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Rodd

M101 LRGB

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This image has about 10 hours of data-LRGB 20 minute subs 8 per filter.  No calibration yet.  I am considering shooting flats tonight, but am wondering if it will be worth the extra time, as I don't see calibration saving this image from itself.  I have included a few single exposure images of the Cresent Nebula (1 30min Ha sub) and M16 (1 5min Ha sub).  Its hard to believe but the single subs are better than the image with 10 hours of exposure!  

TV np101 is, STT-8300. 

LRGB-final.jpg

Cresent Ha.jpg

M16-5min Ha (1).jpg

Crop.jpg

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Don't be discouraged as M101 is a very faint target. My images recently posted have integrated over 45 hours of data. If you look at M101 in your image you will notice it has a lot of speckles. This is indicative of not enough RGB data i.e. the data is noisy- you simply need more subs & its nothing that cannot be corrected with more data or what you can escape from. Also you may have pushed the saturation too hard as you have blown out star halo's

A star mask would help you to bring out the colours in the stars by increasing there saturation slightly & not affecting the galaxies being shown- there is much you can do to improve the image.

Flats aka calibration frames will always make a difference as your image has quite a lot of gradients which would respond well to gradient Xterminator & a bit of TLC.

As I said its a faint target so get more data next season & watch the image improve- its packed full of exciting data when imaged at perhaps a larger image scale than what your currently presenting.

Edited by pyrasanth
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Think you should do the calibration files... turned to narrow band myself so can't preach!

 

Peter

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On 5/13/2016 at 03:01, pyrasanth said:

Don't be discouraged as M101 is a very faint target. My images recently posted have integrated over 45 hours of data. If you look at M101 in your image you will notice it has a lot of speckles. This is indicative of not enough RGB data i.e. the data is noisy- you simply need more subs & its nothing that cannot be corrected with more data or what you can escape from. Also you may have pushed the saturation too hard as you have blown out star halo's

A star mask would help you to bring out the colours in the stars by increasing there saturation slightly & not affecting the galaxies being shown- there is much you can do to improve the image.

Flats aka calibration frames will always make a difference as your image has quite a lot of gradients which would respond well to gradient Xterminator & a bit of TLC.

As I said its a faint target so get more data next season & watch the image improve- its packed full of exciting data when imaged at perhaps a larger image scale than what your currently presenting.

I removed gradients using DBE--it doesn't work that well.  I used a star mask--didn't help much.  I tried the canon debanding script-to no avail.  Yes saturation is blown, but if I don't over saturate I am left with a gray image.  I have seen images of M101 with less exposure time look worlds better.  In fact--take a look at the attached image--it only has 4 hours of data taken with a DSLR.  I am missing something critical and I can't figure out what.

Well-the forum page does not provide an option for uploading images for some reason.  But the image I mention is several orders of magnitude better than mine at 1/3 the exsposure time using a DSLR.

Regarding flats--the same thing happens with flats.  Mine suck, so they are worthless.  I have a Neumann flat foil--too bright, can't regulate brightness without taking apart and inserting a piece of plastic or paper--but every filter has different requirements so that will be time consuming.  I've tried daytime flats, nighttime flats, T-shirt flats.  None come out the way the are supposed to.  So...its hard not to be discouraged.

 

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4 hours ago, Rodd said:

I removed gradients using DBE--it doesn't work that well.  I used a star mask--didn't help much.  I tried the canon debanding script-to no avail.  Yes saturation is blown, but if I don't over saturate I am left with a gray image.  I have seen images of M101 with less exposure time look worlds better.  In fact--take a look at the attached image--it only has 4 hours of data taken with a DSLR.  I am missing something critical and I can't figure out what.

Well-the forum page does not provide an option for uploading images for some reason.  But the image I mention is several orders of magnitude better than mine at 1/3 the exsposure time using a DSLR.

Regarding flats--the same thing happens with flats.  Mine suck, so they are worthless.  I have a Neumann flat foil--too bright, can't regulate brightness without taking apart and inserting a piece of plastic or paper--but every filter has different requirements so that will be time consuming.  I've tried daytime flats, nighttime flats, T-shirt flats.  None come out the way the are supposed to.  So...its hard not to be discouraged.

 

I figured out what is wrong.- your giving in to defeat- you need to work through all the issues you have & find solutions by asking on the forum. It is much too easy to give up but it's a lot more rewarding to find solutions & conquer the demons. Do you think that anybody imaging on these forums have faced issues any less daunting than the ones you face. Arm yourself with knowledge &  work the problems you face- it's the only route to success.

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1 hour ago, pyrasanth said:

I figured out what is wrong.- your giving in to defeat- you need to work through all the issues you have & find solutions by asking on the forum. It is much too easy to give up but it's a lot more rewarding to find solutions & conquer the demons. Do you think that anybody imaging on these forums have faced issues any less daunting than the ones you face. Arm yourself with knowledge &  work the problems you face- it's the only route to success.

I have been asking for months--I do get help, but I also go round and round in circles--because there is a key ingredient/element missing.  Sometimes I post a pic looking for help and no one responds.  I try every suggestion I get.  Many I have tried before they are given.  I have seen M101 with only 3 hours of data taken with a DSLR.  The fact that my 10 hours is so bad, is not something that will be solved with a single suggestion.  Guiding was good, focus was good, seeing was as least average, the moon was not out.  I did not say I was going to quit.  

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Hi Rodd, sorry to hear about your problems I thought you'd cracked this imaging lark with your Heart Nebula a while back.

Images need calibration first before other stuff so take some flats and start again.

Crescent image looks like it's suffering from a backlash problem.

Dave

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49 minutes ago, Davey-T said:

Hi Rodd, sorry to hear about your problems I thought you'd cracked this imaging lark with your Heart Nebula a while back.

Images need calibration first before other stuff so take some flats and start again.

Crescent image looks like it's suffering from a backlash problem.

Dave

Dave,

I have corrected somethings--using Maxim now instead of CCDops.  Guiding is great.   But as you can see from my M101 image--9-10 hours of data are not looking like one would expect).   That image was the only image effected.  Subs before and subs after were ok (in fact M16 was taken seconds later).  Is it common for weird things like that to happen then disappear?  Never had backlash in my mount before--or since.  Any other possibilities?

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M101 and M16 are at two very different declinations so can show up different problems, balance, cable drag, flexure and stuff have different effects at different elevations.

Always worth recalibrating guiding when moving a long way from one target to the next, even if the software claims not to need it

The Crescent looks like it was guiding OK then jumped a bit to a new spot for a shorter time.

A single affected image is difficult to diagnose, you can try and work out which axis the movement is in but it can be a fruitless task.

We can be forgiven for thinking that having thrown a lot of money at the problem we should have trouble free imaging however this is seldom the case, you either see this as a challenge, to be overcome hopefully, or sell it and spend money on a more relaxing less frustrating hobby :)

Dave

 

 

 

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3 hours ago, Davey-T said:

Hi Rodd, sorry to hear about your problems I thought you'd cracked this imaging lark with your Heart Nebula a while back.

Images need calibration first before other stuff so take some flats and start again.

Crescent image looks like it's suffering from a backlash problem.

Dave

 

1 hour ago, Davey-T said:

M101 and M16 are at two very different declinations so can show up different problems, balance, cable drag, flexure and stuff have different effects at different elevations.

Always worth recalibrating guiding when moving a long way from one target to the next, even if the software claims not to need it

The Crescent looks like it was guiding OK then jumped a bit to a new spot for a shorter time.

A single affected image is difficult to diagnose, you can try and work out which axis the movement is in but it can be a fruitless task.

We can be forgiven for thinking that having thrown a lot of money at the problem we should have trouble free imaging however this is seldom the case, you either see this as a challenge, to be overcome hopefully, or sell it and spend money on a more relaxing less frustrating hobby :)

Dave

 

 

 

I usually re-calibrate for every target-maybe I forgot.  since this is the 1 and only time something like this has happened, I am not to worried about it.  I have plenty of other things to worry about.  I sent my camera to SBIG for them to look at--there was a lose connection, but other than that, working fine.  There has to be a basic reason why a 3 hour image taken with  a DSLR without calibration frames I might add, looks so different than a 9 hour image with a cooled CCD camera, with calibration frames (just not flats).

I have tried everything I can think of.  I went to a week long processing seminar, so I think I have the basics down well enough to know that is not the problem.  Star alignment, Cosmetic correction, Gradient removal (DBE), background neneutralization, color calibration, histogram, then a touch of saturation and contrast curves should produce a pretty decent image.  Yes the image can be made really good using noise reduction, masks and all that other stuff (which I use).  But no amount of that stuff will fix my M101.  I am truly and utterly stumped.  I won't quit because AP has been a dream of mine since 7th grade (I am now 54).  

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Just been trying to image M94 at 2500mm focal length with the SCT and it's developed a wobble in RA for no good reason, worked fine last time we had a clear sky, only change is it's a bit further past the meridian so I'll go and play with the balance.
These things are sent to try us, still better than sitting in front of the TV :)

Dave

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1 hour ago, Davey-T said:

Just been trying to image M94 at 2500mm focal length with the SCT and it's developed a wobble in RA for no good reason, worked fine last time we had a clear sky, only change is it's a bit further past the meridian so I'll go and play with the balance.
These things are sent to try us, still better than sitting in front of the TV :)

Dave

How bad is teh wobble?  What is the period?  

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44 minutes ago, Rodd said:

How bad is teh wobble?  What is the period?  

Just enough to give misshaped stars at this focal length, altered a few settings and moved round a bit to M63 , seems a bit better but got to pack up now as it's getting misty and it's 1.30am here.

Dave

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20 hours ago, Davey-T said:

Just been trying to image M94 at 2500mm focal length with the SCT and it's developed a wobble in RA for no good reason, worked fine last time we had a clear sky, only change is it's a bit further past the meridian so I'll go and play with the balance.
These things are sent to try us, still better than sitting in front of the TV :)

Dave

Dave--I have been thinking--could the issue with my stars in the Crescent not be backlash--but due to the density of the star field?  Their are allot of stars in that area--could the guider have had trouble staying on one?

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Don't think so Rodd, it just looks like something made the mount jump a bit when the exposure was nearly done and it carried on guiding in a new spot.

Dave

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20 hours ago, Davey-T said:

Just been trying to image M94 at 2500mm focal length with the SCT and it's developed a wobble in RA for no good reason, worked fine last time we had a clear sky, only change is it's a bit further past the meridian so I'll go and play with the balance.
These things are sent to try us, still better than sitting in front of the TV :)

Dave

Actually--more like 3 bumps, as there are 4 stars in the square.  One is the original;, then 3 bumps to 3 new positions.  And the line connecting the stars tells me that the bump was not a bump--but a more steady movement no? Otherwise the line would not be exposed.  Hopefully tonight the problem won't show up again.  I just started using Maxim and have not perfected it yet--maybe I forgot to calibrate.  

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Good luck Rodd, I purchased Maxim many years ago and have kept it updated but could never get on with using it for guiding, kept getting "star faded" messages when the star was clearly visible, I even got star faded messages when using the simulator, lol.

This was reported many times on the Maxim Yahoo group but the folks at Maxim refused to acknowledge that the problem existed so I've always guide with PHD since.
A bit annoying as I originally purchased Maxim as a one program does everything solution.

Dave

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24 minutes ago, Davey-T said:

Good luck Rodd, I purchased Maxim many years ago and have kept it updated but could never get on with using it for guiding, kept getting "star faded" messages when the star was clearly visible, I even got star faded messages when using the simulator, lol.

This was reported many times on the Maxim Yahoo group but the folks at Maxim refused to acknowledge that the problem existed so I've always guide with PHD since.
A bit annoying as I originally purchased Maxim as a one program does everything solution.

Dave

I know what you mean--probably a driver issue somewhere--I have all kind of little quirks and troubles throughout my system.  But its a shame about guiding.  I use a dual chip camera, so in order to use PhD guiding, there is a 1 sec delay as the commands have to go first to the main software--say SGP- then to PHD2 and back.  Since Maxim is actually doing the guiding, there is no delay.  I love the fact that i got rid of the guide cable.  Fortunately I have not had guiding issues.  But learning how to guide with one chip and image with the other was difficult.  Even Tim Puckett at Diffraction Limited had to ask technicians.  The funny thing is--its a very popular combo, dual chips and Maxim.  It has to do with something called multi threading in both the camera and filter wheel.  Finally got it.  Now I have to figure out why my images still suck.  I am going to add to the M101 image I posted.  I think you will find that even with 20 hours of data, the image will still be wanting.  I did a 19 hour elephants trunk NB that was lack luster at best.

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I started out a few years ago now, naive and full of enthusiasm thinking I've bought all the gear so it will be no problem, WRONG, I don't think I've ever produced an image I'm totally happy with and have lowered my expectations accordingly.

Getting a new mount next week that can supposedly do 30 minute unguided exposures, we'll see.

Still spending money and having fun though so who cares :grin:

Dave

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14 minutes ago, Davey-T said:

I started out a few years ago now, naive and full of enthusiasm thinking I've bought all the gear so it will be no problem, WRONG, I don't think I've ever produced an image I'm totally happy with and have lowered my expectations accordingly.

Getting a new mount next week that can supposedly do 30 minute unguided exposures, we'll see.

Still spending money and having fun though so who cares :grin:

Dave

I spoke with Astro Physics about unguided exposures.  They said when people take long unguided exposures they still need to use the computer to help counteract the effects of curvature--they use some kind of plate solving/modeling feature.  It is basically guiding with another name. Using plate solving instead of pulse commands. According to them, no mount can really do unguided perfectly because curvature varies over different parts of the sky, and the mount has no way to differentiate.  However, a very good mount will guide better anyway.   Maybe they are wrong--I don't know.

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Plenty of images done with it unguided even longer than 30 min's, it models the sky (not stars) then is driven by encoders and compensate for declination difference effects , atmospheric distortion etc.

We'll see, to quote another forum member "Nothing is foolproof to a sufficiently accomplished fool" :grin:

Dave

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1 hour ago, Davey-T said:

Plenty of images done with it unguided even longer than 30 min's, it models the sky (not stars) then is driven by encoders and compensate for declination difference effects , atmospheric distortion etc.

We'll see, to quote another forum member "Nothing is foolproof to a sufficiently accomplished fool" :grin:

Dave

A rose by any other name.....Same effect, though better than guiding.  When I think of unguided, I think of no correction given at all-just relying on perfect polar alignment.  So, noot guided, but encoded!  (sounds expensive).  I know the lowest end mount AP makes with encounders cost $12,000-$14,000 all said and done.  

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No idea how it works but apparently accurate Polar alignment is not required.

Cost around £6000.00 GBP and can actually run without a laptop, though obviously you need one for image capture.

I looked at a few mounts including AP and decided on this 10 Micron, hopefully all top end mounts should be trouble free but there's always something waiting to bite us.

Dave

Edited by Davey-T

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6 hours ago, Davey-T said:

No idea how it works but apparently accurate Polar alignment is not required.

Cost around £6000.00 GBP and can actually run without a laptop, though obviously you need one for image capture.

I looked at a few mounts including AP and decided on this 10 Micron, hopefully all top end mounts should be trouble free but there's always something waiting to bite us.

Dave

Dave--I seem to have dodges a bullet (for now at least).  Here's the Crescent Nebula I shot last night in Ha.  8 20 minute subs.  I dithered and used 45 sec as a settle down time--not sure it was long enough.  For a few seconds in the beginning of the subs the rms error were  high before they settled down to their normal 0.05-0.15.

crescent Drz.jpg

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