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Venus 1.22.09

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#1 Sol Robbins

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Posted 22 January 2009 - 08:03 PM

Hi,

I had good conditions for observing Venus. Mottled contrasted features were quite prominent. I am posting 3 sketches as I was testing out some new star diagonals with my 6" refractor. There are 2 versions that are dielectrically coated to pass selected wavelengths of light.

All sketches were done with a dirty blending stump along with some fingertip blending.

Below is with a stock diagonal.

Best,

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#2 Sol Robbins

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Posted 22 January 2009 - 08:05 PM

Below with a Contrast Enhancing Diagonal 1, (CED1), from Burgess Optical.

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#3 Sol Robbins

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Posted 22 January 2009 - 08:07 PM

Below with a Contrast Enhancing Diagonal 2, (CED2), from Burgess Optical.

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#4 Sol Robbins

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Posted 22 January 2009 - 09:11 PM

Included here is a template for anyone who may like to try sketching Venus.

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#5 frank5817

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Posted 22 January 2009 - 09:42 PM

Sol,

The contrast enhancing diagonals really do seem to work well for the low contrast on bright Venus. Excellent sketches and thank you for the Venus template.:waytogo:

Frank :)

#6 Sol Robbins

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Posted 22 January 2009 - 10:41 PM

Thanks Frank. Venus is positioned well while its still light out.

I'm glad I left my scope in the garage so it was acclimated when I got home.

Thanks again,

#7 Tommy5

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Posted 23 January 2009 - 12:18 AM

Very nice Venus sketches,thanks for the template, the albedo features on Venus do seem darker near the terminator,i don't know if it is a contrast effect or what, i did observe this feature last time venus came out in the evening as did most observors, thanks again for posting,are you doing some testing for Burgess? I remember you did some filter testing for another company,.

#8 cildarith

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Posted 23 January 2009 - 12:26 AM

Sol, thank you for presenting this excellent and informative series of Venusian sketches. :bow:

Thanks for the template, also! *yoink*

#9 Rich (RLTYS)

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Posted 23 January 2009 - 06:35 AM

Below with a Contrast Enhancing Diagonal 2, (CED2), from Burgess Optical.


Sol

This is the best sketch of the three.

Thanks for the views.
Rich (RLTYS)

#10 Sol Robbins

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Posted 23 January 2009 - 07:09 AM

Thanks very much guys.

T:

I used to beta test for a company called Sirius Optics. I don't really beta test for Burgess Optical. I just think Bill has good ideas that once realized, are offered a comparatuvely good prices while keeping quality high. That means I can afford them.

The CED 2 with my 6" achromat works well though I have not a chance to try on the Moon, Jupiter or Mars. Through the Burgess Yahoo Group, Bill's offer was that if I didn't like it I can send it back and he'd credit me an extra $20. I figured I couldn't lose anything but some time.

Best,

#11 Special Ed

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Posted 23 January 2009 - 12:37 PM

Sol,

The CED2 looks like a winner to me--pretty amazing differences among your sketches.

Bill comes to the Greenbank StarQuest and I bought one of his 8mm BO/Planetary EP's in 2007. I was so happy with it (and the price) that I wanted to get a 6mm EP when I saw him in '08. He didn't have any with him because he was in the process of improving them so I got on a waiting list. The new 6mm Planetary EP came a couple of weeks ago and I hope to try it on Saturn if I get the opportunity and the seeing. :cool:

Bill and his wife are nice folks and I look forward to seeing them again this year at Greenbank--maybe they'll have these contrast enhanced diagonals with them. :)

#12 Sol Robbins

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Posted 23 January 2009 - 01:40 PM

Michael,

The difference was striking.

I can't see why this diagonal can't be used in a SCT.

#13 rodelaet

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Posted 23 January 2009 - 03:17 PM

Sol,

These are beautiful sketches with interesting equipment. :bow: :bow: :bow:

What are they developped for?
Are these intended to replace filters, for planetary observations or even for deep-sky also?

#14 Sol Robbins

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Posted 23 January 2009 - 04:15 PM

Thanks Rony,

They were developed to increase contrast. There have been reports that say these diagonals benefit all sorts of objects like nebulae and globulars. For myself, I am not so sure about that.

They do cut light and during my limited use, work well for the Moon and double stars. The CED 1 appears to cut ~30% of brightness. The CED 2 cuts more, like ~ 50%. Along with the light cut CA is also somewhat suppressed. Probably just darkening it to my eyes. That said, they both present very clean images, cut light scatter to nearly nothing and don't shift color. Inteference filters when used with achromats with 3 peaks at blue ( 450 nanometers), green ( 530 nanometers ), and red ( 640 nanometers ) can show wierd artifacts. Meaning an achromat can't reconcile the blue and red togetherr.

All filters cut light, but a telescope's aperture determines resolution so that remains. The diagonals are said to be at 1/10th wave afters coatings. Mine were extremely well collimated. Lastly and since the mirror surface is at a 45 degree angle, there is no weird reflections from from my eye and back.

I think any telescope that can use a star diagonal is OK to use these.

Best,

#15 Kris.

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Posted 27 January 2009 - 01:47 PM

great sketches with striking results results Sol!

i while ago i wanted to sketch venus too, but i could not see even as much detail as your first sketch shows, i think a saw -some- irregular darkening near the terminator but just couldn't convince myself my mind wasn't playing tricks on me so i decided against making a sketch.
could you give some pointers to get me, and other fellow sketchers, started on venus-sketching? i think i didn't cut down enough on the glare, or maybe my magnification wasn't right? :shrug: do some colorfilters help? i've got a light-blue, orange and green one. what time of the day would be best? i presume when venus is at it heighest, so as early as possible? thanks!

#16 CarlosEH

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Posted 27 January 2009 - 03:42 PM

Sol,

Thank you for posting some of the finest observations of Venus that I have ever seen. The amount detail that you have recorded over the goddess of love is very impressive. The Burgess Optical CED1 and CED2 diagonals appear to do their job very well by cutting down the glare of this beacon planet. Are these diagonals available to the public yet? I look forward to your future observations.

Carlos

#17 Sol Robbins

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Posted 27 January 2009 - 07:27 PM

Kris and Carlos,

Thanks for the compliments.

Kris: I would suggest using the orange filter for an 8" telescope. I use magnifications as high as my telescopes can use. Usually 225x-40x, somewhere in there. Get your telescope cooled down and collimated. The earliest I can spot Venus visually is between 4pm-4:30pm, so that's when I start observing. Currently, that leaves me about an hour of time to get through these observations unless you can locate Venus even earlier.

An Orange filter will show markings appropriate to an orange filter's wavelengths. Mottled features tend to dance around initially. With a bit of time you will be able to see that some details stay put. The details are low contrast so making a sketched interpretation of what you can comes off as heavy handed. At least for me it does. I really don't know how to keep the details more subtle and still be able to render what differences within these details, let alone end up with a scanable drawing that retains the details I sketched. A person with your talents will be able to get past that easily enough. Patience is the key.

Carlos,

I believe that both of these diagonals are available now from Burgess Optical. There's a link for them on the CN homepage margin for sponsors. I would recommend calling them over using e-mail.
Thanks again,

#18 Kris.

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Posted 28 January 2009 - 01:15 PM

Sol, thanks for the advice, next time i'm out, i'll give the orange filter a try!

#19 Erix

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Posted 03 February 2009 - 09:27 AM

Excellent sketches and comparisons Sol. And I appreciate the advice you've given for observing and rendering its features.

#20 Sol Robbins

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Posted 03 February 2009 - 02:18 PM

Erika,

Thanks and you're welcome!

Weather has been terrible most of the time here and I hope to get busy enjoying the sky somethin' fierce.






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