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Old 23-07-2019, 09:18 PM
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M8 Lagoon Nebula - First Attempt

After much messing around with processing, I think I have rendered a passable Lagoon Nebula...

First imaging outing with the Meade 5000 80mm Triplet... a few issues with my mount that I am still investigating & only limited time for exposures until plastic on plastic engagement occurred. Canon 1100D, unmodded.

Approximately 52 Lights (1600ISO/30 sec & 800ISO/60 sec mix), 16 Darks stacked in DSS & processed initially in Startools with some further tweaking in Afinity Photo...

I'll be honest, I'm not sure if I should be happy with the result or not; I thought I had some pretty good data albeit, only relatively short exposures & not a massive amount of them. Getting it to this state was fairly challenging...

As always, comments & advice are more than welcome
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Old 24-07-2019, 05:06 AM
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That is exceptional for a first effort and you can be very proud of such a fine result. Getting everything right takes time and usually there is something that can be done better one must just keep trying.
Just take more and more and select the best 300 for stacking☺
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Old 24-07-2019, 05:08 AM
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I think if you are combining two exposures you need darks for each and stack separately.
Alex
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Old 24-07-2019, 05:29 AM
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Quote:
Originally Posted by xelasnave View Post
I think if you are combining two exposures you need darks for each and stack separately.
Alex
Hi Alex,

Thanks for your comments. I had darks for each & they were setup as 2 groups in DSS for stacking with associated darks in each group

Cheers
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Old 24-07-2019, 09:43 AM
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I presume you are going unguided? Which is great as in my view it is best to determine the mount behaviour. I find my mount likes the balance biased somewhat and not consistent with a perfect balance. Concentrate on RA get that as good as possible and perhaps live with dec problems. Do you have a focuser mask? How are you finding CSP?
I am sincere that your image is something to be happy with as a first attempt..even for later in the game really.
I started using short exposures because I could not get the mount to perform somewhat as a compromise but now U am cinvinced one can get better results with short exposures...you are able to drop subs with little remorse...I have stacked huge numbers of subs and I suggest that you limit the number only with reference to what you computer can manage..if it will do 500 and it takes all night to stack that is ok.
My Lagoon was a build up of many subs over various nights with only the best making it but in the end I think I stacked around 300 (maybe more)...my first image was rather ordinary but the last one U was very happy with and frankly U doubr if I could improve upon that last one...that was with the eight and the nikon.
I suggest the following regularly but I doubt if any take my suggestion seriously but I use a long baffled dew shield to minimise light. I thought of the idea and implemented it before I found Hubble engage in a similar practice. If you look you will see that they extend baffling well past the secondary for what U believe are obvious reasons. The idea is to exclude star light (or street lights☺) from hitting the lens or enterinf the tube..we dont see it but it is there and the sensor picks it up. Mine is about two feet on the 80 mm. I cant provide a photo but it is a sumple cardboard tube with baffles...draw a duagran and mark what light can reach the lens but with and without if you want motivation☺.
Alex
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Old 24-07-2019, 09:48 AM
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Also wuth PA I take into account that there may be a slight refractuon due to atmosphere which may vary on the wetness of the sky...So even when pole master says it is perfect and you find there is still a slight drift sky refraction may be the reason...These are my ideas and U can cite no authority so I may be talking thru my hat. .. and of course that could apply to everything that I have said really☺.
Alex
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Old 24-07-2019, 04:41 PM
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It's definitely passable Carlton; you can probably get your best improvement by getting to know the processing software better. I never had any luck with Startools but others here are doing well so take hints from them.

Guiding makes image capture a lot easier too and you can take longer subs, although the warm temperatures of Cairns might limit sub length with a DSLR.
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Old 24-07-2019, 05:05 PM
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Quote:
Originally Posted by xelasnave View Post
I presume you are going unguided? Which is great as in my view it is best to determine the mount behaviour.

Yes, unguided at this stage... trying to get setup, PA & imaging routine set first before exploring the intricacies of guiding. also have a lot to learn about processing

I find my mount likes the balance biased somewhat and not consistent with a perfect balance. Concentrate on RA get that as good as possible and perhaps live with dec problems.

Now that I have some smaller weights, I have good balance in RA... not sure if my mount prefers any bias & not sure how to work that out either... At present my Dec balance is a little out as I am limited by the mounting setup of the Meade 5000. I have tube rings on order which will give me greater flexibility of scope placement & I should be able to get Dec balance spot on too then

Do you have a focuser mask?

Yes, I used Alpha Centaurus for my focus & used a Bhatinov mask


How are you finding CSP?

My Celestron CG5 Adv GT EQ mount has a PA routine in the handset. I think it's called all star alignment, basically it allows you to pick a star & then it off sets, you guide back to centre using handset first, then it offsets again & you use azimuth screws & latitude screw to recentre... I generally do two to three iterations of this. On Monday night I had PA of 4 arc sec in Azimuth & 12 arc sec in Alt. I usually choose a star relatively close to SCP.. in this case I used Alpha Centaurus


I am sincere that your image is something to be happy with as a first attempt..even for later in the game really.

Thankyou, most humbled

I started using short exposures because I could not get the mount to perform somewhat as a compromise but now U am cinvinced one can get better results with short exposures...you are able to drop subs with little remorse...

I'm still working on exposure lengths as well as ISO combinations, hence the mix of 30sec @ 1600 ISO & 60 sec @ 800 ISO. Trying to get least amount of noise & best colour range... basically still experimenting on this. I did try a 90 sec exposure but, to be honest the stars were a bit eggy to decided 60 sec was the limit on Monday

I have stacked huge numbers of subs and I suggest that you limit the number only with reference to what you computer can manage..if it will do 500 and it takes all night to stack that is ok.
My Lagoon was a build up of many subs over various nights with only the best making it but in the end I think I stacked around 300 (maybe more)...my first image was rather ordinary but the last one U was very happy with and frankly U doubr if I could improve upon that last one...that was with the eight and the nikon.

I was limited in the number of exposures I could take mainly because of where Lagoon Nebula was in relation to my mount. Basically I had about 10mm of RA travel remaining before the plastic cover on the Dec part started belting into the plastic cover on the RA part of the mount.... I had been having some issues with my mount on the previous outing on Friday night (which meant I didn't capture any data at all) & had done a factory reset... it dropped out all my movement limits (which I kinda forgot) so, I had to monitor everything carefully to ensure I didn't damage the mount... I probably could have got more subs in but, I'm not the most patient at times. I have some more to learn about the app I am using to control my DSLR; I know I can setup sequences... I just haven't done so yet... this will allow me to walk away & let it do it's thing instead of having to manually initiate every shot. There are some things I need to turn off in my camera too... such as shooting in Raw only, turning off in camera noise reduction, etc... just need time to figure out how to do all that


I suggest the following regularly but I doubt if any take my suggestion seriously but I use a long baffled dew shield to minimise light. I thought of the idea and implemented it before I found Hubble engage in a similar practice. If you look you will see that they extend baffling well past the secondary for what U believe are obvious reasons. The idea is to exclude star light (or street lights☺) from hitting the lens or enterinf the tube..we dont see it but it is there and the sensor picks it up. Mine is about two feet on the 80 mm. I cant provide a photo but it is a sumple cardboard tube with baffles...draw a duagran and mark what light can reach the lens but with and without if you want motivation☺.

Actually Alex, this does make a lot of sense... my dew shield extends probably 6 inches past the objective & I had a dew strap on to minimise dewing... I do suffer in my backyard from neighbours lights & some glow from lights my wife might have on inside the house... Should be simple enough to make though, can you explain the 'baffles' part of it in a little more detail please

Alex
Quote:
Originally Posted by xelasnave View Post
Also wuth PA I take into account that there may be a slight refractuon due to atmosphere which may vary on the wetness of the sky...So even when pole master says it is perfect and you find there is still a slight drift sky refraction may be the reason...

I need to read up a little more on drift alignment so that once I have done the All Star/Sky or whatever Celestron call their PA alignment process I can look at drift to refine my PA. Other option is to use BYEOS with my DSLR as it incorporates some software for refining PA but, that costs more money so, maybe in time... at the moment I use an app on a tablet called DSLR Controller & I rather like the convenience of not having a laptop out with me

These are my ideas and U can cite no authority so I may be talking thru my hat. .. and of course that could apply to everything that I have said really☺.

There is no substitute for years of experience Alex & I am grateful for your sharing of information & experience with me


Alex
How is your observatory & caravan setup going?

Cheers

Carlton
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Old 24-07-2019, 05:14 PM
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Originally Posted by casstony View Post
It's definitely passable Carlton; you can probably get your best improvement by getting to know the processing software better. I never had any luck with Startools but others here are doing well so take hints from them.

Guiding makes image capture a lot easier too and you can take longer subs, although the warm temperatures of Cairns might limit sub length with a DSLR.
Thanks Tony,

I'm generally happy with my alignments, PA & imaging routine thus far although, there will always be room for improvement & learning.

Couldn't agree more in relation to processing..... I find Startools can be very aggressive at times... I'm still trying to get my head around what it's doing so as to better understand the process, the controls, etc... Karlsberg sent me a link to a work flow a while ago which I generally use... I have the manual but, need to find time to sit down, read it thoroughly & truly understand what each module is doing & how to control it better.

Guiding will come in time.. I want to get the basics down first before I take that step...

Night time temps have been quite cool up here of late (freezing by our standards at around 11 - 14 degrees but, I don't think you Antartic dwellers will agree with my assessment of what constitutes freezing... )

I need to go through my camera & turnoff unneccessary features as this will reduce sensor temps a little.. I'm using a 'dummy' battery now which I believe helps keep internal temps down a little too

A long way to go still..... but, I now have a pretty good imaging scope with excellent colour correction... I may also be acquiring a 130mm Vixen Newt soon but, I don't really want to go any bigger than that for imaging... so, I am getting there albeit slowly & carefully...

Cheers

Carlton
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Old 24-07-2019, 05:49 PM
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Carlton.
My observatory is going slower than I expected but then I am most unreasonable in my demands upon others and indeed myself..heck it was a one day job yet it is still going If I had another worker I would fire myself...I blame the short time I had in the public service...actually they are rather efficient at higher levels not shown to the public...anyways given I am a stand in cripple ..its going well.
As to a baffled dew tube. .. make a cardboard cylinder... .out of cardboard ...the baffles are made out of cardboard strips ..fold in half with one side having little triangles cut out...the un cut section is glued on the cylinder wall and the triangle section folds in to make a reasonable circle... paint black sprinkle saw dust on wet paint dry and paint again...the more baffles the better so if confronted with a like model you can boast the most baffles.
You need the cylinder to be larger than rhe lens and a smaller cylinder to act as go between the scope (it needs a snug fit..I use some rubber strips) and the main baffled cylinder. ..sorry to be brief but if you need more just ask.
Alex
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Old 24-07-2019, 05:55 PM
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More over you are doing very well and really you should always be asking what to do better...my Son would say to be 100% more effective you just hsd to do one hundred things one percent better..that is so wrong but hints at the way we get better..each little aspect you do a little better..be more pedantic be more tiresome in focusing etc etc...but the baffled dew tube is so wonderful you will find you can be slack with everything ...it is that good ☺
Alex
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