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A40farinagolf

Imaging - hints on what to do next please.

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Hi,

I'm lucky enough to have some decent kit but no significant experience of AP. I've taken a few images of the moon and M45, M42, M101, M57 etc but never autoguided.

I have the following kit:

AZEQ6

Altair Astro 130mm triplet frac F/7

Alatir Astro 0.7x reducer/field flattener

astro modified Canon 600D

Altair Astro 80mm guidescope

I'm due to receive a Baader Smartguider 2 (complete standalone autoguider package incl. camera and built in software)from Santa as I don't have access to a laptop. (Not into processing either for obvious reasons)

What I'm looking for is some hints and tips to make the transition to autoguiding as simple and as rewarding as possible. If I could achieve a few quick wins in terms of improved image quality I'd be delighted.

i.e

What ISO should I use,

What exposure lengths,

What subjects to start on,

Should I use the reducer / field flattener

etcetera

I can polar align OK using Kochabs clock and can use the GOTO to find objects, my sky quality is reasonable (7/10)i.e semi rural / away from major towns. reasonably open outlook with Southerly view being better than Northern view.

Any help would be gratefully received.

Thanks,

M

Edited by A40farinagolf

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That's some pretty tasty equipment you've got there which should get you quite far in imaging.

When I used a canon DSLR my default ISOs were 1600 for large diffuse objects, and 800 for brighter ones. Over time I built up a darks library by putting the camera in the fridge and taking exposures in stages from 180 to 480 seconds as the sensor cooled.

However, the excellent Backyard EOS software package was an invaluable tool in this process, not least because it gives a readout of the sensor temperature, thereby acting as a guide to which darks from your library to use. Otherwise you could, of course, get an intervalometer to time your exposures, which doesn't necessitate getting a laptop.

You can get away without the reducer/flattener on small, bright objects like planets or planetary nebulae, which only occupy the centre of your FOV, but wider images will need it to prevent star distortion towards the edges.

You don't say if you have a desktop for processing. If you're serious about imaging you need to be able to process the results, from alignment and stacking, through stretching and using 'curves' to maximise your signal-to-noise and bring out the detail. There really is no comparison between a 'raw' image and a processed one. YouTube has masses of video guidance for this.

As far as targets are concerned, there's plenty of information on this forum. Lots of people start with M31 and/or M33 for a spectacular but comparatively easy win, and it's the right time of year for these.

Good luck

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Hi StevieO,

Thanks for your comments, much appreciated.

The Baader smartguider I'm getting is fitted with a camera control system and timing exposures etc will be included.

I don't have enough spare time to process images (and to be honest I don't really have the inclination to start doing it as it doesn't appeal to me yet) What I'm looking to do at the moment is to obtain images "relatively" easily that I can view on my TV and share with family. I have access to a laptop but it doesn't belong to me so can't load any software onto it.

I'll research online regarding suitable targets as you suggest.

Sounds like trial and error is part of the way forward, if/when the skies clear I'll give it a go and see what I achieve. You never know I might share them on the forum.

Regards,

M

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I don't know much about imaging but what I will say is from my limited experience images captured on the camera really aren't that special until they are tweaked/stretched etc on a pc.

Not being a poo pooer but I reckon you'll be disappointed by your captures unless processed.

As a vague guide, quality of images on a scale of 1 to 10 would be ...

1 - eyeballed image through eyepeice

3 - same but dark site and dark adapted eyes

3 - single unprocessed dslr image

8 - several stacked and processed dslr images

10 - same but cooled dedicated ccd

BUT DON'T GIVE UP !

your questions,

What ISO should I use, ------------ try 800 and 1600 /  use the best to suit your target
What exposure lengths, ---------- Try 30 to 60 seconds depending on subject, sky conditions and tracking / polar alignment
What subjects to start on, -------- This time of year have a crack at Orion neb, Pleides, M13 all should be fairly doable
Should I use the reducer / field flattener -------- Yes and no ! yes as it will gather the light quicker and make stars better near edges of image but no as the spacing can be critical ? 

But definitley have a go !

All the best and good luck

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That's some expensive gear! But you just want to show them on a screen! You're on the wrong track. You want video astronomy.

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Processing your raw images is just as much fun as the actual capture, and actually more satisfying as the details emerge it becomes an artform, so it's a skill worth learning.

Just as an indication of the difference processing can make, here is a single 'sub', unprocessed, of M31, compared with a stack of several subs, stretched and curved.

Regards

StevieO

post-39242-0-32923700-1450436498_thumb.j

post-39242-0-10825600-1450436526_thumb.j

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Astrophotos do need processing. The levels of light collected are not comparable with those of the daytime and the relative difference between background and target is far slighter.

My images rarely look like more than a few stars on a black background until stretched, when the entire frame, quite literally, might be full of nebulosity.

The suggestion to try video astronomy is not daft if the porocessing side doesn't appeal. For me that's the interesting bit, though!

Olly

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Hi,

I'm lucky enough to have some decent kit but no significant experience of AP. I've taken a few images of the moon and M45, M42, M101, M57 etc but never autoguided.

I have the following kit:

AZEQ6

Altair Astro 130mm triplet frac F/7

Alatir Astro 0.7x reducer/field flattener

astro modified Canon 600D

Altair Astro 80mm guidescope

I'm due to receive a Baader Smartguider 2 (complete standalone autoguider package incl. camera and built in software)from Santa as I don't have access to a laptop. (Not into processing either for obvious reasons)

What I'm looking for is some hints and tips to make the transition to autoguiding as simple and as rewarding as possible. If I could achieve a few quick wins in terms of improved image quality I'd be delighted.

i.e

What ISO should I use,

What exposure lengths,

What subjects to start on,

Should I use the reducer / field flattener

etcetera

I can polar align OK using Kochabs clock and can use the GOTO to find objects, my sky quality is reasonable (7/10)i.e semi rural / away from major towns. reasonably open outlook with Southerly view being better than Northern view.

Any help would be gratefully received.

Thanks,

M

As an aside I will be very interested how you get on with the Altair reducer.  I have recently acquired one and will use it on my 102 Altair Astro triplet when conditions allow.  However, the spacing is frighteningly critical according to the AA website and to make matters worse they don't stock the spacers.  I finally found spacers eventually in Italy of all places.  So I will be trying it out soon.

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As an aside I will be very interested how you get on with the Altair reducer.  I have recently acquired one and will use it on my 102 Altair Astro triplet when conditions allow.  However, the spacing is frighteningly critical according to the AA website and to make matters worse they don't stock the spacers.  I finally found spacers eventually in Italy of all places.  So I will be trying it out soon.

I spoke with Ian at Altair Astro to clarify spacer requirements as the spacer chart on their website stops at 105mm and he assured me that a spacer isnot required for my 130mm scope. I've used it a couple of times but IMHO I'm not really competent to review whether it's optically good, bad or indifferent. When I get my smartguider up and running I'll hopefully have some decent images to review. Thanks, Mark

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Processing your raw images is just as much fun as the actual capture, and actually more satisfying as the details emerge it becomes an artform, so it's a skill worth learning.

 

Just as an indication of the difference processing can make, here is a single 'sub', unprocessed, of M31, compared with a stack of several subs, stretched and curved.

 

Regards

 

StevieO

Hi Stevio, I see what you mean in terms of the difference, at this stage I'd be happy to achieve image 1 but achieving image 2 would be brill.

How much imaging time and processing time did you spend to progress from 1 to 2?

What level of software competence is needed to be able to drive it to achieve such improvements i.e Are the software operations intuitive or are they difficult to learn. I look forward to your response. Regards, M

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Astrophotos do need processing. The levels of light collected are not comparable with those of the daytime and the relative difference between background and target is far slighter.

 

My images rarely look like more than a few stars on a black background until stretched, when the entire frame, quite literally, might be full of nebulosity.

 

The suggestion to try video astronomy is not daft if the porocessing side doesn't appeal. For me that's the interesting bit, though!

 

Olly

Hi Olly,

Thanks for your feedback, I have recently joined a local astronomy club and one of the attendees there is very proficient in AP so plan to pick his brains if he'll allow me :-) You know him its Paul Kummer and at a recent meet he presented some of his images taken at yours. Regards,

M

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That's some expensive gear! But you just want to show them on a screen! You're on the wrong track. You want video astronomy.

Hi BeanerSA,

Might sound a silly but what do you mean by video astronomy? I have a ZWOA120MC camera that I've used to video the moon and Saturn through my CPC925 and the results are watchable. I'd be grateful if you could describe how I'd produce images of DSO with a video either through my ZWO or EOS600. Thanks M

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Hi Olly,

Thanks for your feedback, I have recently joined a local astronomy club and one of the attendees there is very proficient in AP so plan to pick his brains if he'll allow me :-) You know him its Paul Kummer and at a recent meet he presented some of his images taken at yours. Regards,

M

Say Hi to Paul. He's more than proficient! I thoroughly enjoy imaging with him because, as well as being an excellent imager and an excellent guy, he's a real physicist as well.

If you pick his brains you'll do fine...

:grin: lly

Edited by ollypenrice

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Hi Stevio, I see what you mean in terms of the difference, at this stage I'd be happy to achieve image 1 but achieving image 2 would be brill.

How much imaging time and processing time did you spend to progress from 1 to 2?

What level of software competence is needed to be able to drive it to achieve such improvements i.e Are the software operations intuitive or are they difficult to learn. I look forward to your response. Regards, M

There were 5 x 200sec 'subs' with a Canon EOS 700D at ISO1600. I also used 'dark', 'bias' and 'flat' frames to reduce noise. For an explanation of these, I recommend Forrest Tanaka's series of videos on YouTube. Less bright targets need longer exposures and more of them. You should aim for the spike in the histogram on the DSLR to be about a third of the way along. With a DSLR  diminishing returns regarding signal to noise set in at about 6-8 minutes per exposure.

All frames were fed into an excellent and easy-to-use application called Deep Sky Stacker which you can download free. DSS combined the subs and subtracted the darks, bias and flats to produce a stacked image, which I opened up in Photoshop (although there are many image processing applications out there, some free, which will do the job just as well). I 'stretched' the contrast to bring out the detail in the image, using the 'levels' and 'curves' tools.

A basic stretch of an image can give pleasing results in a couple of minutes once you've had a bit of practice. This one took me about 20 minutes, including the stacking routine. Fine tuning an image to suit your personal taste can take quite a bit longer, of course. Remember, you're not manipulating the image to put in what's not there, just bringing out the detail that already exists. As I said before, the processing bit is equally as fascinating as the date capture, and you can do it in the warm and dry.

I can't recommend highly enough the processing instructional videos on Anna Morris's website.  http://www.eprisephoto.com/  Her way of doing things is now my way.

I hope all the above helps. Oh, and anything Olly Penrice says is likely to be the goods, the man is a master.

Regards

StevieO

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StevieO,

Many thanks again and you've provided much food for thought, the statement that made the biggest impact with me was

"you're not manipulating the image to put in what's not there, just bringing out the detail that already exists."

Might sound naïve by my preconceived view of processing was a bit like using software to embellish the appearance of celebrities so the final image isfalse. I will certainly look at the youtube explanations and the tutorials.

Thanks,

M

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StevieO,

Might sound naïve by my preconceived view of processing was a bit like using software to embellish the appearance of celebrities so the final image isfalse. I will certainly look at the youtube explanations and the tutorials.

Thanks,

M

This opinion is widely diffused but it isn't correct, though some processing is cosmetic. Removing dead columns, hot pixels, light pollution gradients etc. However, I tend to compare processing with an archeological dig. On it's long flight through space, and in particular in the last few kilometres of its journey through our soupy atmosphere, light from afar has become somewhat contaminated. Processing is all about separating the true object from the contamination. The information is in there. You don't invent it, you separate it. You then modify its dynamic range so that it can fill the dynamic range to which our eyes are sensitive. Faint nebulosity which is too close to the background sky to be seen can be photographically further separated so we can see it. However, the separation is in the data to start with. That's vital.

Olly

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I like that way of explaining it, Olly  (and will use it next time I'm asked the question!)

Adrian

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