A few from Friday night - M1 & M82

[JohnP]

OK - First time out in I think 3 months so not expecting too much more of an exercise to see if I could remember how everything went together.. Anyway decided to do Crab - M1. Below are results - 1st image is just the L - then the combined LRGB - I only took 5mins each of RGB so not enough colour I know. 3rd image is resized (yep - noise starting to show) & then finally I took about 5 subs of M82 just to see what it looked like.

It was good to get out again.

Cheers,  John.

[Tony G]

John,

Seems like that couple of hours setting up was worth it then.
Great images.

Tony G

[JohnP]

Yep - cheers Tony I got there in the end & thks for the cable - I owe you (again.....!!!) John

[Fay]

Well John, there is nothing wrong with those.  Really a lot of colour considering the 5 min subs. How many did you do for the L?

I am not good at star colour at the moment, always look white, but you have got a lot!

I looked for M1 but could not get it. I also looked for M81 but could not find it. Good job Rosette was big!!!!!!

I suppose you will be out tonight?

[JohnP]

Thks Fay - L was approx 20 X 4mins ha with atik 16ic & MN56. RGB was 5 x 1min each (no ha or cls) which is why i kept subs to 1 min - I should have done longer on RGB...

Not sure about 2night - I'll see,

John

[MarkS]

John,  that's a great Crab Nebula.  What camera/scope combination were you using?

[Daniel]

Loving the crab nebula! I tried imaging it a few nights ago and failed, may have to see if I can bring anything out in stacking, love the M82, I did a wide field of that with M81 the other night too, but im getting a lot of vignetting around the edges so it's hard to fit both in without degrading one of them, that said, I have a 2" adapter on order, so once I have that I shall image again and post the results!

would love to hear how you guy's go about photographing in LRGB, are you using seperate filters for each pass?

[JohnP]

What camera/scope combination were you using?

Thks Mark - I use an Atik 16ic (which I got 2nd hand about 6mths ago - it's a great little camera) & a 2nd hand Intes Micro MN56 which I've had a few years mounted on EQ6Pro.

would love to hear how you guy's go about photographing in LRGB, are you using seperate filters for each pass?

Thks Daniel appreciate the comments. Yep for LRGB I use separate filters - the important bit is the L - I usually either use my CLS filter or Ha filter for that bit - You need to spend as long as you can getting the L data. The RGB bit is another set of three exposures through seperate R,G & B filters. These exposures can be a lot lot shorter than the L - all they do is provide the colour info. Typical you would aim for total RGB to be about 1/3 of the L but I often (lazily) do a lot less. For example for my Crab the L bit consisted of approx 20 X 4min subs (80mins total) whereas each RGB was just a set of 5 X 1 min subs (total 15mins). There are lots of useful websites showing you how to combine LRGB etc. Don Waid has a great PShop tutorial which is essential how I process.

Thks again,  John

[Rocket Pooch]

very nice

[JohnP]

Cheers Chris....

[Daniel]

I keep hearing about the CLS filter, how much better would it be for cutting out light pollution over a UHC-S filter? Im thinking of getting one, but im right now in the process of moving to using 2" filters for my prime focus photography to get rid of vignetting, so I imagine it'll be expensive

[Mike]

Great image John.

[Tom C]

would love to hear how you guy's go about photographing in LRGB, are you using seperate filters for each pass?

Thks Daniel appreciate the comments. Yep for LRGB I use separate filters - the important bit is the L - I usually either use my CLS filter or Ha filter for that bit - You need to spend as long as you can getting the L data. The RGB bit is another set of three exposures through seperate R,G & B filters. These exposures can be a lot lot shorter than the L - all they do is provide the colour info. Typical you would aim for total RGB to be about 1/3 of the L but I often (lazily) do a lot less. For example for my Crab the L bit consisted of approx 20 X 4min subs (80mins total) whereas each RGB was just a set of 5 X 1 min subs (total 15mins). There are lots of useful websites showing you how to combine LRGB etc. Don Waid has a great PShop tutorial which is essential how I process.

Thks again,  John

So...would that mean it is possible to use a monochrome camera, and then "tell" the computer which colour is which subs when processing, and thus add in the colour digitally? Or am I completely wrong here??

[Mike]

About 99.9% of all astrophotos, including those made by Hubble, are all done with monochrome cameras.

[Tom C]

About 99.9% of all astrophotos, including those made by Hubble, are all done with monochrome cameras.

Ok..so is the colour added digitally, or is it simply a matter of the filter itself...eg. if you shine a torch through green glass you get green light coming out the other side?

[Ian]

both really. In fact, without that sort of processing you'd not get images from Spitzer or Chandra, being IR and X-Ray respectively. There are many advantages to using a mono camera and filters, but bear in mind, cost isn't one of them

[Daniel]

Just as an experiment, could I change my camera to monochrome mode then shoot 3 images with seperate R G and B filters then add these into a photoshop file in the correct channels?

[Rick]

A colour digital camera usually has a mask on the detector. When you mix that with filters you sometimes get real weird effects...

[Daniel]

I might actually try that then, just to see what it comes up with!