Posts Made By: John Wilson

Anyone know whether the SP-DX will handle an MN-76 for reasonably stable visual use? Or would a beefier mount like the G-11 or EM-200 be required?

Hi. Does anyone out there have experience with the Orion 15 x 63 Mini-Giants? I'm interested in them because of the long eye relief listed in the Orion catalog... I need it for observing with glasses. Is the long eye relief for real and does the image hold up at all well off-axis? Thanks in advance, John.

On paper, the Nikon 16 x 50 "Action Extreme ATB" binocs have a reasonable afov (56 degrees) and nearly 18mm of eye relief. Does anyone have experience with them for astro use? Can you share any impressions? Thanks...

Hi Brian.

I recently bought a used Vixen 90mm f/9 fluorite and found that there were hazy spots between the 2 objective elements. Afraid they might be fungus, I contacted the Vixen North American folks and asked what I could do about lens cleaning. To make a long story short, I sent the scope back to Japan (through the NA rep). They not only cleaned the objective (& did a great job) but also collimated the scope and adjusted the focuser. The scope looked like new when they returned it.

The downside was the cost. At first, they estimated that it would be about $300 but it ended up costing about $480 (For the record, they gave me the updated cost before they sent the scope to Japan. I *really* wanted this particular scope to be OK so I went through with it...).

I don't know how recent economic changes have affected currency exchange rates but you could probably get a good cost estimate from Vixen. If you're interested in checking out this option for your Vixen-made scope, you could try contacting the fellow I spoke with, Mike Fowler: m.fowler@vixenoptics.com.

Hope this is useful,
John

Hi everyone... I'm looking at the 18mm orthos by University Optics (both the volcano tops and HD versions) and the Baader 18mm ortho. Does anyone know whether these eyepieces have enough "functional" eye relief that someone wearing glasses can see the entire field?

Thanks in advance,
John

I believe some of the Nikon eyepieces sold by Markus Ludes of APM are (were?) adapted fieldscope eyepieces. You might ask him whether this is true and, if so, whether he might let be willing to let go of a couple of adapters.

Good luck,
Jay

Assuming you're talking about the 77mm with 440mm focal length, I believe Company 7 has adapters to use 1.25" eyepieces in the scope.

Cheers,
Jay

Hi Paul. I've owned several scopes in this size range and currently use an AS80/1200 for my "small" scope. There's no question that it's the sharpest and most contrasty of any scope of this size I've owned or looked through (including a Tak FS-78) and provides more detail on Jupiter, the Moon, etc. Also, although it's termed a "semi-apo", it might as well be called an apochromat... I looked at Venus the other day and saw no blue color. On the limb of the Moon, there's just a smidgeon of color off axis but none on axis. No more "extra color" than in my Tak FS-78.

Having said that, it has some drawbacks. An f/15 refractor, even an 80mm, has a lot of torque and needs a pretty good mount to hold it solidly. I use a GM-8 now and am happy with it but have tried smaller mounts and found them too shaky. Also, the field of view is limited to about 2.17 degrees with 2" eyepieces. Most folks want an 80mm to provide them with a wider field of view. Finally, it only shows what an 80mm scope can show. The light-gathering ability is clearly limited and resolution maxes out at 1.5 sec. Also, as sharp and contrasty as it is, a top-notch 100mm will show more lunar/planetary detail (though a less than top-notch one won't).

My particular tube was made in the 60's by Zeiss and I've seen at least one other tube like it on Astromart (APM had one for sale several months ago). Usually, though, I think the AS80/1200 shows up for sale as an objective and you can build the tube (or get it built) to your specs.

Hope this is useful.

John

Paul, there is an AS100/1000 objective for sale in the German-language section of eBay. The item number is 1353461446 and if you search on that number you'll reach the auction. (This note is placed on the 17th of May and there are still 9+ days left to the auction.)

Cheers,
John

Hi Rick.

Vixen makes a nice 2" 30mm eyepiece with a 60* apparent field (though it's sometimes mistakenly listed in ads/ on web as 50*) and long eye relief. It's a 6-element ep and did a nice job in my f/8 refractor, though I don't know how well it will work in your shorter f-ratio scope... But it might be worth considering. I bought mine for about $170 new through University Optics or you could presumably get one through the new Vixen North America company.

Cheers,
John