Posts Made By: Ron Bee

The seeing was so rock steady last night (would have been perfect if transparency was 100%). My TV-102 Light Cup and I went out to catch "near collision" of Io and Ganymede. At 9:20pm (5:20am UT) blocked by thin clouds, they looked like a cleanly split close double stars at 146x (6mm Radian) through the clouds - neat! Noteably, both moons
looks like equal size disc. Jupiter itself was rock steady but very low contrast through the clouds :-(.

I noticed that Saturn wasn't covered by clouds and indeed the view was very steady and sharp enough at 293x (3mm Radian). Then I noticed the shading on the B-ring at both ansae, something I've never seen before. Going down to 176x (5mm Radian and Tak LE) and 220x (4mm Radian) resulted in higher contrast. I quickly ran into the house, grabbed my drawing pencils and blank paper and here's the sketch I
made at 176x and 220x. (Boy, I need to print out a few copies of the planet's templates so they're ready to go :-().
http://members.cox.net/ronby/Planet-Sketches/Saturn-B-shade.jpg

Checking with Eric Jamison's guide, the feature is called Shading on the B Ring.
http://home.fiam.net/ericj/saturn_color.html

I usually dismissed cloudy skies but tonight I learned rock steady seeing could be had during moments when the clouds parted ;-).

One question for sketchers. Although the full moon was nice for sketching, I found that I couldn't tell the difference between my various pencils :-(; they're all the same colors (dark green)! I had to use my red light to read the number - very annoying and distracting to say the least. How do you guys solve this problem? BTW, I now
see the difference between the regular eraser and artist eraser (you know the one that feels like clay ;-).

Thanks,
Ron B[ee]

Well, before I take the Dobs plunge, I was looking at the Legault's web site again (eg. Alpine Valley). While there, those pictures through his 12" Meade SCT impressed me greatly as they look very high contrast and has high sharpness.
http://perso.club-internet.fr/legault/

I realized the question has been asked about SCT vs refractor. But what about 8" SCT such as Celestron/Meade vs 8" Dobs such as Discovery PDHQ? Perhpas the central obstruction and contrast degradation is a myth; for if it weren't, how then could these pictures be so contrasty and sharp? As you can see, I've never looked through an SCT. I'm looking for an 8" for visual use only. Also, having a driven mount is nudgingly superior ;-). I won't need
the NO-GO ;-) BTW. I need the 8" for light polluted DSO observing (dark sky trip some times) and want superb planetary/lunar city observing.

Celestron seems to have a new SCT called the "Advanced Series" touted to be hand figured which made me drooling just reading about it!
http://www.astronomics.com/main/product.asp?tog=2&n1=2&t1=4&styp=3&vid=4&product%5Ftype%5Fid=1&sku=ASC8&bURL=tCelestron%2Easp&mystype=Schmidt%2DCassegrains

What do you guys think? Am I being a sucker :-( if I go with an SCT?

Thanks,
Ron B[ee]
PS My TV-102 will be my primary scope and the SCT/Dobs will reside in my garage ;-).

I was out observing Jovian moon for an eclipse/occulation last night. Io and Europe came so close I couldn't split it with my 4" APO at 586x (the seeing was steady). I was using the slow motion knob (RA axis) on my EQ mount to track (I've gotten new batteries for my drives but haven't put them in yet :-().

A thought occur to me especially in the light of the SCT prose. I can manual track my refractor at 220x with no problem and 293x is just about the limit of tolerance; 586x was miserable. Not only did the image fly through my 60d AFOV very quickly, but it's also vibration induced by tracking. With an 8" Dobs, I should be able to reach 400x in steady steady providing the PDHQ mirror is really good.

The question is: how do you find Dobs nudging at high magnification? Is there vibration after you taken your hand of after nudging (BTW, there's little or no vibration at 293x with my slow motion providing I don't let it go springing ;-)? For example when I touch the focuser of my refractor and let go, there's always vibration afterward. What's the maximum tolerable magnification with nudging
on the 8"/10" Dobs before it becomes a pain?

Thanks,
Ron B[ee]

Indeed, a fellow with the TV-85 (3.3") over in the Tele Vue
eGroup reported it as well. Isn't the little refractor
transcendingly fun, Ed ;-)?

Ron B[ee]

By jove you're right Ed; I hadn't even notice it. Do we really need two forums 'cause at times, the traffic was really slow!

Ron B[ee]

Well, I kept waiting for that perfect night I had last year on Jupiter and still waiting :-(. So what the heck, tonight I sneaked out to watch Saturn and it was quite steady. A quick back in for dinner and out again and the sky was full of fog :-(. So back in came the 4" TV-102 Light Cup and out again at 10pm (over two hours ready). A
quick 10 minutes cool down and it's ready. The seeing was somewhat steady with moments of blur. There were still some haze around Jupiter. Magnification used was 146x (6mm Radian) and 5mm (5mm Radian and Tak LE). Total time was from 10:10pm-11:20pm PST.
http://members.cox.net/ronby/Planet-Sketches/Jupiter-022203.jpg

GRS was at near the CM with salmon color. Three bands (NEB, SEB, and EB) were seen and one more (must have been the SEtB) that passed underneath the GRS like a 4-string guitar. The SEtB didn't make it all the way across the disc or it's darker on one side. Dark barge was seen in NEB. This year I haven't had excellent night like last
year where 9 bands were seen :-(. Two ovals were seen, one next to the GRS and another a little further. However, with #12 the ovals were easier to see. With the #82A and #8 filters, 3 ovals (with possible more not sure) were actually seen lining up at 176x looking more like infectious pus especially with the yellow filter ;-)! A
dark barge? that seems to form an arc on one side of the GRS was now noted with the #12 filter at 146x that wasn't noticed before. Has anyone seen this feature? If so, what is it?

After I coaxed the Light Cup back inside, I couldn't help but thinking if I had that 8" SCT or Newt, would I have been able to play yo-yo and avoid the fog and quickly catch the GRS at the CM?

This is my first sketch of Jupiter. Commments, critiques, oval eggs throwing ;-) are kindly welcome.

Ron B[ee]

Olympus Mons on Mars is the largest volcano known in the solar system at 5500 km (roughly the size of Arizona). At opposition of 25.1 arcsec and equatorial diameter of Mars at 6800km, it means that 270km is approx. 1". Since Olympus Mons is 550km wide, I speculate that it should be visible through an 8" Newt and at least as a dot with my 4" TV-102 APO.

Has anyone seen Olympus Mons? If so, will it be possible with the 4" aperture? If not, why not?

Thanks,
Ron B[ee]

Having bad luck this season, my 4" TV-102 Light Cup kept missing out on the Jovian lunar mutual events due mostly to bad weather :-(.
http://skyandtelescope.com/observing/objects/planets/article_771_1.asp
Tonight with clear sky but seeing only III (using ALPO Antoniadi scale), we watched our first occulation (Io occulted Europa) between 10:40pm PST(6:40UT) to 10:53pm. Most of the observation was at 293x (3mm TV Radian), though poor seeing seems to be ok for Jovian lunar with some disc vibration. Here is the "sectional" sketch I made (with
an enlarged scale to see the moons clearly ;-).
http://members.cox.net/ronby/Planet-Sketches/Io-O-Europa-030203.jpg

At 10:40pm, Europa and Io were close but well separated. I could see the shadow transit from Io near the rim of Jupiter nearing the end earlier. At 10:44pm, Io and Europa were just touching. At 10:47, a scarcely sight was seen; Io and Europa merged into one!! Because S&T indicated that occulation would be only 76%, I had expected to see elongation. Why then? The Light Cup expounded that the
"expected" elongation must have been less than 1 arcsec resolution and thus couldn't be detected by the 4" :-(. At 10:49pm, elongation was detected. Both Io and Europa were seen as disc just touching one another again at 10:51pm. Finally, both moons were seen with a clean split at 10:53pm.

Still pondering on this wonderful vue, the Light Cup told me that the whole experience is what an eclipsing binary star really should look like ;-).

Ron B[ee]
PS - Did the Light Cup carry sketching a little too far, sketching
nothing but a couple of disc ;-)?

I've often heard this expression by reading some report of Saturn's observation through large aperture. I can't remember what was the typical magnification used to expressed the Cassini in these terms. Well, all I know is I can't even squeeze my sketching paper through the Cassini Division through my 4" TV-102 APO refractor :-(, let alone my old VW Beatle!

Using Ed Grafton's photo, the Division sure looks large enough to pass a lot of things through.
http://www.ghgcorp.com/egrafton/s01-05.jpg

I reduced it to 25% of original and displayed it on my 15" LCD monitor (looks just about the right size through my 4" TV-102). Well, what do you know; I can hardly squeeze a piece of paper through either ;-).

The question is: how many of you with large aperture scope use this expression? Do you see through the eyepiece such a wide gap in the Cassini Division like in the photo? If so, what magnification do you have to deploy to open the gap for those "trucks" ;-)?

Thanks,
Ron B[ee]

I didn't do it, honest! The Light Cup passed this cartoon to me to be posted ;-).
http://members.cox.net/ronby/Photos/Observer-vs-Collector.jpg

Ron the Trolling B[ee]