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Posts Made By: Jim Carpenter

May 28, 2013 02:14 PM Forum: Landscape Photography

San Juan River Goosenecks

Posted By Jim Carpenter

Just back from southeastern Utah. Here's a panorama composed of three images of the great gooseneck bends of the San Juan River near Mexican Hat, merged and processed in PSE. Nikon D7000 w/ 12-24mm f4G.
Jim

January 13, 2015 08:21 PM Forum: Wildlife Photography

Bighorn Sheep - Waterton Canyon

Posted By Jim Carpenter

It's been a while since I posted anything here, so here's a recent shot of some bighorn sheep crossing the river in Waterton Canyon, a few miles southwest of Denver. Nikon D7000 with Tamron 200-400mm @ f/8, 1/800 sec, ISO 400. This was at 200mm (300mm equivalent with crop factor of the APS-C sensor), uncropped -- yes, the sheep were that close.

April 13, 2015 06:29 PM Forum: Landscape Photography

Carlsbad Caverns

Posted By Jim Carpenter

My wife and I recently revisited Carlsbad Caverns for the first time in many years. Here's a few shots from that visit, all taken with a Nikon D5000 and Nikkor 35mm/f1.8 lens, handheld, using the "natural" cavern lighting. Next time I'll take a tripod smile

First one is the natural cave entrance:

August 10, 2015 03:02 PM Forum: Wildlife Photography

Red Tailed Hawk

Posted By Jim Carpenter

This immature red tailed hawk perched on our fence for at least a half hour before flying over to the grassy berm surrounding the reservoir behind our house, where he caught a vole or pocket gopher (not sure which). He then returned to the fence, where he proceeded to consume the unfortunate small critter before departing.

November 13, 2002 12:56 PM Forum: Equipment Talk

Discovery 10" f4.5 PDHQ Weight

Posted By Jim Carpenter

Hi Tim,

I have 10" F/4.5 PDHQ. Everything is exactly the same as the f/6 version except the tube is 49" long vs 64". I have not weighed it, but guess you would save maybe 10 lb in the sonotube difference. I've been considering boring some 2"-3" diameter holes in the altitude bearings to reduce weight, since those hunkers are 12"+ in diameter double thickness solid particleboard. Otherwise I am very pleased with the scope.

Jim

November 27, 2002 01:17 PM Forum: Equipment Talk

Short tube vs long tube refractors

Posted By Jim Carpenter

Be a discriminating shopper and do your homework. Some short tube refractors, including achromats, have better color correction than others. Check Stellarvue (see reviews by Ed Ting and Cloudy Nights).

Jim

December 18, 2002 09:25 AM Forum: Equipment Talk

Telescopes for School

Posted By Jim Carpenter

Hi Steve,

Congratulations on your efforts to set up the astronomy supplement to the physics course. As a satisfied Stellarvue owner (AT1010 and 102EDT), I'm happy to see your mention of Stellarvue as your initial choice for a wide-field refractor. I'm sure you won't be disappointed if you go that way. Rather than considering "best bang for the buck," I'd suggest letting the best value be the deciding factor, and the AT1010 certainly fills this bill. Does it gave APO images -- no, but very close, and certainly better than the typical Chinese imported achromat of the same aperture.

BTW, I agree with David on the alt-az mount. The students may easily tire of the hassles of an EQ mount. Either a UniStar light on a Bogen tripod or a Televue Telepod make a good match for the AT1010. While I prefer the UniStar Light, both are simple, lightweight, and easy to set up and dance around the skies. Whichever refractor you get, I'd recommend a red dot-type finder on the refractor and a Telrad or Rigel Quikfinder on the Dob rather than optical finders. As you probably know, these are much more intuitive, particularly for inexperienced viewers like the students.

Jim

January 21, 2003 07:23 AM Forum: Equipment Talk

Refractor Mounts

Posted By Jim Carpenter

Hi Clyde,
Owen has given good advice on how to overcome the balance issue. Even if you decide to go with rings to mount the OTA, you'll need some sort of adaptor plate for mounting the rings since most 80mm rings other than the TV clamshells will not fit within the yokes of the Upswing mount. Some sort of pan head is therefore required on the tripod. The photo shows a simple home made adaptor plate with a pair of rings for a Stellarvue 80mm refractor. The mount in the picture is a Telepod, which other than having an integral azimuth bearing, is the same as the Upswing.

Jim

February 9, 2003 02:10 PM Forum: Equipment Talk

EPs for terrestrial viewing ?

Posted By Jim Carpenter

The guys in the Birding Optics forum may have some good suggestions for you. I'd consider the TV 8-24mm zoom or the Vixen and Orion equivalents. I use one occasionally in my Stellarvue AT1010 for terrestrial viewing and find it convenient to be able to zoom in on wildlife without changing EP's. Otherwise, any of the mid to long focal length (upper teens to 30mm or so) length Plossls would be a good choice for kids. Also, the inverted image diagonal may be confusing for kids, so I'd stick with the 45* correct image.

You didn't mention what type of mount you're using, but I'd recommend alt-az over EQ for terrestrial use. Something like a Telepod or Unistar Light.

Jim

February 14, 2003 07:45 AM Forum: Equipment Talk

Telepod Head vs. Manfrotto 410 Gear Head

Posted By Jim Carpenter

The rule of thumb I use for tripods is to use half the mfr's specified weight capacity for astronomical use. The Bogen 3021 is rated at 13 lbs, so the combined weight of the OTA, Telepod, balance aid, EP caddy, and EP's should not exceed 6.5 lbs. You do the math -- it appears a tripod may be a little light. Still useable, but probably will be a bit shakey. Perhaps leave off the EP caddy and the weight of the EP's. You may be able to get by without the balance aid by judicious adjustment of the altitude bearings on the Telepod.

As for the mount itself, I think the Telepod would be a great improvement over the geared head, although I suggest you look at the Unistar Light as another alternative. I heve both a Telepod and Unistar Light, and prefer the Unistar Light because of better balance in the altitude axis.

Jim