Latest Issues - M81 This Time

[gnomus]

I thought I would write up my latest cack-handed attempt at imaging.  I think this is my 4th attempt at AP.  Each effort has brought many varied and unexpected issues.  I hope that my mutliple errors will help other poor souls starting out on this journey.  As usual all comments/advice would be most welcome. 

I went out last night (15 Dec 2014) with the intention of photographing M81.  My thinking was that this was not too far away from the NCP and, therefore, would place less stress upon my imperfect polar alignment.  I also now had the gear to do guiding.  It was, however, over 2 hours before I could start capture.  My numerous gaffes included:

1) Changing over the battery on my Nikon (so that I would have a fully charged one, of course) whilst 'Live View' was still on.  This had the effect of giving me an "Err" message.  Multiple attempts at cycling the On/Off switch - including removal and reinsertion of the battery would not clear the "Err".  It was only when I took the camera indoors into the light that I realised the mirror had locked up.  A press of the shutter button cleared the error message.  20 minutes of my life that I will never get back.

2) I had multiple difficulties getting the correct exposure using the guide cam.  Should I set it on Auto or not?  Eventually I got something that seemed to work (but see next point), however the picture on screen (PHD2) seemed awfully noisy.

3) (This is my favourite.)  Having got things mostly set up, I found that my mount wouldn't calibrate.  PHD2 reported back some message concerning the chosen star not moving sufficiently during the calibration process.  I assumed that this was something to do with the noisy image on screen (see above).  I re-tried again and again.  (Didn't Einstein have something to say about repeating the same process and expecting different results?)  At least half an hour went past - probably nearer 40 minutes.  I came very close to crying...  Eventually, I discovered that, out there in the dark, I had plugged the autoguiding cable into the "Aux" socket on the mount instead of the "Autoguider" socket.  At this point, the entire rig nearly ended up being thrown into the neighbour's garden.  

4) All told (I won't bore you with my attempts to polar align using PHD2), I've now been out there for 2 hours and I have yet to observe anything let alone take any pictures.  Another highlight was to follow.  During the messing around with the camera (step 1) I inadvertently managed to slip the clutch on the mount a little bit.  I thought this was going to require a realignment.  But finally I caught a break.  On the PHD2 screen I could see a little "smudge".  That must be M81.  I centred the galaxy.  Everything now seemed good to go.  I began the capture process and took 20 frames at 2 minutes ISO 800.   I was intending to take more frames, but I cut down the number because of the loss of time (see 1-3).  I got all 20 lights.  I took 20 darks.  I decided to use the Bias frames from another session.  And, I decided against flats - I was now FREEZING (I cannot stress enough how cold I was).  Strangely things seemed to go OK during this bit.  I uploaded all the frames to the PC and set Pixinsight (trial evaluation) off through the night.  I woke early and went through to the PC ready to be bowled away by my image of M81...............

.... Noooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo!!!!!!   &*%%$£**)*

    

[Daniel-K]

star shapes are very good, fine detail in the galaxy. theres not much wrong here just its lacking the red channel. where is it? 

i think you just a little time on processing, good effort 

[iksose7]

Your 3rd point has happened to me more times than i can count, not putting the cable in the wrong place but the 'star did not move enough' error message. Thankfully i have my guiding game down now though so it doesnt happen anymore but for a few months it did happen quite a lot and yes, it does bring you close to tears!

I should also note that your thought of imagine close to the NCP to compensate for inaccurate polar alignment is a bit flawed. Imaging close to the pole is actually where you need excellent alignment! The further from the pole the less accurate you need to be, at least this is my understanding.

Saying that though, looks like you got away with it and came up with a nice image! Some great structure visible in the galaxy, well done

Callum

[FunkyKoval35]

Nice shot As, Daniel mentioned, your picture has a potential, but need better processing

Also, something for cold nights... If you have second laptop/PC at you home, and wireless broadband you can control your whole setup from home Just instal TeamViewer on both machines and that`s it I am using it, and it is very comfortable solution. The only thing I need to do is prepare whole setup(polar alligment, etc) and set focus manually - I have no auto-focuser. But, everything else I am doing from home

[Feral Rabbit]

I assume that the picture you took was of M82 and not M81 which I assume is what you were really after.

Still, if it was me, I would be happy with what you've taken.

From what I've gleaned on here AP is a heart breaking, steep learning curve of a mistress and you will learn from your mistakes and accidents along the way.
 

I will be following you down this road in the not to distant future and I am under no illusion that I will have varying degrees of disappointment along the way.

 

[gnomus]

star shapes are very good, fine detail in the galaxy. theres not much wrong here just its lacking the red channel. where is it? 

i think you just a little time on processing, good effort 

I went looking for the missing red channel.  Not sure I found it, but this certainly seems different from the first attempt.

[Polar Bear]

That does look much better. Great detail, star shapes good, asthetically pleasing. I would be very happy with the result.

I think we can beat ourselves up a little too much on what are fundamentally very good images. Thanks for sharing and I look forward to your next image....

[Knight of Clear Skies]

Great detail on the dust lanes there.

[iksobarg]

Nice, yet somewhat painful, post Gnomus. I'm taking notes! Thanks for sharing. And dress warmer or go more wireless? !

[Astrosurf]

That's a gorgeous image! I've never got that much detail!

And, oh, I feel your pain. I've had evenings like that and I have cried! Well done for sticking at it.

Alexxx

[gnomus]

That's a gorgeous image! I've never got that much detail!

And, oh, I feel your pain. I've had evenings like that and I have cried! Well done for sticking at it.

Alexxx

Thank you all for your kindness.

[peroni]

Nice shot As, Daniel mentioned, your picture has a potential, but need better processing

Also, something for cold nights... If you have second laptop/PC at you home, and wireless broadband you can control your whole setup from home Just instal TeamViewer on both machines and that`s it I am using it, and it is very comfortable solution. The only thing I need to do is prepare whole setup(polar alligment, etc) and set focus manually - I have no auto-focuser. But, everything else I am doing from home

+1 for Teamviewer

I used it for the first time on Saturday and it saved me a very chilly night. A word of caution though....

Unattended telescope use has it's dangers! I returned to my scope after 4 hours tracking and found it completely inverted and the camera almost jamming up against on of the tripod legs.

Kind of obvious that the scope would do this (when I think about it) but I'll be checking more regularly in future.

If a pier is used, or a tripod extension, then this issue of camera hitting tripod leg is resolved. More money to spend on the hobby 

[glowingturnip]

tha's a very creditable M81 M82 ! Who cares if you got the wrong galaxy, it's a very good shot.

'star did not move enough' - yep, been there loads of times

[kalasinman]

Very nice! I wish I could do as well. Don't worry about time lost never coming back. It's a hobby and learning tolerate if not enjoy the journey is a great thing for one's personal growth IMO. --Jack

[johnrt]

Great image, some great detail in the galaxy.

My advice would be as follows. Your background is very dark, and the image needs a further stretch as you have some more galaxy to bring out. The colours a still a little unbalanced, too much blue and when you start to stretch there are some large halos round the stars, perhaps from deconvolution or sharpening? Did you use flats too as there are some dust bunnies there?

But! Don't take that as negative! This is your 4th image?!?! I wish my 4th image looked half as good as this!!! Looks like you're somewhat of a natural!!

[gnomus]

Great image, some great detail in the galaxy.

My advice would be as follows. Your background is very dark, and the image needs a further stretch as you have some more galaxy to bring out. The colours a still a little unbalanced, too much blue and when you start to stretch there are some large halos round the stars, perhaps from deconvolution or sharpening? Did you use flats too as there are some dust bunnies there?

But! Don't take that as negative! This is your 4th image?!?! I wish my 4th image looked half as good as this!!! Looks like you're somewhat of a natural!!

Thanks for the interest.  I agree that my background is probably a little dark.  I am using PixInsight (trial).  I really like the results, but it is very different from Photoshop (a program I have used for many years).  As a result I am following along with various tutorials.  The Harry's Shed ones seem the best, but it is not always clear to me what each process is doing.  Is HDR Multiscale Transform a type of sharpening process, for example?

For this image I found something on YouTube -  following a chap who suggested using a tool called Range Selection. This seemed to pick out all of the bright objects.  That tutorial did suggest boosting the saturation of the galaxy using curves, and then (by inverting the mask) bringing the background down a bit.  This seemed to bring down the dust bunnies and made the galaxy stand out a bit more.

I think the mask produced by the Range Selection, along with my perhaps heavy handed bringing down of the background (using the curves tool) produced the haloes.  

I had no flats - the darkening of the background gave the advantage of making the bunnies less obvious thus egging me on to make it a bit darker.  (These bunnies are much more apparent than when I use the camera for regular photography - I suppose it is obvious that they should be if you think about it for a minute.)

I'm not sure how much more detail there is in the galaxy.  I did have a further play and wasn't convinced there was a whole lot more there.  These were only 2 minute exposures at 800 ISO.  I intend to go for 5 mins at 400 ISO next time.

I am not taking any advice as a negative.  I want to get better at this.  Thanks for taking the time to offer constructive criticism. 

[gnomus]

I thought it may be helpful to show the full frame image from which my M82 was cropped.  (Note that I did get a bit of M81.)

This seems to be a consistent picture that I get using my D800 (36MP) full-frame camera.  There is marked vignetting at the edges - which I was expecting.  The odd thing though is the "inner halo" that surrounds the centre of the image.  I was not expecting that and I am not entirely sure what it is.  The few photos I have taken do have to be cropped from this much smaller area.  I am thinking that I may be as well just shooting in DX mode (essentially the camera crops itself).  

The scope is an Edge HD 8" and I am using the focal reducer that is made for the scope.  

Is the "halo" a normal occurrence?  I would imagine that it has a profound impact on things like the Dynamic Background Extraction and Color Calibration Processes in Pixinsight.  I put the attached image through a DBE, Background Neutralization and Colour Calibration and, as you can see, it is quite orange.  For the earlier attachments, I cropped the picture so that I had just the central portion, and then run the above processes.  

[Astrosurf]

That's strange. I'm sure someone will be along soon to help!

[gnomus]

That's strange. I'm sure someone will be along soon to help!

The blurb on the Celestron website says that the focal reducer is "Optimised for APS-C sized sensors...".  I am using it with a full-frame sensor.  I am beginning to think that that is the issue.  When I get a chance I am going to take some daytime pictures through the scope to determine if that is indeed the issue.  I'll post the results of my findings.  It may be that the focal reducer is no good with FF sensors.  

[gnomus]

...  When I get a chance I am going to take some daytime pictures through the scope to determine if that is indeed the issue.  I'll post the results of my findings.  It may be that the focal reducer is no good with FF sensors.  

I have now done that.  Please excuse these test images.  The weather is so poor at present that I had to shoot through my dining room window.  In addition the wind was howling, so the trees were moving around.  Finally, I didn't pay too much attention to focussing (which is way off).  I just wanted some quick and dirty shots to look at the vignetting.  The first shot is the Nikon shooting full frame with the Edge HD 8" focal reducer in place.  The second shot is Nikon shooting full-frame but without the reducer.  I am using the first half of the Celestron T-Adapter (I assume that using the full length of the adapter would make matters worse).  The "secondary" vignetting with the Focal Reducer in place was obvious to me, but was more difficult to see in the 800 pixel JPG that I was going to upload here.  I have exaggerated this quite a bit in Photoshop to make it more obvious.  And I have replicated that on the no-focal-reducer image to show that the secondary vignetting is either not there, or is very minor.  

The vignetting on the full-frame plus reducer image looks very similar to that seen in my M82 full-frame view a few posts above.

My conclusion is that the Edge HD 8" focal reducer is really only usable with DX cameras or when shooting in DX mode on full-frame cameras. 

[Astrosurf]

It certainly does look like the reducer. Thanks for the education. I didn't know about this!