Return to the Cloudy Nights Telescope Reviews home pageAstronomics discounts for Cloudy Nights members
· Get a Cloudy Nights T-Shirt · Submit a Review / Article

Click here if you are having trouble logging into the forums

Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User

Astrophotography and Sketching >> Sketching

Pages: 1 | 2 | 3 | 4 | 5 | (show all)
Asbytec
Guy in a furry hat
*****

Reged: 08/08/07

Loc: La Union, PI
Re: Stray's Sketchbook new [Re: stray1]
      #5555090 - 12/05/12 04:22 AM

Oh! Festoons! Yea, probably for sure, Stray. First off, you are making great strides and repeating the same nervous behavior I engage in, sipping coffee...walking around...then going back to look. Not a bad habbit, really. Relax a little.

Okay, at 0730UT on 5 Dec, you were at System I meridian (EZ and EQ belts, basically) of ~34 degrees.

You can find that here. http://www.arksky.org/newcmcalc.htm

Now, double check from here (or the CN imaging forum, but they almost never list what longitude they imaged.)
http://alpo-j.asahikawa-med.ac.jp/Latest/Jupiter.htm

Initial look shows some images at Sys I ~50 degrees. Close enough for an initial peek. Guess what? Two faint festoons! Well done!

http://alpo-j.asahikawa-med.ac.jp/kk12/j121204z.htm



Post Extras: Print Post   Remind Me!   Notify Moderator  
frank5817
Postmaster
*****

Reged: 06/13/06

Loc: Illinois
Re: Stray's Sketchbook new [Re: Asbytec]
      #5556404 - 12/05/12 08:54 PM

-stray- The sketching collection keeps growing here - very fine work.

Frank


Post Extras: Print Post   Remind Me!   Notify Moderator  
stray1
sage


Reged: 09/03/12

Loc: SW Ohio
Re: Stray's Sketchbook new [Re: frank5817]
      #5556872 - 12/06/12 04:12 AM Attachment (14 downloads)

Thanks everyone for your pervious comments. They are greatly appreciated!

I tried something different this morning during my Jupiter observation. Rather than sketch it and then attempt to transfer over to paint.net, I simply scanned the sketch that I made at my rig and cleaned it up a little. I think this results in an image somewhat closer to what I am actually seeing thru my EP.

I believe that I captured another festoon along the lower edge of the NEB as well as a couple of areas where the EZ seemed to “cut” into the NEB and SEB. The SEB seemed thinner than usual, but I think this because the GRS had just passed through and churned things up a bit (did not see the GRS). The NPR and NTB were apparent (NPR smaller than usual) as well as the SPR (usually small for me with few exceptions) but, nothing south of the SEB was detectable (basically a void). Additionally, I am beginning to detect that both big belts take on a “speckled” appearance, like they were hit with a thin stream of white from an airbrush; however, I cannot say that I am actually seeing white spots, etc. These details are vague for me.

According to the notes that I jotted down before going outside (sometimes I get distracted and forget my purpose…heck, sometimes I forget to jot notes) my objectives this session were: a) split the NEB, b) detect festoons, and c) detect the GRS (according to Stellarium it should have just been visible along the preceding limb).

a) Split the NEB: No.

b) Detect festoons: Yes (at least a dark spot/blob in the proper location…lol).

c) Detect GRS: No.

Before packing up for the morning I swung over and had a peek at M42/43. Outstanding! I also swung over to take a gander at ETA Cas but, alas, Cas had settled into the LP dome to my north. Plus, a thin layer of clouds was beginning to move in. Rain in the forecast over the next couple of days. T-storms on Saturday


Post Extras: Print Post   Remind Me!   Notify Moderator  
stray1
sage


Reged: 09/03/12

Loc: SW Ohio
Re: Stray's Sketchbook new [Re: stray1]
      #5556873 - 12/06/12 04:15 AM

Oh, yeah, Norme, thank you very kindly for the links. These will be invaluable to me in the future. Now, if I can just figure out what System(s) I-III mean...



-stray-


Post Extras: Print Post   Remind Me!   Notify Moderator  
Asbytec
Guy in a furry hat
*****

Reged: 08/08/07

Loc: La Union, PI
Re: Stray's Sketchbook new [Re: stray1]
      #5556892 - 12/06/12 04:51 AM

Me, too Stray.

Best I can derive, system I is the faster rotating system of belts that include the EZ and most of the NEB and SEB. North and south of that region are the north and south tropical, temperate, and polar regions. That is system II, the slower rotating cloud belts. System II I believe is radio frequencies and we can safely ignore it.

Your sketching is great and your observing seems to have improved. You're getting much closer to what your scope can deliver. It may have a little more to offer.

The dents on the underside of the NEB are probably caused by festoon "roots" bulging into the EZ. This gives it that undulating appearance, and some parts are darker as you've shown.

Not sure what caused that dent in the north of the SEB, but it looks interesting. It could be part of the wake. It might also be some of the broader, white features in the southern EZ (SEZ.) Need to check that out.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Chopin
Canis Insanus
*****

Reged: 02/03/05

Loc: In the doghouse.
Re: Stray's Sketchbook new [Re: Asbytec]
      #5557151 - 12/06/12 09:39 AM

I like your computer generated images, but I think I like this pencil sketch even better, Stray! You are really starting to pick up those details well.

I agree that your undulation is undoubtedly caused by festoons, or "festoon roots" as Norme so brilliantly named them. Keep going. You are starting to see that 90mm is capable of digging into the Jovian surface once you recognize the landscape.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Special Ed
Postmaster
*****

Reged: 05/18/03

Loc: Greenbrier Co., WV 38N, 80W
Re: Stray's Sketchbook new [Re: Asbytec]
      #5560494 - 12/08/12 08:00 AM

Stray,

Just got a chance to look at your virtual sketchbook--you have a nice collection of drawings here. Your perserverance in studying and sketching Jupiter is showing results.

Quote:

Best I can derive, system I is the faster rotating system of belts that include the EZ and most of the NEB and SEB. North and south of that region are the north and south tropical, temperate, and polar regions. That is system II, the slower rotating cloud belts. System II I believe is radio frequencies and we can safely ignore it.






Just a slight correction to what Norme says here--System I is the region about 10° north and south of the Jovian equator. System I is basically the Equatorial Zone (EZ).

System II is the rest of Jupiter from 10° N/S to the poles.

I think there is a typo about the radio signal system--it should say System III, not System II.

Good luck with your Jupiter observations!


Post Extras: Print Post   Remind Me!   Notify Moderator  
Asbytec
Guy in a furry hat
*****

Reged: 08/08/07

Loc: La Union, PI
Re: Stray's Sketchbook new [Re: Special Ed]
      #5560495 - 12/08/12 08:06 AM

Thanks, Michael. I never could find a source that said it explicitly. So, I stretched it to the jets in the northern NEB and southern SEB thinking that would be about right.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Special Ed
Postmaster
*****

Reged: 05/18/03

Loc: Greenbrier Co., WV 38N, 80W
Re: Stray's Sketchbook new [Re: Asbytec]
      #5560529 - 12/08/12 08:45 AM

No problemo. And since System I is about 10° N/S, I believe it includes the jets on the northern SEB and the southern NEB.

Here is one source of info about Jupiter.

http://www.britastro.org/jupiter/guide.htm

John Rogers is the head of the Jupiter section of BAA and Damian Peach is one of the best imagers in the world.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Asbytec
Guy in a furry hat
*****

Reged: 08/08/07

Loc: La Union, PI
Re: Stray's Sketchbook new [Re: Special Ed]
      #5560585 - 12/08/12 09:47 AM

Thank you, read that a while back. Still trying to decipher Systems. And, yes, I think system III should be corrected above. It was a typo. I think I got that from you in an earlier post.

But, this is confusing, from the link above.

"DL2: Peak speed in System II (degrees per 30 days), as calculated from the first two columns.
(Note: DL1 = DL2 – 229; DL3 = DL2 – 8.)
Eastward (prograding) jets have positive u3 and negative DL2.
Westward (retrograding) jets have negative u3 and positive DL2."

Okay, first they mention only System II, that's already confusing. But, the positive DL2 retrograde winds are at latitudes ~17N and ~20S. This seems to mean everything between across the EZ, including the NEBs and SEBn, probably blows eastward at varying speeds. Their chart shows that. This is what I thought was system I. Gaa!

If we (meaning me) ever figure this out, it can be referenced in Stray's sketchbook.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Special Ed
Postmaster
*****

Reged: 05/18/03

Loc: Greenbrier Co., WV 38N, 80W
Re: Stray's Sketchbook new [Re: Asbytec]
      #5560712 - 12/08/12 11:19 AM

I think I understand what you are confused about. One source I read says the the EZ extends to about 7° north and south of the Jovian equator.

The jets along the south edge of the NEB (+8-5 degrees latitude)and the north edge of the SEB (-7 degrees latitude) both flow eastward (prograde) and gradually diminish in speed towards the middle of both belts (this drop off in wind speed causes rifts in the NEB according to Peach).

By the time we reach the north edge of the NEB or the south edge of the SEB, the jets have reversed and are flowing westward (retrograde).

One way to remember this is that eastward jets are on the equator side of the belts and westward jets are the polar side of the belts.

You're probably waiting for me to get to the point so here it is. The two Systems have to do with the differential rotation speed of Jupiter, not the wind speed or direction. As you know, System I rotation time is about 5 minutes faster than System II for a full rotation. So maybe the BAA is counting those east flowing jets bordering the EZ and the two main belts as System II because they have been observed to rotate slower than the EZ.

Because we're talking about something with no hard surface there probably isn't a distinct border. When I read this material on the BAA website, I see the words about and approximately from time to time.

Maybe someone like Paul Abel (or Carlos Hernandez) could provide more insight.

One result of this discussion--I usually only include the System II longitude in my drawings. I think I'll start including System I as well.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Asbytec
Guy in a furry hat
*****

Reged: 08/08/07

Loc: La Union, PI
Re: Stray's Sketchbook new [Re: Special Ed]
      #5560751 - 12/08/12 11:40 AM Attachment (14 downloads)

Sure, the EZ and the equatorial belt boundaries do have the faster rotation. And maybe that is the key distinction. I included, as you surmised, a bit more latitude because of the wind direction being the same. In fact, referencing their chart below.

I was not sure if the slower speeds north and south of the EZ were that distinctive in rotational time. Surely winds blowing the opposite direction would, so I made that leap of faith. It's interesting both NEBs and SEBn bordering the EZ rotate at over 220 degrees/month (apparently along with the EZ) while NEBn and SEBs slow considerably and change direction. To change that much in a month would require a pretty large change each day. So, yea, not having read it anywhere, that's how I came about it.

Surely the boundaries are not defined exactly. Makes sense, though. Thanks, interesting and a bit confusing, as is why prograde EZ winds blow in the opposite direction of it's rotation. (Actually, the DL2 figures are, of course, proportional to the wind speed and direction over Jupiter's longitude.)


Post Extras: Print Post   Remind Me!   Notify Moderator  
stray1
sage


Reged: 09/03/12

Loc: SW Ohio
Re: Stray's Sketchbook new [Re: Asbytec]
      #5563422 - 12/10/12 12:51 AM Attachment (15 downloads)

Chop: Thanks for your comment. Yes, I believe that my eye is beginning to catch on to what the 90mm is showing me.

Ed & Norme: Great discussion on the systems! Now we at least have a working knowledge of what is meant by Systems I and II in terms of belts and zones. System III designates the rotation of the planet’s core (I think) and would probably be of little value to us (well, to me at any rate).

Anyway, this weekend has been a bust observing-wise; been overcast and raining/drizzling for the past three days. The sketch below was drawn from a photograph and is another practice drill. I focused specifically on the belts and zones south of the SEB simply because when viewed through my scope this area is a big blank spot. I generated the sketch starting from the SPR and working my way north.

Hopefully this will help me to draw a mental map of the region so that the next time I have it in my EP something will jump out at me similar to the way that the festoons became apparent once I knew what I was looking for. If not, there are always barges and chevrons to seek out.

Sketch was done on printer paper using HB/ 2H pencils and a kneaded art gum eraser. Put no time limit on it. Took about half an hour.



-stray-


Post Extras: Print Post   Remind Me!   Notify Moderator  
stray1
sage


Reged: 09/03/12

Loc: SW Ohio
Re: Stray's Sketchbook new [Re: stray1]
      #5563444 - 12/10/12 01:12 AM

I think I might transfer this over to MP3 format, download it to my Sansa, and listen to it the next time I'm out observing.

https://www.youtube.com/watch?v=ImuLz1Oo9c8

Maybe this one, too.

https://www.youtube.com/watch?v=phhUy1VsnG0



-stray-


Post Extras: Print Post   Remind Me!   Notify Moderator  
stray1
sage


Reged: 09/03/12

Loc: SW Ohio
Re: Stray's Sketchbook new [Re: stray1]
      #5563505 - 12/10/12 02:59 AM

Quote:

I think I might transfer this over to MP3 format, download it to my Sansa, and listen to it the next time I'm out observing.

https://www.youtube.com/watch?v=ImuLz1Oo9c8

Maybe this one, too.

https://www.youtube.com/watch?v=phhUy1VsnG0



-stray-




On second thought, no I won't. It appears that YouTube has gotten a bit "dystopian" as of late concerning MP3 conversions. Something about copyright infringement. Who holds the copyright on the sounds of Jupiter and Io? NASA?

Oh, well...I can still listen to Astronomy Cast.

http://www.astronomycast.com/



-stray-


Post Extras: Print Post   Remind Me!   Notify Moderator  
Asbytec
Guy in a furry hat
*****

Reged: 08/08/07

Loc: La Union, PI
Re: Stray's Sketchbook new [Re: stray1]
      #5563535 - 12/10/12 04:01 AM

Man, if you could hear the planets, well, that would be real observing. Maybe elephants can hear them?

I am wondering if sketching images can suffice as observing practice? Maybe. If nothing else, you are gaining familiarity and learning to get those details down quickly. Can't hurt, have at it. And you have a nice style, surely your real time sketching reflects it.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Chopin
Canis Insanus
*****

Reged: 02/03/05

Loc: In the doghouse.
Re: Stray's Sketchbook new [Re: Asbytec]
      #5563604 - 12/10/12 06:33 AM

Yeah, Stray, that pencil work has a beautiful look to it. If you can start seeing that much detail in your 90mm, you've got it made!

Post Extras: Print Post   Remind Me!   Notify Moderator  
stray1
sage


Reged: 09/03/12

Loc: SW Ohio
Re: Stray's Sketchbook new [Re: Chopin]
      #5565437 - 12/11/12 06:17 AM

Norme: I really hope that my practice sketches using photos are not considered cheating or inappropriate for this forum.

My intent with these is to create a mental map; a neural pathway between my eyeball, by brain, and my fingers so that the next time I'm at the EP if something that I've drawn before "jumps" out at me in real time I can capture it.

Ultimately, does it really matter if my first view was through the EP or from a photo? As I mentioned in a previous post, at the EP I sketch only what I actually see so it's not like I'm going to add some detail just because I think it "should" be there. I try to err to the side of "I doubt it" or "Maybe" .

Jason: Thanks for your comments on the pencil sketch. My fingers really are making the effort to loosen up a bit.

As for the 90mm, I assure you that it is showing me a lot more than I'm currently seeing. I took that color/hue test that was posted on one of your threads. Discerning subtle differences between the yellow/brown end of the scale is on of my weaknesses.

Figures...



-stray-


Post Extras: Print Post   Remind Me!   Notify Moderator  
Chopin
Canis Insanus
*****

Reged: 02/03/05

Loc: In the doghouse.
Re: Stray's Sketchbook new [Re: stray1]
      #5565471 - 12/11/12 07:23 AM

Mark, you couldn't have been cursed with a more challenging color weakness. Often times, individuals with less sensitive color perception are blessed with higher sensitivity to contrasts. Just draw what you see. The more you draw, the more you'll see.

As for the 90mm, I agree that you will definitely be able to see much more as you get better nights of seeing, and train your brain to pick up those minute details. AFAIC the 90mm refractor is darned near the perfect all around "living room" scope. Keep it setup near the couch with a couple of key eyepieces and grab it when you want. Very little cool down time, less transport weight, yet still enough aperture for most nights. I'd love to trade up from my AT 72-ED to a TMB 92-L. I can't imagine a better grab and go scope on the market. But I digress.

Keep up what you're doing with the practice sketches. It's an exercise that is helping you enjoy the hobby. And like Michael (Special Ed) pointed out in one of my recent threads, amateur literally means: for the love of it.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Asbytec
Guy in a furry hat
*****

Reged: 08/08/07

Loc: La Union, PI
Re: Stray's Sketchbook new [Re: stray1]
      #5565473 - 12/11/12 07:26 AM

Mark, I hope I did not imply such. I know you're practicing. I was just commenting off the cuff about how it might help and wondering myself. I couldn't tell ya, I hope it does.

Edited by Asbytec (12/11/12 07:30 AM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | 3 | 4 | 5 | (show all)


Extra information
2 registered and 11 anonymous users are browsing this forum.

Moderator:  cildarith, JayinUT, WOBentley 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 5182

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics