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Deep Sky M81/M82

Tracy

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Gain:   100
Offset:   30
Exposure Time:   120 seconds
Camera Temp:   -5 °C
Filters:  
  1. Luminance
  2. Red
  3. Green
  4. Blue

Camera:   ASI533MM Pro
Telescope/Lens:   WO ZenithStar 103mm
Still muddling along.... these were a series of 4 120s LRGB exposures of M81/M82 with a pretty good dose of high clouds present shortly before I called it a night.

M_81-a.jpg
 

OhNo

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Glad to see you posting some of your work.

M81 and M81 look pretty good, but something is off about the stars. They seem oblong on this (/) angle. I suspect it was a guiding issue, but the focus seems soft also. The guiding may have been less than great due to poor sky conditions. one way to check if there was a "Stinker" in the stack is to check the FWHM or HFR (depending on the integration program used). The best data is always the goal. Without it you are struggling to make a "silk purse out of a sows ear). You might thry the star shape tool in Deconvolution in PixInSIght.

I am only saying this in an attempt to help. Figuring out what is going on is the hardest part of the hobby. It can only be discovered by trial and error. Sound advise (some call it critical opinions) with alternatives to try are priceless.

If it helps, you are pickin' up the whole acquisition thing quicker than I did (am doing).
 

Tracy

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Tracking was HORRIBLE that night. The BEST I could get my total RMS down to was around 7.5. The high level clouds were bad enough that when the moon rose up, you could clearly see them as a "heavy fog" around the moon at most times, with periods of scud flowing through... I'm honestly surprised that it came out as clean as it did. And then let's talk about the wind gusts up to 20mph that would "burst" through!
This was more to play with combining the LRGB and tweaking the colors more than anything. There also may be some slight camera tilt with the addition of the Pegasus Falcon that I need to check on. Was trying to figure out why my total RMS was kicking up into 30 the night before with no wind and decent sky and the scope would slew the opposite direction than I wanted... so decided before the front started moving in to grab a few captures since it was already set up.

With only 4 captures of LRGB, I'm not going to do a lot of chasing with it until I can get a few hours worth with clear(er) sky. 🌃
 

Tracy

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This is what the sky looked like that night.
520C2332-F55A-4070-BE4B-BEC06E96FA52.jpeg
 

OhNo

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I set my tracking limit so it will stop if the Total RMS is above 3. It will scrub that exposure and re-start once the RMS is below 3. It was worth noting though that we should have a look at out FWHM or HFR (program dependent) to see what we have.

AP is a awful lot like farmin', dependent of the weather... Ya never win in a scrap with Momma Nature.o_O
 

Tracy

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I set my tracking limit so it will stop if the Total RMS is above 3.
Yeah... that night I was working more on other issues with the mount and StellarMate OS, so tracking wasn't a "real" concern, more being able to get the scope to go to the target. :eek:
 

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(y)
 

OhNo

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Did you get your auto focus issues worked out? The baclash setting can throw the process out of whack if you use the wrong backlash. Mine works the best at 30 steps.
 

Tracy

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Did you get your auto focus issues worked out? The baclash setting can throw the process out of whack if you use the wrong backlash. Mine works the best at 30 steps.
Not really sure what it's at.... would have to hook it all up to find out for sure, but think I was at 15.
The biggest issue I was having was the # of steps in the auto-focus routine for StellarMate. Was at 20, and once I went to 50 it seems to do better.
 

OhNo

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The step response is probably different for every scope due to the ratio and tooth size of the mechanical part of the focuser. I am lucky both scopes of mine seem to have the same backlash (as I swap the actual focuser back and forth).

There was some text instructions, and videos on the "how to". Nope too convoluted for me. I fired it up on a evening that the sky was stable and started playing with it. I found a mag 7 or 8 star *****Note: Don't use the brightest star in the sky, use a good size one that isn't too bright or dim.**** and found the best focus I could get by running the program manually. Once I had a real good focus I noted it and saved it as the start point in the focus tool box.

I then set my step size to 25. Go up 25 steps, take an image a note the HFR. Go down 50 and note the HFR, then back up 25 steps (gets you back to the original Focus point). note the HFR. If it is close to the original HFR your backlash is correct. If not adjust your back lash and repeat until you get back to a great focus like when you started.....

With my set-up I set the Auto focus to run at 25 step increments. It always goes up a hundred steps and comes down 50 before it even takes an image. I have selected the Curve option. It varies on how many iterations it does, and seems dependent on the sky conditions. I have had as high as 29 on a single run, and then it will make a second run. I normally have the binning set at 2x2 and take 20 second exposures. This will vary on your scopes f/, I am at ~f/4.2 average with my 2 scopes. One is f/3.9 and the other is somewhere around f/4.6 or 4.7......

This is where you become real familiar with you gear. It's like the difference of having a car that runs and a finely tuned race car.....
 

Stan

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The 3 different scopes I use have larger differences in focus step size. The RedCat is 7, 80Ed is 25 & Edge HD is 10
 

OhNo

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I Think I better get another focuser before WWIII starts. They have changed them since I bought mine. Mine is 12V and has a plug-in to the left of the USB port and a HC/Temp Sensor port to the right of USB port.
 
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Stan

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I Think I better get another focuser before WWIII starts. They have changed them since I bought mine. Mine is 12V and has a plug-in to the left of the USB port and a HC/Temp Sensor port to the right of USB port.
Yes good idea
 

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But now that I've been put out to pasture I have nothing but time to tinker. Doesn't take long to swap it back and forth. Ticks me off they keep changing voltages though.

The question is always "Cycles to failure".
 

Tracy

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Well, time to hit the interwebz and find a weight to put on the front of my Vixen mount to equalize the weight on the back. Think that's one of my main issues with my DEC being so high right now. Can't get a good balance because my scope is at the limit of the mount point for it.
Have temporarily solved the issue by some good old country boy engineering. Attached a a set of welding clamps to the front of the rail and it's sitting good now.

Think I will probably be going with this

 

OhNo

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Creativity goes a long way in this hobby, almost a pre-requisite!
 

Tracy

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Creativity goes a long way in this hobby, almost a pre-requisite!
It really does with most things in life. I am pretty sure us "red-necks" that can engineer solutions like this will survive longer than most others. ;)

I just ordered the Baader from HighPoint Scientific (same place I got my Falcon from)... so hopefully it will be here shortly. I'm been tracking steadily at below 0.75 total RMS for the last few hours with my current solution... so I'm pretty confident once the weight comes in it will help.
 

OhNo

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Might be "Red-necks" down your way, up here it's "Farmer" fixed! :ROFLMAO:

My Dew shield for my C-8 is made from a Black plastic 20L 15W-40 Engine oil pail. Used as much of the pail as I could, like you I was having issues with the balance wih the length pf dovetail I had. Functional and the prices was right!
 

Tracy

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More captures... but haven't duplicated the processing as well as the first one above.

M_81-b.jpg
 

Tracy

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And some playing with StarTools (first go at it).

M81_M82_StarTools.jpg
 

Tracy

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Some additional processing.

M_81-c.jpg
 

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Still working learning the processing, as I know that this image could be MUCH better... but I am seeming more structure with the additional captures.

M_81-e.jpg
 

Tracy

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And a little crop here, a little crop there... and some more tweaking.

M_81-cropped.jpg
 

Tracy

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M81 and M81 look pretty good, but something is off about the stars. They seem oblong on this (/) angle.
I think I found what the issue was... the Pegasus Falcon adjustments caused the optical train to loosen from the tube assembly... which may have presented some tilt to it.
 
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