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Having downsized to exclusively 1.25" eyepieces for financial reasons, I found myself missing widefield views. Recent price hikes mean the Ethos range are well out of reach, so I looked into alternatives. First up on my budget list was Burgess Optical TMB 40mm 68 degree afov. I purchased this used last year and it is a very nice, relatively compact and lightweight eyepiece. In comparison with the grenade that is a 41mm Panoptic it is positively slender! I've yet to use this under a dark sky where it would excel, but so far have used it to get a decent fov in my C925 from home and have been pleased with the results. I found this comparison with a 41mm Panoptic on line which makes interesting reading. I would be surprised if the differences were as marked as is described here. The description of a flat field also puzzles me, I understand it to be related to field curvature i.e. Where the focus point is consistent across the field, rather than related to increased magnification towards the edge. Any thoughts? http://ejamison.net/equipment_reviews6.html Next up on my list was a used 20mm Explore Scientific 100 degree. Last night was the first time that I had a good chance to use it, and I was pleasantly surprised. Looking at a variety of old favourites such as M45, the Double Cluster and other OCs such as M36, M44 etc, the contrast was impressive, sky background dark and star shapes consistent across the field. I guess the Tak at f7.4 is not a tough test, but these objects certainly looked great even under skies that were at best mag 19.35 on the trusty SQM. Finally, I could not resist a new 30mm ES 82 degree. This has yet to have much of a run out except from the back garden, but I have every expectation that it will deliver good results. Hopefully I will get away camping to Dorset or Devon camping for a week or two this summer. Effectively the 20, 30 and 40 go head to head with the 21mm Ethos, 31mm Nagler and 41mm Panoptic. It is curious why There is a 1mm difference in focal length across all of these eyepieces, given that the ES at least are pretty much direct copies I don't understand why they would differ? I'm sure that ultimately the Ethos range will have an edge under good conditions and in faster scopes, but for the moment I am content with what I have. I need to sort some foam for a case to put them in to add to the Show Us Your Eyepiece Case thread .
Well, it was going very well, and I genuinely have shifted a huge amount of kit, leaving just my Tak and TAL (well actually two TALs but that's another story!) I do miss my little Taks (60 & 76) though especially for taking abroad so when this little beauty came up, I couldn't resist. It's a Burgess Optical 91mm Triplet Apo. Very compact scope for the aperture, and even better, it splits in half so making it very convenient for air travel. The objective is in near perfect nick, I understand it's a cemented triplet with fpl-53 and Lanthunum glass elements. The weak point is the focuser, but I acquired a nice Moonlite from the FLO clearance which should go on nicely. A FeatherTouch would be much lighter and in keeping but I cannot afford one currently. Perhaps a future upgrade, and I can put the Moonlite onto a 120ED when I eventually re-buy one. First daylight views are promising. Straight out of a warm house, there was some CA present off axis, but on axis it was nice and sharp. After around 30 mins, it appears basically CA free (looking at thin branches and aerials against the background sky), so I'm hopeful the Astro views will be similarly positive. Whilst it's windy today, it looks like there will be some clear patches coming through so I'll have a little chance for first light hopefully.
I say first light, it's actually second light but I had a better go this time although still fairly brief. The fine focusing was not working when I first got the scope, so I had a play around with that and successfully sorted it, plus made the overall movement better. Having bought a Moonlite for it, I actually think I'll stick with the original focuser, it does the job and is a fair bit lighter and less bulky, so more suitable for travel. When my numbers come up on the lottery I'll fit a FeatherTouch to it, but for now I'm happy. The Burgess is an f6.6, 600mm focal length scope with a cemented triplet objective of fpl-53 and lanthanum glass. It has a removable section in the tube, perfect for binoviewing at native focal length, but also handy for travel as the tube splits apart. The scope actually takes quite a while to reach ambient temperature. During cool down, the star shapes were pretty dodgy, looking a bit like pinched optics, but once cooled it looked fine. When I've finished my Harold Suiter book I'll make a more informed comment about the star test ?. Collimation looked fine though. I was using the TAL alongside for comparison on the Giro-WR mount, with a 7mm BGO in the TAL and 3 to 6 Nagler Zoom in the Burgess to give roughly similar mags at around x140 to x150 but I mainly used the Burgess at 6mm ie x100. There is some flaring around bright stars, perhaps just the objective needing a clean or muck somewhere else in the optical path so I'll check that out. Colour correction is excellent. No false colour on the moon and a nice neutral tone to the views. Side by side with the TAL, the differences are very noticeable, the TAL actually shows its larger aperture by way of a brighter image and slightly, but noticeably higher resolution on the moon and Jupiter, but also has a fair amount of false colour on the limb and on brighter stars. I didn't buy the Burgess as a planetary scope obviously, but it's nice to know that it gives enough detail on Jupiter to be of interest. Even while it was still low, there was detail in the two main belts and a couple of the temperate belts were visible in the polar regions. Interestingly though I didn't notice the GRS in either scope which should just have been visible towards the end of my session but to be fair I didn't spend long on Jupiter. I am more interested in the widefield views, the main reason for getting this scope is to be able to take it south and view some of the wonderful objects in Sagitarius from dark sites. My lowest power eyepiece currently is the very nice 24mm Panoptic, nice and compact for travelling and giving a 2.72 degree fov. With a 31 Nagler it would be 4.24. The scope has a fairly flat field with the Panoptic, giving sharp stars across the fov. The field was definitely flatter than some of the faster ED doublets I've owned and the Pleiades looked lovely, as did the Double Cluster. Despite the bright moon, the DC was showing delightful tiny pin points of light with good colour variation in the red and orange stars. Rigel's tiny secondary showed up clearly, although the flaring around the primary was more than I would have expected. Polaris split nicely. On to M42, and although washed out by the moon, there was plenty of detail in the nebulosity even unfiltered, and the Trapezium was, well it was the Trapezium. Seeing wasn't brilliant but it looked sharp. In summary, I'm very pleased with the scope. It is built like a tank, but is very compact still. With the focuser removed it fits nicely in my new 1510 Pelicase which is airline portable. I'll post a link to my contribution to the Grab and Go thread where there are pictures of the kit. The only negative really is that being a cemented triplet, I can't use it for solar without a front mounted D-ERF. I do have a 75mm one bought for a PST mod though, so perhaps I can source an adaptor to fit it on the dew shield and just accept the lost aperture. More to follow when the moon is out of the way ?