Author Topic: Geminid meteor shower  (Read 1211 times)

Řivind Třien

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Geminid meteor shower
« on: December 19, 2018, 14:04:18 »
It did not look good for the Geminid meteor shower here in Fairbanks - bad weather forecast and it was snowing almost to midnight before December 14. But then it magically cleared up and stayed clear past 6am in the morning with temperatures around -23°C. I had my D5100 with 10.5mm fisheye (braced on a box) and D7100 with 28mm f/2.8 AIS on fixed tripod out the whole night, powered on AC power, collecting 60GB of image data. The fisheye body exposed for 20sec at f/3.2, and the D7100 at f/2.8 to f/3.2 for 8-15 sec, both at ISO 1600 except the 8sec exposures at ISO 2000. And luckily the two moose that had been hanging around in the neighborhood had not come by and trampled my rigs during the few hours I was asleep.

I noticed some really bright traces by eye that was not caught in any frame, strange how the camera happens to be right between exposures at those moments! In the same line, only one meteor were caught by both cameras even if the 28mm field was completely contained in the field of the fisheye; each camera caught 8 meteors. I aimed west, to the side of the radiation point due to heavy light pollution, and perhaps not the best transparency of the atmosphere. I often see meteors combined into a single frame, but not sure how to do that with this much foreground and star movement, so here we go:
#1


Two meteors in the same frame if one looks closely:
#2


#3


#4


#5


#6


The most frequent meteors were caught around 2-3am, but even at 7am in the morning, a meteor showed through the clouds that were drawing in. This just to show that one should never give up even if conditions are not ideal.
#7



At the very start I made a short tracked attempt on the 46P Wirthanen comet with the 300mm PF before it disappeared behind some trees. While working on framing I caught this trace during an 8sec test exposure. I suspect it is a rotating man made space object as the trace is very narrow, but I got pretty exited right away...
#8



If you have any images of the Geminid meteor shower, feel free to add them to this thread.
Řivind Třien

Akira

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Re: Geminid meteor shower
« Reply #1 on: December 19, 2018, 21:47:42 »
Being aware of the the situation, the faint light scratches look precious!

It is encouraging to know that the single frame can shoot beautiful starry landscapes.  Here in Tokyo, one would need an efficient light pollution filter, though.
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armando_m

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Re: Geminid meteor shower
« Reply #2 on: December 19, 2018, 21:48:05 »
Řivind wonderful images

Was 46p comet visible without aid ?
I shot it from within the city and I needed a stack images, the comet moves faster than the rotation of earth and therefore I got a trace, instead of a dot.
Armando Morales
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Řivind Třien

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Re: Geminid meteor shower
« Reply #3 on: December 19, 2018, 23:15:08 »
Being aware of the the situation, the faint light scratches look precious!

It is encouraging to know that the single frame can shoot beautiful starry landscapes.  Here in Tokyo, one would need an efficient light pollution filter, though.

Thanks for commenting Akira. The light pollution is still present here, this was captured in a red zone, Bortle 7 (Andromeda hardly visible by eye) on the light pollution scale. Light pollution filters may or may not be effective. The switch to white LEDs for city lights is making it harder to filter it out. One can also subtract the light pollution during processing with a level histogram adjustment. This makes it easier to maintain natural colors. However on these captures I just used contrast/exposure/color adjustment etc, not my usual deep space work flow.
Řivind Třien

Řivind Třien

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Re: Geminid meteor shower
« Reply #4 on: December 19, 2018, 23:28:23 »
Řivind wonderful images

Was 46p comet visible without aid ?
I shot it from within the city and I needed a stack images, the comet moves faster than the rotation of earth and therefore I got a trace, instead of a dot.

Thanks for the enthusiastic comment Armando. I do not think I could make out 46P by eye; I troubled quite a bit finding it although I had the position from Stellarium. I have seen an example where it is even visible in a fisheye image, but then from a darker zone.

Yes, stacking comet images is a little tricky. DeepSpaceStacker has a comet stacking mode that allows separate stacking of comet and stars. It requires marking the position of the comet in several frames. It is also possible to register on the comet only, causing star trails. I have seen some nice examples of that.

I messed up most of the few frames I got of the comet - forgot to remove the Bahtinov mask in the hurry :-[ so I only got two OK frames with different framing from the one above. I have not had another chance since then.
Řivind Třien

Seapy

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Re: Geminid meteor shower
« Reply #5 on: December 19, 2018, 23:51:14 »
Řivind, may I  ask, you seem to be using an external intervalometer, can you tell me a little about that, why and what are the advantages?  I know the Nikon cameras limit exposures to 30 seconds but how long an exposure can you would you want to make in real terms?
Robert C. P.
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Akira

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Re: Geminid meteor shower
« Reply #6 on: December 20, 2018, 00:17:47 »
Thanks for commenting Akira. The light pollution is still present here, this was captured in a red zone, Bortle 7 (Andromeda hardly visible by eye) on the light pollution scale. Light pollution filters may or may not be effective. The switch to white LEDs for city lights is making it harder to filter it out. One can also subtract the light pollution during processing with a level histogram adjustment. This makes it easier to maintain natural colors. However on these captures I just used contrast/exposure/color adjustment etc, not my usual deep space work flow.

Thank you for the details.  I wonder if the "dehaze" slider would help removing the light pollution as well in post?  I'm pretty sure that the light pollution in Tokyo is way worse.  I'm not sure how far the city lights are replaced with LED here.

Also, thank you for reminding me of the Baftinov mask.  Just ordered one on amazon.com.   8)
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Řivind Třien

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Re: Geminid meteor shower
« Reply #7 on: December 20, 2018, 06:40:54 »
Řivind, may I  ask, you seem to be using an external intervalometer, can you tell me a little about that, why and what are the advantages?  I know the Nikon cameras limit exposures to 30 seconds but how long an exposure can you would you want to make in real terms?

When I image with my 300PF on deep space objects with my tracker, I typically want to expose for one minute, so yes it is needed. I also find it easier to change the interval than with the internal timer (with reservation that the LED display gets slow at very low temperatures) and to stop and start a series of exposures, just a single button click with no need to touch the body (which could cause things to get out of alignment). The body is set to bulb mode so the all control (interval from end exposure to new exposure, length of exposure, delay before first exposure, and number of actuations) is on the intervalometer. Also I think it is more reliable than the internal timers, especially with the D5100, works well even at low temperatures. When the body hangs up due to a power glitch, it will still continue, so the the next release will clear the locked up shutter mechanism, while the internal timer would likely be stalled. They are quite inexpensive, so cost is not much of an issue. I really should have had another one for occasions like this and backup.
Řivind Třien

Řivind Třien

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Re: Geminid meteor shower
« Reply #8 on: December 20, 2018, 06:49:07 »
Thank you for the details.  I wonder if the "dehaze" slider would help removing the light pollution as well in post?  I'm pretty sure that the light pollution in Tokyo is way worse.  I'm not sure how far the city lights are replaced with LED here.

Also, thank you for reminding me of the Baftinov mask.  Just ordered one on amazon.com.   8)

I am not familiar with the dehaze slider as it does not exist in my tools, but the answer is always to try it out and see how it works. It is quite possible it works the same way as a level adjustment, moving the black point up to the left side of the histogram for each color channel.
Řivind Třien

Jack Dahlgren

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Re: Geminid meteor shower
« Reply #9 on: December 20, 2018, 08:39:49 »
I was out rowing on the bay at 5:00 AM and we saw several bright meteors flash across the sky. That and the sunrises are the payoff for such an early morning toil. Unfortunately it is not possible to bring a camera in the boat and even if I did, interrupting the workout would be unwelcome.

Seapy

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Re: Geminid meteor shower
« Reply #10 on: December 20, 2018, 09:42:21 »
I am not familiar with the dehaze slider as it does not exist in my tools, but the answer is always to try it out and see how it works. It is quite possible it works the same way as a level adjustment, moving the black point up to the left side of the histogram for each color channel.

I just ran a hazy image through Lightroom, made two copies, one I dehazed in Lr, one I took into Ps and adjusted the black point of each of the colour channels, the effect was the same, I also took the image I had 'dehazed' in Lr into Ps and examined the levels of each  channel, they were very similar to the other image and the appearance was similar, so, I would agree with that assessment.

I have had excellent results from the use of clarity and dehaze with light pollution and general improvement of night sky, definition and colours.
Robert C. P.
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Seapy

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Re: Geminid meteor shower
« Reply #11 on: December 20, 2018, 10:06:45 »
When I image with my 300PF on deep space objects with my tracker, I typically want to expose for one minute, so yes it is needed.  I really should have had another one for occasions like this and backup.

Thank you for that Řivind, I will look into them, I am very taken with the 'Unleashed' device which allows a smartphone to control the camera, but having spent some time on their website I am coming to the opinion that the Unleashed does not have the capability of controlling the 'Bulb' exposure duration, despite claiming to have night sky capabilities.  Reason being I want to minimise wire connections, in the dark it's not easy dealing with ten pin plugs and trailing wires, to me seems much easier to stand a short distance from camera, or even sit in warm car, monitor and control camera by bluetooth... 8) At most of my night sky venues I can park within feet of the camera.

Does anyone familiar with the Unleashed device know if it's capable of controlling the Bulb shutter timing, to allow an extended intervalometer facility beyond 30 seconds please?  Their website seems very vague about vital details like that.  It seems an obvious feature that it would have but it's not clear in the description, there is no explicit feature list.

Perhaps there are other bluetooth intervalometer devices available...
Robert C. P.
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Birna Rřrslett

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Re: Geminid meteor shower
« Reply #12 on: December 20, 2018, 10:40:04 »
Seapy, send an email to foolography and ask.

Seapy

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Re: Geminid meteor shower
« Reply #13 on: December 20, 2018, 10:52:34 »
Thanks Birna, I will.
Robert C. P.
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Jakov Minić

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Re: Geminid meteor shower
« Reply #14 on: December 20, 2018, 11:53:30 »
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