Rosette Nebula help

[1981suede]

Hello,

Thought I'd have a crack at the Rosette for the first time. Having stacked it and tightened up the levels in photoshop this was the result. Is all the red to the left usual? Doesn't look right conpared to what i am used to seeing.

[Steve 1962]

Hi there

Well - it's definately the Rosette!

Without knowing how many subs you took, what exposure time you used or how far you've stretched the image it's difficult to be precise, but it's some sort of gradient - light polution maybe?

Are you using an LP filter?

Steve

What do the "raw" subs

[perfrej]

Moon? Nebulosity?

This is an Ha of the Rosette taken from an impossibly good sky (Provence, Olly Penrice's place) with an FLT-98 at 494mm focal length. Camera is SBIG ST8300M. In this image, the essence of the nebulosity has picked up very deep, so it is a fair display of how far out the nebulosity really stretches. Compare it to yours.

Also, you really should use sigma clipping to get rid of the satellite trails. Simple to do if you dither and works anyway if the number of subs is large enough.

/per

[1981suede]

Hi there

Well - it's definately the Rosette!

Without knowing how many subs you took, what exposure time you used or how far you've stretched the image it's difficult to be precise, but it's some sort of gradient - light polution maybe?

Are you using an LP filter?

Steve

What do the "raw" subs

Cheers Steve. The image is 15 x 300s subs with darks and flats. I use a Neodynium filter but it could still be light pollution I guess. Like I said it was a very quick stack and stretch as it was getting late. I will try and use some sort of grandient removal this evening to see what effect that has on things.

Moon? Nebulosity?

This is an Ha of the Rosette taken from an impossibly good sky (Provence, Olly Penrice's place) with an FLT-98 at 494mm focal length. Camera is SBIG ST8300M. In this image, the essence of the nebulosity has picked up very deep, so it is a fair display of how far out the nebulosity really stretches. Compare it to yours.

Also, you really should use sigma clipping to get rid of the satellite trails. Simple to do if you dither and works anyway if the number of subs is large enough.

/per

Lovely image Per. I guess it could be nebulosity but looking at yours and other images it should be a lot fainter to the left of the main body. The moon was beginning to rise on that side but was a fair distance from the location I was shooting.

I didn't use sigma clip. Will re-stack with this option in Maxim to see if that removes the satellite trail.

[Quatermass]

I have been struggling with the Rosette for several nights now and my first stacked .tiff images looked very much like that one as well. Seeing conditions have been horrible every night with bright moon, flood lights and bonfire smoke to name but a few of the problems to contend with. Last night I took sixty 2min subs having done my darks and flats the night before and belive me the seeing was pretty poor with Orion faded by thin clouds and mist but even so was able to get this result afterwards.

Your tiff has a some good detail in there an I would start processing it to see what you can bring out but I reckon a very dark sky no moon and 3 or 4 minute subs would be best for this one from what I have found so far..

Here is what I came up with from poor conditions. Proving to be a bit thorny for me to. If you post the .tiff stacked image I will have go at processing it for you if you like see what can be squeezed out from the data.

These were taken with my evostar ed80 over the last few days still working on it just need the cloud to bug off.

[1981suede]

Cheers QM. I shall have a proper go at it tonight. There does seem to be a lot of data in there but if i can't deal with that gradient then it is a bit of a time waster. If i don't have much luck i would gladly let you have a go at the tiff.

This will be my first time dealing with gradients so will be a good learning curve. Quite ironic considering its the first time I have used flats. Actually, could it be a problem with the flats maybe??

It was quite dark last night as the moon rose quite late.

[Quatermass]

Might be your flats but your tiff looks a lot like my first ones did. There was point when it was in a good spot in the sky for me a month ago but didnt have the ed80 then. Its now creeping towards the west and street lights which tends to wash it out a bit if your guiding try longer subs 2 minute subs were not really long enough 4 or 5 would be better.Hope you get some nice clear skies tonight I will be out there having another bash at it as well.

[1981suede]

I am using 5 minute guided subs at the moment although still having balance issues so having to dispose of an uncomfortably high number.

It is still reasonably high if you get an early enough start on the session. Weather not looking good for tonight up my way. Fingers crossed i get a clear night for another go later this week.

[Quatermass]

If not it will be there again in december this hobby teaches you to be patient for sure

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[1981suede]

Well i have re-stacked the image without flats and that has improved things somewhat. Needed some photoshop hackery at the bottom of the image as is pretty obvious for anyone that knows what they are looking at.

Reasonably pleased though as this is my first guided image which has helped bring out way more detail that a 90" sub would of. There is a problem somewhere though (probably light pollution) which i need to troubleshoot.

[Quatermass]

Nice one its a tricky little devil this one if I get another chance im going to clear off in the car to a very dark site for it as the neighbours all have there lights on between 8-12

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[1981suede]

The light pollution in this instance could very well be my own. For some stupid reason i forgot to pull the blinds down

I don't really have the testicular fortitude to take over a grands worth of equipment into a dark site on my own. Plus I'd get as bored as hell while collecting 2+ hours of data

[Quatermass]

i take my missus along she likes to sit in the car and read or just look at the stars with binoculars

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[1981suede]

Even if we didn't have a two year old, my missus would laugh in my face at the mere suggestion of that I wouldnt blame her to be honest. If the stars are out that means only one thing, its bound to be blumming freezing!

[Quatermass]

my kids are all grown up and left home now and from what I recall having a 2 year old is a full time job so star gazing is the perfect way to unwind and be cream krackered the next morning

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