Author Topic: Satellites potentially ruining astrophotography?  (Read 114 times)

moiquadachus

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Re: Satellites potentially ruining astrophotography?
« Reply #15 on: January 21, 2018, 07:01:36 AM »
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Won't using median stacking instead of average or other type of stacking totally eliminate the streak?

Afaik, the standard method is to use a sigma clipping or sigma median...I'm sure someone will correct me if I have that wrong. I don't use subs with streaks as I sample short exposure and stack large numbers of subs.

Rodinald Richards

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Re: Satellites potentially ruining astrophotography?
« Reply #16 on: January 21, 2018, 07:36:33 AM »
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Won't using median stacking instead of average or other type of stacking totally eliminate the streak?

There are a host of stacking methods. I try to always have at least 15 subs. Sometimes use 100. Then I could formerly use kappa-sigma in DSS, and now, linear fit in PixInsight. These more sophisticated methods are excellent in removing outlier data. The key is to have a good number of subs.

Quote

Very nice M51 Whirlpool Galaxy, it is much bigger then what I get on my 127mm refractor (ES ED127 CF), Nikon D5200, 20 minute exposures(Vixen VMC110L with NexGuide CCD, on a side by side D bar with ADM Max-M guidescope aiming device), all on a CGE mount. You must have a C-11 or a C-14 to get pictures that big.. and you must have a great mount, to get single shots with tiny stars.. nice.

Bill

Thanks. The mount is the excellent iOptron CEM-60. The scope is the "inexpensive" 6 inch Ritchey-Chretien. Of marginal quality as received, I worked on it until it's pretty decent, as you noted. Of course, I now have $1200 in the "$400" scope, and many hours of my time.

It's 150" on an ATIK 460EXM, one of the luminance subs. Here's the current version of the final, I'm still working on it.

http://www.astrobin....0752/B/?nc=user

Alex Miller

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Re: Satellites potentially ruining astrophotography?
« Reply #17 on: January 25, 2018, 04:50:13 PM »
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Won't using median stacking instead of average or other type of stacking totally eliminate the streak?

Yes but you really want to use flats and dark flats as well for the best results.

Ken Kamkoff

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Re: Satellites potentially ruining astrophotography?
« Reply #18 on: January 25, 2018, 05:20:04 PM »
Returning to the OP's original question, no, the new Russian satellite will not pose any significanthindrance to astrophotographers. There are currently two other pointless threads running of CN concerning the silly response to this satellite's potential damage to the night sky, largely generate by hobbyists' ignorance of the satellite's characteristics.

As a poster noted upstream, first off this new satellite is in relatively low Earth orbit and will be illuminated by the Sun only a couple of hours after sunset and before sunrise, remaining in the dark the rest of the night. But far more important is that, because its solar reflecting surface is flat, it will behave similar to an Iridium satellite as seen by observers on the ground. Just as with the Iridiums, the further from the satellite's ground-path reflection point, the less solar reflection you will see. Likewise, just as do the Iridiums in their passes, the Russian satellite should start out appearing faint, rise briefly to a flare-like peak, and then fade way during eachs passage. It will not remain very bright the whole time it is crossing the sky. I'd venture that, in fact, it will be near invisible during most passages for observers when the reflection angle is unfavorable and pose no problem what so ever!

Incidentally, the ISS, which remains very bright (up to -4 or so) virtually throughout its passages, is probably the worst offender in our skies and certainly is more of a problem than the Russian satellite ever could be, yet you see very few complaints about it interfering with astrophotograhy.

BrooksObs

unoritvie

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Re: Satellites potentially ruining astrophotography?
« Reply #19 on: January 30, 2018, 01:35:22 AM »
I wonder how this compares with the Echo balloon satellites. I remember watching them fly over when I was a wee lad. Satellite tracks in general can be removed with a sigma clip, though something this bright in the field (likely just one frame) would be a problem. As far as a general contributor to light pollution its effect would be nil, no more than Venus in the evening sky. I wonder how long something with such high surface area and low mass will stay in orbit. We'll get a hint by looking at the second derivative loss terms in the orbital elements once it is launched.

Matt Marquez

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Re: Satellites potentially ruining astrophotography?
« Reply #20 on: January 31, 2018, 12:13:21 AM »
It's a matter of degrees, so to speak...I had a helicopter fly by the other night while imaging NGC 6946. (I'm on the flight path for a pair of Cleveland's main hospitals. Cleveland Clinic and University Hospital.) I have a sneaking feeling that there is no amount of sigma clipping that would remove it's artifacts and leave the sub usable




praccelreber

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Re: Satellites potentially ruining astrophotography?
« Reply #21 on: January 31, 2018, 03:28:37 AM »
Quote
I wonder how this compares with the Echo balloon satellites. I remember watching them fly over when I was a wee lad. Satellite tracks in general can be removed with a sigma clip, though something this bright in the field (likely just one frame) would be a problem. As far as a general contributor to light pollution its effect would be nil, no more than Venus in the evening sky. I wonder how long something with such high surface area and low mass will stay in orbit. We'll get a hint by looking at the second derivative loss terms in the orbital elements once it is launched.


I would imaging that the Russian satellite will be rather brighter, given that its solar reflection will be coming off a flat reflective surface vs. that of the convex surface of the Echo (yeah, I remember watching Echo too!). However, during its passages across the sky Echo remained about its same brightness throughout and was visible over a vast area. On the other hand, the Russian satellite should act much like one of the Iridium satellites, with a brightness exhibiting a rising phase, a brief peak, and a declining phase totalling little more then I'd guess a minute, or so. Likewise, this display will only be visible from a limited area either side of where the solar reflection's center-line traverses the Earth's surface.

BrooksObs

ceicomfeara

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Re: Satellites potentially ruining astrophotography?
« Reply #22 on: January 31, 2018, 07:02:17 AM »
After losing control of a large geo satellite AMC-9 (83.0°W) on 17 June 2017, it now appearsto be breaking up, ground base cameras show flaring and a debris field.
Update: Satoperator re-establishes contact with AMC-9, but unknown if they are now back in full control.

Aaron Maggot

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Re: Satellites potentially ruining astrophotography?
« Reply #23 on: February 02, 2018, 08:22:29 PM »
<p class="citation">QuoteBefore I logged onto this website today, I check yahoo briefly to get an update on world news. I saw this article. It basically talks about Russia planning to launch a satellite that will be magnitude -3.0 or something like that, and it's going to be orbiting around the earth. Its supposed to be very bright.[/quote]

The ISS is brighter, when the Shuttle was still in service and docked to the ISS it was even brighter,
and Iridium satellites can reach mag. -8, so....what's new?

Just wait until the Death Star is finished....

globleferep

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Re: Satellites potentially ruining astrophotography?
« Reply #24 on: February 03, 2018, 05:37:45 AM »
My dark site, though remote, is near some major flights path for cross country flights, both E-W and N-S. I haven't done any imaging in a few years, but it would be hit or miss.