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Posts Made By: Jim Carpenter

December 14, 2003 06:51 PM Forum: Equipment Talk

Orion ED mounting Question

Posted By Jim Carpenter

Marc,
In the long run you'd probably be happier with a dedicated alt-az mount like a Unistar Light or Telepod. Both are good matches for a Bogen 3036 (Manfrotto 075) or Bogen 3046 (Manfrotto 028). A bit more expensive, to be sure, but a much better solution for astronomical viewing than a photo head.

Jim

December 19, 2003 08:55 AM Forum: Equipment Talk

Telepod tripod question

Posted By Jim Carpenter

Marc,

If the Telepod tripod has a 3/8x16 stud (I'm pretty sure it does), it will work with the Unistar mount. I'm assuming you mean the Unistar Light, which is more in the load capacity class as the Telepod. In the long run, you'd probably be happier with either a Bogen 3036 or 3046 (Manfrotto 075 or 028) because they are much more stable. FWIW, I use the following rule of thumb for photo tripods used for astronomy -- select the tripod based on one-half the tripod manufacturer's rated load spec, and be sure to include the weight of the mount itself (Unistar or Telepod) + telescope + diagonal + finder scope + heaviest eyepiece in your calculations. Bogen rates both the 3036 and 3046 at 26 lbs, so half that is 13 lbs. I believe the Telepod tripod is actually made by Davis & Sanford, and is closer to the Bogen 3001, which is rated at 11 lbs or perhaps the 3011, which is rated at 13 lbs.

Jim

January 5, 2004 07:13 PM Forum: Ham and Shortwave Radio

Question from a maybe wanna be newbie

Posted By Jim Carpenter

Gregg,

Check out the following link:
http://www.arrl.org/hamradio.html

Good luck. It's a great hobby, and it's amazing how many amateur astronomers are also amateur radio operators.

Jim WD5BKO

January 19, 2004 09:27 AM Forum: Wildlife Photography

Sub Zero Morning in Utah

Posted By Jim Carpenter

Outstanding!

Jim

January 24, 2004 11:52 AM Forum: Equipment Talk

Need tripod and head suggestions for a TV-76.

Posted By Jim Carpenter

Chris,

Larry at Universal Astronomics recommends using 1/2 the tripod manufacturer's load spec for astronomical use. Be sure to include the weight of the head and your heaviest EP in addition to the OTA when calculating the load. Either the Unistar Light or Telepod on a Bogen 3036 (075) or 3046 (028) would be a good match. You might go as light as the Bogen 3033 (074), but I wouldn't go any lighter than that if you're going to use high power on a regular basis. Note that all the above tripods have center-braced legs.

Jim

January 29, 2004 07:01 PM Forum: Equipment Talk

TV 76 Back Focus

Posted By Jim Carpenter

Bryan,

If you're using 1.25" eyepieces in the 2" diagonal, you might try a 2"-1.25" adapter that has a deeper flange. I have one of Joe Cortolano's adapters that has a 1/2" deep flange beyond the end of the diagonal that might add just enough to bring you into focus. It's very nice, with compression rings and is threaded for filters on the barrel end. I think I paid $25 for it. I think Joe is an Astromart sponsor.

I'd be interested to hear what you think of the WO erecting diagonal after you get it focus.

Jim

February 6, 2004 08:22 AM Forum: Ham and Shortwave Radio

listening with scanner

Posted By Jim Carpenter

Hi Dale,

Yes, it's OK to listen to ham radio communications on a scanner. Many hams get started that way. As for the frequencies, it depends on where you live. Very simply stated, most ham radio activity takes place within two broad frequency spectrums. The long-distance (including world-wide) communications take place in the high-frequency (HF) range, on several slices between 1.8 MHz and 30 Mhz. These frequencies require longer outdoor antennas, although a fairly short -- 20 feet or so -- indoor wire antenna will work for receiving only. Most of this communication takes place using CW (Morse code), various data modes which require special equipment (sorta similar to a modem) or software to interpret, or on a special voice mode called single side band (SSB). Some scanners have the capability to recieve SSB, otherwise, the voices all sound like Donald Duck.

If you live in or near a city of any reasonable size, there's probably a lot of ham activity on the very high frequency (VHF) bands. The most popular of these is the 2-meter band, which lies between 144 MHz and 148 MHz. 99% of the hams on this band use voice in the FM mode, and transmit through repeaters (remote automatic relay stations). Repeaters are typically located on tall buildings or mountain tops, where they extend the range of the typically low-powered VHF/FM radios. This is because at VHF frequencies, the radio waves are usefull only to line-of-sight distances -- since the repeater is high up, it can "see" farther than a person on the ground. Program your scanner to scan at 15 KHz intervals between 145 and 148 MHz and you're sure to hear some hams, especially around rush hour in the morning and evening as they chat on their way to and from work.

More information on frequencies and ham radio in general can be found at www.arrl.org.

Good luck,
Jim WD5BKO

February 9, 2004 07:24 AM Forum: Equipment Talk

TMB105/TV101NP on LX200??

Posted By Jim Carpenter

Have you looked at the Stellarvue SV105? This scope uses a TMB-designed 105mm/f6.19 objective and weighs 12 lbs:
http://www.stellarvue.com/sv105.html
Stephen Pitt recently published a stunning photo of the Witch Head nebula taken with a Canon 10D and SV105:
http://www.light-to-dark.com/witch10D1.html

Jim

February 9, 2004 07:48 AM Forum: Ham and Shortwave Radio

antenna question

Posted By Jim Carpenter

Dale,

I'll answer again with a very broad rule of thumb. Just as aperture rules in astronomy, capture area rules in radio reception -- the longer the antenna the better (more capture area in a longer antenna). It's like using a big net vs a little net when casting for bait. So I'd go for the 15' coax antenna rather than the 15.75" flexible antenna, especially if it can be mounted outdoors. For best results, be sure to mount the antenna vertically since most signals you'll hear on a scanner are vertically polarized.

Jim WD5BKO

February 23, 2004 12:49 PM Forum: Equipment Talk

telrad rigel reticle size vs. sky

Posted By Jim Carpenter

It will never match the full Telrad overlay, which is 4º in diameter, because the Rigel bullseye is only 2º across. That matches the "middle" ring of the Telrad overlay.

Jim