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Astro Projects

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Preparing a talk on Astro-photography

Gina

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I've offered to give a talk with pictures to our local social group and thought a Blog on here would be a good place to prepare and assemble it.  Also, I would welcome any comments and suggestions.  I have a few ideas and will see how it progresses.  I will probably take me several days to get my initial ideas sorted out.

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On 13/03/2019 at 22:25, Skipper Billy said:

Hello Gina

I did a presentation to a Scottish Photographic Society a couple of weeks ago - Powerpoint based. Its attached - feel free to bin it, rip it shreds, do anything you want with it. I dont get prissy about copyright of my images etc - feel free to use any images you might want etc etc. All the astroimages are mine and the none astro ones are all copyright free.

@Skipper Billy  WOW!  That is a very comprehensive presentation :thumbsup:  I have a long way to go to get anywhere near that standard.  OTOH it has given me a lot of ideas - thank you very much.

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Gina

Posted (edited)

Here is a list of sections I'm thinking of including.  The order may change and I've probably forgotten something.

  1. Introduction
  2. Photography Terms
  3. The problem of earth rotation
  4. Types of telescope/lenses
  5. Types of mounting - tripods, piers
  6. Types of mounts - pointing the telescope/lens at the object
  7. Observatories
  8. Objects to capture - moon, planets, galaxies, nebulae, star clusters, sun (white and Ha/K)
  9. Types of astro camera
  10. Filters - LRGB and narrow band - false colour (HST pallet)
  11. Image processing

My main problem is not knowing how long each section will take.  Some could be quite short - I don't want to overload my audience with too much detail - this is a general audience, many with no technical knowledge.  Probably a lot of people take photographs but I doubt many know how a camera works.  I'm looking at an overall time of between and hour and an hour and a half.

I'm thinking on concentrating on the sort of astrophotography I do myself which is mainly DSO, with nebulae uppermost.  I think to cover the whole subject would take a lot longer than 1½ hours.

Edited by Gina

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Useful point from Skipper Billy - one arc second is a tangerine at 3 miles.  But since tangerines vary in size maybe a tennis ball at 3 miles - roughly.  This can be in a part that describes the relative sizes of objects in arc - degrees, minutes and seconds of arc.  And something not actually in my list - guiding, which comes under pointing the telescope.

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Hi, you may already be planning to  discuss this with your audience:

I remember the first galaxy I viewed through a telescope and being mildly disappointed that I couldn't see it in colour :) 

2 minutes on the difference between the human eye and a camera might be useful.

Depending on where you talk about it in your timeline, you can use it or refer back to it as you segway into  the "image processing" section ?

Then you can really wow them when they see your dull grey image get transformed :) 

Just a thought,

Collin

 

 

Edited by Collin
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Gina

Posted (edited)

I had a chance today to talk to another member of the group I'm giving a talk to and she pointed out that most of the group are far from technical and all most will know about photography is to point their mobile phone or camera at what they see and press the trigger.  Cameras these days tend to be totally automatic so exposure or aperture mean nothing.  I think I may have talked myself into a "black hole"!  Also, it seems 40 minutes would be a better length of talk - well, that's good anyway! ?

So... cut out the technical stuff and just fill the talk with lots of pictures.  Any technical issues can always be discussed in the Q&A session after the talk.  Even things like field of view in degree was considered too technical.  This is pretty restricting - seems I need to rethink my whole talk.  At least I have a few months in which to do it.  Fortunately, I do have plenty of photos of my imaging rigs and observatory which was considered well worth having a substantial section for since I built it myself.

Edited by Gina

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Been checking the NASA Images web site and found they are generally not copyright and I can show them in my talk.

Quote

Still Images, Audio Recordings, Video, and Related Computer Files for Non-Commercial Use

NASA content - images, audio, video, and computer files used in the rendition of 3-dimensional models, such as texture maps and polygon data in any format - generally are not copyrighted. You may use this material for educational or informational purposes, including photo collections, textbooks, public exhibits, computer graphical simulations and Internet Web pages. This general permission extends to personal Web pages.

News outlets, schools, and text-book authors may use NASA content without needing explicit permission. NASA content used in a factual manner that does not imply endorsement may be used without needing explicit permission. NASA should be acknowledged as the source of the material. NASA occasionally uses copyrighted material by permission on its website. Those images will be marked copyright with the name of the copyright holder. NASA's use does not convey any rights to others to use the same material. Those wishing to use copyrighted material must contact the copyright holder directly.

 

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Gina

Posted (edited)

Back to thinking about my talk.  This will be practically all pictures with minimal explanation to avoid any technical stuff which much of the audience wouldn't understand (or so I've been told).  So apart from pretty pictures of nebulae and galaxies I plan photos of the astro kit and construction of my observatory.  The trouble is, I have hundreds of photos of the site excavations, concrete work and construction that will need a really serious prune.  I need to sort out a time-line of pics to show the build without overdoing the photos.  I think it would be good to include the various weather conditions with a bit of humour showing a waterlogged building site.

It has been suggested that I include image processing and mainly I agree.  The problem is that this is very technical so I shall need to work out how to describe this as simply as possible.  One thing I would like to show is the improving image as more and more subs are added to the stack.  Explaining the stacking process in lay terms is not going to be easy but this is the principle that is the main part of astro image processing.  Another important part is combining monochrome images to form a colour image.  How does one explain this to people whose only knowledge of photography is pointing the camera at something and pressing the button?  Few people will know how coloured pictures are formed from different coloured dots/pixels or the photographic colour film process of layers on monochrome images derived using colour filters.

Edited by Gina

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40m is not long to describe astro photography.  Indeed 40m wouldn't be long to describe terrestrial photography.  We had a talk on photography at a WI meeting last week which lasted an hour.  I got the impression that that tended to be too technical.

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I think I have an idea of how to explain a telescope and the need for a solid mounting (pier/tripod and mount).  "I think most of you will have used binoculars and realised how difficult they are to hold still and the more magnification the more difficult this is.  Now consider a very much higher magnification of say, a hundred times rather than eight or ten times and you can see why telescopes need a good solid mounting." 

Of course, this doesn't mention time exposures but I don't want to get too much into that as it gets technical.  Nor does it cover widefield imaging but again this has to be outside my brief.  There is so much to cover without covering widefield.  I think the same may apply to NB imaging - explaining very narrow band optical filters would be far too technical.  I may be able to explain NB imaging by saying that there are special coloured filters that only let light through from particular glowing gases.  I can say that hydrogen produces a deep red glow and oxygen a bluey-green or turquoise, glow.  I could demonstrate this with two-colour images such as the Cygnus Loop (thought there is some SII in this).  I think I really need to offer some sort of explanation of NB imaging as this is my main sort of imaging.

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Gina

Posted (edited)

Why do you have an observatory?  Taking night sky pictures needs a lot of equipment, very carefully set up and though some people set up and take down every time they do any astronomy this takes a lot of time and is a problem when the equipment needs very careful setting up.  With an observatory all the equipment can be set up virtually permanently and you only have to open the roof to be ready to go.

Why is your observatory like a strange garden shed when "proper" observatories are dome shaped?  This leads to the sorts of observatory and a very quick discussion of types of amateur telescope covering.  This could take up half the time itself if I let it. 

Edited by Gina

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Hmmm...  I think I'm going to be hard pressed to cram all I want into 40 minutes.  It would be nice if I could cover all these :-

  1. Types of telescope including camera lenses
  2. Types of observatory
  3. Types of camera
  4. Methods of supporting the imaging system - tripod, pier etc.
  5. Different sorts of night sky object - moon, planets, galaxies, nebulae...
  6. Solar imaging - white and NB
  7. Image processing - stacking - colour processing...

It simply won't go into a mere forty minutes!

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Gina

Posted (edited)

Conclusion - even without going into technicalities, astro imaging simply won't go into this short a talk!  I'm going to have to leave a lot out.  Some things could be left for the following Q&A session.

Edited by Gina

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I think I would leave out 6, if anyone is interested and missed it they could use the Q&A section.

I would merge 1 and 5 together as they are linked, target object and size of lens used (whether camera lens or telescope) that way you get wide field in there as well. Here I would have sample images to show from a still from your wide field camera to a nebula in NB to a planet.

Just a couple thoughts and agree what a wide subject to fit in to 40 minutes.

 

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On 19/06/2011 at 20:32, Gina said:

The forecast isn't good but could be worse. Yes making progress gradually :)

Here's a couple more photos, taken this evening :-

1. The pier base hole.

2. the ever increasing spoil heap. This is all hand dug out of the pier base hole.

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On 21/06/2011 at 21:56, Gina said:

Here's some more photos :-

1. Pier base hole - finished - 30" square (at bottom) x 27" deep.

2. Hole 1 of 6 for floor supports - 18" square by 10" deep.

3. Hole 2 of 6 for floor supports - 18" square by 10" deep.

4. Covered up for the night - rain forecast.

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On 24/06/2011 at 19:37, Gina said:

The rain's come in now so that's it for today. 3rd beam cut to length, soil removed to accommodate it and it's more or less in position. Needs level and height checking - to do tomorrow.

Now at last beginning to look as if something's happening :hello2:

Here's a cropped webcam image - too wet to use DSLR!

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On 24/06/2011 at 19:37, Gina said:

The rain's come in now so that's it for today. 3rd beam cut to length, soil removed to accommodate it and it's more or less in position. Needs level and height checking - to do tomorrow.

Now at last beginning to look as if something's happening :hello2:

Here's a cropped webcam image - too wet to use DSLR!

post-25795-13387762322_thumb.jpg

 

 

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I wont be covering the block and pier build in any detail and might not include it at all.

On 03/07/2011 at 12:49, Gina said:

Photos of the pier and base hole concreting :-

1. Equipment set up for pier base hole filling.

2. Pier base hole about half full (15" deep).

3. & 4. About 4" to go.

5. Pier base filled and levelled off ready to take top shuttering.

6. Base top shuttering screwed on and plant pots filled with concrete.

7. & 8. Pier filled with concrete.

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A bit of humour.

On 12/07/2011 at 16:36, nightvision said:

That looks great, coming on nicely, it certainly must be tempting to try it out especially if you get a clear night, you could easily piggy-back your DSLR for some wide-field shots. :D You would find it a refreshing change from all that slog you are putting in!

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On 15/07/2011 at 07:26, Gina said:

I've removed the pots - did it yesterday evening. No problem :) Must say, the pier looks a lot better without them. There are no voids and the concrete surface is absolutely smooth - moulded by the smooth plastic :)

Photos attached (it wasn't as dark as it looks - the automatic flash kicked in) :-

1. Smaller pot removed.

2. Larger pot and most of the duct tape removed.

3. North side view with discarded pieces of plastic pot.

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Pier with mount fitted.  ATM I'm just collecting photos to see which I want to include - it can't be all of these.

On 18/07/2011 at 19:51, Gina said:

It stopped raining for a while this evening so feeling "stir crazy" I went out to the site and tried to level the remains of the soil heap outside the "shed" area but even with the rain we've had, it was still very hard and I made little impression.

However, having levelled off the underfloor area (thereby reducing the tripping hazard) I thought I'd try the mount on the adapter. So having uncovered the pier I lugged the mount outdoors and up onto the pier adapter. Once I'd undone the azimuth screws it sat down on the adapter with a nice close fit but still easily adjustable. But as soon as I'd taken a couple of photos, down came the rain again! So back on went the cover. But this time over the mount as well.

Here are the photos I took of the mount. Only had time for the two.

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On 21/07/2011 at 19:16, Gina said:

Photos of today's progress. floor beams in place with DPC between them and the concrete :-

1 & 2. Viewed from different angles.

3. Took cover off pier and mount.

4. Showing wall ties to be used to secure beams to the concrete blocks - to stop the shed blowing away in a gale (These are on both sides of each beam and at both ends).

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