Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Where is Jupiter's Great Red Spot?

  • Please log in to reply
38 replies to this topic

#1 hlee

hlee

    Explorer 1

  • -----
  • topic starter
  • Posts: 67
  • Joined: 13 Jun 2021
  • Loc: Toronto, Ontario, Canada

Posted 15 July 2021 - 07:25 AM

Last night was the first cloudless night we've had in, I guess two weeks (due to general bad weather and the disruption cased by Tropical Storm Elsa).

 

I was able to observe Jupiter to 100x.  I was seeing (or imagine I was seeing) cloud bands.  I know with Jupiter and my refractor (Meade Adventure Scope 80), I'm at about the limits of my equipment.

 

Anyway, my question is:  Using my 4mm and a mirror diagonal, should I be looking for the Great Red Spot below or above the equator?  Every printed photo that I've ever seen shows GRS below the equator.  If I am looking for GRS below the equator with a refractor, I guess it means that I should be looking for GRS above the equator with a reflector - if I had one?  Does this confuse anybody else?  The GRS might be on the far side and Jupiter rotates once every 10 hours, but I'm not about to wait several hours for a feature that I may or may not be able to see.

 

I know that there is no right-side up or upside-down in space, but is there a convention where publishers/media sources invert/flip their images to match what we see?  I know they do that with the Moon, otherwise images would look strange to us.  Come to think of it, doesn't that do injustice to those people in the Southern Hemisphere, since they see the Moon (and Jupiter) upside-down (sorry, inverted - I'm trying not to be biased)?  My guess is there a Northern Hemisphere bias when it comes to astrophotography.

 

Taking this further, do amateur astronomers invert/flip their images (i.e., not just up-down but left-right) taken through their scopes to match what the human eye would see?  So a lunar photographer in Australia would flip their images left-right to match what they see but not necessarily up-down - since they see the Moon that way, anyway?  Or are they happy just to show what their cameras sees through their scopes without inverting/flipping?  I know that for the vast majority of astro images, it doesn't really matter, but for Jupiter and the Moon, it sort of does?

 

I think I might be answering my own question here, because I seem to remember the Horsehead Nebula with the horse's head always looking to the left.  So if people see their images with the horse's head looking the other way, they mirror flip the image to correct it.



#2 Dynan

Dynan

    Fly Me to the Moon

  • *****
  • Posts: 6,077
  • Joined: 11 Mar 2018
  • Loc: NOLA

Posted 15 July 2021 - 07:58 AM

If you're from OZ and come north of the Equator and observe or image outer space, you have to stand on your head...and vice versa. (He's no fun! He fell right over!)



#3 spereira

spereira

    Fly Me to the Moon

  • *****
  • Moderators
  • Posts: 6,542
  • Joined: 21 Apr 2017
  • Loc: Bedford, NH

Posted 15 July 2021 - 08:03 AM

Moving to Solar System Observing.

 

smp



#4 Migwan

Migwan

    Mercury-Atlas

  • *****
  • Posts: 2,792
  • Joined: 24 Jul 2017
  • Loc: Meeechigan

Posted 15 July 2021 - 08:11 AM

 GRS

 

It's on the SEQ (southern equatorial belt).  In right left reversed SCT and refractors, it appears to be on the lower belt.   In up down reversed Newtonian, it would appear to be on the top belt.


Edited by Migwan, 15 July 2021 - 08:12 AM.

  • E_Look, Redbetter and Mark Lovik like this

#5 Special Ed

Special Ed

    Voyager 1

  • *****
  • Posts: 11,416
  • Joined: 18 May 2003
  • Loc: Greenbrier County, WV 38N, 80W

Posted 15 July 2021 - 08:27 AM

hlee,

 

Since you have a refractor with a diagonal, your view is mirror-reversed.  Ordinarily, it is North up and mirror-reversed with west to the left, but that can vary depending on what position your diagonal is in. 

 

The best way to determine the cardinal directions in your scope's field of view is to let the untracked target drift out of the fov--the direction of the drift is west (preceding).  In your mirror-reversed view, north will be 90 degrees clockwise from west.

 

The GRS is in the Jovian southern hemisphere.  It is partly embedded in the southern part of the South Equatorial Belt (SEB)  and partly in the South Tropical Zone (STrZ).  It is a pale pinkish/salmon/orangish color but is still noticeable.  This is a calculator that can tell you when the GRS will be transiting:

 

https://skyandtelesc...great-red-spot/

 

Good luck with your Jupiter observations!


  • tturtle, Sasa, ShaulaB and 4 others like this

#6 kel123

kel123

    Vanguard

  • -----
  • Posts: 2,073
  • Joined: 11 May 2019

Posted 15 July 2021 - 08:32 AM

In my opinion I don't think you will be looking for the GRS if it is facing the earth. It is easy enough to notice.

#7 vtornado

vtornado

    Skylab

  • *****
  • Posts: 4,147
  • Joined: 22 Jan 2016
  • Loc: 42N 88W

Posted 15 July 2021 - 08:59 AM

The spot has lost some of its redness over the years, it is a little harder to pick out.

Also the spot rotates with Jupiter (every 13 hrs).  So it may be on the back side when you are looking.


  • Gregg Carter, Diana N, therealdmt and 1 other like this

#8 hlee

hlee

    Explorer 1

  • -----
  • topic starter
  • Posts: 67
  • Joined: 13 Jun 2021
  • Loc: Toronto, Ontario, Canada

Posted 15 July 2021 - 09:10 AM

In my opinion I don't think you will be looking for the GRS if it is facing the earth. It is easy enough to notice.

Thank you to everyone for their prompt replies.  I will be looking for the Great Red Spot below Jupiter's equator.

 

Unfortunately, using my scope (ST80 clone), I'm not sure that I can see the GRS if it is facing the earth, given that even the cloud bands are difficult to see.  For example, last night I was also looking at Saturn, and I could not make out the Cassini division at all, unless I go ahead and imagine that I see it!



#9 rblackadar

rblackadar

    Mariner 2

  • *****
  • Posts: 244
  • Joined: 01 Mar 2019
  • Loc: Northern California (Mt. Tam)

Posted 15 July 2021 - 09:42 AM

I usually check the GRS position in Stellarium before observing -- or else afterward, to see if I somehow missed it. And sometimes I do miss it, even with my 8". It all depends on seeing. In general I think it will be very difficult in an ST80 -- I own one and definitely have never seen the GRS in it. (But I don't use it regularly for planets.) Your mileage may vary...

 

Stellarium can't be 100% accurate on the GRS but I've found it to be pretty reliable. Highly recommend downloading a copy, if you don't already have one.



#10 kel123

kel123

    Vanguard

  • -----
  • Posts: 2,073
  • Joined: 11 May 2019

Posted 15 July 2021 - 09:49 AM

I own Orion 90mm f/10 astroview. I regularly see it with the scope. I guess my opinion was compromised by that experience. Of course, the magnification and extra aperture should matter alongside seeing conditions.

#11 Migwan

Migwan

    Mercury-Atlas

  • *****
  • Posts: 2,792
  • Joined: 24 Jul 2017
  • Loc: Meeechigan

Posted 15 July 2021 - 09:51 AM

Not this year, but I've seen it in an ST80 at 32x.  It's pretty much a dot at that power, so descent seeing is a must and knowing where to expect to see it helps a lot.   As mentioned above, it isn't as dark as it has been in the past.   I can't recall seeing the Cassini Division with the ST80.   



#12 CBM1970

CBM1970

    Explorer 1

  • -----
  • Posts: 97
  • Joined: 09 Jan 2021
  • Loc: Southern Maine

Posted 15 July 2021 - 11:55 AM

There is a great Sky & Telescope page that has daily info on GRS transit times. I have used it successfully a few times, but I don't have the link at present.

The last time I was out I forgot to check it, but I thought I saw the GRS. I took some smartphone photos of Jupiter at 150x looked at the photos, and immediately saw it.

After that I knew right where to look for it, and I saw it easily in the eyepiece at 150x and a bit later at 125x. (I didn't go lower than that.)
It didn't stand out a great deal, and the color seemed similar to nearby bands (to my eyes at least). Still kinda amazing.

All my pics are reflector views, and I usually leave them as-is. Maybe this puts me one step closer to a visit to the Southern Hemiphere.

#13 Dave Mitsky

Dave Mitsky

    ISS

  • *****
  • Moderators
  • Posts: 98,918
  • Joined: 08 Apr 2002
  • Loc: PA, USA, Planet Earth

Posted 15 July 2021 - 12:19 PM

There is a great Sky & Telescope page that has daily info on GRS transit times. I have used it successfully a few times, but I don't have the link at present.

https://skyandtelesc...great-red-spot/


  • sevenofnine and CBM1970 like this

#14 Dave Mitsky

Dave Mitsky

    ISS

  • *****
  • Moderators
  • Posts: 98,918
  • Joined: 08 Apr 2002
  • Loc: PA, USA, Planet Earth

Posted 15 July 2021 - 12:25 PM

Thank you to everyone for their prompt replies.  I will be looking for the Great Red Spot below Jupiter's equator.

 

Unfortunately, using my scope (ST80 clone), I'm not sure that I can see the GRS if it is facing the earth, given that even the cloud bands are difficult to see.  For example, last night I was also looking at Saturn, and I could not make out the Cassini division at all, unless I go ahead and imagine that I see it!

I'm afraid that you're right.  An 80mm f/5 achromat isn't the best telescope with which to observe Jupiter.  Your northern latitude isn't helping either.


  • BFaucett likes this

#15 vtornado

vtornado

    Skylab

  • *****
  • Posts: 4,147
  • Joined: 22 Jan 2016
  • Loc: 42N 88W

Posted 16 July 2021 - 07:44 AM

I have not tried this, but maybe a blue #82a, very light blue, filter might help tease the spot out.

Some folks use this filter on Jupiter to enhance detail.

You can also try an #8 this is a cheap way to knock back chromatic abberation a bit.

 

These filters should be available for about $10.00 a piece.   I would NOT buy a filter kit as most of the filters

are way to dark for a small scope and do not include these filters.

 

What time are you looking?  View Jupiter when it is at the Meridian (North South line)   Unfortunately that is at 3:30 AM. bawling.gif

 

There are sites where you can lookup "seeing" conditions.  Mid continent, seeing is usually the best with high humidity and a calm wind regime.

 

I think ... that if you are persistent you can get it. 


Edited by vtornado, 16 July 2021 - 07:45 AM.


#16 smasraum

smasraum

    Viking 1

  • -----
  • Posts: 959
  • Joined: 13 Jan 2008
  • Loc: Houston, TX

Posted 16 July 2021 - 08:20 AM

The last time that I saw the GRS it didn't look like the what you see in photos at all.  I didn't see any red.  What I saw looked like a bite taken out of a band. But, Stellarium showed me exactly what I'd seen with the exception of the more vibrant colors, so I do know that I saw it.


Edited by smasraum, 16 July 2021 - 08:38 AM.


#17 hlee

hlee

    Explorer 1

  • -----
  • topic starter
  • Posts: 67
  • Joined: 13 Jun 2021
  • Loc: Toronto, Ontario, Canada

Posted 16 July 2021 - 05:31 PM

I have not tried this, but maybe a blue #82a, very light blue, filter might help tease the spot out.

Some folks use this filter on Jupiter to enhance detail.

You can also try an #8 this is a cheap way to knock back chromatic abberation a bit.

 

These filters should be available for about $10.00 a piece.   I would NOT buy a filter kit as most of the filters

are way to dark for a small scope and do not include these filters.

 

What time are you looking?  View Jupiter when it is at the Meridian (North South line)   Unfortunately that is at 3:30 AM. bawling.gif

 

There are sites where you can lookup "seeing" conditions.  Mid continent, seeing is usually the best with high humidity and a calm wind regime.

 

I think ... that if you are persistent you can get it. 

I was looking at Jupiter at 2:00 AM.  It was pretty high in the sky at the time.  I didn't get a chance this morning because of clouds.  The forecast for tonight is rain.  When you get into this hobby, you start to realize just how few nights are actually available to you for observing.


  • E_Look, tturtle, Dynan and 1 other like this

#18 Dave Mitsky

Dave Mitsky

    ISS

  • *****
  • Moderators
  • Posts: 98,918
  • Joined: 08 Apr 2002
  • Loc: PA, USA, Planet Earth

Posted 16 July 2021 - 06:49 PM

I have not tried this, but maybe a blue #82a, very light blue, filter might help tease the spot out.

Some folks use this filter on Jupiter to enhance detail.

I sometimes use a Wratten #80A blue filter to enhance the GRS.  However, I don't think that I've ever tried it with one of my 80mm refractors.  Seeing the GRS has always been a matter of using sufficient aperture for me.

 

https://agenaastro.c...ary-filter.html

 

https://sas-sky.org/...al-Filters1.pdf

 

https://www.cloudyni...servation-r3261



#19 rhetfield

rhetfield

    Surveyor 1

  • *****
  • Posts: 1,901
  • Joined: 14 Aug 2019
  • Loc: Suburban Chicago, IL, USA

Posted 19 July 2021 - 03:34 PM

Thank you to everyone for their prompt replies.  I will be looking for the Great Red Spot below Jupiter's equator.

 

Unfortunately, using my scope (ST80 clone), I'm not sure that I can see the GRS if it is facing the earth, given that even the cloud bands are difficult to see.  For example, last night I was also looking at Saturn, and I could not make out the Cassini division at all, unless I go ahead and imagine that I see it!

It does not help that you are up north and the planets are low in the sky.  That makes for more atmospheric interference.  Also you may have smoke to hinder you and certainly have haze.  Being at only 100x magnification makes the job harder also.

 

As others have pointed out, the red spot is not so red anymore and it often just looks like a wide spot in the band.  In my haze, I often can't see the Cassini division even at 140x.  


  • Diana N and vdog like this

#20 vdog

vdog

    Vanguard

  • *****
  • Posts: 2,079
  • Joined: 30 Aug 2018
  • Loc: California Central Valley, U.S.A.

Posted 19 July 2021 - 08:44 PM

As others have pointed out, the red spot is not so red anymore and it often just looks like a wide spot in the band.  In my haze, I often can't see the Cassini division even at 140x. 

Well, this is comforting.  Here I was thinking there was something wrong with my vision keeping me from seeing the GRS.  Yep, and the Cassini division is getting tougher too.



#21 Dave Mitsky

Dave Mitsky

    ISS

  • *****
  • Moderators
  • Posts: 98,918
  • Joined: 08 Apr 2002
  • Loc: PA, USA, Planet Earth

Posted 19 July 2021 - 10:00 PM

The GRS has not looked very red to me for quite some time. 

 

In addition to displaying a generally paler "salmon" color in recent years, the GRS has been shrinking for over a century.

 

https://skyandtelesc...nking-red-spot/

https://skyandtelesc...spot-shrinking/

 

https://skyandtelesc...great-red-spot/

 

https://skyandtelesc...r-but-stronger/


  • Diana N and Redbetter like this

#22 Redbetter

Redbetter

    Voyager 1

  • *****
  • Posts: 11,151
  • Joined: 16 Feb 2016
  • Loc: Central Valley, CA

Posted 20 July 2021 - 02:09 AM

The GRS goes through color phases over periods of years (typically).  It wasn't very red for quite some time, then it became nice and red again for a few years, and now the color is weak and the size is smaller too.  This makes it a challenge for smaller scopes when the seeing is poor/mediocre.  The color contrast really suffers from poor seeing, even in large aperture.  It isn't obvious how much of this is due to seeing blur until you get a night of good seeing--the colors begin to pop.  

 

An 80 f/5 achro suffers considerably because of its inherent chromatic aberration, even in a good sample.  (I have a good one, and one not as good.)  There is a lot of chromatic aberration in this scope, and this blurs color contrast.  Mine operates more like a 60ED in terms of detail.

 

Unfortunately, blue filters have a big weakness in scopes with poor color correction.  The blue CA is the most noticeable/damaging visually, so using a filter that accentuates this tends to make the image worse/less detailed.  That has been my experience even with a 110ED that has some blue color fringing.  The other negative for blue is that it is scattered more by our atmosphere, and it seems to be more seeing sensitive as well.



#23 Redbetter

Redbetter

    Voyager 1

  • *****
  • Posts: 11,151
  • Joined: 16 Feb 2016
  • Loc: Central Valley, CA

Posted 20 July 2021 - 05:58 AM

I took a look tonight in poor seeing (lots of twinkle for stars) at the GRS with my Meade AS80.  I viewed the GRS as it transited about 1/4 of the way across and at 1/2 (on the central meridian of the planet.)  The GRS was detected even at 60x, but merely as a darker contrast bump extending south from the SEB.  At 80x it is more apparent, and between that and 100x were the best for showing the general nature, with hints of some separation from the SEB itself in averted vision.  Beyond that was too much magnification for the scope and conditions.  

 

Exit pupils these small aren't revealing the color contrast of the GRS, at least not in these conditions.  I was seeing the spot primarily because I knew what it looks like already, and can identify it when it is visible, even in smaller scopes.  That doesn't mean it is well seen or has its characteristic hue--a novice likely will not recognize it the first time unless someone points it out to them.  There is a uniform violet halo around the planet with this scope.  



#24 hlee

hlee

    Explorer 1

  • -----
  • topic starter
  • Posts: 67
  • Joined: 13 Jun 2021
  • Loc: Toronto, Ontario, Canada

Posted 20 July 2021 - 07:42 AM

Well, the rains have gone but we've had pink hazy skies the past two nights, because the smoke from all the B.C. fires (correction: Northwestern Ontario fires) have finally reached Toronto.  The stars are completely washed out by this pink glow, with only the moon and Jupiter being visible.  Saturn couldn't be seen at all.

 

Last night I looked at Jupiter at about 4:00 a.m.  I could see the NEB but not the SEB.  Maybe it's because of all that haze, but I wasn't even getting the occasional glimpses of the SEB.

 

It was still worth a look though, if only to see the moons changing their position each night.


Edited by hlee, 20 July 2021 - 08:00 AM.


#25 Dave Mitsky

Dave Mitsky

    ISS

  • *****
  • Moderators
  • Posts: 98,918
  • Joined: 08 Apr 2002
  • Loc: PA, USA, Planet Earth

Posted 20 July 2021 - 12:39 PM

Due to the wildfire smoke, the Moon and Jupiter were the only astronomical objects that I saw last night too.


  • tommy10 likes this


CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics