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DSC October - Actual astrophotography?

Started by Rocket Pooch, Oct 15, 2012, 07:50:49

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Rocket Pooch

Well done all, sounds like a great DSC, as usual I didn't do any astronomy because the house is still a mess, although I did play with the roof on the observatory rolling it on and off :-)

Look forward to the images, anyone do anything difficult?

Ivor


Glad to hear Saturday turned out to be a good night,  I might not have managed to image Friday night but I did learn a few important things:

How to improve my setup in EQMOD (Thanks Duncan)
DSC'ers drink their Pastis drink neat (Thanks Mark)
I quite like Amaretto (Thanks again Duncan)
My father in law's old tent isn't waterproof

I was slightly concerned when Mark, Duncan and Jon took me into the woods to "show me something impressive" fortunately this turned out to be better seeing.

A frustrating maiden DSC, I look forward to the next hopefully with better weather and tent.


Fay

It is healthier to be mutton dressed as lamb, than mutton dressed as mutton!

Fay

Mark, do you just leave everything running & then go to bed?

I had set up but realised that it would not clear until around 1am.

i do wonder if I should let it run & perhaps put a timer to turn of at a certain time, but would probably not sleep in case the camera went into the pier & if the power switched off at a certain time, would the dew & damp play havoc with the connections etc, if they had gone cold due to no power.
It is healthier to be mutton dressed as lamb, than mutton dressed as mutton!

Mike

Fay do you use EQ-MOD? If so you can set limits on the mount to ensure it never goes into your pier/tripod.

http://www.welshdragoncomputing.ca/eqmod/doku.php?id=setting_mount_limits


We live in a society exquisitely dependent on science and technology, in which hardly anyone knows anything about science and technology. Carl Sagan

Fay

I have in the past Mike, but it is an extra palavar setting it up & putting something extra away all the time. often my handset would not play ball, perhaps I should revisit EQMOD
It is healthier to be mutton dressed as lamb, than mutton dressed as mutton!

Mike

I personally find EQ-MOD a lot easier to use that the handset. You have so much greater control and flexibility.

We live in a society exquisitely dependent on science and technology, in which hardly anyone knows anything about science and technology. Carl Sagan

Fay

yes, often the handset does not offer  decent alignment stars. i will get it out again, it is just that it is an extra thing to do when you have to set up & put away all the time
It is healthier to be mutton dressed as lamb, than mutton dressed as mutton!

Mike

Once you get used to it it takes no longer to set up than using the handset. In fact i'd say it was quicker.
We live in a society exquisitely dependent on science and technology, in which hardly anyone knows anything about science and technology. Carl Sagan

JonH

I have to agree about EQMOD.
I started off with the handset and got nothing but a headache from it.
EQMOD once set up I find is easy to use plus along with the mount limits have the auto park option which is handy!
Shoot for the stars, reach the tree tops!

MarkS

Quote from: Fay
Mark, do you just leave everything running & then go to bed?

Either I go to bed or kip in a chair in the conservatory, where I can see the stars/clouds etc.  Last night I knew the scope would hit the tripod at 2am so I kipped in the conservatory and set the alarm to wake me up to perform a meridian flip.  Otherwise I would go to bed and leave it running until morning.

But last night I had a mental aberration - I shot 5 hours of Andromeda Galaxy as half size JPGs!!!!  What a waste!  Dunno how that happened.

Mark

JonH

QuoteI shot 5 hours of Andromeda Galaxy as half size JPGs!!!!  What a waste!

I had a similar issues, upon closing my laptop lid I managed to dislodge the cable from my external hard drive. When I came back to it a few hours later had captured nothing!
I still managed to get 4 5min subs and a load of shorter ones though, but when I went to stop it at 5am found half my 30sec ones and all the 10sec ones were no good due to something moving, the guiding was still going fine so I'm taking a guess that the camera had moved or something like that.  :!
Shoot for the stars, reach the tree tops!

Carole

QuoteI shot 5 hours of Andromeda Galaxy as half size JPGs!!!!  
Oh Gawd! :cheesy:

I go to bed and set the alarm as well Fay, but I must say it is a major effort to get out of "bed" once I have been asleep.
When I say bed, I normally kip on the settee in the lounge fully clothed just with a cover on, so all I have to do is put my shoes and coat on.  I get undressed properly once I've switched off.  I do this at DSC too.  

I once went to bed and got up 2 hours later to find I had set to do only 1 sub (from when I had been doing a "tester for FOV" and forgot to change the number of subs),what a waste of effort as well.

Carole

JohnP

Me also Fay - Normally kip on sofa in front room & set alarm for say 2hrs just to make sure nothing has gone wrong...

Fay

Mark, how do you go cope when having to work the next day
Have visions of you performing  a meridian flip after waking.........

Carole you are such a trouper, i need training. i think you, John & Mark are of a calmer disposition than me, and therein lies the problem................



Also waiting to see everyone,s images from oct DSC
It is healthier to be mutton dressed as lamb, than mutton dressed as mutton!

MarkS

#15
Quote from: Fay
Mark, how do you go cope when having to work the next day

I normally get 6 hours sleep in total.  Interrupted maybe.  But no worse than the interrupted sleep we used to get when we had young babies.  The main difference is that this particular baby has 3 metal legs and one huge eye!

Mark

JohnP

QuoteAlso waiting to see everyone,s images from oct DSC

Me to....

JonH

QuoteAlso waiting to see everyone's images from oct DSC

You might have to wait a little while before mine are ready. I have 90 x 5min subs of M31 stacked which took my poor old laptop something in the reign of 12hours to do!!!  :o
But still load of shorter ones I need to stack and figure out how to combine with the rest, which I still haven't a clue how to do yet. Then I need to process it all without a calibrated monitor.
If I have anything respectable to show this week it will be a miracle!  :-?
Shoot for the stars, reach the tree tops!

Fay

 :lol: :lol: :lol: :lol:

Jon, you are doing very well, dont worry about it, you will soon sort it all out. dont like to tell you but, we all still have lots of problems when outside!!!!!!
It is healthier to be mutton dressed as lamb, than mutton dressed as mutton!

JonH

QuoteJon, you are doing very well, dont worry about it, you will soon sort it all out. dont like to tell you but, we all still have lots of problems when outside!!!!!!

I do hope so! That is exactly what keeps it interesting, if I could just plug everything together and have it spit a perfect image out every time there would be no fun in it at all and nothing to learn!

I have almost finished stacking the last of the subs now, just got to combine the different length exposures then start processing.
I am using Iris to combine the different sets of subs rather than messing about with photoshop, layers, masks etc etc. The method is a bit off an odd one and sorta making it up as I go along, it also means all post processing is done after combining the different length subs which is very unlike using photoshop. If it will work or not is another question altogether!
Watch this space.......
Shoot for the stars, reach the tree tops!

JonH

HA yea right! I really have no idea what I'm doing!
There are SO many variables with Iris figuring out what numbers to feed into it is proving the stuff of nightmares, for the most part I'm simply guessing.
I'm pretty sure I'm heading in the right direction though, all the data has come together as it should (I think) I just can't get it all to process out like it should.
It did just dawn on me though I need to go back a few steps as done something wrong that will make a big difference.

My head hurts!  :-?
Shoot for the stars, reach the tree tops!

MarkS

Quote from: JohnP
QuoteAlso waiting to see everyone,s images from oct DSC

Me to....

You'll have to wait for mine.  M31 is proving a real pig to process - another nightmare of background gradients - exaggerated because the data quality is good enough to perform a fairly extreme stretch.  It's the untold reality of using a DSLR on a very fast scope in a light polluted place.

Mark

Fay

Mark, i am sure it will come out as the most amazing M31 ever taken!!!
It is healthier to be mutton dressed as lamb, than mutton dressed as mutton!

JonH

I'll be very interested to see how your M31 comes out compared to mine Mark. How many subs did you get in the end?
Shoot for the stars, reach the tree tops!

MarkS

Quote from: JonH
I'll be very interested to see how your M31 comes out compared to mine Mark. How many subs did you get in the end?

101x5min subs plus 10x60sec plus 10x20sec so as not to burn out the core.  The HDR image created in PixInsight has a dynamic range of 26bits per channel.

JonH

That should make the difference between our results all the more interesting then!
I got 90 x 5min 20 x 2.5min and 16 x 30sec
So we have quite similar amounts of data the big difference will be your MUCH bigger and faster scope and processing.
How do I get Iris to tell me dynamic range of each channel?
Shoot for the stars, reach the tree tops!

MarkS

Quote from: JonH
How do I get Iris to tell me dynamic range of each channel?

I don't know if you can in Iris.  PixInsight gives this info as it assembles the HDR image. 

Once you have the HDR image, the challenge is to compress the dynamic range into something that is perceived to be "right".

JonH

Yes, that is exactly where my problem is! Or at least half if it....
The dynamic range is there, just not all at the same time. But I have researched the merge_hdr and reduce_hdr commands some more since my last try and have a few good ideas where I might have been going wrong.
In fact I did have another 'revelation' moment earlier to use the merge_hdr command to stack them all at once rather than in three sets with the normal 'add a sequence' method.
But thanks to me deleting all the temporary files that means going threw the registration process again which will take a LONG time!

Smart one Jon!  :-?
Shoot for the stars, reach the tree tops!

RobertM

It's good to see this as on-topic as all the other forum posts :o

Jon, From experience, I've found it very easy to overdo HDR in Astro images.  As Mark mentioned processing it into something that looks sensible and 'right' is the difficult trick.  I applied a bit of HDR to my recent Iris image but only very lightly to tease out more detail in the bright nebula, overdoing it risks loosing precious colour information.

Robert

MarkS

Quote from: JonH
But thanks to me deleting all the temporary files that means going through the registration process again which will take a LONG time!

Time for a processing hint:

During image registration, it is the star matching calculations that take the time.  Iris saves the final image offsets and rotations it has calculated to a couple of LST files.  You can then quickly rerun the image registrations using the FILE_COREGISTER command without all the time time consuming star matching.  Clever eh?  Just remember to save the relevant LST files (you can rename them to something relevant and rename them back just before running FILE_COREGISTER to prevent them being overwritten).

All part of the power of Iris!

I often make use of this to perform stacks with different combinations of darks, flats etc.

JonH

Who has been chopping and changing the threads, confused much!

I think possibly my biggest problem was to use the merge_hdr command you first need to create a text file saved as a .lst which contains the different file names to combine and a number which defines the difference in exposures between the files.
I wasn't sure if that meant exposure per individual sub which is what I have used so far, but now thinking about it is very unlikely to be the correct number since the subs have been stacked into groups making this number rather irrelevant now, or the accumulated difference in exposure between the different groups of subs, FAR more likely to be the correct number.
Except I have a big variable to deal with being that the different groups of subs were taken from different locations with very different levels of light pollution thus again making this number most likely to give me a poor result.
BUT I have just discovered you can used the desc_hdr command in Iris which will look at an area defined by you of the different stacks, calculate the difference in exposure and create the .lst file for you. Thus giving you the correct numbers to use!

Progress is being made!  :D
Shoot for the stars, reach the tree tops!

JonH

Ahhh, thanks Mark that might just save me some considerable time as a full re-stack might yet be on the cards to tease out every last bit of detail!
I'm going to need every scrap of data I can find to stop my attempt at M31 falling into insignificance next to what you have on the way, which it will probably do anyway!  :lol:
Shoot for the stars, reach the tree tops!