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Author Topic: Astrophotography  (Read 47393 times)
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img  TinselKoala
Astrophotography « on: 2017-08-21, 21:27:32 »
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Well.... thanks to Chet and Luc and Larry I finally was able to get my "observayurt" back into functional mode.... thanks again guys for the "kick in the pants" to get this going.

Spent last night setting up the mount and confirming that all the hardware was still working properly, with new firmware updates to the Celestron CGEM mount and NexStar handset controller. I can't see very much of the sky because of all the trees, and it doesn't get very dark because of the neighbor's porchlight and the corner streetlight, but I had fun exploring double stars, particularly the double-double Eta Lyrae, and was able (barely) to make out the Hercules globular cluster, the faint Ring Nebula and wispy dim Dumbbell nebula. But the main reason for the setup was to capture as much of the Solar Eclipse as I could. It was really hot outside, me sweating like the proverbial pig, and partly cloudy, but I did manage to get some pix of the eclipse. It was only about 65-70 percent full here. The photos look unreal, like something faked, but I assure you they are actually photos of the moon obscuring the sun! You can barely make out some roughness on the edge of the moon, caused by craters and mountains along the limb. The big sunspot chain that is visible on the full solar disk was covered up by the moon so there isn't really any detail on the face of the sun. A little editing, and here's what it looked like at just about the maximum totality, which happened at 1:09 pm CDT.

   
img  Chet K
Re: Astrophotography « Reply #1 on: 2017-08-21, 23:42:37 »
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very nice "utilitarian" setup ,and a beautiful piece of equipment .. on a sturdy looking mount .

the Pic of the peak really doesn't look real,

we should all spend a bit more time looking up ... especially at night  !!

Amazing !!

Thx

Chet
   
img  Paul-R
Re: Astrophotography « Reply #2 on: 2017-08-22, 17:13:25 »
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Don't forget that photographing super bright objects (stars, sun moon) can be difficult. The meter is not set up for it. You could try bracketing three stops a bracket and see what happens or if you have a good manual override, just keep taking shots and reducing the aperture two stops a time. Of course, in the olden days, this would have been expensive.

But I don't know how easy it is to burn the CCD target.
   
img  TinselKoala
Re: Astrophotography « Reply #3 on: 2017-08-23, 02:38:00 »
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Well, it does depend on the camera's  metering logic. Modern DSLRs have at least several options for metering: you can use the whole frame, just the center of the frame, or a defined rectangular area within the frame. You can have the camera display, in the viewfinder, the meter's "best guess" at exposure on a bar graph, and then you can choose your shutter speed manually for a selected degree of over or underexposure. Or you can have the camera choose the shutter speed automagically to give the "best" exposure in the previously selected area in the frame. I took a bunch of exposures during the eclipse, some on "full auto" with different areas selected for metering, some with manual shutter speeds based on the meter's indications, some bracketed around the suggested exposure, and so forth. According to the metadata for the above shot I used ISO 800, partial frame metering (center), and an exposure of 1/500 second which resulted in about 1/2 stop underexposure. Aperture and focal length are determined by the telescope and field-flattener-reducer of course so they don't appear in the metadata, but come out to about f/6 for the setup used here.
I usually underexpose astrophotographs because digital processing can stretch (akin to push-processing for film) the histogram and bring out contrast and brightness, whereas overexposure that saturates the sensor just results in lost data, nothing can be done with that.
   
img  giantkiller
Re: Astrophotography « Reply #4 on: 2017-08-24, 16:53:38 »

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img  TinselKoala
Re: Astrophotography « Reply #5 on: 2017-08-24, 19:30:58 »
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That's a nice rig all right. The Paramount line of mounts are certainly among the top-line setups for the amateur. It is a bit pricey for my blood though. I'm surprised it's not located inside some kind of observatory structure. Is there a sliding or otherwise mobile shelter arrangement there?

http://www.bisque.com/sc/shops/store/All+Products/Robotic+Telescope+Mount/default.aspx?PageIndex=0

My own system is the heaviest _portable_ system that I could handle by myself, in addition to being the most expensive I could possibly afford, back when I was still "gainfully employed". I went without lunches for months to be able to pay for my rig. Here's the CGEM mount + 9.25" EdgeHD + ShortTube80 guidescope "on location" in Atascosa County, along with an image obtained with this rig and the Orion Parsec M8300 monochrome CCD camera + RGBL filters:



   
img  Paul-R
Re: Astrophotography « Reply #6 on: 2017-08-25, 15:58:52 »
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Quote from: giantkiller on 2017-08-24, 16:53:38
Toys of friends of mine that I get to play with: SoftwareBisque.com
http://www.youtube.com/watch?v=YeVJ_L6dRlE&feature=youtu.be

I wonder if that motorisation is fast enough to keep up with the space station. I've always thought it might be fun to see what sort of image one might get.

The image is likely to be so small that the bracketing method might be the best. If the camera has an auto bracket facility, ( -5,-3,-1, 1, 3, 5 ), that would be useful on the orbit prior to the preferred orbit. Then, on the preferred orbit, 1hr 32 mins later, the bracketing could be sharpened up. Once the best exposure is determined, that is fixed.
« Last Edit: 2017-08-25, 16:31:11 by Paul-R »
   
img  Chet K
Re: Astrophotography « Reply #7 on: 2017-08-25, 17:54:48 »
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img  Chet K
Re: Astrophotography « Reply #8 on: 2017-08-26, 01:10:08 »
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I hope you fare well with hurricane  Harvey these next few days
« Last Edit: 2017-08-26, 14:27:22 by Chet K »
   
img  Paul-R
Re: Astrophotography « Reply #9 on: 2017-08-26, 15:24:40 »
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Quote from: Chet K on 2017-08-25, 17:54:48

3:27 mark actual speed [get an idea of speed.....difficulty tracking ??
3:48---sequence slowed down

I'm not too sure but I reckon the angular tracking speed will depend on the position in the sky and the magnification, the effective focal length. But it can be seen by inspection easily enough.

I suspect that the shutter speed will be faster than one would imagine.
   
img  giantkiller
Re: Astrophotography « Reply #10 on: 2017-08-26, 21:49:45 »

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This will answer all your questions:
The U.S. Ari Force has bought over 50 of these and stood them around the planet for monitoring the object inventory in the skies. The enemy is now sailing spies through the trash-o-sphere to try and gain a foot hold on things they should not see. The idea is to process 25k images per scope a night, real time, to observe any renegades. Also check out the Dragonfly observatory: http://astronomynow.com/2015/05/26/dragonflys-compound-eye-reveals-very-faint-galaxy-structure/
 and check out the slew rate.
There are many a greater things going on which are not in our purview. But I have seen things that are far beyond reality in this set of tools.
We went up to Buena Vista to photgraph coronal mass ejections. We got a medium one that had an arc with a 4 million mile radius from the inception point in 4 seconds. You read that correctly. We saw light and matter travel at 1 million miles per second. I questioned the qualified members right there about this anomaly. They responded 'We don't talk about that.' I repeated myself and said 'I know what I saw.' They all turned and walked away. My buddy, whose equipment it was just winked at me, 'Its not worth the argument.'


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http://purco.qc.ca/ftp/
   
img  Chet K
Re: Astrophotography « Reply #11 on: 2017-08-31, 11:40:58 »
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Re: Astrophotography « Reply #12 on: 2017-08-31, 20:18:59 »
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You can use this site to determine the exact coords (RA and DEC, or ALT_AZ) for 3122 Florence at whatever time you want:

http://www.minorplanetcenter.net/iau/MPEph/MPEph.html


Output looks like this for me tonight:

03122              [H=14.1]
Date       UT      R.A. (J2000) Decl.    Delta     r     El.    Ph.   V      Sky Motion        Object    Sun   Moon                Uncertainty info
            h m s                                                            "/min    P.A.    Azi. Alt.  Alt.  Phase Dist. Alt.    3-sig/" P.A.
... Suppressed ...
2017 09 01 010000 21 03 15.0 -01 51 03   0.047   1.052  154.9  24.0   8.7   23.66    344.8    289  +26   -02   0.75   040  +37       N/A   N/A / Map / Offsets
2017 09 01 020000 21 02 49.9 -01 28 12   0.047   1.052  154.6  24.3   8.7   23.73    344.4    299  +38   -15   0.75   040  +41       N/A   N/A / Map / Offsets
2017 09 01 030000 21 02 24.2 -01 05 19   0.047   1.052  154.4  24.5   8.7   23.79    344.2    314  +49   -27   0.75   040  +40       N/A   N/A / Map / Offsets
2017 09 01 040000 21 01 58.1 -00 42 25   0.047   1.052  154.1  24.7   8.7   23.83    344.1    335  +57   -37   0.76   039  +36       N/A   N/A / Map / Offsets
2017 09 01 050000 21 01 31.9 -00 19 29   0.047   1.052  153.9  25.0   8.7   23.86    344.0    004  +60   -46   0.76   039  +29       N/A   N/A / Map / Offsets
2017 09 01 060000 21 01 05.7 +00 03 27   0.047   1.052  153.6  25.2   8.7   23.86    344.1    032  +56   -51   0.76   039  +20       N/A   N/A / Map / Offsets
2017 09 01 070000 21 00 39.6 +00 26 24   0.047   1.052  153.4  25.5   8.7   23.85    344.3    052  +48   -51   0.77   038  +10       N/A   N/A / Map / Offsets
2017 09 01 080000 21 00 14.0 +00 49 22   0.047   1.052  153.1  25.7   8.8   23.82    344.6    066  +36   -47   0.77   038  -02       N/A   N/A / Map / Offsets
2017 09 01 090000 20 59 48.9 +01 12 19   0.047   1.051  152.8  26.0   8.8   23.77    344.9    077  +24   -38   0.77   038  -14       N/A   N/A / Map / Offsets
2017 09 01 100000 20 59 24.5 +01 35 16   0.047   1.051  152.6  26.2   8.8   23.72    345.3    085  +11   -27   0.78   037  -26       N/A   N/A / Map / Offsets
... Suppressed ...

Will I be out there tonight looking for it? Probably not.

This is a nice image showing what you might expect in a photo from the backyard:

Quote
A 60-second exposure with a large amateur telescope on August 28, 2017, records asteroid 3122 Florence (bright dot in center). The telescope tracked the apparent motion of the object, so stars are trailing. The long vertical trail on the left is the geostationary satellite AMC-14. The asteroid was about 5 million miles (8 million km) from Earth.
Gianluca Masi / Virtual Telescope Project
   
img  TinselKoala
Re: Astrophotography « Reply #13 on: 2017-09-08, 16:14:28 »
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The ultimate solar astrophotography site:

https://www.helioviewer.org/
   
img  Centraflow
Re: Astrophotography « Reply #14 on: 2017-09-08, 17:28:55 »

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Quote from: TinselKoala on 2017-09-08, 16:14:28
The ultimate solar astrophotography site:

https://www.helioviewer.org/

Very good site O0

A lot of sun activity lately which might be the cause of Earth events .

Regards

Mike 8)


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img  JimBoot
Re: Astrophotography « Reply #15 on: 2017-09-09, 02:43:31 »

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On my way to Astro photo workshop in 15mins :) those rigs look great
   
img  Paul-R
Re: Astrophotography « Reply #16 on: 2017-09-09, 16:11:25 »
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Quote from: TinselKoala on 2017-09-08, 16:14:28
The ultimate solar astrophotography site:

https://www.helioviewer.org/
I have used this one where you type in the month instead of mm and the day instead of dd. Use preceding "0" where applicable (i.e. today would be 2017/09/09. not the most convenient, I must say:

https://stereo.gsfc.nasa.gov/browse/2017/mm/dd/ahead/euvi/195/512/

Alas, NASA have broken the other one, Stereo B. Careless fellows, but we mustn't grumble. We have much to be grateful for (along with Burt Rutan).
   
img  JimBoot
Re: Astrophotography « Reply #17 on: 2017-09-10, 22:11:02 »

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Got to play with some coronado scopes. That was interesting. Here's a shot from my backyard. The moon is out 3/4 hence the blue sky and lit foreground.
   
img  TinselKoala
Re: Astrophotography « Reply #18 on: 2017-09-11, 00:38:30 »
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Pretty. You can see the galaxy in the upper right.

Do you have that image in a full, raw, uncompressed format that you could send me to play with? I can't do much with the png except remove some of the blue and adjust the curves to make the colors of the galaxy stand out a little more. But if you have a raw uncompressed version I might be able to do more.
   
img  JimBoot
Re: Astrophotography « Reply #19 on: 2017-09-11, 03:08:05 »

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I'm getting a new lens f2.8 so I take some pics of Milky way. That was just one still from a 3 hour time lapse sequence.
   
img  JimBoot
Re: Astrophotography « Reply #20 on: 2017-09-11, 09:16:58 »

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I put this on gdrive as YT compression kills the quality. The time lapse I did last night on my 7d MkII 18-35 f3.5 20"exp 1600ISO then batch stitched together in Time Lapse Assembler for OSX
https://drive.google.com/open?id=0BznWQjS-OxzPVWlsVW5sd3BDM2s (86MB)

Tonight I'll be attempting to capture the movement around the south celestial pole but it may not be possible with this lens. The general consensus seems to be Samyang 14mm 2.8 . I think I'll need that aperture to get good definition of the Milky Way.

btw I'd be interested in your thoughts on the various light shows. Some are aircraft, space junk etc but there is one around the 5" mark if you go though frame by frame. It's a weird one because of how long it stays in the video. It's in for 10 frames so 400secs but does not move very far. The exp are for 20" then pause for 10sec. I can't do longer exposures with this lens without getting star trails. I can share the individual pix if anyone wants a close look.
« Last Edit: 2017-09-11, 11:09:43 by JimBoot »
   
img  TinselKoala
Re: Astrophotography « Reply #21 on: 2017-09-11, 14:03:38 »
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Nice time lapse!

You must mean this thing. I think it's an airplane or helicopter, coming in from a long distance away. I count about 19 flashes in one 20 second frame, so that fits with a blinking red rotating beacon or strobe/nav light kind of thing. A slow moving airplane coming in on a trajectory almost towards the camera, so it doesn't move sideways much as it comes towards you.

Yes, please send me a few single frames, as raw and uncompressed as possible, right out of the camera in its raw format if possible. I'd like to see what I can get out of the raw data. There is usually a lot of image information that can be pulled out by stretching histograms, modifying color curves, sharpening and noise reduction, etc. but a lot of this potential image data is lost when shrinking image and compressing from the raw camera format to jpg or png or other methods. One would usually work on enhancing the raw frames first, then put the processed images together for the slide show or time lapse.

I used gimp and PixInsightLE to get this enhanced, cropped, enlarged, stretched, noise-reduced and color curved detail from one of the frames of your time-lapse. Could probably do a lot better if I had the raw frame from the camera, if it didn't automagically already compress internally.
   
img  JimBoot
Re: Astrophotography « Reply #22 on: 2017-09-19, 13:39:26 »

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Damn my posts never made it.

Ok that wasn't it. check around Frame 130 TDC.  Satellite I guess, I have not looked up the time stamp with known flybys yet.
   
img  Chet K
Re: Astrophotography « Reply #23 on: 2017-10-27, 15:40:47 »
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the trajectory of this "thing" from Vega ??
is uncanny IMO

https://twitter.com/tony873004/status/923109368903622656
   
img  TinselKoala
Re: Astrophotography « Reply #24 on: 2017-10-27, 17:54:27 »
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I'm such a lump these days. The weather has been astro-perfect the last few days, so I set up the telescope
in the observa-yurt during the day on Wednesday... then fell asleep and didn't actually look through it.

Same yesterday evening-- all set up, but too lazy to take the roof-tarp off, and went to sleep, no observing
at all. Bad, bad astronomer, no donut for me.

Scope is still set up but we've had some kind of frontal passage and it's windy and partly cloudy. Don't
know if I'll have the energy to look through the scope tonight either.

All the lights from the neighbors and the new LED streetlight on the corner have me really bummed out.
It's never dark in the backyard any more.

I have this nice expensive bandblock photographic filter for mercury and sodium streetlight scatter... but of course its blocking
wavelengths are wrong for the LED streetlights.  And that damn thing is _bright_.
   
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