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alan potts

Messier 13 with 183 MC

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I had a play with this last night the new to me 183MC, far from ideal configuration on a 805mm set-up and using .79 reducer to give a usable 635mm. Conditions were fairly good as far as I could see albeit with a great big Moon in the S East at start. Maybe I have too much new gear at the moment and not focusing on getting it right on any one thing.

I must get something better to deal with gradient as my standard way of making a filter don't seem to work so well on these Zwo cameras I have, like it did for me with the Canon. I guess it is time to buy either the Grad Exterminator or the plug-in that was recommend to me by fellow Mod Steve a couple of weeks back. Are there any programs I could buy that include a good gradient tool that would also benefit my processing. I have to say I don't find processing as easy with these cameras either.

The 183MC had a few people pointing me away from this model, though I bought it really for the very short scopes I have below 420mm, where it is meant to be more at home. Anyway as poor as it is I have posted this M13 shot with a full Moon.

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This was just 5 x 3minute subs and for what ever reason seems to be gradient free compared to M13.

Any tips of a better way to deal with gradient, if indeed it is that, using PS then please point me in the direction of a thread or link.

Alan

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Nice images Alan. I have two questions. Did you take flats and what stacking program do you use?

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6 minutes ago, Allinthehead said:

Nice images Alan. I have two questions. Did you take flats and what stacking program do you use?

Yes I did flats this morning, though in truth I am not really sure the best way. I didn't cool and shot 1 sec using a pair of clean Sloggi's of mine and a negative viewing light box. I did Dark falts the same length and Bais at 0001sec I took a shot of M92 as well and that doesn't seem as bad, this is 10x3minutes. They were stacked in DSS.

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Any advice is always gratefully received.

Alan

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Why did you take bias and dark flats? 

I highly recommend Astro Pixel Processor. There's an excellent gradient removal tool under remove light pollution. I have Pixinsight and DSS and the results i get stacking in APP are in another league. 

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14 minutes ago, Allinthehead said:

Why did you take bias and dark flats? 

I highly recommend Astro Pixel Processor. There's an excellent gradient removal tool under remove light pollution. I have Pixinsight and DSS and the results i get stacking in APP are in another league. 

Because I don't know any different, habit I guess, are you not meant to?

Must have done something wrong in the process as I have has another go and it looks better though still with a tad of gradient. APP, I will have to look at this, I see many use it.

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Many thanks, I will see what I can find on this, my ad stopper seems to not wish to allow me to see it.

Alan

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2 minutes ago, alan potts said:

Because I don't know any different, habit I guess, are you not meant to?

No. I believe dark flats should be taken in place of bias. So you should be calibrating your flats with dark flats and stacked to create a master flat. Then when you stack your lights you use your master dark and master flat. What's probably happening with your flats is they're effectively being bias subtracted twice ie first with dark flat and then with bias.

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8 minutes ago, Allinthehead said:

No. I believe dark flats should be taken in place of bias. So you should be calibrating your flats with dark flats and stacked to create a master flat. Then when you stack your lights you use your master dark and master flat. What's probably happening with your flats is they're effectively being bias subtracted twice ie first with dark flat and then with bias.

Not sure I understand but I will dump the masters and do it different next time. How do you select the Master Flat because I imagine DSS makes one but I just continue stacking 30 of each, never done any different but for sure will try. I find understanding this stuff difficult but I do have a good eye for what good and bad and do try to learn from others that are so much better than me.

Alan 

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Those are good images Alan, especially the reprocess of M13.

I need to find the opportunity to get my new ASI294MC Pro for a run (he clasps and rubs his hands in joy !) 😉

N.

Edited by Skyline

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On 13/10/2019 at 23:33, Skyline said:

Those are good images Alan, especially the reprocess of M13.

I need to find the opportunity to get my new ASI294MC Pro for a run (he clasps and rubs his hands in joy !) 😉

N.

Don't wish to rub salt but we have had a very good run of clear out here, after 43 straight nights we had a touch of rain and cloud now another 8 on the trot. Not every night was without cloud but you could do something, if only visual. I posted up a question a long time back now about your camera and the two I now have 071 and 183MC, some people seem to have a bit of a downer on the 183 OSC but I am beginning to like it. I did really get it for my short scopes so it is on the them soon.

Yes I must have made a mistake in that first M13, I still need something for gradient removal though.

I think the 294 will please you when you get some clear.

Alan

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Nice Alan, especially M57..  DSS puts the master dark and master flats it generates back in the folder it found the individual dark and flats subs in ( at least it does on mine)..  always worth having a look at them to make sure they  look ok..  there’s a trial version of APP which I’m going to look at as a result of Richard’s endorsement 

Dave

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38 minutes ago, Laurin Dave said:

Nice Alan, especially M57..  DSS puts the master dark and master flats it generates back in the folder it found the individual dark and flats subs in ( at least it does on mine)..  always worth having a look at them to make sure they  look ok..  there’s a trial version of APP which I’m going to look at as a result of Richard’s endorsement 

Dave

Dave,

It is there in the folder but does not show and I now see why, I have only Show Fits ticked. The odd thing is even though I grouped all 30 of each, it took no notice when stacking and and stacked what I assume is the master as it didn't scan through any of them like it did first time of use.

That M57 was just a few subs, it's too small on this scope, one to have a play with the Mak 180mm at 2700mm and the OAG. In fact one of the kind people helping suggested to go to the OAG full time, maybe worth a punt.

Alan

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Very nice glob and smoke ring, Alan...

 

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4 minutes ago, MarsG76 said:

Very nice glob and smoke ring, Alan...

 

Did something wrong somewhere, not really sure what though, over stretched it maybe?

Alan

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Maybe subtracting bias twice is the cause  ..  maybe experiment by just stacking the lights, or lights darks and flats, lights bias and  flats and see whether the ‘smoke ring’  is still there .. 

Dave

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2 minutes ago, Laurin Dave said:

Maybe subtracting bias twice is the cause  ..  maybe experiment by just stacking the lights, or lights darks and flats, lights bias and  flats and see whether the ‘smoke ring’  is still there .. 

Dave

Dave, It was something I caused as the second image posted above is the same data stack, I think I may have over stretched it. I still need to get a better gradient tool though, I tend to make my own in PS.

Alan

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3 hours ago, alan potts said:

Did something wrong somewhere, not really sure what though, over stretched it maybe?

Alan

They look good looking at them on my Phone screen and remember that you not only have relatively short exposure time but captured during a full moon.

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On 13/10/2019 at 11:00, alan potts said:

Are there any programs I could buy that include a good gradient tool that would also benefit my processing. I have to say I don't find processing as easy with these cameras either.

Astro Pixel processor has excellent gradient removal and some other great features too.

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Hi Alan

I`ve just purchased the same camera. Can you tell me what gain settings you used? Great images btw!! Gives me hope i might actually not regret buying it!!!

Clear skies

Alan

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6 hours ago, Vixen4eva said:

Hi Alan

I`ve just purchased the same camera. Can you tell me what gain settings you used? Great images btw!! Gives me hope i might actually not regret buying it!!!

Clear skies

Alan

Alan,

Well I have to say I am finding my feet on both the new cameras I have but on the 183 I was just setting 90, which I think is known as unity gain, On my 071 I was working mainly on Zero, in truth I dont see much difference. I was thinking last night to start experimenting a bit to see what happens, but the shots in this thread were at 90. The biggest problem I find is not seeing a clear image from the camera when using APT, not easy to focus like the Canon was.

Alan

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