Making a start with M31 Colour,lights and darks?

[eyepod]

Hi All, this is a re process of my first DSO with my new budget imaging setup (EQ5pro and 130PDS) its only 5 x 120sec and 7 darks, unfortunately the clouds rolled in and i had to stop. I have a some questions though, should M31 have more colour and will that show through with more frames? also how many should i be aiming for i was thinking 40-50 at 90 secs and the same amount of darks?

thanks in advance

Jason

[steppenwolf]

The colours you have achieved are about right for this object. More subframes will give you a 'cleaner' image and increased detail. You will get more colour saturation with increased frame numbers but it will be more of the colour you already have.

I would stick with your 120 seconds exposures and aim for about 30. Take 20 darks, bias and flat frames.

[xtreemchaos]

great image mate.  thanks for sharing.  charl.

[eyepod]

Thanks for the replys  Is it best to take a light then a dark or leave the darks until the end and do them all in one go?

regards

Jason

[gnomus]

Thanks for the replys  Is it best to take a light then a dark or leave the darks until the end and do them all in one go?

regards

Jason

I'd do darks at the end... You can do them after the clouds roll in - no point wasting clear skies. You may also want to consider flats and bias frames. Bias frames are dead easy to do - you can do them any time. Flats need to be done with the same image train, focus, etcetera. But, of course, they can also be done after the clouds roll in.

[brrttpaul]

sorry to jump in on the thread but I was wondering. I took some subs, darks and bias few nights ago but no flats because im not sure on how they work tbh, Could I take the flats now as the camera is still attached to the scope ( but the scope has moved as I have brought it in).  From what I can work out I switch to Aperture priority but do I change the iso? also being a nikon i dont have a histogram untill i have taken the pic, so im guessing take some samples and check the histo on that but what should I be aiming for in the histogram

[gnomus]

sorry to jump in on the thread but I was wondering. I took some subs, darks and bias few nights ago but no flats because im not sure on how they work tbh, Could I take the flats now as the camera is still attached to the scope ( but the scope has moved as I have brought it in).  From what I can work out I switch to Aperture priority but do I change the iso? also being a nikon i dont have a histogram untill i have taken the pic, so im guessing take some samples and check the histo on that but what should I be aiming for in the histogram

I don't think you can do flats after everything has been stripped down for the night. This is because you will not be able to achieve the same orientation of the camera in the telescope, nor the same focus that you had on the night you took the subs. And, of course, you could have knocked dust off of surfaces (or, more likely, have gathered more dust that wasn't there on the night).

Switch to Aperture priority and aim for a peak no more than half way up the histogram. In Aperture Priority, you will probably be there already, but you can use the +/- exposure dial if necessary. No change of ISO.

[laudropb]

Very nice image. Thanks for posting.

[brrttpaul]

Thx for the reply, so would it be better to take the flats first? I,m just thinking that a bright white light out in the garden in the middle of the night is going to annoy some neighbours

[Thalestris24]

That's an awful lot better than my first go which I did last night! That was 48 x 60s @ 200mm - really need more like 48 x 60min!

Louise

[gnomus]

Thx for the reply, so would it be better to take the flats first? I,m just thinking that a bright white light out in the garden in the middle of the night is going to annoy some neighbours

You could take them before starting imaging (whilst in the twilight) - so long as you achieve reasonable focus and don't re-orientate the camera when you start imaging the target.

[eyepod]

Thanks for all your advice, most helpful. I just need the rain to go so i can try again.

Jason

[brrttpaul]

Thx for the reply, when you say dont re orientate the camera you mean when its locked in place on the scope yes? because thats what I was referring to earlier its always locked in, surely it wouldnt matter which way the scope is pointing or turned, what i mean is the camera is still looking down the tube the same way no matter where its pointing or am i looking at this wrong

[KyleStoke]

Thx for the reply, when you say dont re orientate the camera you mean when its locked in place on the scope yes? because thats what I was referring to earlier its always locked in, surely it wouldnt matter which way the scope is pointing or turned, what i mean is the camera is still looking down the tube the same way no matter where its pointing or am i looking at this wrong

You need to maintain the same focus position camera orientation etc but the scope can point wherever you like. wouldn't worry about a white light upsetting your neighbors. 

It doesn't need to be floodlights just a white ipad or laptop screen held close to the front of your scope

[brrttpaul]

Ok I am trying some flats now, the camera is on the scope and focused I am in Ap priority 1600 iso x 15 flats, the scope has a piece of white paper over it and is pointing at a lamp the histogram isnt going over halfway. I will store these for use tomorrow as long as its clear tonight. I will have to move the scope but just taking a chance plus im hoping i can do more later

[Scott]

Thx for the reply, so would it be better to take the flats first? I,m just thinking that a bright white light out in the garden in the middle of the night is going to annoy some neighbours

They should be asleep .

I sometimes take them the next day. as long as nothing is moved (focus, camera etc) it'll be fine.  

[KyleStoke]

Ok I am trying some flats now, the camera is on the scope and focused I am in Ap priority 1600 iso x 15 flats, the scope has a piece of white paper over it and is pointing at a lamp the histogram isnt going over halfway. I will store these for use tomorrow as long as its clear tonight. I will have to move the scope but just taking a chance plus im hoping i can do more later

If you have to alter your focus at all depending on your target these will not work to remove dust bunnies etc, might still work on vignetting though

[brrttpaul]

I,m hoping I havnt got to change focus, but i accept the consequences, its more experimental incase i dont get enough time tonight