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Sol Robbins
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Venus 05.04.07
      #1584510 - 05/04/07 12:14 AM Attachment (270 downloads)

Hi,

I had good conditions and decided to drag out my reflector to view Venus.

Using a Wratten 47 deep violet Venus was rife with albedo features. I believe that large aperture and severe filtering is the only way to dig out these details. Wratten 38 did not really show markings nearly as well. The W47 also cleans up the seeing quite a bit.

Observing Venus is a new experience for me. It seemed that these markings were in constant flux and appeared to change with what I perceived as planet rotation, as well as, moving around the way disturbed smoke changes shape. I didn't think this was simply connected to changing seeing conditions.

As a result, I had to draw really fast in concert with these rapid positional changes, I currently don't think a reliable rendering of Venus is possible. With Venus high in the sky, I certainly am hooked on viewng it.

Sketch was done with an HB pencil with brightenings being erased out.

Best,

Attachment

--------------------
S.R.


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CarlosEH
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Re: Venus 05.04.07 new [Re: Sol Robbins]
      #1584657 - 05/04/07 02:51 AM

Sol,

A truly inspirational observation of Venus. I cannot stress to other members of this forum how difficult it is to detect detail over this elusive object. I agree with you that with your aperture (9.75 inches) a Wratten 47 (Violet) filter will be useful for Venus. I have to point out that when using such a filter the seeing and transparency must be above average. Even then the detail may be fleeting, as Sol points out. Thank you for sharing this outstanding observation with us all.

Carlos

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asteroid7
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Re: Venus 05.04.07 new [Re: CarlosEH]
      #1584866 - 05/04/07 08:30 AM

Fine drawing catching subtle detail

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Clear Nights "Make My Day"

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kraterkid
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Re: Venus 05.04.07 new [Re: asteroid7]
      #1585219 - 05/04/07 11:55 AM

Stunning albeit ephemeral details Sol! Makes me wish San Diego did not have to contend with the thick marine layer that descends on us coastal dwellers every afternoon until late June (May Gray). Superb work!

--------------------
Rich



My CN Gallery




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frank5817
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Re: Venus 05.04.07 new [Re: kraterkid]
      #1585322 - 05/04/07 12:55 PM

Sol,
Another wonderful Venus sketch. I have a Wratten 47 violet filter in my collection. The next chance I get I am going to have a look at the Venus clouds with it.
Frank

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My Gallery


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jgraham
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Re: Venus 05.04.07 new [Re: frank5817]
      #1585349 - 05/04/07 01:18 PM

Very nice. I've found using a blue interference filter designed for imaging works very well. Visually, the details are incredibly soft and quite beautiful. I've tried imaging using a Baader U filter with only mixed results so far.

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-John

The best advice on imaging I've ever been given... don't forget to look!


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Sol Robbins
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Re: Venus 05.04.07 new [Re: jgraham]
      #1585581 - 05/04/07 03:23 PM

Thanks to everyone. It really was a night of good seeing for all the planets.

Thanks again,

--------------------
S.R.


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rodelaet
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Re: Venus 05.04.07 new [Re: Sol Robbins]
      #1585694 - 05/04/07 04:23 PM

Sol,

It is a beautiful sketch with amazing details!!

--------------------
Rony

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Special Ed
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Re: Venus 05.04.07 new [Re: rodelaet]
      #1585897 - 05/04/07 06:52 PM

Outstanding observation, Sol. I understand why you're hooked--it was the transit in 2004 that got me. I was fortunate enough to observe the aureole created by the atmosphere of Venus during egress. Now I've ordered a #47 filter because of your observations. If the 8" SCT isn't big enough to give good results, I'll try Carlos's recommendation of an 80A (light blue) filter.

Btw, Venus has the slowest rotation rate of any of the planets and rotates in retrograde motion (east to west).

Regards,

--------------------

Michael Rosolina
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Sol Robbins
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Re: Venus 05.04.07 new [Re: Special Ed]
      #1586724 - 05/05/07 08:18 AM

Rony & Michael, thanks.

Michael,

I found that the W47 worked well. I tried a deep Blue W38, which didn't seem to worked nearly as well.

--------------------
S.R.


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DSalters
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Re: Venus 05.04.07 new [Re: Sol Robbins]
      #1595040 - 05/09/07 05:38 PM

Anyone else have any thoughts regarding Michael's comment? It's the first thing I thought of when reading Sol's initial post. Venus' ridiculously slow rotational period would keep the clouds there in pretty constant formation. I think noticing constant changes would have to be from actually seeing these clouds in their (relatively steady) positions BUT fighting with seeing conditions here on earth at the same time.

Any thoughts?

-Daniel

--------------------
Daniel Salters

Astro-Tech 72ED
Bushnell Voyager 6" Dob
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"The sun has one kind of splendor, the moon another and the stars another; and star differs from star in splendor." -1 Corinthians 15:41




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Jay_Bird
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Re: Venus 05.04.07 new [Re: DSalters]
      #1595353 - 05/09/07 08:44 PM

I wondered the same thing. As Special_Ed noted, Venus is the roational slowpoke to Jupiter's speed demon, and it seems even with 100's of MPH winds, changes in the clouds of Venus would occur over hours, not minutes. Seeing could make such details much more fleeting, as Carlos said. Certainly a 'pushing the envelope' observation, much fine detail seen and recorded from a challenging subject.

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Sol Robbins
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Re: Venus 05.04.07 new [Re: Jay_Bird]
      #1597532 - 05/10/07 10:06 PM

I looked at my sketch and th rotational arrow is facing the wrong way.

Albedo details also moved left to right rather quickly.

These details never returned back to its former positions.

Limb brightenings rapidly changed size and shape.

I hope to observe Venus again under good to very good seeing conditions.

--------------------
S.R.


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DSalters
scholastic sledgehammer


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Re: Venus 05.04.07 new [Re: Sol Robbins]
      #1598170 - 05/11/07 09:39 AM

I by no means meant to sound critical and hope you did not feel that way. I was just bringing up a point about Venus' rotation and thought maybe that would help anyone curious about its features. The detail you bring out in your sketches is amazing. I look forward to your next Venus sketch. They help us all see what can be seen with the 47 filter and a careful eye.

-Daniel

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Daniel Salters

Astro-Tech 72ED
Bushnell Voyager 6" Dob
10" f/4.2 Springsonian

"The sun has one kind of splendor, the moon another and the stars another; and star differs from star in splendor." -1 Corinthians 15:41




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Sol Robbins
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Re: Venus 05.04.07 new [Re: DSalters]
      #1598889 - 05/11/07 04:19 PM

Daniel,

I don't take what you said negatively in any kind of way. I also hope you didn't think I was being defensive. I honestly appreciate folks for being critical. I guess it might have been the way I wrote my response. I apologize.

I was amiss in that I don't know what I really saw, scientifically speaking, other than what appeared to me observing through my scope. I hope others will seek details, of any kind, when observing Venus. This current apparition has a relatively high elevation at twilight.

--------------------
S.R.


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DSalters
scholastic sledgehammer


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Re: Venus 05.04.07 new [Re: Sol Robbins]
      #1599047 - 05/11/07 05:52 PM

Sol,

I certainly did not think you were being defensive. I just got to thinking maybe I worded things poorly and felt bad, so I said what I did. No need to apologize; everything's all right

You are very correct about this apparition being so high. I always try for details on Venus but never go into it with an open enough mind, I suppose. My 80A filter is not going to help enough either. Perhaps I should invest in a 47 considering it's probably my only hope for seeing any cloud details.

--------------------
Daniel Salters

Astro-Tech 72ED
Bushnell Voyager 6" Dob
10" f/4.2 Springsonian

"The sun has one kind of splendor, the moon another and the stars another; and star differs from star in splendor." -1 Corinthians 15:41




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Special Ed
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Re: Venus 05.04.07 and 5.9.07 new [Re: DSalters]
      #1599116 - 05/11/07 06:38 PM Attachment (118 downloads)

Hello all,

I went on a mini-marathon of observing since we had 3 clear days in a row with solar, planetary, cometary, and DSO observations so I'm a little backed up getting things posted. I made this observation of Venus Tuesday evening (9 May UT) during late twilight.

I don't have the #47 filter yet so I used the #80A. Seeing was decent (V was still high) so I was able to discern some albedo in the Venusian cloudtops. The duskiness was more pronounced near the limb and lightened towards the center of the disk. The limb arc was very bright, even in the filtered view.

I used a template downloaded off the Venus Section of ALPO and modified somewhat. Btw, the template had preceding and following mislabeled--I wonder if they know that? I used a stump loaded with graphite and an eraser.

As Sol mentioned, Venus will be high in the sky all month--this is a really good opportunity to study it and learn more about how to observe it.

Here's my impression of Venus. Thanks to Sol for leading the way on this--he sets the standard for Venus sketches.

Attachment

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Michael Rosolina
Celestron CGE Pro 1400 f/11 SCT
1980 Orange Tube C8 f/10 SCT
4.25" f/4.2 Astroscan Reflector
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Sol Robbins
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Reged: 12/01/03
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Re: Venus 05.04.07 and 5.9.07 new [Re: Special Ed]
      #1599146 - 05/11/07 07:01 PM

Michael,

Great sketch.

I don't wish to start a Venusian mutual admiration society, but I have to admit I am a bit excited about the prospect of trading Venus observations.

I don't remember Venus being so high up in the sky as it is now. Additionally scope cool down is a cinch and we don't have to freeze in order to catch a good view. Don't even need a flashlight to draw by either.

I also recommend sending a copy of this to ALPO's Venus coordinator as Venus images are always a bit small in number compared to the other planets. I think there is also a downloadable page of observing tips as well.

Thanks again,

--------------------
S.R.


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Achernar
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Re: Venus 05.04.07 new [Re: Sol Robbins]
      #1599418 - 05/11/07 09:48 PM

I have a deep violet filter also, but I've never seen this sort of details on Venus. Usually the seeing's just too poor, and these cloud features so faint I usually just see the phase of the planet and how the atmosphere scatters the sunlight around the disk near inferior conjunction. There are substances whose identity remains unknown in the clouds that cause these faint markings, which are whipped around the planet at 200 plus mph because the atmosphere "super-rotates" around the bulk of the planet. This is a nice drawing which echos images taken of Venus at ultraviolet wavelengths from spacecraft.

Taras

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CarlosEH
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Re: Venus 05.04.07 new [Re: Achernar]
      #1599865 - 05/12/07 05:13 AM

Michael,

An excellent observation of Venus showing some albedo features over it's disk. I am glad to see that this detail was visible to you using the Wratten 80A (light blue) filter. I hope to be able to observe Venus and the other planets soon. I look forward to your (and Sol's) future observations.

Carlos

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frank5817
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Re: Venus 05.04.07 new [Re: CarlosEH]
      #1600097 - 05/12/07 09:40 AM

Sol and Michael,

Your gibbous phase Venus sketches stack up nicely together.
Frank

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Special Ed
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Re: Venus 05.04.07 and 5.9.07 new [Re: Sol Robbins]
      #1601332 - 05/12/07 11:02 PM

Quote:


I don't wish to start a Venusian mutual admiration society, but I have to admit I am a bit excited about the prospect of trading Venus observations.

I don't remember Venus being so high up in the sky as it is now. Additionally scope cool down is a cinch and we don't have to freeze in order to catch a good view. Don't even need a flashlight to draw by either.




Yes, I hope we can continue to post complementary observations while Venus is so favorably placed and outdoor conditions are so confortable and easy to work in. I hope others reading this will join in, too.

I have studied up some on Venus (using Fred Price's The Planet Observer's Handbook) and learned some interesting things--some of which are very confusing to think about. Re: the direction of rotation---while it is true that Venus rotates in retrograde motion, i.e., east to west, its axial tilt is 177 degrees. That means that Venus is almost upside down and when you look at a correct image view as with binoculars for instance, the south pole is on top. With a reflector, the north pole would be on top. With my SCT, what I thought was the north pole was actually the south pole, so the N-S directions on my sketch are inaccurate. I do think the direction of rotation is towards the terminator. I thought the ALPO Venus Section template directions were set up for a reflector but maybe I'm wrong. Or maybe with the cloud cover on Venus so thick, it doesn't matter which end is up and one should just use celestial N-S-E-W.

Re: the speed of rotation and changes in the cloud cover albedo---while it is true that Venus rotates slowly (one rotation on its axis every 243 Earth days), the clouds make one complete rotation every 4 Earth days. This was first observed in 1957 and confirmed in 1973 by Mariner 10. And Taras is correct---the winds on Venus are blowing in the cloudtops at ~200 mph (100 meters/second).

Re: seeing detail in the clouds---some say one can't see anything that is really there even with Wratten filters and only UV imaging works---others say one can see the albedo features,depending on the observer, seeing conditions and filters used, also that some people's eyesight is more sensitive in the UV range.

Quote:


I also recommend sending a copy of this to ALPO's Venus coordinator as Venus images are always a bit small in number compared to the other planets. I think there is also a downloadable page of observing tips as well.




I will send my observations to the Venus Section coordinator and I downloaded the observing tips a little while ago.

People have put telescopes on Venus since Galileo in 1610, spacecraft have visited our sister planet, yet there is much about Venus that is still unknown. I know now there is a lot I don't know about it. Once again, observing an object (or a feature) leads one into learning.

--------------------

Michael Rosolina
Celestron CGE Pro 1400 f/11 SCT
1980 Orange Tube C8 f/10 SCT
4.25" f/4.2 Astroscan Reflector
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Edited by Special Ed (05/15/07 11:35 AM)


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LivingNDixie
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Re: Venus 05.04.07 and 5.9.07 new [Re: Special Ed]
      #1603793 - 05/14/07 01:12 PM

Sol,

Great sketch! I have been sketching Venus for the last month for the AL planetary pin. It is fun watching the phase change and the apparent diameter grow as the weeks pass.

--------------------
Preston
Meade 10in LX200R GPS UHTC
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frank5817
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Re: Venus 05.04.07 and 5.9.07 new [Re: LivingNDixie]
      #1605047 - 05/15/07 12:57 AM Attachment (98 downloads)

I made a rather crude sketch of Venus this evening and posted it below. I began observing at 0:00 U.T. 5/15/2007.
I noted the seeing and transparency were both above average. I intended to sketch the planet with a Wratten 47 violet filter but before I did that I looked at Venus with every filter in my collection. The violet filter provided the only view of any albedo features. The features must have changed while I was drawing (30 minutes) because when I finished the features no longer matched my sketch. For experienced planetary sketchers like Sol and Michael Venus sketching may go smoothly. I was challenged but fascinated. I have photographed Venus and even sketched it in the past but I have never looked at it through any filter other than a polarizing pair until this night. I labelled this sketch with 2 letters H is the direction of the horizon and Z the direction of the zenith. For this sketch I used a protractor to draw a 3 inch semi-circle and freehand sketched the terminator. I used white sketching paper, black Conte' crayons filed sharp, index finger for blending and inverted the drawing after scanning and cropping.I sketched for about 30 minutes between 0:30- 1:15 U.T.
10 inch Dobsonian f/5.7 at 241X

Frank McCabe

Attachment

--------------------
My Gallery


Edited by frank5817 (05/15/07 01:29 AM)


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CarlosEH
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Re: Venus 05.04.07 and 5.9.07 new [Re: frank5817]
      #1605215 - 05/15/07 05:44 AM

Frank,

An excellent observation/rendering of Venus. I am glad that you were able to detect albedo features using the Wratten 47 (Violet) filter. Venus is a challenging object to detect detail over. The cloud tops actually rotate in a period of approximately four days (versus the 243 days retrograde rotation and 225 days orbital period).

Good Job!

Carlos

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Special Ed
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Re: Venus 05.04.07 and 5.9.07 new [Re: CarlosEH]
      #1605747 - 05/15/07 11:56 AM

Frank,

Great observation and sketch! I like the appearance of the planet in your rendering.

I also like how you solved the problem of orientation. I was hoping that someone would be able to answer my questions about that. I might e-mail the ALPO Venus coordinator and ask him.

Eric Jamison posted an observation report of Venus on the StarryNights Yahoo group. His observation was made on Sunday evening--he said the seeing wasn't good and he didn't mention using any filters but he reported noticing some dusky markings along the terminator.

Regards,

--------------------

Michael Rosolina
Celestron CGE Pro 1400 f/11 SCT
1980 Orange Tube C8 f/10 SCT
4.25" f/4.2 Astroscan Reflector
50mm f/10 Galileoscope
40mm PST f/10
APM Germany HD 15x70 binoculars
Canon 12x36 IS II binoculars
Mark I Eyeball
My CN Gallery


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rodelaet
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Re: Venus 05.04.07 and 5.9.07 new [Re: frank5817]
      #1606212 - 05/15/07 04:13 PM

Frank,

That is a very cool sketch!!

--------------------
Rony

'The Casual Sky Observer's Guide.'

My Astronomical Sketches

My Binocular Sketches

Callibrate your Monitor with this little strip.



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frank5817
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Re: Venus 05.04.07 and 5.9.07 new [Re: rodelaet]
      #1606294 - 05/15/07 04:47 PM

Carlos, Michael and Rony,

Thank you for the kind remarks. I anticipated I would need to take a good long look. Venus is so brilliant it needs filtering to see well after it gets dark. I have rarely ever used the Wratten 47 filter but I'll be using it now with Venus.
Michael, I took your suggestion on the orientation. I wouldn't want to guess the other positions (rotational poles, direction of rotation, and the like). I'll need to brush up on Venus to fill my knowledge void.

Frank

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Tommy5
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Re: Venus 05.04.07 and 5.9.07 new [Re: frank5817]
      #1606709 - 05/15/07 08:02 PM

Great sketch of Venus,I looked at Venus on the 13th from chicago and had very steady skies,with my #47 violet I saw some albedo markings as well. darker toward the terminator and lighter towards the edge with my 6" achro refractor,I'm in the process of scanning/posting my sketch it is remarkably similiar to yours and these marking are strange,they seemed to come and go,yet they are diffinatly there with the filter and gone without it.

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Sol Robbins
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Re: Venus 05.04.07 and 5.9.07 new [Re: Tommy5]
      #1606932 - 05/15/07 09:48 PM

Great sketch. Looks like seeing some kind of detail on Venus has found its workaround.

Bad weather is setting in on me for the moment. Hopefully others will get a shot at Venus. This seems to be a first time a bunch of sketches of Venus over short periods of time has been put together.

At the risk of making a super-long thread, I would find it interesting and fun to see a whole folio of Venus sketches during this favorable apparition.

--------------------
S.R.


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frank5817
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Re: Venus 05.04.07 and 5.9.07 new [Re: Sol Robbins]
      #1606957 - 05/15/07 09:57 PM

Sol and Tommy,
Thanks!
______________
Sol,
That sounds like a plan

Frank

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Tommy5
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Re: Venus 05.04.07 and 5.9.07 new [Re: Sol Robbins]
      #1607055 - 05/15/07 10:53 PM Attachment (113 downloads)

Good idea about the sketches around this years Venus show .I've read that the cloud marking are easiest to see between superior conjunction and eastern elongation and are more difficult as the planet goes into a cresent phase but we will see, here is my sketch from 5/13/07,the markings were there during the twilight calm and more prominent toward's the terminator they didn't extend as far out as sol's or Micheal's sketch, but since i have only 6" aperture maybe that is why.They were only visible during the steadier moments on a calm twilight and only seen in the #47 violet filter which I thought was useless in my scope.The markings were easier to see then to sketch, the unlit part of the disk was invisible of course, i blacked out a disk from alpo.#47 filter,200x.

Attachment

Edited by Tommy5 (05/15/07 11:03 PM)


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Special Ed
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Re: Venus 05.04.07 through 05.16.07 new [Re: Tommy5]
      #1607165 - 05/16/07 12:06 AM Attachment (101 downloads)

Here's my latest sketch to add to the collection. It was done this evening during twilight (16 May UT). I diagrammed my eyepiece observation using the 0.0=completely black to 10.0=brightest scale and immediately did the sketch on a Venus Section ALPO form using HB and 2B pencils and a loaded stump.

The seeing wasn't the greatest, but in steady moments I could clearly see the dusky features rendered in the sketch. To lessen my confusion, I kept the mirror-reversed orientation of the SCT and used celestial directions.

As Sol said, compiling this series of observations is a good thing--I'm glad to be part of it. And I'm looking in the mail every day for my #47 filter.

Attachment

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Michael Rosolina
Celestron CGE Pro 1400 f/11 SCT
1980 Orange Tube C8 f/10 SCT
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Edited by Special Ed (05/16/07 10:19 PM)


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frank5817
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Re: Venus 05.04.07 through 05.16.07 new [Re: Special Ed]
      #1607601 - 05/16/07 09:25 AM

Tommy and Michael,
Skillful Venus sketches guys.
Frank

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Re: Venus 05.04.07 through 05.16.07 new [Re: frank5817]
      #1609112 - 05/16/07 10:17 PM

Thanks, Frank.

I commented on a Venus observation by Eric Jamison posted on the StarryNights Yahoo group and he and Geoff Gaherty (the moderator) had some information in response to my questions about labeling the directions on Venus observations. According to Geoff, the convention for identifying preceding is the direction that an object (planet, double star, etc.) drifts when the tracking drive is turned off--in other words, celestial west. This holds true regardless of retrograde rotation. The fact that most of the planets appear to rotate towards the west is a happy circumstance. Likewise, north-south is celestial north-south, even if the planet is upside down like Venus, or on its side like Uranus. I have edited the last sketch accordingly.

--------------------

Michael Rosolina
Celestron CGE Pro 1400 f/11 SCT
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Edited by Special Ed (05/17/07 06:23 AM)


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Re: Venus 05.04.07 through 05.16.07 new [Re: Special Ed]
      #1609213 - 05/16/07 11:13 PM

Michael and Tommy,

Excellent observations of Venus showing albedo features over the venusian atmosphere. I am glad to see such an effort on the part of observing Venus which is normally ignored. Detail is easier to note between superior cojunction and eastern/western elongation due to the increase in brilliance (irradiation) of the crescent phase (and therefore reduction in contrast; the planet's apparent diameter is larger during the crescent phase but the increased irradiation diminishes the contrast of albedo features). This is why it is easier to detect albedo features closer to the terminator.

Keep up the good work!

Carlos

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Re: Venus 05.04.07 through 05.16.07 new [Re: CarlosEH]
      #1611908 - 05/18/07 01:16 PM Attachment (92 downloads)

Viewing conditions 1.5 hours before sunset were shaping up to be be very good. I set up my telescope for evening and nightime viewing just before sundown. Venus was clearly visible and I retrieved my Wratten 47 violet filter to view and sketch the albedo features of Venus if visible.

Equipment: 18" f/5 Dob., 6mm ortho eyepiece (381X)
Wratten 47 filter
Seeing: Pickering 8
Transparency: Excellent
Time: 1:10-1:35 UT 5-18-2007
Sketching:
9"x12" black Strathmore Artagain paper
white pastel Conte' crayons, blending
stump, gum eraser, contrast and brightness
adjusted using Microsoft Paint.

Frank McCabe

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Re: Venus 05.04.07 through 05.16.07 new [Re: frank5817]
      #1611936 - 05/18/07 01:36 PM Attachment (100 downloads)

Great sketches of Venus everyone! Here is a sketch of our sister-planet made just over a month ago:

Attachment

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Eric
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Re: Venus 05.04.07 through 05.16.07 new [Re: cildarith]
      #1612153 - 05/18/07 03:55 PM

Eric and Frank,

Excellent observations of Venus! You both have recorded a good amount of detail over our sister planet. Thank you for sharing them with us all.

Carlos

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Re: Venus 05.04.07 through 05.16.07 new [Re: CarlosEH]
      #1612400 - 05/18/07 06:31 PM

Ditto!

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Re: Venus 05.04.07 through 05.16.07 new [Re: Sol Robbins]
      #1612471 - 05/18/07 07:13 PM

Frank, Eric--two astonishingly good sketches. To my eye, Frank's appears like an eyepiece view and Eric's approaches the best imaging we see in the Imaging Forum.

I especially like the diffuse appearance of the terminator edge in Eric's drawing. How did you do that drawing, please?

--------------------

Michael Rosolina
Celestron CGE Pro 1400 f/11 SCT
1980 Orange Tube C8 f/10 SCT
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Re: Venus 05.04.07 through 05.16.07 new [Re: Special Ed]
      #1612542 - 05/18/07 08:03 PM

Thank you gentlemen,
I would like to hire Eric to do my sketching.
Frank

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Re: Venus 05.04.07 through 05.16.07 new [Re: frank5817]
      #1613587 - 05/19/07 02:30 PM

Great sketches frank,eric and micheal,they all look very much like my view through my scope,its great to see such a display of sketching talent on our sister planet.

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Re: Venus 05.04.07 new [Re: CarlosEH]
      #1616177 - 05/20/07 10:53 PM

Great sketches and I appreciate and learned a bunch from the posts. My venus experience has been pretty dismal, but the comments tell me it is do-able. Thanks.

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Re: Venus 05.04.07 new [Re: rolandlinda3]
      #1616968 - 05/21/07 11:40 AM

Thanks for your comments, gentlemen!

To Michael: my sketch of Venus begins with a simple circle template. I do not attempt to "pre-position" the terminator as I've learned that apparent phase of Venus does not always precisely match the theoretical one (the phase usually appears a little bit smaller than it ought to) - so the first step is to estimate the position of the terminator and draw that in.

The unilluminated portion of the disk is then blackened in with pencil and a blending stump is used to "bleed" some of the graphite into the terminator region to give it that dusky, ill-defined look we are all familiar with. Once that is done I begin looking for those subtle variations in brightness across the cloudtops. These are added with the blending stump, dipping it into the blackened area (if necessary) and lightly shading in any apparent features.

Once the sketch has been scanned I apply a light blur to the whole image to further soften the blending stump and pencil strokes and crop a black circle around the disk to return the limb to its original sharpness. Finally I airbrush out any trace of pencil markings in the darkened region beyond the terminator.

--------------------
Eric
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Another Venus 5.22.07 new [Re: cildarith]
      #1618385 - 05/22/07 01:15 AM Attachment (118 downloads)

I had very good conditions for this Venus observation. Got to use 397x and a Wratten 47 deep violet with my slightly stopped down 10" reflector.

This sketch has a 2 step grayscale. I used 4H pencil to lay down a base tone which was blended with my fingers. The darker gray was done with an HB and slightly blended with my fingers. Then the whites were erased out.

Best,

Attachment

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S.R.


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Re: Another Venus 5.22.07 new [Re: Sol Robbins]
      #1618505 - 05/22/07 04:27 AM

Sol,
Great sketch. I took a close look at Venus tonight but sky conditions were poor near and just after sunset.
Frank

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Re: Another Venus 5.22.07 new [Re: frank5817]
      #1618542 - 05/22/07 05:41 AM

What a excellent observation and rendition of this very very bright but difficult to do Planet

Dee


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Re: Another Venus 5.22.07 new [Re: Dee]
      #1618590 - 05/22/07 06:46 AM

Frank & Dee,

Thanks for the compliments.

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Re: Another Venus 5.22.07 new [Re: Sol Robbins]
      #1622285 - 05/23/07 09:55 PM

Sol,
Excellent and impressive rendering of the Venusian cloudtops that you captured with your combination of scope/filter/seeing/eye.

Eric,
Thanks for the info on your technique. I hope you post another Venus observation.

I took a look at Venus last Saturday night while participating in the first International Sidewalk Astronomy Night. I first tried my new #47 filter (during early twilight) and boy did that make the view dark! With the public starting to show up, I didn't have the time or solitude to study the view carefully but I knew it was too dark for the casual observer so I put in the 80A. When asked, several people noticed the albedo features in the cloudtops and the bright limb arc. I never got a chance to sketch that night, but it was nice to be able to show Venus to an appreciative public.

Conditions haven't allowed me to observe since that night, but I'm curious to try the #47 filter again and in slightly darler skies. It was obvious from my first brief look that, as Carlos said, 8" of aperture is at the low range for the usefullness of this filter.

--------------------

Michael Rosolina
Celestron CGE Pro 1400 f/11 SCT
1980 Orange Tube C8 f/10 SCT
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Re: Another Venus 5.22.07 new [Re: Special Ed]
      #1622361 - 05/23/07 10:57 PM

Micheal,

Thanks.

I have been observing Venus while it is still light out. Roughly at 8pm eastern at this point in time. Venus is quite high in elevation and some far off trees keep me and my scope in shade. As said before, the W47 has a 2% light transmission. Until now I have never used a W47 and only in my 10" scope. It is kind of useless in my 6" refractor.

For some reason, I find observing Venus in my 10" reflector quite compelling. I am glad that this apparition is showing details even to your ISAN guests.

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S.R.


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Re: Another Venus 5.22.07 new [Re: Sol Robbins]
      #1624453 - 05/25/07 12:05 AM

Great sketch it looks very realistic, the other night i had some luck seeing the albedo features with a variable polarizer filter, i didn't have time to sketch but these markings are not hard to see but hard to sketch accurately as the seeing blots them out from time to time, your sketch is very close to the way they appear except with my smaller aperture,6" they don't seem to extend as far from the terminator.

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Re: Another Venus 5.22.07 new [Re: Sol Robbins]
      #1624678 - 05/25/07 06:37 AM

Quote:


I have been observing Venus while it is still light out. Roughly at 8pm eastern at this point in time. Venus is quite high in elevation and some far off trees keep me and my scope in shade. As said before, the W47 has a 2% light transmission. Until now I have never used a W47 and only in my 10" scope. It is kind of useless in my 6" refractor.




I was thinking that if the sky was a little darker, contrast would be better and Venus would appear brighter with the filter but maybe I'm wrong. Of course, the trade off for waiting is that Venus is lower in altitude. I guess the best test for this W47 filter in my 8" aperture is to start observing early and keep observing until after dark to compare what I can see with it.

Quote:


For some reason, I find observing Venus in my 10" reflector quite compelling. I am glad that this apparition is showing details even to your ISAN guests.




With Venus shining like a beacon every evening even through cloud cover, it's practically impossible to resist the urge to put a telescope on it whenever the opportunity presents itself.

--------------------

Michael Rosolina
Celestron CGE Pro 1400 f/11 SCT
1980 Orange Tube C8 f/10 SCT
4.25" f/4.2 Astroscan Reflector
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Re: Another Venus 5.22.07 new [Re: Special Ed]
      #1624721 - 05/25/07 07:47 AM Attachment (96 downloads)

I have a sketch of Venus in the Planetary and Solar System Observing forum "Venus at Dusk". One of the reasons for posting it was my surprise at the amount of (very subtle) detail that was visible even without filtration. A double stacked polarising filter did cut down the glare and make observations easier but even so it took a fair bit of concentration to be sure. Unfortunately I had no other filters to hand to experiment with.

Heres a cut down (and enhanced) copy of that sketch.

Joe

Attachment

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Re: Another Venus 5.22.07 new [Re: JoeF]
      #1624855 - 05/25/07 09:39 AM

Joe,
Nice sketch, the albedo features really show well.
Frank

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Re: Another Venus 5.22.07 new [Re: JoeF]
      #1626631 - 05/26/07 10:53 AM

very nice and accurate sketch of the subtle wispy markings on venus keep up the good work it will interesting to see if these markings are still visible when venus moves past elongation and plunges back toward the sun.

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Re: May 27 Venus Sketch new [Re: JoeF]
      #1627732 - 05/27/07 01:18 AM Attachment (80 downloads)

I had good conditions for yet another Venus observation. Venus is appearing lower in altitude than seen in previous observations at around 8pm local time.

Albedo features are still obvious with my 9.75" reflector with Wratten 47 deep violet filter. Sketch shows magnification at 317x. It should read 397x.

Again, this sketch was made using 4H and HB pencils with blending done with my fingers. Bright spots were erased out.

Best,

Attachment

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S.R.


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Re: May 27 Venus Sketch new [Re: Sol Robbins]
      #1627892 - 05/27/07 08:09 AM

Sol,
Very nice Venus sketch. It has been too cloudy to observe here for two evenings.
Frank

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Re: May 27 Venus Sketch new [Re: frank5817]
      #1628022 - 05/27/07 09:54 AM

Thanks Frank. I look forward to seeing what your observations when the weather cooperates.

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Re: May 27 Venus Sketch new [Re: Sol Robbins]
      #1629422 - 05/28/07 03:07 AM

Excellant view of the cloud markings on venus, very similar to what i saw this evening under steady skies in chicago,i'll post my sketch tomorrow. thanks for alerting us to these views, usually i don't even observe venus unless its in a thin crescent.

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Re: May 27 Venus Sketch new [Re: Tommy5]
      #1629683 - 05/28/07 08:55 AM

Thanks T,

Hope to see your sketch soon.

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Re: Venus 05.04.07 new [Re: Sol Robbins]
      #1631249 - 05/29/07 02:22 AM Attachment (99 downloads)

Here is my sketch from last evening 5-27-07,some markings could be seen with a variable polarizer filter, but the markings were more clearly seen with a #47 filter,darker near the terminator but more clearly seen further then in past views,the terminator looked a bit illregular as well,this is my first attempt to scan a photo from my new scanner,seeing was unusually steady as a high pressire area moved in and settled over my home lol. .

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Edited by Tommy5 (05/29/07 02:33 AM)


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Re: Venus 05.04.07 new [Re: Tommy5]
      #1631486 - 05/29/07 09:00 AM

Tommy,
Nice drawing of Venus and the albedo features.
Frank

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Re: May 27 Venus Sketch new [Re: Tommy5]
      #1631986 - 05/29/07 01:40 PM

JoeF,
Thanks for adding your Venus observation to this collection--the albedo features you saw are well rendered.

Sol and Tommy,
Your latest sketches show the albedo features extending closer to the limb than in your previous drawings. This is similiar to what I have viewed (when I had the chance). From your drawings and JoeF's, the gibbous phase appears to be dwindling.

Farm work and weather have prevented me from making any recent observations. The weather was bad over the holiday weekend and finally improved last night but I had to work until dark-thirty getting some things in the ground. I hope to observe again soon.

Keep up the good work, everyone.

--------------------

Michael Rosolina
Celestron CGE Pro 1400 f/11 SCT
1980 Orange Tube C8 f/10 SCT
4.25" f/4.2 Astroscan Reflector
50mm f/10 Galileoscope
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APM Germany HD 15x70 binoculars
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Re: May 27 Venus Sketch new [Re: Special Ed]
      #1632293 - 05/29/07 04:04 PM

T5,

Nice one! I guess seeing albedo features Venus is a bit easier this aparition.

Micheal Venus is shinking. I am not sure, but as Venus dwindles to its halfway point as it is now, I imagine that its disk will grow larger in apparent size when it starts to get past its halfway point.

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Re: May 27 Venus Sketch new [Re: Sol Robbins]
      #1632615 - 05/29/07 07:12 PM

Thanks Frank,Micheal and Sol,it has been fun to compare and view sketches with you guys,frank, congrads on your sketch being on LPOD. Hope to see all of you guys sketches as Venus continues its path around the sun and jupiter rolls on towards opposition.

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Re: May 30 Venus Sketch new [Re: Tommy5]
      #1633064 - 05/30/07 12:05 AM Attachment (88 downloads)

This observation tonight (8:20-9:20 PM local time 29 May) was my first telescopic look in 10 days. In that time, according to information from S&T, Venus has increased in apparent diameter slightly, going from ~19 arcseconds to ~21 arcseconds--not really enough for me to notice much difference.

What was quite noticeable was the change in the appearance of the phase. I was expecting it, thanks to the sketches posted here, but still interesting to see in real time. It looks like Venus will be down to 50% illumination very shortly.

The terminator appeared to turn in towards the dark hemisphere, unless my eyes were playing tricks on me. I tried my W47 filter again, but the disk was featureless with it, perhaps because of the very poor transparency, so I used the W80A.

The sketch was done with HB and 6B graphite pencils, a loaded stump, an eraser, and black ink. I'm happy to contribute another sketch to this thread.

Attachment

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Michael Rosolina
Celestron CGE Pro 1400 f/11 SCT
1980 Orange Tube C8 f/10 SCT
4.25" f/4.2 Astroscan Reflector
50mm f/10 Galileoscope
40mm PST f/10
APM Germany HD 15x70 binoculars
Canon 12x36 IS II binoculars
Mark I Eyeball
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Re: May 30 Venus Sketch new [Re: Special Ed]
      #1633200 - 05/30/07 04:12 AM

Michael and Tommy,

Excellent observations of Venus showing some interesting albedo features. Noting such detail over Venus is always a treat. Thank you for sharing them with us all.

Carlos

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Re: May 30 Venus Sketch new [Re: CarlosEH]
      #1633791 - 05/30/07 12:53 PM

Tommy,
Thank you much.

Michael,
Very nice observation and sketch. I could not see the venusian clouds through the earth bound clouds last evening.

Frank

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Re: May 30 Venus Sketch new [Re: frank5817]
      #1635129 - 05/31/07 01:23 AM

very nice sketch micheal this season of venus watching is getting to be a a memorable one.

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Re: May 30 Venus Sketch new [Re: CarlosEH]
      #1636116 - 05/31/07 03:56 PM

Indeed, excellent sketches from you all!!

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Rony

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Re: June 7 Venus Sketch new [Re: rodelaet]
      #1650482 - 06/08/07 06:16 AM Attachment (81 downloads)

Hi,

I made this sketch Wednesday evening but didn't get a chance to post it until now. The view is still good if you catch it early. I tried several different filters on this observation but settled on the #80A. The sketch was done with an HB pencil and ink from an ep diagram of the different intensities.

Attachment

--------------------

Michael Rosolina
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Edited by Special Ed (06/08/07 06:32 AM)


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Sol Robbins
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Re: June 7 Venus Sketch new [Re: Special Ed]
      #1650491 - 06/08/07 06:33 AM

Nice one Michael. Hopefully I'll have some luck in getting to view Venus soon.

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Re: June 7 Venus Sketch new [Re: Sol Robbins]
      #1650621 - 06/08/07 08:51 AM

Michael,
Excellent Venus sketch. I see you are still picking up some detail.
Frank

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Edited by frank5817 (06/08/07 11:07 PM)


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Re: June 7 Venus Sketch new [Re: frank5817]
      #1651910 - 06/08/07 09:31 PM

very nice sketch good catch on the northern cusp cap, dark markings may become harder to see as venus gets closer and larger and goes into a crescent phase.

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Re: June 7 Venus Sketch new [Re: Tommy5]
      #1651939 - 06/08/07 09:45 PM

Sol, Frank, and T5, thanks. Difficult at best, Venus observing is going to get harder by all accounts. It will still be favorably placed for another month, according to S&T, so watching the phase change and any other phenomena should be interesting. The observing tips from the BAA and ALPO Venus sections (as well as Fred Price's book) have been very helpful.

Btw, Venus will be just north of M44 on June 12 and 13--that should be nice.

--------------------

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Re: Venus 05.04.07 through 05.16.07 new [Re: Sol Robbins]
      #1652221 - 06/09/07 02:44 AM Attachment (90 downloads)

Good viewing conditions 1 hours before sunset gave me an opportunity to view and sketch Venus. I set up my telescope for evening and nightime viewing 2 hours before sunset. Venus was clearly visible and I attached a Wratten 47 violet filter to an eyepiece to view and sketch the albedo features of Venus if visible.

Equipment: 18" f/5 Dob., 6mm ortho eyepiece (381X)
Wratten 47 filter
Seeing: Pickering 8
Transparency: Excellent
Time: 0:15-:45 UT 6-9-2007
Sketching:
9"x12" black Strathmore Artagain paper
white and black pastel Conte' crayons, blending
stump, gum eraser, contrast and brightness
adjusted using Microsoft Paint.

Frank McCabe

Attachment

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Re: Venus 05.04.07 through 05.16.07 new [Re: frank5817]
      #1653788 - 06/10/07 01:05 AM

Very nice sketch frank, you seem to be seeing some albedo features out near the limb and a few near the terminator,great sketch.

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Re: Venus 05.04.07 through 05.16.07 new [Re: Tommy5]
      #1654286 - 06/10/07 11:32 AM Attachment (75 downloads)

Frank,

Great job on your sketch--I saw similiar shadings last night 24 hours after your observation. Like you, I set up early and started observing about 45 minutes before local sunset when Venus was at an altitude of ~50 deg. I found Venus by setting the declination and sweeping along the RA line while I looked through the finder.

I tried my W47 filter but my aperture is just too small. Experimenting with the W80A and W11 filters separately, I then tried stacking them and liked the view. Even though Venus was high, the seeing was below average (it got even worse later) but I managed this sketch. I used an HB pencil, a loaded stump, black ink, and an intensity diagram.

Attachment

--------------------

Michael Rosolina
Celestron CGE Pro 1400 f/11 SCT
1980 Orange Tube C8 f/10 SCT
4.25" f/4.2 Astroscan Reflector
50mm f/10 Galileoscope
40mm PST f/10
APM Germany HD 15x70 binoculars
Canon 12x36 IS II binoculars
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Re: Venus 05.04.07 through 05.16.07 new [Re: Special Ed]
      #1654377 - 06/10/07 12:28 PM

Great sketch micheal, the albedo features look similar to franks good job.

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Re: Venus 05.04.07 through 05.16.07 new [Re: Tommy5]
      #1654739 - 06/10/07 04:13 PM

Tommy5 and Michael,

Thank you both. The weather and seeing conditions were as good as they usually get in south Cook county.
_________

Michael,

Very nice sketch above and congratulations on your Venus sketch on ASOD today.

Frank

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Re: Venus 05.04.07 through 05.16.07 new [Re: frank5817]
      #1658280 - 06/12/07 10:15 AM Attachment (70 downloads)

Sky transparency was too poor before sunset to pick Venus out with the unaided eye so I swept the region of the sky it was located in with a 28mm eyepiece until I found it. I attached a Wratten 47 violet filter to an eyepiece to view and sketch the albedo features of Venus if visible.

Equipment: 18" f/5 Dob., 6mm ortho eyepiece (381X)
Wratten 47 filter
Seeing: Pickering 7
Transparency: below average 2/5
Time: 0:00-0:18 UT 6-12-2007
Sketching:
9"x12" black Strathmore Artagain paper background only
White sketching paper cut to shape of planet
2H graphite pencil blended with index finger
brightness slightly adjusted using Imageenhance.

Frank McCabe

Attachment

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Re: Venus 05.04.07 through 05.16.07 new [Re: frank5817]
      #1658303 - 06/12/07 10:32 AM

Outstanding observations, everyone!

--------------------
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Re: Venus 05.04.07 through 05.16.07 new [Re: Erix]
      #1659275 - 06/12/07 06:04 PM

Fantastic sketches, one and all! Thank you!!

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Re: Venus 05.04.07 through 05.16.07 new [Re: ScottAz]
      #1659958 - 06/13/07 03:26 AM

Frank and Michael,

Excellent observations of Venus. The albedo features recorded are very interesting. Keep up the good work.

Carlos

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Re: Venus 05.04.07 through 05.16.07 new [Re: CarlosEH]
      #1660459 - 06/13/07 11:40 AM

It was great of Sol to start this thread and good that Michael and T5 jumped in early on. I haved learned a lot along the way and so far it has been fun.
Thanks for looking in on us. Hopefully we have weeks to go.
Frank

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Re: Venus 05.04.07 through 05.16.07 new [Re: frank5817]
      #1661155 - 06/13/07 06:28 PM

Frank,

Great observation and sketch. Along with the shadings in the cloudtops, you show a little cusp extension to the north and a little blunting to the south on the terminator as well as a slightly concave terminator. With your observing skills, mega-aperture, and the high altitude of Venus at the time of your observation, I would take this observation to the bank.

Thanks to all for the kind words. Observing Venus this apparition has been a great experience.

--------------------

Michael Rosolina
Celestron CGE Pro 1400 f/11 SCT
1980 Orange Tube C8 f/10 SCT
4.25" f/4.2 Astroscan Reflector
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Re: Venus 05.04.07 through 05.16.07 new [Re: Special Ed]
      #1661343 - 06/13/07 07:46 PM

Another great sketch of venus those albedo features are drawn just as they are seen in the eyepiece great job.

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Re: Venus 05.04.07 through 05.16.07 new [Re: Tommy5]
      #1661608 - 06/13/07 10:01 PM

Really interesting sketched observations.

Thanks.

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Re: 3 Venus Sketches 6.16.07 new [Re: Sol Robbins]
      #1665560 - 06/16/07 01:33 AM Attachment (85 downloads)

Hi,

Finally had clear sky and good seeing. I made 3 Venus sketches using my 9.75" reflector all at 397x. I view in IL, with a Wratten 47 violet and then a Wratten 25A red. Then albedo features were markedly different in each view. All sketches were done back to back.

The sketch below is in IL. This sketch was done with an HB pencil, blended with my finger and whites erased out.

Attachment

--------------------
S.R.


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Sol Robbins
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Re: 3 Venus Sketches 6.16.07 new [Re: Sol Robbins]
      #1665563 - 06/16/07 01:37 AM Attachment (78 downloads)

The sketch below was done observing with a W47 filter.

I used both 4H and HB pencils. Blending was done with my finger and whites were erased out.

Attachment

--------------------
S.R.


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Re: 3 Venus Sketches 6.16.07 new [Re: Sol Robbins]
      #1665566 - 06/16/07 01:42 AM Attachment (78 downloads)

This last observation was done using a W25A filter.

Sketch was done using a tortillion for a base tone, an HB pencil and whites were erased out.

Attachment

--------------------
S.R.


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Re: 3 Venus Sketches 6.16.07 new [Re: Sol Robbins]
      #1665639 - 06/16/07 04:25 AM

Sol,

A very impressive set of Venus observations made in various wavelengths. I am very proud of all of the incredible Venus observations made by all participants of this thread. Thank you for sharing them with us all.

Carlos

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Sol Robbins
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Re: 3 Venus Sketches 6.16.07 new [Re: CarlosEH]
      #1665849 - 06/16/07 09:48 AM

Thanks Carlos.

I also would like to thank everyone who has posted their observations and insights regarding Venus during this apparition.

Its been a lot fun and very interesting. I don't believe there has been a concerted effort for amateurs to memorialize a Venus apparition, other than the BAA, the way it has taken place in a relaxed way here on CN.

Thanks again.

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S.R.


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Re: 3 Venus Sketches 6.16.07 new [Re: CarlosEH]
      #1665853 - 06/16/07 09:50 AM

Sol,

Great sketching, the features do seem to change quite rapidly over time and with different filters instantaneously. Excellent post.

Frank

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Re: 3 Venus Sketches 6.16.07 new [Re: frank5817]
      #1665919 - 06/16/07 10:57 AM

Frank,

Changes in the albedo features with different filters were striking to say the least.

Thanks.

--------------------
S.R.


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Re: 3 Venus Sketches 6.16.07 new [Re: Sol Robbins]
      #1666612 - 06/16/07 08:13 PM

Excellant venus sktches, i think Lowell had sketches "canals" on venus, i can see how your accurate views and and a little imagination could yield such features, great job and thanks for he interesting way you compared different filtered views.

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Re: 3 Venus Sketches 6.16.07 new [Re: Tommy5]
      #1666977 - 06/17/07 12:27 AM

Thanks T.

Isn't it believed that Lowell sketched the shadows of the blood vessels in his eye in his Venus observations?

I think astro-archeo-optometrists ,sp?;), used his Venus sketches to diagnose him having hypertension.

Best,

--------------------
S.R.


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Re: 3 Venus Sketches 6.16.07 new [Re: Sol Robbins]
      #1667464 - 06/17/07 12:18 PM

Sol,

A really great set of observations--fast work, too. Your fingers were flying.

You appear to have recorded cusp caps in both filtered observations. The comparison with different filters (and no filter) was a good idea. The sketch using the W25 looks alot like what I see with the W80A, e.g., the well defined limb arc and shadings out to the limb arc. My last observation I tried a quick look with my W23A filter and was surprised that it seemed to show the same view as the 80A but with better contrast (I ended up stacking the W80A and the W11 for the observation). I'm going to take a longer look with it next time (soon I hope).

This is a great (and educational) thread and your oustanding contributions have set a high standard for it. I'm glad that Tom Trusock has called attention to this discussion.

Btw, according to Price, Antoniadi did not think Lowell's "spokes" on Venus really existed. Linear features were seen and sketched 55 years later by R.M.Baum (who had no knowledge of Lowell's Venus observations).

--------------------

Michael Rosolina
Celestron CGE Pro 1400 f/11 SCT
1980 Orange Tube C8 f/10 SCT
4.25" f/4.2 Astroscan Reflector
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Re: 3 Venus Sketches 6.16.07 new [Re: Special Ed]
      #1667768 - 06/17/07 03:39 PM



This is my latest sketch of Venus, made just hour ago at 18:50UT.

--------------------
I like sketching...

8" F6 Dob - "Betsy"
12" F5 Dob - "Tristac"


Messier Catalogue - done
Herschel 400 - 189 more to go
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Re: 3 Venus Sketches 6.16.07 new [Re: Acheron]
      #1668259 - 06/17/07 09:32 PM

Acheron,

Excellent! Any details like scope size, magnification and filter?

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Re: 3 Venus Sketches 6.16.07 new [Re: Acheron]
      #1668593 - 06/18/07 01:46 AM

Vedran,

An excellent observation of Venus showing some albedo features over the disk. Thank you for sharing it with us all.

Carlos

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Re: 3 Venus Sketches 6.16.07 new [Re: Acheron]
      #1668660 - 06/18/07 04:04 AM

Percival Lowell may be better known for his Mars Canal Hypothesis (proposed in 1895 in Lowell's book "Mars" ( http://www.wanderer.org/references/lowell/Mars/ ) after observations made at the observatory using an 18-inch (46-cm) refractor), but he also explored the rest of the solar system, including our closest planetary neighbor Venus. Lowell, in August of 1896, turned the newly-erected 24-inch (60-cm) f/16 Refractor towards Venus while awaiting the planet Mars to aproach the Earth closer at opposition in December of the same year. Using such an aperture on the third brightest object in the heavens (-4.5m) it is understandable why Lowell was required to "stop down the aperture" (using an adjustable diaphragm at the 24" lens) to a diameter between 1.6 to 3 inches. At these small apertures the disk of Venus exhibited albedo features describes as "spokes of a wheel radiating from a central hub." Lowell believed these "spider-web features" to be permanent surface features comprised of "rock or sand weathered by aeons of exposure to the Sun" seen through the "diaphanous straw-colored veil" of a dense but strangely transparent atmosphere. With all our current knowledge of the dense atmosphere of Venus and spacecraft images it is difficult to understand why this Bostonian astronomer would believe in such a delusion. We must understand that what was known of the Moon and planets at the end of the nineteenth century was derived from visual observations (although photography was in it's nascency at this time). Spectroscopic observations made in the 1920's by Frank E. Ross provided the existence of a dense Venusian atmosphere.

Noted planetary historian William Sheehan and observer Thomas Dobbins upon researching the subject believe that Lowell may have been actually describing shadows cast by his retinal vessels by converting the stopped-down Lowell refractor into an opthalmoscope (an optical device used in the examination of the ocular fundus). It is interesting to compare the retina of the eye to the Venusian drawings made by Lowell. The similarity is very striking! This optical phenomena made possible by the Lowell refractor producing exit pupils between 0.29 to 0.54 millimeters at small apertures (1.6-3 inches (4-7.6 cm)).

Interesting links;
http://en.wikipedia.org/wiki/Martian_canal
http://www.lowell.edu/index.php
http://www.uapress.arizona.edu/onlinebks/mars/chap07.htm
http://en.wikipedia.org/wiki/Venus

Carlos

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Re: 3 Venus Sketches 6.16.07 new [Re: Sol Robbins]
      #1668769 - 06/18/07 07:55 AM

Quote:

Acheron,

Excellent! Any details like scope size, magnification and filter?




Ups

8" F6 Dob, 6mm GSO SuperPlossl, W80A and ND06 filters. Seeing was good for that time of evening.

--------------------
I like sketching...

8" F6 Dob - "Betsy"
12" F5 Dob - "Tristac"


Messier Catalogue - done
Herschel 400 - 189 more to go
http://www.facebook.com/pages/Vizualno-promatranje-Svemira/236702789691880?sk...


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Re: 3 Venus Sketches 6.16.07 new [Re: Acheron]
      #1668840 - 06/18/07 09:19 AM

Vedran,

Nice Venus sketch as are the others at your web page. Cloud features look great.

Frank

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Re: 3 Venus Sketches 6.16.07 new [Re: frank5817]
      #1669426 - 06/18/07 03:05 PM

Vedran, nice job on your sketch--your filter combo allowed you a good view of the cloud shadings.

Carlos, thanks for the information on Lowell and the "spokes". The history and background of the great visual observers of the past is always fascinating and instructive.

--------------------

Michael Rosolina
Celestron CGE Pro 1400 f/11 SCT
1980 Orange Tube C8 f/10 SCT
4.25" f/4.2 Astroscan Reflector
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Re: 3 Venus Sketches 6.16.07 new [Re: Special Ed]
      #1669465 - 06/18/07 03:28 PM

Quote:

Vedran, nice job on your sketch--your filter combo allowed you a good view of the cloud shadings.




Thank you for comment, but...
Cloud features where much more subtle than this. I almost think that my imagination played tricks with me last night.
One second you see them and another second not.

--------------------
I like sketching...

8" F6 Dob - "Betsy"
12" F5 Dob - "Tristac"


Messier Catalogue - done
Herschel 400 - 189 more to go
http://www.facebook.com/pages/Vizualno-promatranje-Svemira/236702789691880?sk...


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Re: 3 Venus Sketches 6.16.07 new [Re: Acheron]
      #1670421 - 06/19/07 12:31 AM

great sketch Acheron,other observors have also commented on the illusive nature of these features some were reluctant to draw or mention them thinking that they were not really there,but they are and now we all have observed similar albedo markings on venus, congrads again on your sketch.

Edited by Tommy5 (06/20/07 04:24 PM)


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Re: Venus Sketch 6.19.07 new [Re: Tommy5]
      #1673317 - 06/20/07 02:11 PM Attachment (83 downloads)

Here's a sketch I did Monday evening just before local sunset (19 June UT). The dusky shadings appeared the same in the W23A and double stacked filter view. The cusp extensions were equal north and south but I messed up a little on the north cusp with ink and couldn't fix it. Also, the phase may be a little off--it's hard to draw accurately right now--those cusp extensions make it seem more pronounced than it really is, I think (the phase was 44%).

Sketch was done from an intensity diagram with an HB pencil and a stump loaded with graphite. Black ink for the phase.

Regards,

Attachment

--------------------

Michael Rosolina
Celestron CGE Pro 1400 f/11 SCT
1980 Orange Tube C8 f/10 SCT
4.25" f/4.2 Astroscan Reflector
50mm f/10 Galileoscope
40mm PST f/10
APM Germany HD 15x70 binoculars
Canon 12x36 IS II binoculars
Mark I Eyeball
My CN Gallery


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Re: Venus Sketch 6.19.07 new [Re: Special Ed]
      #1673942 - 06/20/07 07:04 PM

Excellent Michael. Last time the cusps you mention had a very defined edge w/red filter.

Lastly, did the brightening that appears inward from the limb, at about 10 o'clock in your sketch, pulse with varying brightness with changes in seeing? Though different, these "spots" looked very bright at times and similar to Martian limb brighteningThanks,

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S.R.


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Re: Venus Sketch 6.19.07 new [Re: Sol Robbins]
      #1674208 - 06/20/07 09:55 PM Attachment (78 downloads)

Michael,
Very nice observation of Venus and the albedo features. This has been a fun learning experience for me. I have done more Venus observing in the last month than in the previous 20 years. I have you and Sol to thank for this awakening.

--------------
Sky transparency was average before sunset. Venus was easy to pick up visually at 7:50 pm local time. I attached a Wratten 47 violet filter to a 6mm ortho. eyepiece to view and sketch the albedo features of Venus.

Equipment: 10" f/5.7 Dobsonian, 6mm orthoscopic eyepiece (241X)
Wratten 47 filter
Seeing: Pickering 5
Transparency: below average 3/5
Time: 1:05-0:25 UT 6-21-2007
Sketching:
9"x12" black Strathmore Artagain paper background only
White sketching paper cut to shape of planet
2H, B and HB graphite pencils blended with a blending stump
brightness slightly adjusted using Imageenhance.

Frank McCabe

Attachment

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Re: Venus Sketch 6.19.07 new [Re: frank5817]
      #1674369 - 06/20/07 11:34 PM

Frank,

WOW!

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Re: Venus Sketch 6.19.07 new [Re: Sol Robbins]
      #1674720 - 06/21/07 07:49 AM

Frank and Michael,

Excellent observations of Venus showing albedo features over the disk. The Venus observations continue to be impressive. Thank you for sharing them with us all.

Carlos

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Re: Venus Sketch 6.19.07 new [Re: Sol Robbins]
      #1674890 - 06/21/07 10:10 AM

Sol, Frank, Carlos,

Thank you all. Frank, terrific sketch--it seems that Venus continues to have a hold on us.


Quote:

Last time the cusps you mention had a very defined edge w/red filter...did the brightening that appears inward from the limb, at about 10 o'clock in your sketch, pulse with varying brightness with changes in seeing? Though different, these "spots" looked very bright at times and similar to Martian limb brighteningThanks,




Sol, I agree--the cusps were very well defined, I would even say prominent, in red light and with the stacked filters.

The bright area you refer to is a little more shaded than the scanner picked up. It did vary in intensity as you describe but as you know, Venus won't sit still for very long so it's hard to confirm anything.

One other thing I noticed that I didn't include in my brief report was that, while bright, the limb arc did not appear as bright as in past observations. In my diagram, I put it at 9.5 instead of 10.0 just to show a slight perceived change.

Susan Delaney on the Starrynights Yahoo group kindly provided this link to the book Celestial Objects for Common Telescopes by Rev. T.W. Webb published in 1859. It has some fascinating stuff in it about early Venus observations. More on Rev. Webb can be seen here.

Best to all,

--------------------

Michael Rosolina
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Re: Venus Sketch 6.19.07 new [Re: Special Ed]
      #1676319 - 06/22/07 12:30 AM

frank and micheal, great sketches of venus we certainly have a lot of data on cloud patterns of venus.

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Re: Venus Sketch 6.19.07 new [Re: Tommy5]
      #1694596 - 07/01/07 11:09 PM Attachment (89 downloads)

Sky transparency was above average all day. I was able to pick Venus out with the telescope before it crossed the local meridian in the afternoon. From Venus I moved the scope to the position of Saturn, but could not pull it out of the blue background. So I have had better transparency in the past. Venus was easy to pick up visually by 4 pm local time. I attached a Wratten 47 violet filter to a 6mm ortho. eyepiece to view and sketch the albedo features of Venus.
About 3.5 hours after finishing the sketch I was able to see both Venus and Saturn in the same field of view using a 28 mm eyepiece. That doesn’t happen ever day.

Equipment: 10" f/5.7 Dobsonian, 6mm orthoscopic eyepiece (241X)
Wratten 47 filter
Seeing: Pickering 6
Transparency: above average 3.5/5
Time: 22:00-22:20 UT 7-1-2007
Sketching:
9"x12" black Strathmore Artagain paper background only
White sketching paper cut to shape of planet
2H, B and HB graphite pencils blended with a blending stump
brightness slightly darkened using Imageenhance.

Frank McCabe

Attachment

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Edited by frank5817 (07/01/07 11:12 PM)


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Re: Venus Sketch 6.19.07 new [Re: frank5817]
      #1694664 - 07/01/07 11:35 PM

Nice sketch, Frank. The crescent phase is really taking hold now. Having Saturn nearby was a real bonus, wasn't it?

--------------------

Michael Rosolina
Celestron CGE Pro 1400 f/11 SCT
1980 Orange Tube C8 f/10 SCT
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Re: Venus Sketch 6.19.07 new [Re: Special Ed]
      #1694874 - 07/02/07 02:43 AM

Michael,
Thanks. You are right, the crescent phase and the decreasing distance between earth and Venus are now notable.
Seeing Saturn and Venus in the same field of view was very impressive.
Frank

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Re: Venus Sketch 6.19.07 new [Re: frank5817]
      #1695081 - 07/02/07 08:17 AM

This is really cool stuff! Great job to all of you!

--------------------
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07.03.07 Venus Sketch new [Re: Erix]
      #1696996 - 07/03/07 07:22 AM Attachment (74 downloads)

This Venus observation was made during twilight with very good seeing conditions. Venus now sinks rapidly and there is not a lot of time to observe it as nearby trees get in the way.

The crescent phase is becoming more pronounced and Venus' apparent has increased.

Observation was made with my 9.75" @ 397x with a Wratten 25A red filter.

Sketch was done with 4H and HB pencils. Blending done with my fingers and whites were erased out.

Best.

Attachment

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Re: 07.03.07 Venus Sketch new [Re: Sol Robbins]
      #1697457 - 07/03/07 12:29 PM

Sol,

Another excellent observation of the goddess of love. You have rendered the delicate albedo features very nicely. Thanks you for sharing it with us all.

Carlos

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Re: 07.03.07 Venus Sketch new [Re: CarlosEH]
      #1697615 - 07/03/07 01:53 PM

Thanks Carlos.

I have to admit this has been a really interesting Venus apparition. About 10 days ago Venus showed its blurred albedo features in my 3" refractor at the Rockland Astronmy Club's last public night.

Many thanks to all who contributed their Venus observations to this thread.

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Re: 07.03.07 Venus Sketch new [Re: Sol Robbins]
      #1697969 - 07/03/07 04:53 PM

Sol,

Another great Venus sketch indeed. You really pull out a lot of variability in brightness in the albedo features.

Frank

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Re: 07.03.07 Venus Sketch new [Re: frank5817]
      #1698096 - 07/03/07 06:01 PM

Great sketch, it's interesting that the red filter now brings out the albedo features.

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Re: 07.03.07 Venus Sketch new [Re: Tommy5]
      #1698432 - 07/03/07 09:48 PM

Thanks Frank & T5.

I was going to try for 3 sketches in IL, deep red and deep violet. I simply didn't have enough time as Venus disappeared behind some trees.

Best,

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Re: 07.03.07 Venus Sketch new [Re: Sol Robbins]
      #1698579 - 07/03/07 11:04 PM

Nice one, Sol. The crescent phase and cusp extensions rendered by you and Frank compare well to the image posted by Kruno in the Venus thread in the SSO forum.

I hope to observe Venus myself while I am at the Green Bank Star Quest the next four days. If I have any luck with the weather, I'll post the results here.

--------------------

Michael Rosolina
Celestron CGE Pro 1400 f/11 SCT
1980 Orange Tube C8 f/10 SCT
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Re: 07.07.07 Venus Sketch new [Re: Special Ed]
      #1708881 - 07/10/07 06:00 AM Attachment (82 downloads)

Quote:


I hope to observe Venus myself while I am at the Green Bank Star Quest the next four days. If I have any luck with the weather, I'll post the results here.




Well, I'm quoting myself here because I just got back from the StarQuest and I was able to observe Venus. Meanwhile, it appears everyone here has been very busy--I have a lot of catching up to do in order to see everyone's work.

With the help of a friend's sharp eyesight, I put the scope on Venus around 8PM EDT and was able to observe it for over an hour. Since my last observation on June 19th, Venus's apparent angular size has grown from 27 arcseconds to 34 arcseconds and the "horns" are very prominent.

The sketch was done in the field using HB and 2B pencils, black ink, and a stump. Once again, I did the sketch from an intensity diagram. As Sol mentioned, Venus goes down fast now--faster than I can work. The view with the blue and red filters was very similiar.

I didn't think I'd still be sketching Venus in July, but here it is.

Attachment

--------------------

Michael Rosolina
Celestron CGE Pro 1400 f/11 SCT
1980 Orange Tube C8 f/10 SCT
4.25" f/4.2 Astroscan Reflector
50mm f/10 Galileoscope
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Re: 07.07.07 Venus Sketch new [Re: Special Ed]
      #1709030 - 07/10/07 08:43 AM

Michael,

Wonderful Venus sketch. I got a brief look at it a few days back. You captured the darkening along the terminator beautifully.

Frank

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Re: 07.07.07 Venus Sketch new [Re: frank5817]
      #1709820 - 07/10/07 05:19 PM

Great sketch, it looks like we will be able to capture markings on venus this late in the season.

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Re: 07.07.07 Venus Sketch new [Re: Tommy5]
      #1710009 - 07/10/07 06:52 PM

Frank, T5, thanks! The shading along the terminator was *very* prominent even in integrated light. It will be interesting to see what remains visible as Venus progresses more into the crescent phase. I hope you both get to observe and sketch beautiful Venus again.

Best,

--------------------

Michael Rosolina
Celestron CGE Pro 1400 f/11 SCT
1980 Orange Tube C8 f/10 SCT
4.25" f/4.2 Astroscan Reflector
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Re: 07.07.07 Venus Sketch new [Re: Special Ed]
      #1710455 - 07/10/07 11:08 PM

Michael,

Great Venus sketch!

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S.R.


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Re: 07.07.07 Venus Sketch new [Re: Sol Robbins]
      #1711212 - 07/11/07 12:09 PM

Thanks, Sol.

--------------------

Michael Rosolina
Celestron CGE Pro 1400 f/11 SCT
1980 Orange Tube C8 f/10 SCT
4.25" f/4.2 Astroscan Reflector
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Re: 07.07.07 Venus Sketch new [Re: Special Ed]
      #1712550 - 07/11/07 11:09 PM Attachment (89 downloads)

Micheal here is a snapshot of venus taken 7-11-07 the day of greatest brightness,with a red 23a filter,some darker areas were visible near the terminator and very subtle shading appeared further across venusian cloudscape.

Attachment

Edited by Tommy5 (07/11/07 11:10 PM)


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Re: 07.07.07 Venus Sketch new [Re: Tommy5]
      #1747074 - 07/30/07 01:15 AM Attachment (88 downloads)

This is a midday observation of Venus before it crossed the meridian. Sky transparency was good 4.5/5 seeing poor 4/10. I tried an assortment of filters with a pair of polarizing filters giving the best view.

Equipment
10" f/5.7 Dobsonian with a 9mm ortho. eyepiece (161x)
Polarizing filter pair
Seeing: Pickering 4/10
Transparency 4.5/5
Time:7:10-7:30 UT 7-29-2007
Sketching:
9"x9" black Strathmore Artagain paper background. White sketching paper cut to the shape of the Venus phase.
2H and HB graphite pencils blended with a blending stump.

Frank McCabe

Attachment

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Edited by frank5817 (07/30/07 01:18 AM)


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Re: 07.07.07 Venus Sketch new [Re: frank5817]
      #1748369 - 07/30/07 06:34 PM

Great sketch of venus, good idea catching it in the afternoon, i'll try to catch it after sunset, it is getting very low,nice shading at the terminator, this is the best venus season i have ever had thanks to you guys at cn.

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Re: 07.07.07 Venus Sketch new [Re: Tommy5]
      #1751033 - 08/01/07 07:34 AM

Frank,

Nice sketch--the crescent of Venus must come close to filling the eyepiece by now, but it looks like all those cloudtop albedo features we were seeing earlier are hard to make out now. I wonder how much of the duskiness at the terminator is a contrast effect.

Tommy,

I agree--the best Venus apparition by far for me, too.

--------------------

Michael Rosolina
Celestron CGE Pro 1400 f/11 SCT
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Re: 07.07.07 Venus Sketch new [Re: Special Ed]
      #1753009 - 08/02/07 04:50 AM

Frank, Michael, and Tommy

Thank you all for your excellent observation and image of Venus. Michael's observation shows albedo features across the venusian disk. Faint albedo features are visible in Franks' observation. Tommy's image shows albedo features towards the terminator. Keep up the good work!

Carlos

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Re: 07.07.07 Venus Sketch new [Re: CarlosEH]
      #1761475 - 08/06/07 01:32 PM

Tommy, Michael and Carlos,

Thanks for your comments. I was really struggling to see any kind of albedo features with this thin crescent. The daytime atmosphere was very turbulent and the sun was cooking my scope.
Frank

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Re: 07.07.07 Venus Sketch new [Re: Special Ed]
      #2869357 - 01/16/09 04:20 PM

Hi Michael, thanks for allowing me to use your Venus Sketch in my NASA What's Up podcast this month (January 2009). Here it is: http://www.jpl.nasa.gov/video/index.cfm?id=798 Your sketch is about 1 minute 36 seconds in from the beginning. :-)

For February I am again looking for sketches that match Galileo's lunar sketches. Not high magnification, but low power small telescope sketches like those sketch 400 years ago. :-) Jane

--------------------
Jane Houston Jones
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Re: 07.07.07 Venus Sketch new [Re: janehoustonjones]
      #2870226 - 01/17/09 12:30 AM

Awesome sketches fellas! I'll have to set up my scope a little earlier next time and attempt a daylight obs of Venus.

--------------------
S 38º 00' E 145º20'

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Re: 07.07.07 Venus Sketch new [Re: janehoustonjones]
      #2870958 - 01/17/09 12:54 PM

Quote:

Hi Michael, thanks for allowing me to use your Venus Sketch in my NASA What's Up podcast this month (January 2009). Here it is: http://www.jpl.nasa.gov/video/index.cfm?id=798 Your sketch is about 1 minute 36 seconds in from the beginning. :-)

For February I am again looking for sketches that match Galileo's lunar sketches. Not high magnification, but low power small telescope sketches like those sketch 400 years ago. :-) Jane




Thank you, Jane. It was both satisfying and humbling to see my sketch included with those giants of the past.

I'm sure that someone on this forum has a low power lunar sketch--there are lots of lunies here.

--------------------

Michael Rosolina
Celestron CGE Pro 1400 f/11 SCT
1980 Orange Tube C8 f/10 SCT
4.25" f/4.2 Astroscan Reflector
50mm f/10 Galileoscope
40mm PST f/10
APM Germany HD 15x70 binoculars
Canon 12x36 IS II binoculars
Mark I Eyeball
My CN Gallery


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