Seanelly

3 hours ago, carastro said:

I am pretty sure I read somewhere that to long as you tick a Canon camera of some sort it will be OK. 

On a whim I de-selected the 'CANON EOS REBEL XTi' (seemed closest to my REBEL T6i) in DSS and selected instead the 'CANON REBEL' and my problem is now manageable. It takes a couple of strong curve changes with the usual levels adj to start noticing the bands, and I can work around this. I do so love SGL and all the great members willing to spend time on others' problems. Thanks, and the way things are going, you'll probably read me soon enough on another technicality!

48 minutes ago, Anthonyexmouth said:

not a lot, 760 has an lcd screen on top and maybe a couple of other little tweaks but the same camera 

My banding problem is now reduced to a workable state. It takes two good curve stretches to start hinting at them. In DSS I de-selected the 'EOS REBEL XTi' (the closest the list comes to my camera) and selected instead the 'EOS REBEL' (there is also an EOS REBEL XT, but I did not try it). If you are using DSS do you know what camera is selected? I'd like to think I helped someone for a change.

26 minutes ago, Anthonyexmouth said:

i've got the 760d

By the way, do you know what the difference is between the 750D and 760D? I can't find any variation in the specs.

11 minutes ago, Anthonyexmouth said:

this is the pattern in mine

Definitely the symptoms I'm seeing if I really stretch out the image. Perhaps someone with a good grasp of PS will chime in, but in the meantime I'll start asking questions on their forum and reading up on the options. Thanks for the help.

2 hours ago, carastro said:

I am pretty sure I read somewhere that to long as you tick a Canon camera of some sort it will be OK.  I never had my camera listed when I used to use one and DSS and just ticked the closest match and was always OK.

Carole 

Hi again, Carol. Well, a restacking with a Rebel DSLR selection in DSS has improved the image, but not completely eliminated the banding, as even with a mild curve stretch they start making their ominous appearance, and now that I know they are there, it's all I can see. I'm reminded of the time my father took me with him to get new tires for the family car (this was 50 years ago when just about every car had whitewall tires) and all the way home I could look at nothing but the whitewall tires on every other car around us!

Seriously, Anthonyexmouth above has delivered an unsettling bit of proof that it could be the AF pixels on the DSLR sensor, which if true leaves me wondering why anyone would use a DSLR for astroimaging. But the fact that they do and do it well makes me wonder even more what the heck I've done wrong here. Maybe when I add more data, and understand Adobe PS better, I can hide these artifacts. 

I've never been 100% sure of my flats, as it seems such an arbitrary process, with many stated ways of achieving results, but then this may just be an indication that the parameters are wide, and so I will restack without them and see what gives, also the darks and biases if the bands persist. Also I will try another Canon selection in DSS, as there are three for the Rebel. Thanks for hanging in there with me.

1 hour ago, Anthonyexmouth said:

i've been seeing the same thing. from what i can find out its the AF pixels on the sensor, only shows up when really stretching the data, i could be wrong, but thats the only explaination i found for my issue, count them, if its 7 or 8 pairs of lines thats what it is. cant remember if its 7 or 8 off the top of my head

Hi, thanks for the input. The latter half of what you've stated is bang on, as I'm counting 7 bands of 5 or 6 tightly grouped lines in each, but I'm baffled by the stretching you mention as a possibility, as the bands are evident even without a curves stretch, as shown in the first image I posted, which only has a level adjustment, while the second image does have a slight stretch, but very slight, and could not be defined as 'really stretching' in any way.

I thought Carol's reply might be the ticket (I did not select my DSLR camera in DSS), but as it turns out, while the right DSLR selection has seen the bands faded to a degree after restacking, it is still evident with a slight curve adjustment.

I'm going to try several restackings again if necessary while leaving out of each either the darks, flats, or biases, as Rush has suggested, to see what effect that has, as I'm not 100% confident in my flats being bright enough, at least, but your pinning the tail right on the donkeys ass with that info about the sensor has me wondering if I made the wrong choice in going with a modded DSLR over a CCD camera. The Canon T6i (750D) has the upgraded DIGIC 6 processor, one of the reasons I was convinced to go with it, but if this is the best it can do, I'm surprised that anyone is using it for astroimaging. There surely must be a way around it in Adobe, but I've only had the program for a week and don't know it very well. I'm a rookie with pretty much everything I touch in this pastime!

18 minutes ago, Rush said:

Suspect its comming from the Cali Frames. try only with darks and see if its the same. Looks as if those flats too are not matching.

Cs

Rush

Thanks for responding. I will try as you suggest if Carol's discovery doesn't pan out (the DSLR box was not checked in DSS). I'll restack with that done and see what I get. (Man, every time I think I've got everything under control, something else pops up!)

4 minutes ago, carastro said:

It looks like a grid pattern to me ? wrong bayer matrix.  Did you select the correct camera in DSS. It's in the settings Options Raw/Fits box near the bottom.

Carole 

 

Thanks for responding, Carol. You're on to something here, as I'm checking the settings now and the box was not checked for a DSLR (just before you answered I edited my post to add the modded Canon T6i 750D I'm using).

There's no hiding my ignorance in all this!

But while there are three selections for the Digital Rebel, I don't see a selection that exactly matches my DSLR, a Canon EOS REBEL T6i (750D). Is close enough okay, or do you know which of the three I should choose? (I'm thinking you have access to DSS).

How frustrating!

3 sessions and 11 hours total of data on M81 and M82 and I can't get rid of these horizontal lines that litter the full image. I've cropped M82 to give you a better look.

Both examples shown here are 11hours of 5m exposures at 1600i with modded Canon T6i and went untouched from DSS with 50 each of dark, flat, and bias to Adobe PS. The d,f, and bias frames all came from the first 3.5 hour imaging session, at about -15C, and the other two imaging only sessions were around -10C.

The first (1) image shown has a careful levels adjustment only in AdobePS, and the second (2) image has an additional very light curves adjustment.

After the first 3.5h imaging session was processed I thought the lines would go away as additional data was added, but that is not the case. Something tells me the problem is from the dark, flat or bias frames, but I was very careful in collecting them and I've looked at each one individually along with every light frame and all data looks good. The only thing that I can think of is that perhaps the flat frames were not bright enough?

I've left both images as tif files to download so that you can see them exactly as they are.

Further info, if possible, available upon request. Ideas, suggestions, or a solution would be greatly appreciated, as I have no idea what in Heaven's name (or Earth's) is happening here.

(1)

DSS 11h 2m 5ex 1600i level adj only.tif

(2)

DSS 11h 2m 5ex 1600i level adj and slight curve.tif

On 06/02/2019 at 15:51, ollypenrice said:

Yes. Thanks. Our internet has been dodgy this afternoon. My result using this method is below.

Olly

Thanks, I'll check out the link. (What a great image, here!)

I have Affinity on my list of potential software. Now that I have a 64-bit operating system I will look into it. What I like about it thus far is that you can buy it, rather than continuous monthly subscription, and it has good reviews as an alternative.

42 minutes ago, Adreneline said:

Sean, with my f2 Samyang 135mm and Atik428ex combination I can blow out the core with 20s LRGB exposures let alone 5 minutes.

I have found it a very difficult target to image successfully without recourse to layers in Photoshop to get an acceptable result.

I've tried a huge range of exposure timings from 5s LRGB up to 5 mins Ha/OIII/SII and most things in between.

M42 is a real challenge; however, it does provide you with plenty of processing experimentation on cloudy nights!

Adrian

 

Hi, thanks for responding. I'm beginning to realize that processing the data is pretty much everything when it comes to Orion, and that surely must be the case with all other data as well, which makes sense. I just got a dedicated laptop for the scope and data processing, as my old one was running 32-bit Windows and Gimp imaging led to crashes, so I should be good to go with Gimp, but AdobeCC ($!) will have to wait a while, yet.

So much to learn, and such weather to learn in. I got 40 minutes of Orion data last night (8x5m between two trees!) but set-up was in -18C and tear-down was -20C (Ottawa, Ontario), and my limited experience and the continuous crappy weather not giving me a chance to practice, set-up was long and brutal even with hand and toe warmers! Tear-down was as fast as humanly possible, all the stiff cables and ice-cold paraphernalia quickly placed in the covered plastic container I use to keep the laptop and camera remote warm (I have a lightbulb on inside), and the whole mess then laid out in the den to warm up and dry off before repacking.

My wife is beyond thinking I've lost my mind, given the fact that I've been out with the Dob so often in cold weather that she's given up trying to analyze what makes a man do such a thing voluntarily time after time. And now this.

We have an unspoken agreement, I think: I don't question the strange stuff she does and vice-versa!

50 minutes ago, Sunshine said:

Ok for what my opinion is worth, i did see an episode of Astro Backyard where Trevor imaged M42. I did notice he used photoshop I believe to adjust the core, I’m guessing it’s hard to image M42 without blowing the core. I hope this link helps. Coming from a guy with no AP experience, if I embarrassed myself just point it out and laugh haha I’m cool with that.

heres the link.

 

Hello, again, thanks for the link. I checked out the video, but he does not explain how he manages to achieve the spectacular final image with such core detail shown at the end, other than a couple of hints, being 'hundreds' of ten-second images combined with many three-minute images for a total of several hours of data. He does not mention any special changes to the camera settings during imaging, which leads me to believe that he is somehow using the ten-second images for the core and the long-exposure images for the outer structure, though in what way is not mentioned. 

P.S. I just found his U-tube video on processing all (3h, 8m) of the Orion data in AdobeCC, and he mentions using just the default parameters in DSS and removing the final stacked image straight to Adobe without any alterations, so that tells me that his final image is achieved stricly through Adobe processing.

I willl now watch that video in it's entirety, but I will not be able to use the help for a while, because I do not yet have Adobe Photoshop. I just shelled out for a dedicated laptop for running the scope and processing the data and have used up my financial 'allowance' for a while.

All this info is great to have, however, as at some point this year I will have the software and hopefully the data and more experience to achieve better results.

How do I prevent core blowout of my M42 image?

I have 8x5minute quality light frames plus 12ds, 12fs, and 12bs. When I stack them (DSS) the core is obviously already blown, and removal without any DSS processing (I believe the recommended procedure) straight to Gimp is no help, the core is blown no matter what I do.

I'm using the APO equipment listed in signature, with the modded Canon T6i (750D) and D1 LP filter.

Is it just a matter of filters (Ha, etc.) which I don't have yet ($!!!) or is there something I can do during imaging or before stacking to prevent or at least minimize core blowout?

1 hour ago, thekwango said:

ah Coolio - the D3100 doesn't support infra-red for some reason but I have a remote cable kicking about somewhere

cheers - as above I have a remote cable kicking about somewhere though I can't remember if I ever figured out how to set length/delay and number of exposures...….must get onto google!

 

as a side note, how does one go about editing existing posts?

Believe me, once you see the user's layout of these digital releases you'll be surprised how easily and quickly they can be programmed.

If you'll check the bottom of the post you should see a + box, a quote box, and an edit box.

I use a cheap ($30) battery operated digital timer that plugs into the camera. You can program length, delay between, and number of exposures.

https://www.amazon.com/Shutter-Release-Control-Digital-Cameras/dp/B011BK84BE

This is an example, and  I wouldn't recommend this particular one for your Nikon, as I bought a similar one for my Canon and it wouldn't work in cold (<0) weather, so I upgraded, but you get the idea.

Since viewing is the priority, I'm with anyone else here suggesting a 6"-8" dob. I've owned (and used) a 10" for twenty years, and my daughter at 8yrs old was using it easily (once I set it up) after only a few evenings, getting the nudging perfected in no time. None of these scopes would be too big for your son to get used to (maybe with a small step-stool on occassion), they are a great bang for the buck, and they are the simplest to use, with no boring waiting around for set-up (most kids today have even shorter attention spans than they used to). Caring for them is easier than you might think, and collimating is a breeze once you've actively puttered around with the mirrors a few times to see how everything works. 

10 hours ago, vlaiv said:

Both 6" and 8" are fairly easily portable with even small car.

Both tubes are around 1m and a bit long (1200mm focal length, but not all of it goes into tube length) - so fit nicely on the back seat lied down. Dob base can fit into most booths. You need an observing chair - look for foldable one or one you can take apart and put together with ease. Eyepiece case and you are all set.

In reality such dob is about as portable as EQ mounted shorter dob - you need place to put tripod and mount and scope. You might not need observing chair for EQ mount - but it is much more comfortable observing while seated down.

For really compact and portable design you need to look at folded scopes - here you will find that you will be limited by aperture even second hand for your budget - like Mak 127 you mentioned - it will gather about x2.5 less light than 8" dob. Mind you, nothing wrong with 5" Mak or SCT - very good scopes and very light for their size - Dobs are often said to be the best bang for the buck - meaning the most aperture at lowest price, and aperture is important for visual (as long as one can manage bulk).

Don't count out the 10" f/4.5 Meade Starfinder dob if you can find a used one with good mirrors, one of which I've hauled out to the back yard, roadsides, and dark sky locations with relative ease for twenty years. The tube is three inches shorter than the f/8-f/6, while the overall weight is still less than 100 lbs. Bring along a 1m square of 3/4" plywood and you're set up in minutes anywhere.

I realize I may be blowing your budget, but aperture fever is only funny when you're not afflicted with it. After starting with a 4.5" and then soon buying a 6", I was finally cured with the 10", the length of time I've owned and used it proof of it's overall practicality to me.

My first, and only, two.

M31 (20x30s lights, 1600iso) a month ago, and M45 (16x180s lights, 1600iso) a few days ago.

My scope is 900mm with a .85x reducer/flattener, so M31 is mostly core, but the Pleiades fit very nicely.

No flats, biases or darks, both worked somewhat in DeepSkyStacker, and the Pleiades falsely coloured in a Microsoft photo editor, because my wife says I don't get Adobe PhotoshopCC until Christmas!

I did a lot of preliminary groundwork before attempting anything, and I'm very proud of them.

we

This is a remarkable image. Inspiring!

8 minutes ago, Susaron said:

These cloudy days I am reprocessing some of the 2018 SW130PDS "Greatest Hits", as long as I am increasing the knowledge on the tricks of PixInsight.

Here I leave you some of the pics.

Cheers.

Mario.

 

Very nice. I'm partial to globular clusters, and these are prime examples.

Beautiful stuff. I'm partial to globular clusters, and these examples are prime. I repeat myself below.

On 26/07/2016 at 07:36, Moonshane said:

Here's mine

 

Fantastic, so to speak.

On 02/01/2009 at 17:31, John said:

As someone who has been in the hobby for many years now I found that many of the hints, tips and pointers in this article are right "on the button".

John

I have been called impulsive (ask my wife), and though true at times, I can argue the opposite when it finally came to purchasing my astrophoto kit.

   In 1979, when I was ninteen, my father died, and left me the old pair of virtually unused Zeuss 10x50 binoculars that he had displayed in their leather case high on a shelf in his den for as long as I could remember. Those binoculars sat in that case on a shelf of my own for another twenty years, until on a whim I grabbed them as a last item while heading out the door on a camping trip up in northern Ontario. My binoculars were the hit of the entire week among the five of us. They were passed around every evening, virtually all evening, and from that trip grew my love of the night sky.

   I soon acquired a small reflector, then a larger one, and twenty years ago my trusty old 254mm Meade Starfinder dob. I learned the night sky not the hard way, but the best, most fullfilling way, by studying charts and spending hours under the glorious stars.

   Since getting that dob I saved my pennies, did my homework, threw most of it away and did it all over again, until finally I was ready to purchase my astrophoto kit about six weeks ago. The learning curve is steep, no doubt, and I'm nowhere near where I want to be, of course (who is?), but I'm happy to report that there isn't a thing I'd do differently.

   The truth in that Sky and Telescope article should help anyone who feels the call of the night sky but doesn't know where to turn, and I just thank my lucky stars I was able to get into the hobby without too many errors.