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Jupiter 9.11.2012 - first time seeing oval BA

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#1 Sasa

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Posted 10 November 2012 - 03:58 PM

Hello,

finally I saw yesterday for the first time the large oval BA preceeding GRS:

Posted Image Posted Image

The conditions were far from being perfect, but it was clearly there! Not many other details were seen, some festoons, parts of equatorial belt, and the GRS was bordered on its preceeding side with white rim.

#2 Special Ed

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Posted 10 November 2012 - 07:50 PM

Hi Sasa,

A very fine sketched observation of the King of Planets. Lately, Oval BA is prominent and relatively easy to see given halfway decent conditions. Keep up the good work. :)

#3 Asbytec

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Posted 10 November 2012 - 10:58 PM

Sasa, yes, it is clearly there. Well done. It was a first for me, too.

I dunno, I like the contrast you pulled out of Jupiter given the conditions, especially the two toned NEB. That's not easy.

#4 Sasa

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Posted 11 November 2012 - 03:18 AM

I dunno, I like the contrast you pulled out of Jupiter given the conditions, especially the two toned NEB. That's not easy.


It was not easy but it was there (the equatorial side was visibly darker). Few days earlier, in better conditions, I could even see in the same telescope some white long spots in NEB:

Posted Image Posted Image

#5 Asbytec

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Posted 11 November 2012 - 04:32 AM

It was not easy but it was there (the equatorial side was visibly darker). Few days earlier, in better conditions, I could even see in the same telescope some white long spots in NEB.


Yep! You got it! Again, great observation, Sasa! I think that bright spot in the left sketch has been dubbed "the beacon" by some imagers. I think that's it. Did you post your previous sketches?

#6 Sasa

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Posted 11 November 2012 - 02:46 PM

Did you post your previous sketches?


Not many, you can find all my sketches on my web page. Jupiter, in particular, can be found here.

#7 Dean Norris

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Posted 11 November 2012 - 03:37 PM

Sasa,

Excellent sketches of Jupiter. Congratulations on observing Oval BA. Your sketch on the 6th of Nov. depicts the region of Jupiter I observed last night. Lots of detail in the NEB and EQZ in your sketches.

Thanks for posting. Dean

#8 E_Look

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Posted 11 November 2012 - 08:08 PM

Really! Oval BA, to me, is elusive to view, and here he is, with a great sketch of it.

#9 Asbytec

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Posted 11 November 2012 - 08:30 PM

Not many, you can find all my sketches on my web page. Jupiter, in particular, can be found here.


You have been busier than I have been. Excellent work.

#10 george golitzin

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Posted 14 November 2012 - 02:14 PM

Very nice sketches, Sasa, and congratulations on Red Junior! It seems to be getting a bit easier to pick out, or maybe I've just had pretty decent seeing lately. :)
I saw it clearly in the 18-inch two nights ago (ok, maybe that much aperture is cheating, but wow, there were some very interesting details in both the main belts, and the equatorial band was very wide within the EZ, but I digress...), and again last night I caught it in the 10-inch, just rotating into view on the eastern limb.

Thanks again for posting your fine sketches.

-george

#11 Sasa

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Posted 14 November 2012 - 02:32 PM

Thanks George, I saw your sketch in the other thread. It is very nice and full of details. Definitely bigger aperture counts here. I still have two bigger scopes than 100mm ED: AS110 and ED130. Haven't seen Jupiter through them this season yet. Sill not in the same league as 18" mirror, but I'm definitely curious how much more details (if any) I will be able to glimpse.

#12 Asbytec

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Posted 14 November 2012 - 10:15 PM

...Red Junior! It seems to be getting a bit easier to pick out, or maybe I've just had pretty decent seeing lately.

-george


Good question, George. BA has always avoided detection - for me. But, it is easy these days. It must be getting darker, or it would have been this easy last year when (only?) I failed to see it. Would like to look back over my sketches to see if I inadvertently captured it. Asking Dean about BA last fly by, he might have mentioned it was difficult. Apparently, not anymore.

Sasa, get that ED 130 out there! Or let me borrow it. :)

#13 Sasa

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Posted 19 November 2012 - 04:11 PM

Today, I had a literally 20minut window to observe Jupiter. It was clear that we would be soon covered by inversion clouds, so I took out just small refractor that I know temperates quickly, AS80/1200 (sorry, no ED130 yet). It was worth at the end, as the GRS was just on meridian. I could spot quite some details (including the junior spot, it is still visible even in 80mm, although it is more just some wave on the belt then individual spot):

Posted Image

#14 Asbytec

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Posted 19 November 2012 - 08:17 PM

Second time spotting it? It is so much easier this time around. Not sure why.

Yes, most times it appears, to me, as a bump much like you've presented. At the best moments it seems to tighten up and near the meridian that smaller dark oval can be held (as a distinct, tiny spot or as a slightly darker patch) for as long as the seeing holds.

Well done, thanks for sharing, Sasa.

#15 Rich (RLTYS)

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Posted 20 November 2012 - 07:48 AM

Usually once you see a difficult feature the first time it becomes easier to spot as you now know what to look for.

Rich (RLTYS)

#16 Dean Norris

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Posted 20 November 2012 - 04:33 PM

Sasha,

Great sketch of Oval BA and GRS. It's fun to see this feature pass by the GRS as it zips around Jupiter.

Dean

#17 Rutilus

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Posted 30 November 2012 - 07:49 PM

I too picked-up Oval BA for the first time this evening.
It was quite easy to see in my 100mm f/13 and 100mm f/12 Achromat refractors.
Also preceding BA, but in the SEB was a very bright white spot. Also some bright bays in the southern edge of the NEB,
and a couple of large festoons.

A thin equatorial belt also visible. Jupiter is a real joy to observe at the moment, so much going on.

#18 Sasa

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Posted 01 December 2012 - 05:25 PM

Congratulation Rutilus, yes Jupiter is fun. I just came from another session. Unfortunately again short (about 20 minutes), the clouds were moving in again. I took only 80mm refractor out (I promise, I will take out something bigger at some point), still I was rewarded by nice view on GRS, junior spot and few other details in SEB and equatorial region:

Posted Image

#19 Asbytec

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Posted 01 December 2012 - 08:44 PM

Sasa, that's an amazing sketch. That you captured that amount of detail in an 80 Refractor speaks to both the scope and your skill as an observer. I applaud you.

#20 Sasa

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Posted 02 December 2012 - 05:25 PM

Thanks Norme for your compliments, you made me blush. I guess it is just Jupiter which makes the show. The details, bands, red junior, etc. are showing nowadays quite some contrast. There were only 2 difficult features that I spotted that night, the most eastern and most western festoons were just ghost. Other features, including the middle festoon, were more or less easy to see. One just had to wait a little bit for calm moments.

Concerning the optics, AS80/1200 is indeed a nice scope. Especially for short sessions like this. I also own 80mm triplet (Lomo 80/480mm), which I bought for astro imaging. I found the AS80 is providing sharper images: here.

#21 Asbytec

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Posted 02 December 2012 - 08:41 PM

Jupiter is quite beautiful this time around, Sasa. I am having the time of my life, and so are you, I'd guess. Yes, the festoons are ghostly lately. Earlier, there seemed to be more prominent blues and arcing wisps into the EZ. Those are no longer prevalent. Again, great observations. All of them, including the one's on your site.

#22 Sasa

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Posted 05 December 2012 - 07:07 AM

Hello guys, two days ago I actually took out 130ED to watch Jupiter. The weather looked promising, at least it looked like that the clouds would be off for at least one hour. In fact, they came a little bit earlier in 45 minuts. To make it short, I did not see red junior at all, I could barely see rising GRS (but hey, it was at least of orange cast; last time I saw a color on it was in my former 250mm Newton).

The problem was big temperature drop (about 20C) between room and outside temperature. Well at least, I got a feeling how quickly this 130mm beast thermalizes. In about 20 minutes of being outside, the image was still very bad. Jupiter was hidden behind strong greenish misty veil. The veil was about 10" larger than Jupiter. I could barely discern main belt. In 30 minutes, veil shrink a little bit (it was now about 5" larger than Jupiter), image improved, but it was still very bad. In 40 minutes, the veil was very small and I could start to see interesting features, like rising GRS but no red junior yet. In another 5 minutes, the experiment was terminated by clouds.

So, the moral is: bigger is not always better. With AS80/1200 I would be done with observing in about 20 minutes and I'm sure, I would record much finer details.

#23 Eddgie

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Posted 05 December 2012 - 03:20 PM

This is interesting because there was a thread in the refractor forum about cool-down and many people seemed to think that refractors could cool very quickly.

My expeience was that the bigger they were, the more the cooldown time they needed and that at 6", it could take a couple of hours to cool (still faster than a big reflector or SCT which can literally go all night without cooling).

Anyway, glad you got to see the BA. It is actually very large and even a small aperture has sufficient angular resolution to show it, but it starts with very low contrast that even in larger telescopes, it doesn't really "jump out" like GRS. In smaller scopes though, the already soft edges are further softened makeing the transition from surrounding region to the only slighly higher contrast of the BA less easy to spot. Much "crisper" in bigger scopes, but at the same time, never really "Crisp" at the edges. At least not the times I have seen it. It is very pale pastel splotch rather than a hard spot. At least that is the way it looks to me even in the C14. Not hard to see, but not obvious at all.

#24 Sasa

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Posted 06 December 2012 - 05:45 AM

Eddgie, I agree with you, I would say since ED130 takes at least about 45 minutes with ~15-20C temperature drop to thermalize to some reasonable level (still far away from perfect) , it starts to be comparable with my former N250/1600. My experience in the similar weather with the dobson was that when I left it outside with running fan for about an hour, and then continue observing Jupiter with fan switched on, it was already providing visibly more detailed images than for example ED100. So it was worth to take it out. ED130 seems to operate at the same level as N250, even after 45 minutes it was still showing less details than AS80 after 20 minutes of beeing outside. So in my conditions in winter time, I would say than even 5" refractor (and we are talking about doublet, not triplets which are even worse) is at the edge with about 10" Newton concerning thermal effects.

Since I mostly operate on short sessions from my backyard (and I do enjoy all type of observation especially such type of observations that put my observing skills to my limit, from doubles, planets, Moon to DSO), I gain some experience about how quickly the telescopes thermalizes in order to be able to do this demanding type of observation.

For deeply frozen nights (we are talking about 35C temperature drop), in winner, clear winner is AS80. It needs only about 10-15 minutes and one can start with "serious" work. For example, last winter I was testing how long it will take AS80 to split Rigel. It took it 15 minutes before I started seeing the faint companion. This 15 minutes agrees more or less with what I see when observing Jupiter. Nice feature of AS80 (and AS110) is its removable lens. So if I decided to go out on short notice, I just put the lens outside on the window sill and I gain additional 10 minutes which usually takes me to prepare the staff for observing (dressing, atlases, papers, pencils, eyepieces...).

I have another 80mm telescope of different nature, the 80/480 Lomo triplet (SV80S). Some time ago I did direct comparison on Moon between AS80/1200 and SV80S. Difference was startling, even with ~10C temperature drop, the triplet was not there on the level of AS80 (there is a link to this report in some of my previous replies in this thread). So even tiny 3" refractor could be quite sensitive to thermalization. If I would not have an "etalon" (AS80) to compare the image with, I would probably not noticed it and I would classified it as a bad seeing.

Next step is ED100, this is very good compromise between the power (diameter) and thermalization speed. It is definitely slower in thermalization than AS80, but the difference is not that big if one does not operate in really cold nights. This is normally my choice number one. Except in winter time, when I prefer for short sessions AS80. For example during one night, with temperature drop of about 20-25C, I could not split theta Aur even after 30 minutes of observing (star test was still showing signs of pinched optics), after another 30 minutes, theta Aur was clear and nice split in ED100 (and the signs of pinched optics were gone).

I also have short experience with ED120. My friend came to visit me for common observations. I do not know the temperature drop, but it was summer, definitely not very cold night (but the telescope was in the car). Even after one hour one could see some signs of thermal effects when observing Saturn (our etalon was at that time my ED100).

I do not have too many experiences with AS110, but there are thermal effects as well. During October (so not so cold), I was observing some doubles and I noticed that in first 10-15 minutes, the lens was showing in star test signs of strong spherical aberration. In about 20 minutes they were gone. I t looks like it will be at the same level as ED100.

BTW, yesterday I was observing Jupiter, this time with AS80 since it was difficult to judge how long the sky will stay clear. Again, it was providing quite quickly images with high contrast and clarity :

Posted Image

No red spot junior this time, but I noticed towards the end of my observation very thin and hard to spot bend on the western hemisphere just south of SEB. Never noticed it before in 80mm refractor (but I saw it in ED100 a month ago).

#25 Asbytec

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Posted 06 December 2012 - 06:33 AM

Yes, that STB "bend" is becoming more noticeable. Still pretty faint. Great catch!

Interesting on the cool down, I would expect a large refractor lens and Mak meniscus to cool /relatively/ quickly as they are exposed to the open air. The inner workings of Cats, however, are not and require a bit more time. As Eddgie said, I have seen Cats that never cool at all.

But, there are so many variables, it's easier to argue in generalities that probably do not apply equally across everyone. Contrary to their reputation, my Mak has zero cool down issues, after it's cooled down. :lol: That takes about an hour, then it's clear sailing all night.

You really nail Jupiter in your 80, Sasa.






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