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02-11-2009, 01:41 PM   #16
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QuoteOriginally posted by GaryML Quote
I finally had a chance to use the Pentax 7 XW eyepiece last night. Conditions were not ideal as the jet stream is still overhead and the upper atmosphere is quite turbulent. Overall, I really like this eyepiece. It brings out the best in my current telescope and it is ready for anything i might get in the future. Eye relief is fantastic for this focal length, and the 70 degree field of view is perfect for me. You can get "black-out" and "kidney-beaning" if your eye is too close. But if I crank out the eye shade to the right length, then I can hit the focus spot with ease.

About an hour after sunset Venus was setting to the west and the full Moon was rising in the east. Venus looked good and was equally sharp across the entire field of view. M 42 looked beautiful and was also sharp edge to edge. The 4 brightest stars of the Trapezium were clear and sharp, but with the turbulent air and the moon glow the fainter stars were not visible. My wife came out at that point and was was quite impressed with the view of M 42 (or maybe just humoring me with my new toy). She had no problem getting the focus spot.

A couple of hours later I went out again to look at Saturn and the Moon. Saturn looked good with the edge-on rings just super-crisp. I could just barely make out a hint of banding on the surface of Saturn, but the air and the Moon glow were affecting visibility. The Vixen has a two-piece lens cap for the objective, and you can remove the center section to "stop down" the scope. I used this to look at the Moon. I have to say that the 7mm was a bit too much for such a bright Moon. Looking through the 7mm, some detail was lost because everything looked "overexposed." I saw more detail with my 12.5mm Celestron Ultima. Maybe a filter would have helped with the Pentax 7mm.
Interesting impressions. I was always looking for nice wide-angle eyepieces at an affordable price tag. But 7mm is already very short for my scopes (my main instrument is a Cassegrainian 225/3000) and I love using the binoviewer, which requires slim eyepieces. So I have a nearly full set of older Zeiss orthos, some University Optics Koenigs (cheap and wonderful!) and some tack sharp Pentax Orthos (better clarity than the older Zeiss) and loads of others, mostly just for comparisson.

What I would like to know is, whether focusing on the moon was as easy as on stars with the XW? Moon is in my experience (quite like the planets, but for other reasons) tricky to really focus sharply.

Ben

02-11-2009, 02:57 PM   #17
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I have no clue what you guys are on about, but does it have something to do with the sky?

Seriously, this is all quite intriguing. I had no idea Pentax made top-notch astronomical optics.
02-11-2009, 03:23 PM   #18
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QuoteOriginally posted by rparmar Quote
Seriously, this is all quite intriguing. I had no idea Pentax made top-notch astronomical optics.
Yes they absolutely do. Most people don't know, that also Nikon has made astronomical telescopes and ofcourse Fuji makes some wonderful equipment, too.

Ben
02-11-2009, 03:27 PM   #19
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QuoteOriginally posted by GaryML Quote
The sad part is that the salesman told me that Pentax had stopped production of their telescopes and eyepieces, and once the current stock is gone then they will no longer be available.
Gary, I just remembered an advertisement I saw recently. In that it was claimed, that Pentax was now manufacturer for the BORG OASIS telescopes, too (I guess it was in S&T). So, I think, that either they "just" drop the astronomical equipment from their own product line and concentrate on their work as a supplier or quite to the contrary of the salesperson's notion, Pentax is on its way to increase the astronomy part of its product line.

Ben

02-11-2009, 08:38 PM   #20
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QuoteOriginally posted by Ben_Edict Quote
Interesting impressions. I was always looking for nice wide-angle eyepieces at an affordable price tag. But 7mm is already very short for my scopes (my main instrument is a Cassegrainian 225/3000) and I love using the binoviewer, which requires slim eyepieces. So I have a nearly full set of older Zeiss orthos, some University Optics Koenigs (cheap and wonderful!) and some tack sharp Pentax Orthos (better clarity than the older Zeiss) and loads of others, mostly just for comparisson.

What I would like to know is, whether focusing on the moon was as easy as on stars with the XW? Moon is in my experience (quite like the planets, but for other reasons) tricky to really focus sharply.

Ben
That 225mm Cassegrain sounds nice. I always wanted to try a bino-viewer. The sky conditions are not very good where I live, so I need portability for the opportunities when I can go to dark skys (in the mountains and desert east of the city). I used to have a 200mm Newtonian on an equatorial mount. It was just too big to take on any sort of trip, so I switched to smaller scopes. The 100mm refractor I have now is probably the maximum size I can transport with ease.

Some of the older eyepieces have some really sharp optics, at the expense of eye relief and field of view. It seems like you are a bit of a collector, both camera gear and telescope gear.

Funny you should mention the focus on the Moon, as I did had to refocus when moving from Saturn to the Moon. Maybe I didn't have the focus perfect on Saturn, as I can't believe that the telescope focus was different for these two objects. I thought it was odd at the time. I will explore this further.

I didn't see the ad, but I read a comment in another thread here on PT that Pentax will make lenses for the Borg system. Rather a neat line of travel scopes. It's a pity that Pentax won't share their plans for their astro products, and we have to rely on rumors from the Internet and from store sales people.

Last edited by GaryML; 02-11-2009 at 09:59 PM.
02-12-2009, 05:04 AM   #21
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QuoteOriginally posted by GaryML Quote
That 225mm Cassegrain sounds nice. I always wanted to try a bino-viewer. The sky conditions are not very good where I live, so I need portability for the opportunities when I can go to dark skys (in the mountains and desert east of the city). I used to have a 200mm Newtonian on an equatorial mount. It was just too big to take on any sort of trip, so I switched to smaller scopes. The 100mm refractor I have now is probably the maximum size I can transport with ease.
Yes, I think the sensible limit is 100mm for a portable scope. Add the mount and paraphernalia and you are arriving at 15kgs all in all, anyway. I use either the tiny Pentax 75 or a slightly bigger 100/600 Semi-Apo on an old Vixen SuperPolaris mount, when I need to be mobile. The Cassegrain (by the way, its 250mm, I got it wrong in the last post) is permanently mounted in my rooftop dome and is certainly not portable (the OTA alone weighs in at 30kgs)

QuoteOriginally posted by GaryML Quote
Some of the older eyepieces have some really sharp optics, at the expense of eye relief and field of view. It seems like you are a bit of a collector, both camera gear and telescope gear.
Orthos are really made for high resolution planetary oberservations and the Zeiss ones excel at that, though I find the Pentax orthos at least as good, may be with a somewhat higher transmission due to the SMC coating.

Yes, I fear I have some kind of a hunter-gatherer gene... I have a lot of old Zeiss equipment, including the rare 150/900/2250 Cassegrain.

QuoteOriginally posted by GaryML Quote
Funny you should mention the focus on the Moon, as I did had to refocus when moving from Saturn to the Moon. Maybe I didn't have the focus perfect on Saturn, as I can't believe that the telescope focus was different for these two objects. I thought it was odd at the time. I will explore this further.
Planets are hard to focus, as you don't have hard contrast edges. The view is more like somewhat fuzzy blobs and I always need some time to find the best focus for me. The moon on the other hand is so bright, that the pupil contracts and gives you more depth of field, thus making focusing hard. One problem with two different causes...

QuoteOriginally posted by GaryML Quote
I didn't see the ad, but I read a comment in another thread here on PT that Pentax will make lenses for the Borg system. Rather a neat line of travel scopes. It's a pity that Pentax won't share their plans for their astro products, and we have to rely on rumors from the Internet and from store sales people.
You'll find the ad by Hutech on page 53 of the current S&T issue. They advertise the 125SD, which is made by Pentax. Whether it is the same optics as the Pentax 125SD I don't know, but I would expect that. As always, Pentax is very poor in marketing and communications.

Ben
02-12-2009, 09:14 AM   #22
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QuoteOriginally posted by Ben_Edict Quote
Yes, I think the sensible limit is 100mm for a portable scope. Add the mount and paraphernalia and you are arriving at 15kgs all in all, anyway. I use either the tiny Pentax 75 or a slightly bigger 100/600 Semi-Apo on an old Vixen SuperPolaris mount, when I need to be mobile.
My 100mm with the mount & tripod is about 22 lbs. Both fit in one padded bag with a big padded divider down the middle. My bag with my other stuff (eyepiece case, binoculars, SkyScout, flashlight, etc.) is probably about 6 lbs. So total travel weight is about 28 lbs. or 12.7 kgs.

QuoteOriginally posted by Ben_Edict Quote
You'll find the ad by Hutech on page 53 of the current S&T issue. They advertise the 125SD, which is made by Pentax. Whether it is the same optics as the Pentax 125SD I don't know, but I would expect that. As always, Pentax is very poor in marketing and communications.
I'll look for the ad. I just re-subscribed to S&T after a lapse of a few years. I'm waiting for the March issue in the mail (and no Borg ads in the issues I have on hand).

QuoteOriginally posted by Ben_Edict Quote
The Cassegrain (by the way, its 250mm, I got it wrong in the last post) is permanently mounted in my rooftop dome and is certainly not portable (the OTA alone weighs in at 30kgs)
Dome-nice! [Photo of Mauna Kea summit deleted.]

Last edited by GaryML; 03-10-2009 at 12:35 PM. Reason: Deleted photo
02-12-2009, 10:13 AM   #23
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QuoteOriginally posted by GaryML Quote
Dome-nice! Oh, I forgot to mention my domes in the back yard (actually, the photo is from my trip to the top of Mauna Kea in Hawaii last November):
I wouldn't want to pay the electricity bill (air conditioning) for this dome!

Ben

02-12-2009, 02:07 PM   #24
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The only thing cooler than an observatory is a radio telescope array.
02-12-2009, 10:32 PM   #25
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QuoteOriginally posted by rparmar Quote
The only thing cooler than an observatory is a radio telescope array.
Radio telescopes are fine, but I love fine optics. Nothing is better than a fine lens, either on a camera or in a telescope system. I am just amazed at how anyone can make such pure, bubble-free glass, then shape it perfectly within thousandth of an inch, and coat it so that almost no light is lost. Add a finely made, precision focusing mechanism to create a perfectly sharp image and I'm in heaven.
02-12-2009, 10:39 PM   #26
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QuoteOriginally posted by Ben_Edict Quote
You'll find the ad by Hutech on page 53 of the current S&T issue. They advertise the 125SD, which is made by Pentax. Whether it is the same optics as the Pentax 125SD I don't know, but I would expect that. As always, Pentax is very poor in marketing and communications.
I saw the March S&T in a bookstore today and saw the ad. It said that Hutec has a new partnership with "Pentax Japan" to make objectives. Maybe this means that Pentax will keep open the Japanese factory that makes the astro optics. Or maybe they just have tens of thousands of lenses in some warehouse and they are selling them to Hutech at a bargain price. Or maybe they will make these parts in their Vietnam or Philippines factory.
02-13-2009, 02:44 AM   #27
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QuoteOriginally posted by GaryML Quote
I saw the March S&T in a bookstore today and saw the ad. It said that Hutec has a new partnership with "Pentax Japan" to make objectives. Maybe this means that Pentax will keep open the Japanese factory that makes the astro optics. Or maybe they just have tens of thousands of lenses in some warehouse and they are selling them to Hutech at a bargain price. Or maybe they will make these parts in their Vietnam or Philippines factory.
That's the old Pentax problem: Nobody knows, where they are going and they don't tell their customers what to expect next...

Ben
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