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Posts Made By: Jim Nelson

April 29, 2004 03:56 PM Forum: Equipment Talk

Good Telescope Wanted for an 8 Year Old

Posted By Jim Nelson
If your kid seems relatively serious about astronomy, the 4.5 inch XT dobsonian from Orion is a major bargain and a decent little scope. Not too heavy, easy to use. The Starblast is a smaller, lighter version, and might be a little easier to use, but is definitely not as good of an all-around performer as the XT (but still much better than many "kid" telescopes).

On the other hand, a decent 80mm refractor - from a good source, not a cheap department store model - is more generally usable for daytime use as a spotting scope - birds, scenery, etc.

And, in my opinion, the first step for anyone should be some good books and binoculars - and of course binoculars are VERY useful even if the astronomy interest wanes.

May 2, 2004 09:59 PM Forum: Solar System Observing

Light Cup trapped Lunar Opossum

Posted By Jim Nelson
Ah, I've missed your observing reports Ron! Always get me itching to get out there myself.

May 5, 2004 01:38 AM Forum: Equipment Talk

Build a small eyepiece collection - suggestions?

Posted By Jim Nelson
The best quality/price ratios around are at University Optics. They specialize in older designs, many of which perform poorly at short focal ratios, but the 80ED is f7.5, which isn't too short at all. The Konigs are superb eyepieces, although they're a little tight at 16mm and 12mm. I used to have a 20mm Super Erfle and it was quite a bargain, and a good general purpose eyepiece (slightly soft at the edges at f8, but not distractingly so). And of course the Orthoscopics are famous for bang-for-the-buck planetary performance.

Helix, a A-M sponsor on the front page, is a good source for U.O. stuff if you want to buy online (U.O. itself being somewhat in the dark ages when it comes to the Internet).

Alternatively, for a little more than most of U.O.'s eyepieces, the Ultimas/Ultrascopics are my personal favorite moderately priced eyepiece - noticeably better performers than the current Meade Plossls.

That's the direction(s) I'd point you. Oh, and don't skimp on a barlow if you get one - that's one place you might want to spend the bucks on Tele Vue, you might even consider the 2.5x Powermate, which is not cheap but won't dissapoint.

May 5, 2004 01:44 AM Forum: Equipment Talk

wide field ep for a 12.5" f/4.7

Posted By Jim Nelson
24 Panoptic. There, that's three unanimous votes. I have an irrational affection for this eyepiece.

May 5, 2004 05:19 PM Forum: Equipment Talk

Star party eyepieces

Posted By Jim Nelson
The 26mm Meade Plossls that EVERYONE has is a great star party eyepiece. I find that with that and a barlow I can be set for an entire public viewing event. They give good views, and they're comfortable and easy for a novice to use, and the eyelens is recessed so it isn't easily soiled - not that it's exactly hard to replace this eyepiece.

May 6, 2004 07:40 PM Forum: Deep Sky Observing

What am I missing?

Posted By Jim Nelson
You had LOTS of strikes against you, and M66 would not be a great choice for first galaxy anyway.

Right now the pair of M81/M82 are probably the best, brightest galaxies currently available. Try those next dark night. Of course many other objects will be easier than galaxies, but Spring is galaxy season.

May 7, 2004 02:16 AM Forum: Equipment Talk

Russell Optics 65 & 85 mm EP

Posted By Jim Nelson
Most Big Dobs have focal ratios around f5, even less. With an f5 scope, the 65mm eyepiece will give a 13mm exit pupil, and the 85mm eyepiece will givea 17mm exit pupil. If you're young and healthy, your pupil might dilate to as much as 7mm. You're wasting a LOT of light. Wasting a little light may not be so bad to trade off for a wide field, lots of people "cheat" with 7 or 8mm exit pupils even if their pupils aren't that big, but 13 - 17mm? That's getting a little extreme. And, while I still don't understand all that determines this effect, with really large exit pupils you might start seeing the secondary mirror as a shadow in your view.

You need the right tool for the right job, and big Dobs don't really do the Pleiades - not easily, if at all. Buy a little rich field scope for that, IMO.

May 7, 2004 03:43 AM Forum: Equipment Talk

Question about TV Powermates

Posted By Jim Nelson
The real value of a PM comes in certain special circumstances and applications, or if you want 5x(!)...but I went ahead and splurged on one because I was tired of disappointing barlow performance and went straight to the top. It's a superb accessory, essentially invisible except for the power increase - but a good TV barlow or the Ultima will likely be as good for most applications.

The only reason I would sell mine is if I eventually spend the money on premium short focal length eyepieces that give me good eye relief. I suspect that's one reason many of them eventually get sold by owners. I've never - and I mean NEVER - heard of someone being disappointed by their performance.

May 16, 2004 03:47 PM Forum: Equipment Talk

Are Televue "package" components worth it ?

Posted By Jim Nelson
If your budget is tight, I'd reconsider going the apochromatic refractor route. Inversely, if you're set on going the apochromatic refractor route, don't worry about scrimping a few dollars here and there on the accessories!

May 17, 2004 05:28 AM Forum: Eyepieces

Planetary eyepieces and AFOV

Posted By Jim Nelson
Wide field & few elements = poor edge of field performance.

At least, I don't know of any exceptions to this rule. Alas, there's no perfect eyepiece.

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