8Likes
LinkBack URL
About LinkBacksLately I've been trying to get a handle on precession of the equinoxes but I'm finding it a little tricky to understand. Is it due to a rotation of earth's rotation axis or is there something else involved? Maybe the something else is actually different precession by a different name. As you can see I'm just a little confused.
Welcome to the Astronomy Forums | Telescope Forums & Reviews | Astronomy Community.. Please login below or register now.
Results 1 to 9 of 9
Thread: Precession confusion
- 03-16-2016, 10:09 PM #1
Bright Giants
Achievements:
- Join Date
- May 2012
- Location
- Calgary Canada
- Posts
- 563
- Points
- 7,061
- Level
- 58
- Thanks
- 54
- Thanked 104x 97 Posts
Precession confusion
Skywatcher 90mm refractor, Skywatcher 8" traditional Dob
- 03-16-2016, 11:17 PM #2
Bright Giants
Achievements:
- Join Date
- May 2012
- Location
- Calgary Canada
- Posts
- 563
- Points
- 7,061
- Level
- 58
- Thanks
- 54
- Thanked 104x 97 Posts
Re: Precession confusion
I'll try to clarify the question. Something causes a change in which star is our north star. Right now it is Polaris. Over time that will change. Is that due to precession and what type of precession is that? Another thing that happens is that perihelion, I believe, will change seasons over time. Right now it is in January but will change over time. Is this another type of precession?
Am I asking too much?Skywatcher 90mm refractor, Skywatcher 8" traditional Dob
- 03-16-2016, 11:33 PM #3
HYPER GIANT
Achievements:
- Join Date
- May 2014
- Location
- Everett, WA
- Posts
- 2,663
- Points
- 16,524
- Level
- 88
- Thanks
- 661
- Thanked 1,027x 787 Posts
Re: Precession confusion
From my understanding, earths rotation has a slight 'wobble' to it so over time the 'north star' will change. Someone else smarter than I will have to chime in for more details (or any corrections in my statement).
https://en.wikipedia.org/wiki/Precession-Oliver
To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
:
To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
XT8i, Zhumell Z12
EP's: Orion Expanse 9mm, Tele Vue 10mm Delos, ES 68° 16mm, ES 68° 24mm, 2" Q70 32mm, 2x Orion Shorty
To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
(and various Plossls)
Bino's: 12x42, 12x60
- 03-16-2016, 11:41 PM #4
Super Moderator
Achievements:
Awards:
- Join Date
- Jan 2016
- Location
- Slovakia
- Posts
- 19,555
- Points
- 84,714
- Level
- 100
- Thanks
- 3,712
- Thanked 6,028x 5,064 Posts
- Blog Entries
- 5
Re: Precession confusion
This explains it fairly well. Right omeek, It wobbles on its axis (23.5*) every 26 000 years
https://www.youtube.com/watch?v=0qHjtp4cdCARefractors: Antares 105 f/15, Celestron 150 f/8, Stellarvue NHNG 80 f/6.9, TAL 100RS f/10, TS 102 f/11, UR 70 f/10, Vixen SD115s f/7.7
Mounts: Celestron SLT w/ pier mod & EQ-3 tripod, Celestron hypertuned CG-5 w/ tracking motor & Argo Navis, Manfrotto 028B w/ Stellarvue M2C, Manfrotto 055PRO w/ 128RC, TAL-1 HD EQ, Vixen SXP w/ HAL-130 SXG & half pier
Diagonals: 2" Astro-Physics MaxBright, 2" Zeiss/ Baader prism, 2" Baader Herschel Wedge (Photo Version), 2"
To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
Amici prism, 2" Stellarvue Dielectric, 2" TeleVue Everbrite
Eyepieces: A-Z
To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
The weakest link in the optical chain is the large nut located directly behind the
To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
/ camera. - Gabrielle
Ya gotta keep this Apo/
To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
thing in some balance of perspective. Apos are awesome, but long focus Achros aren't that far behind them - Siriusandthepup (CN)
Refractors kick arse precisely because they don't hide behind excuses. That is, they have no obstructions to hide behind. - Jon Isaacs (CN)
-
The Following User Says Thank You to Gabby76 For This Useful Post:
omeek (03-16-2016)
- 03-17-2016, 12:21 AM #5
Bright Giants
Achievements:
- Join Date
- May 2012
- Location
- Calgary Canada
- Posts
- 563
- Points
- 7,061
- Level
- 58
- Thanks
- 54
- Thanked 104x 97 Posts
Re: Precession confusion
Yeah I get that part. That's what I meant by the rotation of earth's rotation axis but the other thing is the change in perihelion over time. I think that's some kind of precession also.
Skywatcher 90mm refractor, Skywatcher 8" traditional Dob
- 03-17-2016, 12:35 AM #6
HYPER GIANT
Achievements:
- Join Date
- Jul 2014
- Location
- Independence, MO
- Posts
- 4,394
- Points
- 29,208
- Level
- 100
- Thanks
- 5
- Thanked 1,375x 960 Posts
Re: Precession confusion
The Earths orbit is an ellipse. The perihelion and aphelion shift sligntly each year. Think of a spirograph....
It's called Apsidal precession
https://en.wikipedia.org/wiki/Milank....6_smaller.gif
ScottCelestron Classic 8, Old Sears 60mm f/15 refractor, Old Edmund Scientific 6 inch F/8 newt, GSO 2" Diag, ES 30mm/70, ES 25mm/70,
To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
32 Super Plossl, Mead 24mm MA,
X-Cel LX 18mm, Luminos 15mm, F/6.3 reducer, Luminos 2.5x
To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
, Telrad, Celestron 9x50 RACI, DIY Baader Solar Filter, Celestron Skymaster 20x80, Bresser EXOS-2
To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
, Revolution Imager R1
To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
No trees were killed in the sending of this post. However, a large number of electrons were terribly inconvenienced
To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
-
The Following User Says Thank You to smeyer8015 For This Useful Post:
rayian (03-17-2016)
- 03-17-2016, 12:37 AM #7
Super Moderator
Achievements:
Awards:
- Join Date
- Nov 2010
- Location
- Nova Scotia
- Posts
- 25,217
- Points
- 173,721
- Level
- 100
- Thanks
- 6,660
- Thanked 14,992x 9,547 Posts
- Blog Entries
- 3
Re: Precession confusion
... and yes, the precession of the perihelion point of the Earth's orbit is different from the precession of the Earth's axis/equinox.
To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
DSO AP:
To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
Newtonian Astrograph; ATIK 383L+; EFW2 filter wheel; Astrodon Ha,LRGB filters; KWIQ/QHY5 guide
To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
; Planetary AP: Celestron C-11; ZWO ASI120MC; Portable: Celestron C-8 on
To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
pro; C-90 on wedge; 20x80 binos; Etc: Canon 350D; Various EPs, etc. Obs: 8' Exploradome;
To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
(pier);
To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
.
To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
- 03-17-2016, 12:58 AM #8
Bright Giants
Achievements:
- Join Date
- May 2012
- Location
- Calgary Canada
- Posts
- 563
- Points
- 7,061
- Level
- 58
- Thanks
- 54
- Thanked 104x 97 Posts
Re: Precession confusion
Ahhh. Apsidal precession. That helps. I just couldn't see how axial precession could have the effect of changing the season of perihelion. Hence, confusion.
Skywatcher 90mm refractor, Skywatcher 8" traditional Dob
- 05-10-2018, 06:46 PM #9
Banned
Achievements:
- Join Date
- May 2018
- Location
- Miami
- Posts
- 3
- Points
- 22
- Level
- 1
- Thanks
- 0
- Thanked 0x 0 Posts
Re: Precession confusion
certainly the orbit has a slight mismatch and the northern star will change position over time
Similar Threads
-
precession
By Yokel in forum UK Astronomy ForumReplies: 2Last Post: 01-05-2010, 12:50 AM -
Precession of the Solstices
By Dennis Allen in forum Amateur Astronomy ForumReplies: 10Last Post: 10-07-2009, 01:48 PM -
Precession question
By Dennis Allen in forum Amateur Astronomy ForumReplies: 2Last Post: 01-25-2007, 01:22 PM -
precession of the equinoxes?
By Tom Linden in forum Solar Viewing ForumReplies: 0Last Post: 11-05-2006, 08:01 PM
