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Astrophotography and Sketching >> Sketching

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Paul G. Abel
sage


Reged: 01/28/10

Loc: UK
Uranus 20" DK.
      #5451738 - 10/02/12 11:29 AM


Greetings all,

Attached is an observation made of Uranus made with Dr. Hugh Sasse using the University of Leicester's 20" DK planewave telescope, last night. Conditions were only average at best with seeing around AIII-IV and some drifting cloud. A bright waning Moon also hampered observations a little. The planet was examined both in IL and with a red W#25A filter, the results were as follows:

(i) Drawing 1 (IL) [2214UT- 2226UT]

The planet was examined at x356 and x540 and there appeared to be a brighter EZ. Just 'below' this was what appeared to be a darker greyish band. A brighter spot was suspected on the limb (indicated). Interestingly there appeared to be a slight change in colour compared to when we last observed the planet with a stronger cyan component being present.

(ii) Drawing 2 (W#25A)

Examined the planet in a deep red W#25A filter. Due to the presence of high cloud we had to reduce power to x288, but the disk size was just large enough to be able to make some observations. In particular, the brighter EZ seemed to still be present, along with the darker band which MAY have been easier to see in this filter (impossible to be certain). The brighter spot also seemed to be present. We made plans to observe the planet with a blue W#80A filter but alas clouds came up and we were forced to stop observations on this rather inconclusive note.

Best wishes,
-Paul.




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niteskystargazer
Carpal Tunnel
*****

Reged: 10/05/09

Loc: 41-43'-28" N 87-42'-39" W
Re: Uranus 20" DK. new [Re: Paul G. Abel]
      #5452162 - 10/02/12 03:36 PM

Paul,

Nice drawings of Unanus .

CS,KLU,

,

Tom


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Andrev
Post Laureate
*****

Reged: 02/08/11

Loc: Montreal, Quebec, Canada
Re: Uranus 20" DK. new [Re: niteskystargazer]
      #5452541 - 10/02/12 07:43 PM

Paul

Beautiful. Are you serious, you can see such clouds on Uranus ?

Andre.


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azure1961p
Postmaster
*****

Reged: 01/17/09

Loc: USA
Re: Uranus 20" DK. new [Re: Andrev]
      #5452766 - 10/02/12 10:18 PM



Nice work Paul, as always one of my favorite observer/artists.


Pete

Edited by azure1961p (10/02/12 10:18 PM)


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frank5817
Postmaster
*****

Reged: 06/13/06

Loc: Illinois
Re: Uranus 20" DK. new [Re: azure1961p]
      #5452881 - 10/02/12 11:30 PM

Paul, Very fine filtered sketches of the planet Uranus.

Frank


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Jef De Wit
Carpal Tunnel


Reged: 03/06/09

Loc: Hove, Belgium
Re: Uranus 20" DK. new [Re: frank5817]
      #5453050 - 10/03/12 04:03 AM



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Paul G. Abel
sage


Reged: 01/28/10

Loc: UK
Re: Uranus 20" DK. new [Re: Jef De Wit]
      #5453112 - 10/03/12 06:41 AM

Thanks :-D @Andrev, indeed yes! I have been able to make out the brighter EZ with my 8" reflector on a good night when I can use a power of x400 or so (there are records of people seeing this with a 6"). The University of Leicester's 20" 'scope used here brought out the cloud band rather well. It appeared in three different eyepieces and a W#25A filter which suggests to me it is a real thing. More people should be looking at this world!

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Andrev
Post Laureate
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Reged: 02/08/11

Loc: Montreal, Quebec, Canada
Re: Uranus 20" DK. new [Re: Paul G. Abel]
      #5454034 - 10/03/12 07:24 PM

Paul.

So let me tell you, you are lucky. I never seen any band on Uranus with my C14 because the few times I observed it, I never got a decent seeing for this planet to increase to a such power.

Last night I observed Jupiter easily at 434X for a real clear view and the moon at 782X !!! I should have had a look at Uranus but I don't.

Andre.


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whirlpoolm51
professor emeritus
*****

Reged: 01/05/12

Loc: pittsburgh,pa
Re: Uranus 20" DK. new [Re: Andrev]
      #5454407 - 10/04/12 12:14 AM

how can you see cloud bands on uranus and hubble cant!!!!! hahaha i thought uranus and neptune were featureless balls off gas and ice except for the occasional aurua

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Paul G. Abel
sage


Reged: 01/28/10

Loc: UK
Re: Uranus 20" DK. new [Re: whirlpoolm51]
      #5454587 - 10/04/12 05:26 AM

If you care to examine the ALPO website http://alpo-j.asahikawa-med.ac.jp/Latest/Uranus.htm you will see others have seen similar things. Similarly, if you care to read A. F. O'D Alexander's book The planet Uranus:
a history of observation, theory, and discovery, you will find similar observations in the historical records.


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stanislas-jean
Carpal Tunnel


Reged: 10/22/08

Re: Uranus 20" DK. new [Re: Paul G. Abel]
      #5456017 - 10/05/12 01:35 AM

Good job Paul with the scope in use and assessed also with Mr Hugh.
About the the brightening you noted both in AL and red color I will try to check this at the same longitude you reported. If this is a bright spot it will have a certain duration and not drifting a lot.
Hope the weather will be with us, rainy now since a week and next week forecasted.
Good hope.
Stanislas-Jean


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rolandlinda3
Post Laureate
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Reged: 01/24/06

Loc: Crozet VA 22932
Re: Uranus 20" DK. new [Re: stanislas-jean]
      #5457156 - 10/05/12 10:02 PM

I am sure impressed.

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stanislas-jean
Carpal Tunnel


Reged: 10/22/08

Re: Uranus 20" DK. new [Re: Paul G. Abel]
      #5468268 - 10/13/12 12:41 PM Attachment (37 downloads)

At last a hole into the clouds for making this report about Uranus.
I engaged a new 250mm scope for getting a compromise with the seeing and the resolution ability.
It has a proven strehl ratio of 0.966 global on the tube, the central obstruction needs to be deducted for getting a true equivalent perfect diameter of 168-170mm approaching the cassegrain 305mm performance. Therefore the contrast levels are almost similar.
Last evening was average and in spite of this, during calm times (7/10 images) I could drawn the attached report for your perusal. It should interresting to compare with some other documents issued on the site (the oval brigthening near the limb in the south temperate belt).
The weather being stormy here it is difficults to perform better.
Good hope
Stanislas-Jean


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mikesemmler
sage


Reged: 06/01/09

Re: Uranus 20" DK. new [Re: stanislas-jean]
      #5468394 - 10/13/12 02:14 PM

Paul - great scetch, congratulations for your fine observation

Michael


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azure1961p
Postmaster
*****

Reged: 01/17/09

Loc: USA
Re: Uranus 20" DK. new [Re: mikesemmler]
      #5469126 - 10/13/12 11:53 PM

Im having a bit of a time comparing Pauls work to Stans as Im not clear on what end is north or south in Pauls. The renderings seem reversed with the arc of the EZ curving one way in Pauls work and the opposite in Stans. Moreover the image Stan refers to [in a different post ] of Uranus iaged with a 16" sct shows a winjupos image with South being at the edge of the equatorial zone with no correlate to a pole at all. The ambiguety here muddles the waters a bit.

Pete


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chrisrnuttall
Professor Emeritus


Reged: 12/29/10

Loc: York, England
Re: Uranus 20" DK. new [Re: azure1961p]
      #5469300 - 10/14/12 04:36 AM

Paul used a Dall Kirkham, and Stanislas used a Maksutov Cassegrain, and both sketches were made at a similar local time (albeit on different days)so the image orientation should really be the same, perhaps one of them has a diagonal mirror and one does not?

Also the Central meridians are 100 degrees apart between the two sketches, so actually the bright spot is on one limb in Paul's and the opposite limb in Stanislas' (just to confuse you more Pete!).

It's quite interesting that (if the mirror inversion between the two drawings is indeed due to telescope design or something like that) the two sketches agree very well indeed.

Edited by chrisrnuttall (10/14/12 04:38 AM)


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stanislas-jean
Carpal Tunnel


Reged: 10/22/08

Re: Uranus 20" DK. new [Re: azure1961p]
      #5469362 - 10/14/12 07:14 AM

You see Pete, any view performed even by well known imager is controversial.
Pole or not is a result of a method and local conditions. This overall aspect is never until now duly assessed except by experience, of what.
This is not an argument.
The presentation of the sketch are clear if you follow, not on CN but on the japanese alpo the results given.
Uranus south given and rotation. Here the morning limb.
The brightening is not named as a spot but a brigthening.
Have you saw the limb darkening, because this may interfere with the brightening for getting a spot looking appearance.
You see, visual observers are prudent, imagers hardly thinking, and without assessments, also comparative assessments.
Now the brigthening is interresting to note and needs more data for a firm evaluation for saying this is the same.
In first, assessment with time to see if this is rotating with the planet, i got no enough time for.
In second, assessment day to day for collecting the same features.
In third, to assess what was changed around, the dark collar bordering the pole has gone.
etc...
When you see an imager getting a similar approach, ring me.
For the moment they stay on banding structure collected on a favorable period, because constrast had raised. And the banding idea stays on pure circles shape, nothing else can exist, and they don't know exactly behind desks.
Stanislas-Jean


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azure1961p
Postmaster
*****

Reged: 01/17/09

Loc: USA
Re: Uranus 20" DK. new [Re: stanislas-jean]
      #5469572 - 10/14/12 10:55 AM

Stan,

Thats not fair to imagers or the technology behind the cams and processing software used these days. This isnt the days of tri-x or ektachrome anymore and the CCD is in another realm. I dont think your assesments of visual versus ccd is accurate.

pete


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stanislas-jean
Carpal Tunnel


Reged: 10/22/08

Re: Uranus 20" DK. new [Re: azure1961p]
      #5469758 - 10/14/12 12:56 PM

For the moment technology is not involved but just the method in use or the approach against problems that is un-acurate.
Stanislas-Jean


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Achernar
Postmaster
*****

Reged: 02/25/06

Loc: Mobile, Alabama, USA
Re: Uranus 20" DK. new [Re: Paul G. Abel]
      #5472337 - 10/15/12 09:42 PM

You had very good seeing to be able to see what you saw on Uranus, which always appears to me at a pale turquouise dot even through my 15-inch Dob. I can go well above 500X, but the blasted seeing here never quite lets me get a sharp view on all but very few nights. Impressive work, a testament to the quality of the telescope and the dillegence of your observations and sketching.

Taras


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