# Possible good comet coming! **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [September 17, 2024, 10:15pm UTC](https://boards.straightdope.com/t/possible-good-comet-coming/1007410 "2024-09-17T22:15:13Z")\ **Posts on this page:** 18\ **Page:** 3
**Author:** ![Spectre\_of\_Pithecanthropus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/spectre_of_pithecanthropus/32/12343_2.png) [@Spectre\_of\_Pithecanthropus](https://boards.straightdope.com/u/Spectre_of_Pithecanthropus)\ **Post date:** [October 18, 2024, 4:01am UTC](https://boards.straightdope.com/t/possible-good-comet-coming/1007410/41 "2024-10-18T04:01:43Z")
> [@pjd](#): > > That image appears to have been reversed (like most pics on the internet these days !) ! It’s not reversed. Mine came out the same and I know that wasn’t flipped. ---
**Author:** ![Spectre\_of\_Pithecanthropus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/spectre_of_pithecanthropus/32/12343_2.png) [@Spectre\_of\_Pithecanthropus](https://boards.straightdope.com/u/Spectre_of_Pithecanthropus)\ **Post date:** [October 18, 2024, 4:13am UTC](https://boards.straightdope.com/t/possible-good-comet-coming/1007410/42 "2024-10-18T04:13:19Z")
> [@beowulff](#): > > I think those are “Darks.” > They are used to remove the small amount of data that is present due to thermal effects. Based on what I’ve read online at astronomy-related sites, and also the stacking programs I use or have used in the past, the lights are your image files. For darks you leave all your camera settings the same as they were for the lights, but now you thoroughly black out your lens. I don’t think a lens cap is good enough by itself, so I use one of those lens covers with drawstrings, that you slip over the lens barrel, plus I hang a hat over the camera. Bias frames are like darks, except here you use the shortest available exposure time. Vignetting frames?? I don’t know how to make those and I wish I did. Astro Pixel Processor would probably work much better if I added those. To be clear, I’m just following and repeating what a website told me to do. I don’t know enough to justify these statements. ETA: I see that what you called lights are the vignetting frames. I’ll have to try that next time. Do vignetting frames have to be in sharp focus? I’m wondering if I can just put the camera a few inches away from a diffuse light source, and I wouldn’t be able to focus at that range. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [October 18, 2024, 4:17am UTC](https://boards.straightdope.com/t/possible-good-comet-coming/1007410/43 "2024-10-18T04:17:34Z")
We are both slightly wrong: > Usually three different types of image are required for the stacking process: _Light frames, Dark frames and Flat frames_ . The images containing the astronomical motive are called Light frames. Dark frames are images obtained by taking images with a closed lens cap. They do not contain any real image information but merely consist of sensor noise. These images provide important information on the electrical and thermal state of the imaging sensor. The third type of image are Flat frames. They are usually taken against a synthetic white background and help to eliminate effects caused by dust on the sensor and vignetting. ---
**Author:** ![Spectre\_of\_Pithecanthropus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/spectre_of_pithecanthropus/32/12343_2.png) [@Spectre\_of\_Pithecanthropus](https://boards.straightdope.com/u/Spectre_of_Pithecanthropus)\ **Post date:** [October 18, 2024, 4:34am UTC](https://boards.straightdope.com/t/possible-good-comet-coming/1007410/44 "2024-10-18T04:34:37Z")
> [@ThisOneGuy](#): > > Good shot. I think those are satellites rather than meteors. They stay the same brightness throughout the exposure where meteors tend to vary. I noticed the satellite trails in the first image in my post above, and likewise thought they were meteors at first. Over by the right margin, it looks like there are four meteors emanating from a common center, but when I stacked this part of the images it became clear that they were regular satellites whose paths just happen to cross there. Regarding satellites, I almost never get more than one trail in an entire stack, let alone a single frame. I think the reason we’re seeing so many satellite trails is because it wasn’t that long after sunset, and some LEO objects were still illuminated by the sun. ---
**Author:** ![pjd](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pjd/32/3009_2.png) [@pjd](https://boards.straightdope.com/u/pjd)\ **Post date:** [October 18, 2024, 8:35am UTC](https://boards.straightdope.com/t/possible-good-comet-coming/1007410/45 "2024-10-18T08:35:40Z")
Odd. It’s just that Bob\_Blaylock said that the meteors and aircraft were on the left, but in that pic they’re on the right… ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [October 18, 2024, 9:04am UTC](https://boards.straightdope.com/t/possible-good-comet-coming/1007410/46 "2024-10-18T09:04:01Z")
Taken on Sunday at Henry W Coe state park south of the the CA Bay Area. [![Imgur](https://i.imgur.com/7d2Z7hq.png "imgur.com") ](https://imgur.com/7d2Z7hq) Conditions were not great. As mentioned, the moon was quite bright, and there was a lot of haze that lit up. Easily naked eye visible, but no anti-tail. Taken with a Pixel 9 Pro XL phone in Night Sight mode. ---
**Author:** ![Alessan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alessan/32/465_2.png) [@Alessan](https://boards.straightdope.com/u/Alessan)\ **Post date:** [October 18, 2024, 9:48am UTC](https://boards.straightdope.com/t/possible-good-comet-coming/1007410/47 "2024-10-18T09:48:50Z")
That cactus looks like it was surprised by the comet it while masturbating. ---
**Author:** ![Hatchie](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hatchie/32/3983_2.png) [@Hatchie](https://boards.straightdope.com/u/Hatchie)\ **Post date:** [October 18, 2024, 6:02pm UTC](https://boards.straightdope.com/t/possible-good-comet-coming/1007410/48 "2024-10-18T18:02:06Z")
_ **\>That cactus looks like it was surprised by the comet it while masturbating.** _ A new internet meme! ---
**Author:** ![Bob\_Blaylock](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bob_blaylock/32/3235_2.png) [@Bob\_Blaylock](https://boards.straightdope.com/u/Bob_Blaylock)\ **Post date:** [October 18, 2024, 6:26pm UTC](https://boards.straightdope.com/t/possible-good-comet-coming/1007410/49 "2024-10-18T18:26:29Z")
> [@pjd](#): > > Odd. It’s just that Bob\_Blaylock said that the meteors and aircraft were on the left, but > in that pic they’re on the right…   Sometimes, I get left/right mixed up, and in this case, I misspoke.  The two brighter streaks, that I assumed to be meteors, that I was referencing, are on the right.  I later realized that there are two , much fainter streaks, on the left. ---
**Author:** ![Spectre\_of\_Pithecanthropus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/spectre_of_pithecanthropus/32/12343_2.png) [@Spectre\_of\_Pithecanthropus](https://boards.straightdope.com/u/Spectre_of_Pithecanthropus)\ **Post date:** [October 18, 2024, 7:04pm UTC](https://boards.straightdope.com/t/possible-good-comet-coming/1007410/50 "2024-10-18T19:04:54Z")
> [@pjd](#): > > It’s just that Bob\_Blaylock said that the meteors and aircraft were on the left, but > in that pic they’re on the right… I did notice that as well. ---
**Author:** ![pjd](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pjd/32/3009_2.png) [@pjd](https://boards.straightdope.com/u/pjd)\ **Post date:** [October 18, 2024, 7:28pm UTC](https://boards.straightdope.com/t/possible-good-comet-coming/1007410/51 "2024-10-18T19:28:04Z")
Ah ! That explains it ! ---
**Author:** ![Spectre\_of\_Pithecanthropus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/spectre_of_pithecanthropus/32/12343_2.png) [@Spectre\_of\_Pithecanthropus](https://boards.straightdope.com/u/Spectre_of_Pithecanthropus)\ **Post date:** [October 19, 2024, 2:20am UTC](https://boards.straightdope.com/t/possible-good-comet-coming/1007410/52 "2024-10-19T02:20:02Z")
> [@Dr.Strangelove](#): > > Taken on Sunday at Henry W Coe state park south of the the CA Bay Area. Great shot, especially from a phone and in an urban area. ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [October 19, 2024, 2:24am UTC](https://boards.straightdope.com/t/possible-good-comet-coming/1007410/53 "2024-10-19T02:24:25Z")
South San Jose, maybe Morgan Hill. Not 100% sure. The bright lights over the horizon are planes flying into SJC, which unfortunately didn’t help the light pollution situation. But yeah, still a decent shot given the conditions. I did bring a DSLR but the shots ended up worse. Stabilization + advanced postprocessing does wonders! ---
**Author:** ![Spectre\_of\_Pithecanthropus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/spectre_of_pithecanthropus/32/12343_2.png) [@Spectre\_of\_Pithecanthropus](https://boards.straightdope.com/u/Spectre_of_Pithecanthropus)\ **Post date:** [October 19, 2024, 2:35am UTC](https://boards.straightdope.com/t/possible-good-comet-coming/1007410/54 "2024-10-19T02:35:04Z")
@Dr\_Strangelove Are those incoming airplanes below the comet? ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [October 19, 2024, 2:40am UTC](https://boards.straightdope.com/t/possible-good-comet-coming/1007410/55 "2024-10-19T02:40:47Z")
The big one is, for sure. Not 100% sure about the smaller one–I forgot to check if there was a bright star/planet in that position. It disappeared not long after, either because the plane turned, or the star/planet went below the horizon. ---
**Author:** ![Spectre\_of\_Pithecanthropus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/spectre_of_pithecanthropus/32/12343_2.png) [@Spectre\_of\_Pithecanthropus](https://boards.straightdope.com/u/Spectre_of_Pithecanthropus)\ **Post date:** [October 19, 2024, 4:35am UTC](https://boards.straightdope.com/t/possible-good-comet-coming/1007410/56 "2024-10-19T04:35:41Z")
> [@Dr.Strangelove](#): > > The big one is, for sure. Not 100% sure about the smaller one I checked my astronomy app. The smaller one must have been an aircraft too; there weren’t any stars that could be that bright at dusk, and Venus was well out of the frame to the left. Also it makes sense that incoming planes would be lined up like that when seen head-on. ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [October 19, 2024, 6:18am UTC](https://boards.straightdope.com/t/possible-good-comet-coming/1007410/57 "2024-10-19T06:18:58Z")
Thanks for checking. I was _pretty_ sure that was the case, just not certain. I did see the bright “star” to the left. Thought it was likely Venus, but it also seemed possible that it was another bright object and the one below was Venus instead. Which app do you use? SkySafari is pretty good. A friend of mine (cubesat collaborator) wrote it. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [October 19, 2024, 6:59am UTC](https://boards.straightdope.com/t/possible-good-comet-coming/1007410/58 "2024-10-19T06:59:13Z")
> [@Spectre\_of\_Pithecanthropus](#): > > For darks you leave all your camera settings the same as they were for the lights, but now you thoroughly black out your lens. My late, great Sony F707 took exposures up to 30 seconds. For anything 2.5 seconds and longer it took a mandatory equal time dark frame, then took forever computing the two together. (There was no need to use the lens cap for the dark crame). [Previous page](https://boards.straightdope.com/t/possible-good-comet-coming/1007410.md?page=2)