Siebert 36 Observatory first light

My Siebert 36mm Observatory arrived on Saturday, and for once the sky was clear - at least for a while. It was also first light for my 12.5 inch F5 dobsonian. I got everything together and collimated just as daylight was fading away. I don't get a lot of time to observe - busy life and rainy winters right now. I also had a lot of new toys to play with, so I only spent part of the time really evaluating the Siebert 36 Observatory in any way, but I did end up using it a LOT, as it was quickly apparent it was my best low-power eyepiece.

The appearance of the 36mm Observatory is nicely different from my other commercial eyepieces. Lots of visible aluminum, and nicely finished. I also appreciate the relatively light weight. My dob could not focus out quite far enough to bring this eyepiece in focus, so I had to slide the eyepiece out slightly in the focuser. Luckily the 36mm Observatory is fairly long and I still felt secure that the eyepiece would not fall out. I have the same problem with my two Meade UltraWides (8.8 and 14) but I don't feel secure with them slid out slightly in the two inch focuser - the skirts are too short. I prefer to use them in my helical fine focus adapter which is also a 2 inch to 1.25 inch adapter.

As for the view, it was very good. Nice wide field of view - I could get the 7 bright stars of the Pleiades in the FOV with a little room to spare, something I cannot do on the same scope with a Celestron Ultima 30 or Meade 32mm Super Plossl. The image was flat and sharp to near the edge. I seem to remember it getting slightly soft at the VERY edge - maybe the last 3 or 5% of the radius, but I need to confirm that. I also seem to remember the field stop being just a little less sharp than on my Meade Ultrawides - not bad, and just vaguely softer. I looked at this for a while, trying to figure out if it was a problem, or if the edge of the field stop was fuzzy - it wasn't it just didn't seem quite as sharply defined as on the two Meade UWAs I was also using.

As a point of comparison, the view through my Meade SWA 13.8mm on my F5 scopes is just awful - severely distorted image starting about halfway out the radius. No amount of refocusing could make the outer edge look anything close to decent. It looked fine barlowed to F10, but at F5 the Meade SWA 13.8 is just horrible. The Celestron Ultima 30 and Meade 32mm Super Plossl did just fine at F5, as did the Meade 26mm Super Plossl.

I have never looked through a 35mm Panoptic, but for the price and performance I am getting from the 36mm Observatory I would need to be totally amazed by a look through the 35 Panoptic to consider spending the extra money. I consider my money well spent and consider the Siebert to be one of my three best eyepieces (along with the Meades UWAs).

I also got a Siebert 2X 2-inch Ultra Barlow, but I did not really evaluate it. I did look through it a fair bit, and certainly didn't notice anything wrong with it. Later I plan to compare it to my other three barlows (Orion Shorty Plus, University Optics Klee and GSO 2X 2 inch).

I also have to add that Harry Siebert is a very nice person to deal with. I talked with him on the phone several times, and he was very helpful. I can't say enough good things about him personally.

I have the Siebert 36 and it appears to be a permanent eyepiece for me. I put a clamp on the skirt to make it parfocal with my televue eyepieces. I also compared it briefly with a 35 mm panoptic and prefer the siebert (although the panoptic may have slightly better edge performance). It is far superior in flatness of field and edge performance to the B&W 30 mm superwide (which is still a good deal at $95). Field stop appears to be 40mm on the Siebert.

I was considering the Meade 32 SWA but after reading a bunch of reviews and then looking through the 13.8 SWA, I decided against it. New the Siebert 36 Observatory eyepiece costs the same as the sale prices I am currently seeing on the 32mm SWA and I think the Siebert is the better value here. Harry Siebert offers a 30 day return guarantee on his eyepieces so if you don't like it, send it back. Meade won't do that for you.

I read both your posts about your scope and wanted to say that it is possible that you can fix the out focus limitation with out replacing anything.
If you lower the primary equally with all three collimation bolts it will give you more out focus. It is common to find the screws have been run up the adjustment too far when collimating or assembling the mirror and cell to the mirror box. You might want to try this before you buy new poles or any other expensive parts.
The other solution is to simply place a 1/4" wooden or plastic spacer under the focuser between the board and base. It is easy to cut the center out to match the barrel diameter and the mounting screw holes.
Floyd

John,

On my 8" Atlas I sometimes need a little more out travel on the focuser. I have found the easiest solution to be to just add a 2" extension. These are available from a number of sources.

Also if you like the Siebert 36mm as a single eyepiece, you should see what it is like looking through two of them on a 45mm Elite binoviewer. 8O