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David Knisely
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Reged: 04/19/04

Loc: southeastern Nebraska
Re: Uranus cloud bands in a C8 new [Re: azure1961p]
      #5512624 - 11/10/12 02:12 AM

azure1961p wrote:

Quote:

I still want to see enckes and M57s central star in my 8. I may never and banging my head against the wall isn't going to make it any better.




Well, in an 8 inch, Encke's division is probably not going to be visible due to resolution issues, but I wouldn't give up hope on the central star in M57 in an 8. I saw it quite unexpectedly in my NexStar 9.25 inch SCT one evening from my driveway, so under outstanding conditions and with some patience, it might not be out of the question in an eight inch aperture. As far as seeing definite detail on Uranus is concerned, well, my experience says that probably isn't going to happen (especially in telescopes much smaller than 10 to 12 inches). Even after getting repeated bouts of seeing that was more than good enough (and using a large enough aperture at 14, 16, and 24 inches), I still haven't seen anything on Uranus. I may take an occasional quick look in the future, but for now, I think I have probably had enough of scanning that featureless disk for hints of something which probably wasn't there to begin with. It's pretty much time now to go on to better things. Clear skies to you.


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stanislas-jean
Carpal Tunnel


Reged: 10/22/08

Re: Uranus cloud bands in a C8 new [Re: azure1961p]
      #5512665 - 11/10/12 04:18 AM

It's not exact.
1000x makes the apparent size at the eyepiece to be 1 degree (2 times the moon with the nake eye)
500x makes at the eyepiece the size apparent equalling the full moon size.
For 2% contrast feature on the planet, you get 1% at the eyepiece in the 300mm, this will do 1.7% only at the eyepiece in the 1000mm. But at 1000x the eye is not working in good conditions, image too bright and these low contrasted features are covered by the light glare. It is needed say 1700x for getting the best conditions where the light glare is absent and the images not still blurred by the optics. Remain the seeing problem well understood and that apertures need a perfect site with stable atmosphere exceptionnal, FWHM less than 0.1".
So reporting some visual observation with 1000x only means a lot also.
But at final apart the seeing conditions, capturing 1% or 1.7% remains a must.
As a certain example viewing of the encke in a 250 involves a contrast of about 5%, a thin grey line, not black.
On uranus banding is of 1" width lined feature with 1 or 1,7% contrast level.
If this is an help for the approach visually.
An other way can be: draw line on a paper of that level contrast (5% in the word software is possible) and try to see this, show this around you to somebody else, collect the results. If you get few % having seen something, you will have a tendency of abilities. I did also.
Stanislas-Jean


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stanislas-jean
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Reged: 10/22/08

Re: Uranus cloud bands in a C8 [Re: stanislas-jean]
      #5521555 - 11/15/12 04:44 PM Attachment (78 downloads)

Here is the observation of Uranus of last 15th performed with the 305mm cassegrain.
Good to excellent images on the calm times (1-2sec).
The more conspiscious results are given with the use of the W8 filter: brightening on the sun rise limb side on the equatorial zone. The albedo variations are given on the sketch with darkenings on the south edge of the equatoriale zone.
No enough time to show rotation of these features as the local haze became too thick for continuing the observations.

The images were enough good for showing the darkening edge effect on the planet limb.
The magnification of 435x and the sky transparency were optimum for the visual capture of the albedo variations.
Stanislas-Jean


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stanislas-jean
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Reged: 10/22/08

Re: Uranus cloud bands in a C8 new [Re: stanislas-jean]
      #5534798 - 11/23/12 02:59 AM Attachment (57 downloads)

Here is the Uranus observations performed with the 305mm with 435x.
The images were just average sometimes poor.
However the present report is produced for your perusal.
This is more here an overalll feeling as the perception was too fugitive.
Unfortunately the sky this evening is not open and this will be for days now.
The south hemisphere seems to be covered by 3 parallel darkenings as shown.
It's to be taken with an extremly care and needs a more consistent evening for confirmation
Stanislas-Jean


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Asbytec
Guy in a furry hat
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Reged: 08/08/07

Loc: La Union, PI
Re: Uranus cloud bands in a C8 new [Re: stanislas-jean]
      #5534880 - 11/23/12 05:02 AM

Stanislas, you are "da man," as we say. (It's not derogitory, but a compliment in American slang.)

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stanislas-jean
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Reged: 10/22/08

Re: Uranus cloud bands in a C8 new [Re: Asbytec]
      #5534977 - 11/23/12 08:03 AM

The last pictures needs to be taken with cautious as this is strange and with the sky limited conditions in use.
But there is the worst and the best that are issue on the forum.
Stanislas-Jean


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stanislas-jean
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Reged: 10/22/08

Re: Uranus cloud bands in a C8 new [Re: stanislas-jean]
      #5549818 - 12/02/12 05:13 AM Attachment (51 downloads)

The observations of Uranus last 29th nov.
Average conditions of sky and on a short periods of few minuts.
The brightening on the equatoriale zone is still collected (pay attention of the sense of rotation, no diagonal mirror used).
Stanislas-Jean


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stanislas-jean
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Reged: 10/22/08

Re: Uranus cloud bands in a C8 new [Re: stanislas-jean]
      #5551956 - 12/03/12 12:34 PM Attachment (48 downloads)

Here is the report for Uranus performed on the 2nd december with the 305mm.
Still the brightening on the equatorial zone sunrise side.
South temperate belt seems thick with borderlines darker.
A darkening on the south colar belt bordering the polar regio, on the sunrise side.
Stanislas-Jean


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stanislas-jean
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Reged: 10/22/08

Re: Uranus cloud bands in a C8 new [Re: stanislas-jean]
      #5563477 - 12/10/12 01:58 AM Attachment (49 downloads)

Here is the uranus observations of last 8th with a 235mm cassegrain.
Excellent conditions with fixed images on the period.
The brightenings were observed on the sun rise side with 70min time difference.
This shows a reinforcement of the brightening intensity at the issue stopped by clouds and be ginning of sky quality degradation.
Anyway the present report.
Stanislas-Jean


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stanislas-jean
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Reged: 10/22/08

Re: Uranus cloud bands in a C8 new [Re: stanislas-jean]
      #5567693 - 12/12/12 02:20 PM Attachment (42 downloads)

An Uranus report for the last 11th performed with the 305mm cassegrain.
Excellent to perfect images at last for a sufficient time for collecting the banding system as shown.
Fixed images during minuts at 18H00UT with 506x.
See the brightenings on the equatorial zone both limb sides.
Banding is triple on the south temperate hemisphere.
1st time I got such quality level images with the 305 on this target.
Stanislas-Jean


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Asbytec
Guy in a furry hat
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Reged: 08/08/07

Loc: La Union, PI
Re: Uranus cloud bands in a C8 new [Re: stanislas-jean]
      #5568004 - 12/12/12 05:43 PM

How is your optimize testing coming?

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stanislas-jean
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Reged: 10/22/08

Re: Uranus cloud bands in a C8 new [Re: Asbytec]
      #5568578 - 12/13/12 01:41 AM

For the moment the few nights we have here are just dedicated for this present activity.
We will see later.
Stanislas-Jean


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stanislas-jean
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Re: Uranus cloud bands in a C8 new [Re: stanislas-jean]
      #5576051 - 12/17/12 05:05 PM Attachment (39 downloads)

Here is my contribution to Uranus observation of last 17th.
I just acquired an old C11 Ultima, tested with excellent results and tried it on the subject.
Images were just average and poor at the observation issue.
This should be considered as a trial, however I submit this material for reporting.
Think the scope is good enough as a medium size for the current survey (estimated to be 150-160mm perfect equivalent aperture which is enough, 175mm for the 305mm currently used).
Anyway, with regards to the target, the equatorial zone was seen fuzzy with 2 brightenings on the equatorial zone and on the south temperate hemisphere at the opposite limb, the polar cap being clearer also.
I think with better images we could go further.
Stanislas-Jean.


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stanislas-jean
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Reged: 10/22/08

Re: Uranus cloud bands in a C8 new [Re: stanislas-jean]
      #5597805 - 12/31/12 11:45 AM Attachment (30 downloads)

The last probably observation concerning Uranus this year.
This was performed with the 235mm cassegrain and 327-375x magnification under an average sky, transparency and seeing.
Anyway, the brightening at CM 190 degree, sun rise limb remains still present. The contour of this zone is too difficult to show acurately.
I tried to report the grey tone variations as it appeared at the eyepiece during the 2 separate periods.
The time now to transmit to readers and present forumers all my best wishes for the new incoming year,
Stanislas-Jean.


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stanislas-jean
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Reged: 10/22/08

Re: Uranus cloud bands in a C8 new [Re: stanislas-jean]
      #5600707 - 01/02/13 03:25 AM Attachment (30 downloads)

Here is the observation report for Uranus performed last 1st January.
Average images under a transparent sky with the 280mm cassegrain at 400x.
An Irridium satellite was crossing the disk at 19H40UT (the virtual path) with a light flare each 3-4 sec period.
2 Uranus satellites were suspected.
Stanislas-Jean.


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stanislas-jean
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Reged: 10/22/08

Re: Uranus cloud bands in a C8 new [Re: stanislas-jean]
      #5606441 - 01/05/13 11:57 AM

Here is a link from the japanese alpo site where a UK observer, David Gray, experienced, reported the presence of a spot on Uranus equatorial zone:
http://alpo-j.asahikawa-med.ac.jp/kk13/u130101z.htm
His drawings are not seemsly oriented as mines.
Interesting reports anyway. Didnot catch this present feature on the same days with the 280mm.
Uranus is quite changing from a period to an other, this is sure.
Stanislas-Jean


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stanislas-jean
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Reged: 10/22/08

Re: Uranus cloud bands in a C8 new [Re: stanislas-jean]
      #5617444 - 01/11/13 03:14 PM Attachment (19 downloads)

Here is the Uranus report for 11th january.
A brightening on the equatorial zone as shown (however considerably amplified0
The cassegrain of 280mm was used with 400x under a transparent sky and average good seeings.
Several brightenings at the limbs.
The sketch on the left is the draft performed at the eyepiece and sketch on the right is respecting as possible the albedo ratio between area.
Not bad, the scope can do deeper under better conditions.
Stanislas-Jean.


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stanislas-jean
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Reged: 10/22/08

Re: Uranus cloud bands in a C8 new [Re: stanislas-jean]
      #5628144 - 01/17/13 01:56 PM Attachment (13 downloads)

Here is the report for Uranus performed last 16th with the Cassegrain 235mm and 375x.
Short time period of 20 min with good images helped me to draw what is given.
It was captured the similar brightenings than those reported last 11th (CM about 70 degree).
Stanislas-Jean


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DHurst
super member


Reged: 03/10/06

Re: Uranus cloud bands in a C8 new [Re: stanislas-jean]
      #5629826 - 01/18/13 12:03 PM

Stan,
I think you have some streaks on either your eyepieces or objectives. You should never clean fine glass with steel wool!


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stanislas-jean
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Reged: 10/22/08

Re: Uranus cloud bands in a C8 new [Re: DHurst]
      #5629902 - 01/18/13 12:51 PM Attachment (20 downloads)

Sorry for these bad qualities!
However,
Here is my contribution for Uranus observed last 17th with the cassegrain 280mm and 400x.
Good images sometimes during the period, bad after 17H45UT.

Now the weather becomes cloudy and snowy for long days.
Stanislas-Jean


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