Posts Made By: Jim Mahon

Just a note for anybody thinking of going to the North Rim (I'm arriving there Saturday):

According to the Park Service site, there is no ATM at the North Rim. I don't recall that, but I trust them. Might have to drive 80 miles to Kanab to find an ATM or bank. Jacob Lake (44 miles) might be another possibility, but I can't recall if there was an ATM there last time I passed through.

So cash up before you drive the final leg!

Jim

What an incredible difference it makes to have a well designed GEM as opposed to the stuff I've had in the past. I'm finally going to become a good lunar observer (among other things)! The lack of backlash, the transparent nature of the friction clutches once correctly set, and the precise, smooth slewing make using this mount an absolute joy.

I'm posted this in the Losmandy forum as well, but since the traffic seems rather light there, I wanted to put it here as well. I know this is based on a single night, but I'm already thoroughly convinced that the GM-8 is worth every penny. Thought others who might be considering moving up from a Vixen or Vixen clone might be interested.

Clear Skies!

Jim Mahon

Some of you might have noted the following already in a discussion Mark Rieck and I had over in equipment talk, but just in case....

GCSP 2003 is tenatively scheduled for June 21st through 28th. This is a bit later than Dean usually tries to schedule due to the possibility of early monsoon activity that close to July. For those of us with kids in school, though, it's certainly a more attractive date than the early June alternative based on lunar phasing. Final confirmation of dates will come early next year from the Park Service, but these dates will most likely hold.

I already started the domestic star party campaign (you know, the process of convincing your spouse that you really will reserve some nights for sleep so that you'll be conscious for normal activities once or twice...) and it looks like I'll be able to talk the wife and daughter into attending. Back to the North Rim for me!

Clear Skies!

Jim Mahon

Marc, I got your message regarding the bino mount, but when i reply, your e-mail addy keeps coming back as invalid...

I've got

[email protected]

Tried to respond agan this morning. No dice. FYI, I'm afraid the reply was a negative - sorry.

Jim Mahon

Does anybody have a source for some uncemented Huygenian, Ramsden or other simple eyepieces for use in solar projection?

I'm trying to advise a newbie on a low-cost projection arrangement, but am not certain that the modified achromats out there are suitable designs - I think the achromatic doublet in these IS cemented.

Jim Mahon

Anybody who is thinking of attending the North Rim GCSP needs to reserve their campground pretty quickly. There were only about 10 left for the week of the party when I got mine last week.

http://reservations.nps.gov/

Select Grand Canyon and North Rim campground. If you're going the the South Rim, Mather campground. I suspect the RV village is already booked, but if you want hookups, it's the only game in the park.

Cannot wait!

Clear Skies!

Jim

Whatever you saw, it couldn't have been the Soyuz reentry. It was way over your horizon by the time they hit the ballistic portion of the flight. The retrofire only shaves a few hundred MPH off orbital velocity, so the spacecraft looks like any other medium-sized satellite in a low orbit - crossing horizon to horizon in five minutes or so. Entry interface, when they begin aerodynamic deceleration, sees the spacecraft still doing about 17,000 mph. The aerodynamic drag pulls the spacecraft down to a free-fall at airliner altitudes, with the drogue chute deployed, in about 8 minutes. No hanging around for half an hour.

Jim

Looks like mild overnight temperatures in the 40s for RTMC, with mostly clear conditions currently forecast for Friday and saturday nights.

Getting the RV ready!

Jim

I had a chance to look through several Coronado-equipped scopes at RTMC, including my own, both with and without a shiny new Denkmeier Two.

I was put on the road to binoviewing by a huge gain in solar disk detail seen last summer when a friend dropped his Lomo viewer into my Genesis SDF with Coronado Solarmax 60 mounted. He had a pair of 17mm Nexstar plossls in the viewer, and despite the fact that I'd never been particularly fond of these eyepieces, the increase in contrast and definition on filaments, plage, and all sorts of granular detail (which I'm probably too lazy/new to h-alpha to know the proper terms for..) was simply breathtaking.

I'd begun to wonder as I waited for an ordered Denk Two whether I'd begun to exagerrate this effect in my own mind, and was sort of soft-pedaling the experience to friends. Absent the viewer to SHOW them, I didn't want to overstate the truth. This weekend removed any doubts.

The increase in visible detail on the disk/proms was absolutely stunning when a single eyepiece was replaced by either the Denk Two or the Denk standard a guy camping nearby offered for comparison. It didn't really matter much what eyepieces were used in the viewers - they all showed a huge improvement over any single eyepiece. Looked through some Coronado CeMax, TV Pans in 19mm and 24mm, Nexstar plossls, and UO orthos. As IÕd already ordered a Denk, comparing the two Denks was my interest. In retrospect, I should've tried to rustle up a couple of other brands for a quick comparison, but I didn't really want to be juggling various correctors and such with very little time for a careful comparison. There were no huge optical differences between the two other than an impression of a slight increase in sharpness when the Denk Twos replaced the Standards. Both were very good views!

The main point was that the gain in detail when going from cyclops to either viewer with any eyepiece set was very close to the gain seen when adding a second stacked etalon (the h-alpha interference filter) to the single-etalon instrument in cyclops mode. Not QUITE as good as the stacked rigs with their narrower bandpass, but very close and a whole lot cheaper even when figuring in the cost of a pair of premium eyepieces.

The stacked view plus binoviewers was even better, but I came away sure that a single etalon plus a binoviewer is the most cost-effective approach for me - and that not even taking into account night use of the viewer! Another guy who was present changed his mind on the spot and decided not to order a stacked etalon setup, but rather to order a single etalon outfit and a binoviewer instead. I admit to a twinge of envy when he walked over to a vendor and bought a pair of 24mm Panoptics on the spot...

All in all, an instructive weekend. Russ at Denkmeier told me my viewer will come in time for the Grand Canyon Star Party.

CAN'T WAIT!

Jim

I recently had occasion to advise a friend who is the proud owner of a brand new 30" Obsession (apparently one of the last; Dave doesn't seem to be taking orders for them any more..) to buy himself a nebula filter for his 2" Naglers and Panoptics. He observes primarily from a slightly light-polluted yard near Lake Tahoe and needed some contrast gain on certain faint DSOs in my opinion.

Lumicon hadn't yet been resurrected to my knowledge, but the Tele Vue O-III was just becoming available, so I confidently told him to grab a 48mm filter from TV, assuming that it would be at least the equal of my trusty Lumicons. On a recent visit to his place, we briefly experimented with my late-eighties Lumicon O-III and the Tele Vue O-III out of curiosity. This was an afterthought at the end of the evening; we'd been working on his starhopping skills, this being his first non-driven scope, and were previously looking at bright objects just for the fun of seeing them in a 30 inch instrument. We chose the Veil as our target - and the old Lumicon absolutely blew the Tele Vue O-III out of the water on this object in the 30! I was quite surprised. The TV did show more natural star colors, but the nebulosity was very dim by comparison, with much lower contrast than shown in the Lumicon filter. The old O-III showed the Veil as indecently bright in the big scope, with a wealth of filamentary detail too extensive to adequately describe.

Has anybody done any comparisons of their own? I'd love to hear some results on other objects, as we didn't have time to do more that night and I had to leave the next morning. I've always had boundless faith in TV products, and rightly or wrongly I expected comparable performance since they chose to use the O-III moniker.

Clear Skies!

Jim