Harry Siebert Optics Standard 7mm


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Subject: Seibert 7mm
By: Anonymous (xxx.xxx.94.141)
Date: 05/04/2002 06:52:51 pm PDT
I finally received my Seibert Optics 7mm eye piece a couple of days ago after an 8 week wait. Thanx to Canada Customs and not due to Seiberts shipping practices, although their was a shipping error. Landed cost was just shy of $75.00 Canadian.

At first glance, these eyepieces have a definate "homemade" appearance. The entire eyepiece has a one piece appearance, with a thin rubber cladding over the business end of the EP being only barely thicker than the pebbled, flat black coating covering the copper tubing which makes up the barrel of the EP. I know that it is copper because it has already flaked off in two spots where I have been sliding it into a barlow with the thumbscew inadequately loosened. This textured coating is also applied to the inner surface of the tubing which makes for a very low reflecting surface, perhaps the best I've seen, and no doubt contributes to enhanced contrast. Contributing to the homemade appearance is the hand written focal length, marked in white on the barrel.

The rubber cladding has a molded grip band which protrudes only 1.5 mm, which is barely enough to keep it from slidding through my homeade holder on the side of my Dob. I suspect this should be adequate for most factory accesory trays, but imagine it could lead to wedging into slightly oversized holes.

The exit pupil on this eyepiece is a substantial 12mm which compared to most Plossles of equal focal length is better than double. The objectives are coated, though I'm not certain the quality, although Harry Seibert claims to use only good quality optics from Edmund scientific.

The eye relief is advertised at 6mm which I'd say is about right. I find that I have to get my eye right up against the eyecup, but can easily visualize the entire circumference of the field stop without having to jam my eye into the the exit objective. No need to freeze contacts to the eyepiece, but glass wearers would be dissappointed. Compared to Meade 4000 Plossls and their Super Plossles, the eye relief is comparable if not superior. In fact, I find with my friends 4000 6.4, I must fold down the eyecup to visualize the fieldstop, owed to the small exit pupil.

The apparant FOV is a pleasant plus, being 65*. When held to the eye against an bright light source such as a lamp shade, the entire field appears evenly illuminated. With a comperable Superplossl I found the brightness tended to fall off towards the edge which may have been in part due to vigneting by the edge of the much smaller exit pupil.

Field performance is the bottom line though, and so far I have been quite satisfied. I have only had the opportunity to compare it against a Meade 4000 6.4 and my Speers Waler 14mm barlowed 2X. So far the Seibert has faired commendably.

Compared to the plossle, images are brighter and more detailed, with considerably less ghosting. The Seibert out performs the S-W in the brightness and contrast department, although both showed similar amounts of detail on Jupitor. I suspect seeing may have limited detail comparisons. There was definately more ghosting with the S-W, however, given the S-W and barlow had better than double the number of elements, it faired quite well. Where the optical performance of the Seibert became most apparant was with fainter star images. Viewing M13, which was still quite low in the sky, their were clearly more stars resolved with the Seibert, compared to the S-W/2x combo. In fact, averted vision was required with the latter, to visualize some of the dimmest stars and the glow from the unresolved core, with the Seibert, the same starfield was visible with direct gaze and averted vision tended to reveal more resolved stars. I'm looking forward to getting out to dark skies to use this puppy on smaller galaxies.

Edge performance was quite acceptable. The S-W barlowed clearly won out in this area, however, I found that the barlow tends to correct for spherical abberation in the primary and the S-W, un-barlowed performs about the same as the Seibert, similarly, the Seibert barlowed resolved stars sharply to the edge. The S-W also has a substantially better apparant field and eye relief giving it a "space-walk" feel comparable to Naglers.

Chromatic abberation was acceptable with slightly better performance by the Meade. The Seibert tends to impart a slight yellowish tinge to the images of Jupitor with slight blue fringing. The S-W/2x was similar to the Seibert in this department.

In summary, the Seibert is an excellent eyepiece for the money. It comes in at less than half the cost of the S-W , close to half that of most quality Plossls, and almost a quarter the cost of high end EPs. Comparing it to Naglers, Lanthinums, or Mead Ultrawides would indeed be comparing apples with oranges, however, given that my S-W barlowed 2x compared favourably to a Nagler 7mm in a past comparison, I'd say the Seibert is an impressive eyepiece irregardless of cost. If one has astygmatism and must view through glasses, than the Seibert will not provide adequate eye relief and some of the above EP's will likely be the only option. However, I'd highly recommend it to anyone whether on a budget or not. If your concerned about appearance, this may not be the EP for you, but I can't see the difference in the dark, so, that doesn't factor in to my decision.


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Subject: Re: vote by xxx.xxx.212.173
By: Anonymous (xxx.xxx.37.236)
In Reply to: Anonymous (xxx.xxx.212.173) (Original Vote)
Date: 01/01/2003 07:51:55 am PDT
>... but the ep was really no better than a 6mm huygens that came with the scope. I've got to suspect the many gushingly favorable Siebert posts on this site.


Very strange results! and very contrary to my own experiences. No reason for suspects - your eyepiece is definitly broken. I own some Siebert eyepieces and the 7 mm also (two of them!) they perform great (believe me I own some high quality EP's e.g. Pentax, University Optics, Celestron Axiom, ...).


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Subject: Re: vote by xxx.xxx.212.173
By: Anonymous (xxx.xxx.44.85)
In Reply to: Anonymous (xxx.xxx.37.236) (Original Message)
Date: 12/29/2003 05:31:16 am PDT
>>... but the ep was really no better than a 6mm huygens that came with the scope. I've got to suspect the many gushingly favorable Siebert posts on this site.
>
>
>Very strange results! and very contrary to my own experiences. No reason for suspects - your eyepiece is definitly broken. I own some Siebert eyepieces and the 7 mm also (two of them!) they perform great (believe me I own some high quality EP's e.g. Pentax, University Optics, Celestron Axiom, ...).


Well I would just lok at the field of view. This is by far better then most plossl packed with scope. I sell optics for a living, and when I do planetry view I pull the Harry Seibert 7mm out.


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Subject: Re: vote by Thompson
By: Anonymous (xxx.xxx.44.85)
In Reply to: Thompson (Original Vote)
Date: 12/29/2003 10:53:32 am PDT
I would have to disagree with the better off spending $225 on 1, then $175 on four. The compairson with a $225 eyepiece seems a little tough on Harry also. Here is a person working out of his own shop building eyepieces for $49 that someone is compairing to a $225 eyepeice. The reviewer says in his review " Siebert gave up surprisingly little to the Pentax." Then says but you should spend $175 more on the Pentax, would you spend $175 to get a "suprisingly little" more?

Point being for a 3 element economy eyepiece the is increadable. I use my Siebert eyepiece to this day for planetary viewing. Great for star parties, public viewings, and personal viewing. Show me another eyepiece with 65 degree AFOV for $49!



>I took the time the other night to A-B the 7mm Siebert against my 14mm Pentax XL with the Orion Ultrascopic 2X Barlow. That's a pretty tough contest for the Siebert, given that the Pentax XL sells for five times the price. But I figured some people might like to know just how well or how badly the Siebert compares against premium glass. I used both eyepieces in our 10" f/5 Dob and our 90mm f/11 refractor. Here's what I found out:
>
>f/5 Dob
>-------
>
>The Siebert 7mm is worlds ahead of the typical 9mm Ploessl or Kellner bundled with inexpensive scopes. It provides about the same true field but with significantly higher power, which results in a darker sky background and better contrast. At about 7mm, the Siebert's eye relief is somewhat better than the 9mm Ploessl. Despite the Siebert's lack of multicoating, contrast is excellent. Sharpness is at least as good as the Ploessl on-axis, although the Siebert becomes slightly soft in the outer 10 degrees or so of its apparent field. The eye lens is much larger than the tiny eye lens of the 9mm Ploessl, which makes the Siebert more comfortable to use.
>
>As expected, when I compared the Siebert to the Pentax XL, it wasn't even a contest. The Pentax XL provides 20mm of eye relief, which makes it usable by someone who wears glasses. The Pentax image was sharp to the edge of its field. Although the Pentax XL and the Siebert are both rated at 65 degrees apparent field, the Pentax feels noticeably wider. It also has noticeably better contrast, as you'd expect from an ocular with world-class multicoatings. Stars that were visible with direct vision in the Pentax XL required averted vision with the Siebert. The long eye relief, huge eye lens, and eye cup of the Pentax XL made it much more comfortable to use than the Siebert.
>
>f/11 refractor
>-------------
>
>Here the optical differences were much smaller, particularly in terms of edge performance. The Pentax XL still performed superbly, but the Siebert was only a step or two behind. At the edge, the Siebert still showed a bit of softness, but I really had to look for it. Once again, the Pentax had noticeably better contrast, and of course the advantage of better eye relief. It remained a lot more comfortable to use. But, given the price difference, the Siebert gave up surprisingly little to the Pentax.
>
>Summary
>--------
>
>I own four Siebert eyepieces, the 4.9mm, 7mm, 12.5mm, and 21mm, and have had a chance to compare them against standard Ploessls and premium eyepieces of similar focal length. There's no question in my mind that the Siebert eyepieces offer higher bang-for-the-buck than any other eyepiece available. Recognize, though, that the Siebert eyepieces simply can't compete with premium eyepieces, not that any reasonable person would expect them to.
>
>If you have a fast scope like an f/5 or f/6 Dob or a short-tube refractor, the Siebert 7mm will beat your bundled Ploessl hands-down as a high-power eyepiece. If budget limits you to eyepieces in the $50 range, I don't think you can do better than a Siebert 7mm. The main drawbacks are noticeable edge softness and eye relief that's too short for eyeglass wearers. If you're certain that you will remain in the hobby and you can possibly afford it, I'd recommend spending the extra money to buy a 7mm Pentax XL.
>
>If you have an f/8 or slower scope, such as a small Dob, long-tube refractor, or Mak-Cass, you'll find that the Siebert 7mm gives you most of what a premium eyepiece does, other than multicoating and long eye relief. The Pentax XL is still a better eyepiece, noticeably so, but the difference is less significant than with faster scopes.
>
>I've retired my four Siebert eyepieces for use with our slow refractor, at public observations, and so on. Although I don't regret buying them, in retrospect I would have been better off spending $225 on one Pentax XL than $175 on four Sieberts. But that's not a slam against the Sieberts, because they remain the best value per dollar spent of any eyepiece line I know. If you're on a tight budget, don't hesitate to buy the 7mm Siebert. You'll like it a lot.


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Subject: Comment to vote dating 5\03\04
By: Anonymous (xxx.xxx.138.136)
In Reply to: Anonymous (xxx.xxx.201.82) (Original Vote)
Date: 05/15/2004 01:50:33 pm PDT
Comment to vote dating 5\03\04

It used to be a roughly finished eyepiece with a less then workable filter attachment. If you return it I will put it in an updated aluminum body with standard filter threads at no charge. My apologies


Harry Siebert


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Subject: Re: vote by Thompson
By: Anonymous (xxx.xxx.187.166)
In Reply to: Anonymous (xxx.xxx.44.85) (Original Message)
Date: 04/11/2006 01:00:43 am PDT
The value of the 7mm Siebert Eyepiece is incomparable to eyepieces made by other companies. It is strangely close to nagler performance at 1/5th the cost. Remember, Harry is an American, making his devices himself, the good old-fashioned American way. I found very little to complain about viewing Saturn at 170X without a Barlow. At 340X, with a mid-range 2X barlow, the view was crisp, contrasty, and bright. I have a 6" dobsonian that retails for less than 500 bucks. If you have a 5,000 dollar telescope, spend the money on high-end hardware, but don't pass up the chance at Harry's unique eyepieces. They are definitely worth the money. There's a difference between inexpensive and cheap. This is a high quality product at a low price.

Pros:
Wide Field of View, as advertized.
Brightness
High Contrast
Good Eye Relief
Made in America
Very Low Cost

Cons:
More testing needed, but fairly conclusive:
Slight reflection seen in elements on very bright objects, only slightly annoying at acute angles (near center).
Some distortion near outer edge of FOV, more noticable with a barlow.

These are not flaws; I believe they are choices Harry made in balancing the cost of production, to offer more for our money than anyone else does.

Summary: I'm grateful to Harry for providing such a high quality product at such an affordable price.

Thank you, Mr. Siebert


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Subject: Re: vote by Thompson
By: johnfdean
In Reply to: Thompson (Original Vote)
Date: 08/16/2006 11:10:05 pm PDT
>I took the time the other night to A-B the 7mm Siebert against my 14mm Pentax XL with the Orion Ultrascopic 2X Barlow. That's a pretty tough contest for the Siebert, given that the Pentax XL sells for five times the price. But I figured some people might like to know just how well or how badly the Siebert compares against premium glass. I used both eyepieces in our 10" f/5 Dob and our 90mm f/11 refractor. Here's what I found out:
>
>f/5 Dob
>-------
>
>The Siebert 7mm is worlds ahead of the typical 9mm Ploessl or Kellner bundled with inexpensive scopes. It provides about the same true field but with significantly higher power, which results in a darker sky background and better contrast. At about 7mm, the Siebert's eye relief is somewhat better than the 9mm Ploessl. Despite the Siebert's lack of multicoating, contrast is excellent. Sharpness is at least as good as the Ploessl on-axis, although the Siebert becomes slightly soft in the outer 10 degrees or so of its apparent field. The eye lens is much larger than the tiny eye lens of the 9mm Ploessl, which makes the Siebert more comfortable to use.
>
>As expected, when I compared the Siebert to the Pentax XL, it wasn't even a contest. The Pentax XL provides 20mm of eye relief, which makes it usable by someone who wears glasses. The Pentax image was sharp to the edge of its field. Although the Pentax XL and the Siebert are both rated at 65 degrees apparent field, the Pentax feels noticeably wider. It also has noticeably better contrast, as you'd expect from an ocular with world-class multicoatings. Stars that were visible with direct vision in the Pentax XL required averted vision with the Siebert. The long eye relief, huge eye lens, and eye cup of the Pentax XL made it much more comfortable to use than the Siebert.
>
>f/11 refractor
>-------------
>
>Here the optical differences were much smaller, particularly in terms of edge performance. The Pentax XL still performed superbly, but the Siebert was only a step or two behind. At the edge, the Siebert still showed a bit of softness, but I really had to look for it. Once again, the Pentax had noticeably better contrast, and of course the advantage of better eye relief. It remained a lot more comfortable to use. But, given the price difference, the Siebert gave up surprisingly little to the Pentax.
>
>Summary
>--------
>
>I own four Siebert eyepieces, the 4.9mm, 7mm, 12.5mm, and 21mm, and have had a chance to compare them against standard Ploessls and premium eyepieces of similar focal length. There's no question in my mind that the Siebert eyepieces offer higher bang-for-the-buck than any other eyepiece available. Recognize, though, that the Siebert eyepieces simply can't compete with premium eyepieces, not that any reasonable person would expect them to.
>
>If you have a fast scope like an f/5 or f/6 Dob or a short-tube refractor, the Siebert 7mm will beat your bundled Ploessl hands-down as a high-power eyepiece. If budget limits you to eyepieces in the $50 range, I don't think you can do better than a Siebert 7mm. The main drawbacks are noticeable edge softness and eye relief that's too short for eyeglass wearers. If you're certain that you will remain in the hobby and you can possibly afford it, I'd recommend spending the extra money to buy a 7mm Pentax XL.
>
>If you have an f/8 or slower scope, such as a small Dob, long-tube refractor, or Mak-Cass, you'll find that the Siebert 7mm gives you most of what a premium eyepiece does, other than multicoating and long eye relief. The Pentax XL is still a better eyepiece, noticeably so, but the difference is less significant than with faster scopes.
>
>I've retired my four Siebert eyepieces for use with our slow refractor, at public observations, and so on. Although I don't regret buying them, in retrospect I would have been better off spending $225 on one Pentax XL than $175 on four Sieberts. But that's not a slam against the Sieberts, because they remain the best value per dollar spent of any eyepiece line I know. If you're on a tight budget, don't hesitate to buy the 7mm Siebert. You'll like it a lot.


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Subject: Re: vote by Thompson
By: johnfdean
In Reply to: Thompson (Original Vote)
Date: 08/16/2006 11:17:22 pm PDT
My last post escaped before I began typing. I am holding back on voting on this EP. I have owned the 7mm for several months and am less than happy with it. While I find the 34mm Observatory to be great, the 7mm appears to have problems in both my Nighthawk and 14" dob (f/4.7). The star images are less than pinpoint across the fov. My Orthos of the same fl have no problems. Still, the weather in my region has been horrible, and I am holding back on passing judgement. My overall satisfaction with Seibert products has been good, and I still suspect the problems might be somewhere other than the EP.


>I took the time the other night to A-B the 7mm Siebert against my 14mm Pentax XL with the Orion Ultrascopic 2X Barlow. That's a pretty tough contest for the Siebert, given that the Pentax XL sells for five times the price. But I figured some people might like to know just how well or how badly the Siebert compares against premium glass. I used both eyepieces in our 10" f/5 Dob and our 90mm f/11 refractor. Here's what I found out:
>
>f/5 Dob
>-------
>
>The Siebert 7mm is worlds ahead of the typical 9mm Ploessl or Kellner bundled with inexpensive scopes. It provides about the same true field but with significantly higher power, which results in a darker sky background and better contrast. At about 7mm, the Siebert's eye relief is somewhat better than the 9mm Ploessl. Despite the Siebert's lack of multicoating, contrast is excellent. Sharpness is at least as good as the Ploessl on-axis, although the Siebert becomes slightly soft in the outer 10 degrees or so of its apparent field. The eye lens is much larger than the tiny eye lens of the 9mm Ploessl, which makes the Siebert more comfortable to use.
>
>As expected, when I compared the Siebert to the Pentax XL, it wasn't even a contest. The Pentax XL provides 20mm of eye relief, which makes it usable by someone who wears glasses. The Pentax image was sharp to the edge of its field. Although the Pentax XL and the Siebert are both rated at 65 degrees apparent field, the Pentax feels noticeably wider. It also has noticeably better contrast, as you'd expect from an ocular with world-class multicoatings. Stars that were visible with direct vision in the Pentax XL required averted vision with the Siebert. The long eye relief, huge eye lens, and eye cup of the Pentax XL made it much more comfortable to use than the Siebert.
>
>f/11 refractor
>-------------
>
>Here the optical differences were much smaller, particularly in terms of edge performance. The Pentax XL still performed superbly, but the Siebert was only a step or two behind. At the edge, the Siebert still showed a bit of softness, but I really had to look for it. Once again, the Pentax had noticeably better contrast, and of course the advantage of better eye relief. It remained a lot more comfortable to use. But, given the price difference, the Siebert gave up surprisingly little to the Pentax.
>
>Summary
>--------
>
>I own four Siebert eyepieces, the 4.9mm, 7mm, 12.5mm, and 21mm, and have had a chance to compare them against standard Ploessls and premium eyepieces of similar focal length. There's no question in my mind that the Siebert eyepieces offer higher bang-for-the-buck than any other eyepiece available. Recognize, though, that the Siebert eyepieces simply can't compete with premium eyepieces, not that any reasonable person would expect them to.
>
>If you have a fast scope like an f/5 or f/6 Dob or a short-tube refractor, the Siebert 7mm will beat your bundled Ploessl hands-down as a high-power eyepiece. If budget limits you to eyepieces in the $50 range, I don't think you can do better than a Siebert 7mm. The main drawbacks are noticeable edge softness and eye relief that's too short for eyeglass wearers. If you're certain that you will remain in the hobby and you can possibly afford it, I'd recommend spending the extra money to buy a 7mm Pentax XL.
>
>If you have an f/8 or slower scope, such as a small Dob, long-tube refractor, or Mak-Cass, you'll find that the Siebert 7mm gives you most of what a premium eyepiece does, other than multicoating and long eye relief. The Pentax XL is still a better eyepiece, noticeably so, but the difference is less significant than with faster scopes.
>
>I've retired my four Siebert eyepieces for use with our slow refractor, at public observations, and so on. Although I don't regret buying them, in retrospect I would have been better off spending $225 on one Pentax XL than $175 on four Sieberts. But that's not a slam against the Sieberts, because they remain the best value per dollar spent of any eyepiece line I know. If you're on a tight budget, don't hesitate to buy the 7mm Siebert. You'll like it a lot.


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