Posts Made By: Rod Kaufman

Jim,
Do you get a "warp factor" with your computer? If so, what is it?

I recently purchased a new meade f5 schmidt newtonian ota directly from meade.(This is the improved LX75 version and not the older LX55 and they're blowing them out at a discounted price btw) I intend to use it primarily for imaging. The collimation appears to be off with my EZ laser collimator: the laser dot appears about an inch or so outside of the doughnut on the mirror and the return laser dot from the primary is on the periphery of the face of the laser collimator. Normally, in a newt, you'd simply adjust the screws on the secondary to place the laser dot in the doughnut and then adjust the primary to place the return image of the laser dot on the target face of the laser collimator. At present, I can't even get the cap off the secondary on the schmidt newt to get to the screws. Assuming I can eventually get to the screws, does the process with the laser proceed in the same fashion as in a newt or is it different? I understand the mirror needs to be offset in a schmidt newt but this is supposed to be done at the factory.
Anybody out there have one of these scopes and can offer some advice?

http://framework.latimes.com/2012/03/15/palomar-observatorys-200-inch-telescope-mirror/
They removed 4.5 tons of glass during the grinding of the mirror. Yikes!

Joseph Babendreier said:

I think I pushed my 10" mirror as far as I could. The conditions were both clear and steady. I was using a 3mm Zhummel EP. Since the FL = 1118mm, that would be about mag = 375X. (I had collimated using a barlowed laser.)

I was viewing Saturn almost as zenith in the early morning after the moon had set. I could see the shadow of the planet on the rings (a first for me ).

I suppose that means the mirror must be good quality -- to give that kind of resolution. Or is this pretty common for dobsonians, no matter the quality of the mirror?

Clears,
Joe

Joe,
While it's certainly a good sign your mirror can utilize a 3mm eyepiece without degradation of the image, seeing the shadow isn't necessarily a criteria for optical perfection. Star testing, examining the intra and extra focal rings at high power, for symmetry and lack of aberration, is a much better measure of optical quality. The latter takes some time and experience but it's probably one of the best methods you can do in the field to determine optical quality.
I wouldn't get too fixated on it though, just sit back on a good observing chair and enjoy the view!

Optical cleaning fluids that is...
When it comes to cleaning eyepieces and my 16" mirror, I'm of the philosophy(these days)that less is better. BUT, living in Southern California with pollinating flowers and bugs on overtime in the springtime AND peculiar creatures known as amateur astronomers that habitually drive up at the last second and kick up road dust all over your cooling optics, a regular cleaning or two becomes mandatory. Speaking of amateurs, I recall the case of an amateur that we'll call Paul(his real name). Now, mind you, this isn't the guy named Paul up at Pinos who HAS to broil the thickest steak he can haul with him with the resulting smoke of burning fat wafting over the entire parking lot and any set of optics within 200 yards in any direction. No, this is a different Paul who showed-up at twilight and kicked up more high desert dust on my scope and that of Linton's 14.5" starmaster in Lockwood valley a year or two ago than you can dust off with the witch's broom of the Veil nebula! I recall Linton looking at me and me looking at him and thinking the same thing: "that stupid jerk!"
Now that we understand what we're up against, it's obviously time for cleaning your optics.
For eyepieces, I've used and recommended Zeiss cleaning fluid which generally does the job. However, I did find it necessary and irksome to use several applications to remove some residual haze on the lens surfaces so I decided to try the Zhumell optics cleaning kit available at Telescopes.com for about ten bucks. In my experience, this kit is the easiest to use and the most effective one I've tried thus far. When Zhumell recommends ONE drop of their cleaning fluid on a lens surface, ONE drop is all it takes to remove the dirt and the haze. Simply blow off the surface dust with their camel hair brush-bulb, add a drop of their cleaning fluid and remove with a wad of their cloth. It's done without reapplying again and and again.
Finally, a safe and effective cleaning kit that actually works and is easy to use and won't cost you an arm and a leg. Zhumell wins this one...

Stick one of these on your scope, if it works keep it, if not send it back...
http://www.telescopes.com/telescope-accessories/focusers/zhumellsctdualspeedfocuser.cfm

Observing at Pinos this past Saturday July 6th was decent enough despite the grand station character of the crowds at night; however, visual observing from Mammoth Lakes, Yosemite area is simply phenomenal. Although I didn't bring my 16'' scope with me, the grandeur of the Milky Way in its entirety, arcing across the sky at new moon, is something to behold. I would estimate the Milky Way appearing as a thundercloud to be several times more intense in its character than what you would see at Mt. Pinos. The only downside is there are ten to twenty mile per hour winds at these altitudes but the view is worth it. My dob would probably be a sailboat up here, but the entirety of the Milky Way up here is simply overwhelming.
Coming to you from Mammoth Lakes and Yosemite, and additional reports if wifi permits...

Last night at Mt Pinos was less than expected with cloudy conditions coming and going and not predicted by the clear sky clock. Nevertheless, I could see 13.4 magnitude planetaries in Draco, and some pleasing views of the usual summer time objects and a rather detailed view of the Helix nebula. All of which involve what attracted most of us into astronomy: the fascination of discovery.
Now, it was a typical summer time night on a Saturday up at Pinos and yes that means the usual suspects were up there: the lookie lu's in force in battalion strength. Additionally, a commanding presence of imagers were up on the back of the parking lot doing whatever it is they do. Generally, I've come to learn that means bitching about their equipment not working or more likely, not knowing how to use it. And when the equipment does work and they actually know how to use it, a good number of them retreat into their RVs and booze it up while leaving their equipment set on "auto". In particular, one individual couldn't figure out how to use his stuff, and turned on a pair of head-mounted LED red lights and were about as bright as the typical 4x4 driving in at mid-night. That in turn attracted the rest of the imagers, buzzing around him and offering advice on computer programs, PHd guiding, and the like. It went on for hours. I'm trying to observe DSO's and these guys are firing up their laptops and their lights with complete disregard for their fellow amateurs.
Frankly, that brings up a bigger issue: the reason behind imaging. I mean why do it in the first place? Granted, I see some very nice images posted on the AM. But you can also look at the astronomy picture of the day or view images remotely without the expense of buying your own equipment. And some amateurs do image remotely while at home. But viewing an object in real time and observing many of them instead of imaging the same object again and again--M13 and M31 were big favorites among the imagers last night--begging the question of how many times do you need to image the exact same object? It seems like imagers fixate on one object per evening, sit in front of a laptop staring at it, then bitch about it, go back in their RVs to eat and drink, come back out, if they remember to do so, and then bitch some more until they finally leave. What's the point of it?

Here's Ed Ting's recent(5-1) review of it on his excellent scopereviews website:
http://www.scopereviews.com/page1aj.html#2
Note the optical performance is essentially perfect. Of course, this is a data point of only one. But I suspect it's a safe bet if it were to fall into the hands of a CN member first, it would have likely been returned for "optical problems", not to mention an inability to achieve optical and mechanical collimation, after it had been taken apart, with the center spot being determined to be off center by .000454 microns. The focuser would likely have the following ISSUES: a) inability to hold a fifty pound camera b) inability to be adjusted for proper spring ball bearing surface pressure and tension as determined by a computerized axial tomography and c) inability to install flocking on circular in-congruent surfaces. Now to the spider: inability to perform co-axial adjustments with an exacto knife and inability to bring the optical mechanical axis into the exact geometric center of the secondary for required opto-mechanical alignment.
And that's just for starters. So, next time Ed, conduct a proper review...

Take a gander:
http://interferometrie.blogspot.com/2014/10/201410-optical-test-reports.html?view=sidebar