Posts Made By: Doug Peterson

This is the one I started the thread about:

http://www.buytelescopes.com/product.asp?t=&pid=7092&m=

I will have one in a couple days.

Just to give you an idea what I'm seeing--outside of focus the fresnel rings are oval, inside the same rings in the same direction, coma, no spherical. At the plane of focus, approximately 3 diffraction rings laterally on one side of the airy disk, none on the other. Perhaps a half wave of coma?

At 66x the image on terrestrial sources is sharp, if for no other reason than the aperture advantage. At 22x my own eye abberations dominate--this may well be a good RFT, a super monocular, with a standard-thread low power Erfle.

There is some small violet fringing the fresnel rings, this certainly is a very good color correction result at the price and justifies the ED label. It is far better than the so-called semi-APOs. In focus, there is no sign of the swimming in color that an achromat would exhibit. So colors are saturated and accurate.

The body appears to be plastic, but substantial, not flimsy. The zoom is a wanna-be, easily replaced, too much spherical abberation of the exit pupil, not a good thing in a daytime scope.

Nevertheless, if it were not for the coma, this indeed would have been the dream come true, a bigger, badder Orion ED80.

I've owned several, from the orange tube '70s through a recent Nexstar. They were excellent optically. This confirms the word on the street that for some reason they have been consistently good.

They do have a relatively large central obstruction of nearly 40%, but within that limitation you get bang for the buck, roughly equal to a 3" refractor in planetary performance.

Also, the simple swing through fork mount of the older models can't be beat for quick look-sees in altaz mode, more convenient than the hand control recent models once you get over the novelty of goto.

As an OTA, it is much better than the C130 maksutov which in my experience is not as good optically, much heavier and longer.

That is a possibly unique F number. Do you have a photo for us astro-geek historians?

Let the rumor-mongering begin:

1) Celestron and Orion have demonstrated that China can produce high quality APO optics. Skywatcher (Synta) is rumored to be readying 5-6" aperture semi-APOs and petzval astrographs. Burgess, etc. are talking about asian 7" triplets. I'd like to see Meade do the same with larger apertures to replace the discontinued line.

2) Some sort of large, I mean computer-monitor-sized flat screen, touch-screen-type display, with an integrated computer both for starmap and for image-display purposes. Bolted directly to the mount of your big brawny SCT. All this stuff is becoming so cheap now.

3) Over on the s.a.a. speculation includes a computerized solar telescope

Yes, this is an amazing gaff on Meade's part, to say nothing at all, rather than at least some preliminary info. If the announcement is intended to get attention/fanfare, and then they have nothing to say, it makes you wonder about their commitment to their customers.

I asked Orion if they had plans for DSCs or GO-TO for the Atlas, and the answer was

"At this time we have no plans to offer such a product. However, we appreciate your suggestion and I will pass it along to our Product Development Team for their review."

Bummer!

I recently sold some miscellaneous adapters for Unitron, including what you are looking for; they are out there and pop up from time to time. You can check alpineastro.com/Baader and Borg/Hutech for Japanese metric adapters if all you need is the adapter, not the drawtube.

I see that Astronomics is taking Pre-Orders. Picture looks nice with William Optics tube, rings, diagonal. 799. Certainly looks like it has potential. Claimed 8x color correction of an achromat.

I have had or seen several scopes that reacted oddly to cooldown:

1) a 90s C8 that was perfect at room temp but would develop 1/4 wave of spherical at cool temps--and never settle out until it warmed back up! Celestron replaced the coatings and the problem went away; I had heard of stress in coatings, but wow.

2) a TV60 that was perfect at room temp but would go triangular on stars at cold. Loosening very slightly the three radial tilt screws made the problem go away.

3) a fanless 7" mak that tracked the air temp very closely, it would cool, setttle out as the temp stablized in the early evening, then go weird again as the temp dropped later. This must be the reason they invented fans.