Posts Made By: Darren Drake

I just had some amazingly steady views this morning of Mars and the Trapesium through the 18-inch with the Ethos and a 2X barlow and the 7mm Pentax XW. The seeing was rated a very rare 9.5 out of 10 and Mars was 10.2 arcseconds. While going back and forth between the Ethos/barlow combo and the Pentax, I could see no noticeable difference in contrast and overall detail which was amazingly good for such a small Mars.
The best view actually came when using the barlow with the pentax giving 560X. The details were amazing as the steadiness let the scope do it's thing.
Next was the trapesium. The 6 stars with the Ethos/barlow combo were amazing. The H component which has eluded me for years was finally glimpsed and in very low transparency skies in severe light pollution. The view with the Pentax was again pretty much the same only at a slightly lower power.
The notion that more complex eyepiece designs can't compete with simpler designes such as the orthos has never been convincingly shown to be true for me. I suppose I should have pulled one out for a true comparison but the Pentax has always been seen as a planetrary eyepiece despite having a lot of glass in it. Maybe someone out there can compare an Ethos with a TMB monocentric. Sounds crazy I know but the results may be surprising.

A friend recently asked me to help fix up his Sky 90 as it had been determined that it was out of collimation. After getting that all done I decided to compare it head to head with my WO 80 FD. I tested them a number of times under different conditions and found the results somewhat interesting.
The WO has a fl of 555mm with an f/ratio of 6.9 and has fpl-53 glass and the Tak Sky90 has a focal length of 500mm and an f/ratio of 5.6 with a front flourite element.
The WO has always been a tremendous preformer for an ED doublet. The star test is quite good with only a slight hint of spherical aberration and virtually no color in focus. The Tak surprisingly showed significant spherical aberration in the form of undercorrection. To determine if it's significant to affect performance I slowly moved the focuser through focus and it was apparent that all the zones of the lenses were not quite focusing at the same exact point. The inside focus rings were very sharp and the outside focus rings were quite diffuse and il defined. While the focused image is respectable it didn't seem to deliver images that a first class apo should dliver.
While examining lunar and terrestrial features at high power the extra aperture of the Tak seems to deliver a slightly higher resolution image when compared to the WO but the contrast is definately better in the WO. This is confirmed by examining the the airy disk patterns at high power. The WO has a clean disk with a very dim first diffration ring on the brighter stars. The TAK definately has a brighter ring and hence a lowered contrast on extended objects. These are critical observations under high power it should be mentioned here. At most mags the Tak should perform quite nicely. The color is a little more noticeable in the Tak but is not at all significant while the WO is basically color free.
While it seems that the Tak isn't quite measuring up it should be mentioned that it is an f/5.6 which is extremely fast for a refractor. I do wonder how the 1.6X extender would affect the Tak. I know that color will be reduced but does it help SA? Anyways I thought I'd mention my findings here on the mart

This is a 100mm Erfle that Dan Joyce got for $25 from a science store a few years ago. It has about a 60 degree aparent fov and gobs of eye relief.

I recieved an email stating that Meade is going to sell back Coronado to the Lunts and they will rename the company Lunt Solar Sytems. Can anyone confirm this?

So with this likely government check totalling at least $600 for every tax payer this summer is anyone here thinking of purchasing any astro gear or eyepieces with this free money. I have an ethos myself so I'm good for now.

Is there a point when the level of CO2 in the atmosphere no longer adds to the amount of energy that becomes trapped? In other words could we already be at or near a point where it won't matter any more if there is any more CO2 added and that all this climate change is all hype?

It's an 8mm.
http://www.televue.com/engine/page.asp?ID=2

I was aware of this earlier today and thought it might be considered an April fools joke but now I see there is proof.
http://explorescientific.com/blog/2009/03/testing-prototype-100-series-14mm.html

Drumroll please...........
http://www.televue.com/engine/page.asp?ID=374#holefiller

Drumroll please......
http://www.televue.com/engine/page.asp?ID=374#holefiller