ive got the software to do so, and once we have the master frames we can both have a go at our own processing (which should be fun!).

It might be worth doing on m16 becuase its such a low down and difficult one to get for me, and the window is short - maybe a month or two and its gone. According to stellarium, the ideal time for me is towards the end of July.

Same goes for M8 and the Trifid - which is way down in the murk and would require a night of exeptional seeing to attempt.

[AndyUK]

Thanks Olly - I have to say that although I've read up about binning (and think I understand the principle) it's not really something I'd like to do for choice - I understand that it's generally used to "paint" in the colour but it just seems odd (lazy?) to take subs at less resolution when you can get a lot better resolution by just taking more time... . However, I didn't consider the effect that binning would have on this particular type of object and now understand a bit more about when not to use it!

This being a first (real) night out though, and having made such an initial mess of using Artemis (I left the loop button checked, which takes the first frame via the sequencer, but thereafter reverts to taking the remainder of the number of frames via the exposure window!) I was effectively running out of time hence taking what I thought was the shortcut of binning the RGB. Still, it turned out to be a good exercise in seeing if/how I could cope with having to process binned RGB, so I'm glad I got it out of the way...

However, with regards to post-processing, the tutorial I followed for the PS aspects on #2 was much more convoluted than my fumbling about with the first version (for anyone interested it's here), and I'm not sure I really understood what was going on, so that obviously requires a lot more practice...

Cheers Mike - It certainly is a relief that I was finally able to get it working... I still can't get over the lack of noise and how flat the background is compared to the 40D, or indeed the difference in FOV, but I think it'll be quite a while before I attempt using the Mak 180 with this camera. Mind you, it might be interesting to try sometime (if the seeing were ever to allow it - It then really would be simply a complete mass of stars!)

Uranium - Okay... I'm still game... I've just had a look on Stellarium and I guess that, at the moment M16 is probably accessible (in the Eastern to Southern murk) for me about now (if I went "out and about"). I need to practice with the Ha filter in the garden first, but as / when / if I can, I'll see if I can start getting some 15 min Ha subs with the Equinox 80 - At this time of the year I guess I'll be lucky to get 10 subs/session, but it'll be a start!

For anyone interested in comparing the FOV of a 285 chip with a 40D (APS-C), I thought it might worth posting an older version of M13 taken with the 40D side-by-side (both taken with the MN190)

[roundycat]

A couple of points that might be of interest:

Binning is over rated. Its main use is for when you are read noise limited as turning four pixels into one quarters the read noise. Secondly, it is useful if you are chasing after very faint detail and there certainly isn't any faint detail in the average cluster.

LRGB is also a technique best used on faint objects as you can get more detail more quickly through a clear filter. I still wouldn't bin with LRGB as your colour resolution flys out of the window. Remember that LRGB is also (in my opinion) over used. The deeper L exposure will give you more info on the fainter parts of the target than the colour exposures. So you have a tendency for the colour to go grey in the fainter parts of the picture. Exaggerate that effect slightly and all that hapens is that L washes out all the colour.

I would save layering brightness using different exposure lengths for the objects where it is really necessary such as the notorius M42. Carefully stretching a single layer should cope with the brightness range of all clusters.

You mention applying darks and bias to the L, one or the other please, not both!

With the exposure time you gave you should have some colour but how near saturation were the brighter stars? If they are all up near the 16bit limit consider using 2-3m exposures.

Don't worry too much about G2V calibration if you have yet to characterise your camera and filters. A tiny bit too much exposure and you are into the non-linear range of your camera. At that point the different filter transmissions will cause all sorts of colour headaches.

I have a sneaky feeling that DSS is useless for aligning/combining mono CCD frames, you need MaxIm or CCD Stack. You cannot align accurately using Photoshop and any mis-alignment will make things look out of focus or as if you have guiding errors. Getting the colour channels aligned properly is essential.

Take some flats ASAP and study them. You need to know about the chip characteristics. Flats are not just for removing dust and dark corners.

A nice, sharp result. That is about 85% of it?

PS: where is the unprocessed TIFF???

Dennis

[AndyUK]

Thanks very much for all that info Dennis - I obviously don't understand as much as I thought about binning!

I think you mentioned to me before about using unbinned RGB frames to effectively create a luminance layer(?) in another thread - One of my concerns was (is) that without an LP filter the signal using L might be flooded out... but using unbinned RGB to create the L would effectively cut out the LP with the spectrum gap between R and G (I think).

You mention applying darks and bias to the L, one or the other please, not both!

Does this apply to ALL filters, or just L?

For this image I guessed at the exposures - I forgot to use the autostretch to check the saturation level and when reviewing the raw frames in DSS, it was then that I thought that maybe I'd "overcooked" them. Having said that though, I also have a nagging thought in my head that I may not have followed the combining process correctly, and I may actually have put 2 lots of L in here (which would certainly account for lack of colour!) - I'll try another rework to check over the weekend.

I certainly know already that I'm going to need to get some extra software (as you mentioned, trying to align in PS was a right PITA) and I know I'm going to need to get some flats sorted - Again, now that I've remembered about using the autostretch feature, I can check the ADU to get them exposed correctly.

(Which tiff file would you like me to post? I seem to have so many!!!)

[Uranium235]

Cool, 15min subs it is then. But I will PM you beforehand to ensure we are using the same camera orientation, if I go with the OIII from the start we can get colour after the first run by using OIII as the green channel too. Four hours per channel should be pretty good

[Coolhandjo]

You picked a difficult target for first light ccd. Nebulas are far more forgiving! Well done on the image. It's good.

[swag72]

This is making an interesting if rather daunting read. Certainly makes me think twice about going down the CCD route that I really did quite fancy.

[Parallax]

I certainly know already that I'm going to need to get some extra software (as you mentioned, trying to align in PS was a right PITA)

Andy

You can align your R,G & B files to your L file in DSS. It's been a long time since I have done this but it goes something like this :-

Load your STACKED L and your R files into DSS

Check all the R files but UNCHECK the L file

Right click the L file and Set As Reference

Hit the 'Go' button and the R files will be stacked & aligned to the L file.

Repeat for the Green and Blue.

Steve

[roundycat]

Andy, I would do the simple stuff first, forget the L for most targets.

If calibrating sub frames you should subtract darks OR bias and then flat field. Then align them all. If you can use DSS to align everything with, say, the first Red frame they should all align automatically in PS. Stack the three aligned channels in DSS and save as 16bit integer TIFFs then open them all as grey images in PS and then use Channel Merge.

I would like to see the DSS output if in RGB TIFF form or the three separate channels in 16bit TIFF form. Unstretched.

Dennis

[nightvision]

Great first image. On the blue-star cosmology question see here for some background on blue stragglers:

Blue straggler - Wikipedia, the free encyclopedia

http://www.solstation.com/x-objects/bluestrag.htm

Tony.

[RobH]

Very nice first image. Well done.....you must have noticed how much more sensitive the 285 chip is compared to a DSLR

I agree with Olly and Dennis.....certainly, on a bright target like this, you don't want to bin the colour, and I'd also concur that luminance isn't really neccesary, or desirable when imaging clusters especially. Have a look at Peter Shah's images....he just shoots RGB for most of his images, and the colours are very rich.

Cheers

Rob

[Catanonia]

Great 1st image and some really great tips in this thread.