M45.

[Paulus17]

Managed a few hours out in the back garden last night so set up my ED80 on the EQ3 mount with HEQ5 tripod and targeted M45.

I managed to get 30x60 sec lights and 15x60 sec darks,stacked in DSS and processed using Photoshop CS3.Camera was a Nikon D90.

Not sure what the orange is in the middle thought it may have been a cloud but all my subs are clear but have been told it is nebulosity which i haven't seen before in M45??

M45.

[iksose7]

I dont think the orange glow is nebulosity, its not in the right place. If your original subs are all good, then its more likely its maybe been over stretched quite a bit in processing?

I would have another go at processing and if the orange appears again, re-stack the subs

[Jannis]

I'm guessing the orange glow is actually just light pollution in the center of the frame as you didn't take flat frames?

It looks like you've been a bit too rough in post processing, but you've got some nebulas at least.

[Pete Presland]

its easily done but, i think you might have been way too aggressive with your processing, i pursuit of the nebulosity that surounds the stars. i did 180seconds exposure of M45 i have processed them yet and i would expect some nebulosity around the stars, but i am guessing i will trying to push the image as far as possible to pull more and more out.

i would give the processing another go, be a little more restrained and see what you can get. your focus looks ok and you can always add some more data later, good luck and keep at it

[Paulus17]

Thanks for the comments and advice folks,there was me thinking i'd got summat special

Here is a toned down version now so hope ypou approve of this effort

M45.

[Jannis]

Aha, that one looks much better indeed!

The reason it's brighter in the center compared to the corners is because you haven't taken any flat frames to compensate for it. I've done the misstake of not taking flat frames for like 2 years, thinking i'll start with that once i get a little better with capturing and processing - big misstake!

So a top tip, learn to take flat frames first, then processing will be a whole lot easier

[x6gas]

Yes the second process is much better, and a nice capture.

+1 for flat frames.  I spent more than I needed to trying to avoid having to take them (for instance by using 2" filters) but that was my naivety.  I'm now a flat frame convert although I do my best to avoid dust bunnies so that I can use one set of flats to correct for vignetting.  Use to try to do it in software by the results of properly reducing the frames using flats are so much better...

[Paulus17]

Thanks Both.

Yes i was/am doing the same regarding flats etc,hoping to get used to DSS and PS to start with and then add flats etc as i felt more confident.

So not really knowing what flats do or how to do them which is the easiest and cheapest way of doing flats,i take it that it would be a white Tshirt stretched across the scope??

If so can this be done at night or has it gotta be in daylight,how many do i need to take,how long expos??

[x6gas]

Thanks Both.

Yes i was/am doing the same regarding flats etc,hoping to get used to DSS and PS to start with and then add flats etc as i felt more confident.

So not really knowing what flats do or how to do them which is the easiest and cheapest way of doing flats,i take it that it would be a white Tshirt stretched across the scope??

If so can this be done at night or has it gotta be in daylight,how many do i need to take,how long expos??

Flats correct for variations in the illumination of the frame due to mechanical aspects in your imaging train.  A common one here is vignetting which is a darkening of the image towards the edge of the frame, but they also correct for dust bunnies (dust motes that - out of focus on the image - usually look like doughnuts).  They correct your lights and are subtracted from or divided into them, or something.  And that's the point - I could look up the mathematical process (OK I just did: they are divided in to your lights) - you don't need to know because software like DSS just applies them for you - it's easy-peasy!

The sleepless nights for flat fields come from actually taking them.  The t-shirt method works for me.  Plenty of explanations on the web, but I take about 40 and the intention is to get the maximum brightness of the flats to be about 40% of saturation.  As I say, I try to keep my kit free of dust so my flats are basically correcting for vignetting which means I take a set for each scope / reducer / binning combo and they have improved my images a lot.

Oh and you take them in daylight.  Dawn or dusk is common, but the sky brightness can change quite quickly at that time of day so keep an eye on the histogram to make sure your flats aren't over saturated.

As usual, Steve's book Making Every Photon Count is worth a read and explains all.

[andyo]

That second process is a big improvement.Backyard eos makes setting the exposure for taking flats easier as it has a drop down menu which you can select av-flats and it does the exposure length automatically.

[ollypenrice]

The second one is much better and really just needs the green sorting out. It has a big green gradient. Flats realy are the key, though. They make all the difference.

Oll