经上週开光及前晚调试完成后，昨日是第一次把0.8米反射运到星河科研社于青协大美督的基地活动，为四十多位来自不同学校的香港资优教育学苑学生进行为期半年的天文观测培训。基地靠海，视宁度可以十分理想，是我投入天文爱好多年来所罕见。昨晚开始时月球仰角只有四十多度，已能用 TeleVue Ethos 8 mm 目镜以350 倍观察，然后再转用 TMB Supermonocentric 5 mm 目镜推上 550 倍，因为集光力及解像度充足，酒海边沿的西奥菲勒斯 (Theophilus) 坑的环形山峰呈现如刀峰一样的对比度。大气未至于完全静止，但日落后才一个多小时，这种视宁度也是罕见。

之后指往土星，仰角只有三十度，视宁度略受影响，但近乎扁平的光环，其阴影如刀割一样横切土星本体，那种对比度，不是我当年那单镜筒都要三十万元的 TMB 203 APO 折射镜能比。我也曾拥有 TMB 254 APO，但更像我在深圳西涌天文台，安装好造价数百万元的TMB 304 APO 双筒后目视土星的情景。土星两边共五颗卫星一目了然，第六颗距离较远，不在像场内。要承认，至今用的望远镜经验只看过五颗土星卫星，但颇肯定只要大气透明度合理，加上星图确认，可以看到十颗以上。

之后便是猎户座大星云，Ethos 21、13、8 一级级对上去，中央的四合星轻易而举，旁边还有 10 等多的 E 及 F 星，也明显比 TMB 203 APO 轻鬆得多（我 2010 年也在高美古用当时全国最大 2.4 米 RC 望远镜目视这四合星）。可恨昨天没时间重看日前在城门河畔貌似看到但被厚云层干扰的天狼星伴星。一如日前的情况，星云绿色很明显，更是第一次明确看到这星云的红色(之前试过在理想环境下用40公分Dob隠约看过)。更特别的是现在的绿不像过往从小望远镜看到的绿(少年时用10公分反射在家里阳台也能看到)，而是掺杂了红的混色，即从中央四合星位置的青绿，往外为粉红，再往外为褐红的过渡。刚好手上没有目视光害滤镜及合适接环，手持Antlia RGB Triband Ultra滤镜在彗差镜前试试，星云的丝状云气涌现，对比度大幅提升。二十年前我在德国来回测试 Starmaster 24 吋反射及 TMB 254 APO，很期待到夏天时再看同一堆深空天体，特别是 M57 戒指及 M27 哑铃星云那种层次丰富的云气，还有戒指中央的原白矮星。

然后天色开始转差，但仍争取时间指向木星。大红斑刚好在正面，就算在云层后，大红斑的色彩饱和度也远胜在场我天文台内的Celestron EdgeHD 14。同时以昨晚情况来看，观察木星面那些像鲨鱼鳍的云彩 (festoon)、白斑 (oval) 及黑斑 (barge) 会轻鬆得多，特别是木卫三的圆面很清晰。天气好一点时，看卫星表面地貌(我用203APO拍过)也肯定比之前用 TMB 203 APO 及配有 Mike Lockwood 45公分主镜的 Obsession 18UC舒服得多。

其实这段时间忙得要命，星河科研社一个週五六日可以有五至八场活动，加上昨日有数十位学生要进行培训并评审第一阶段科学报告，但也坚持趁天气转坏及进入雨季前把镜运入基地测试。主要是要及早完成电脑化台架的指向及追踪调校，检测精确调整光轴并调好彗差修正镜后焦点的光学表现，把一齐要天气配合的调试完成，确定这镜能实现预期中的表现。结果十分美满，这镜先天精度极高，是足厚度主镜及科研级的RMS 1/30波长精度，而后天的机械装配及调校，再加上高视宁度环境，让目视表现超越我过往任何一台望远镜，也打破了一直以来的观念即f/3短焦反射不可能是高水平行星月面镜，而且也初步测试了行星拍摄的可能性。可以说我已重燃目视的兴趣，收起多年的、总值十万元的两套全焦段 TMB Supermonocentric / Aspheric Ortho 目镜可以出山了，也会看看这镜的月面行星摄影会比自己的 Celestron EdgeHD 14 好多少。当然也跟学生提过，他们很幸褔，初接触天文便能用全港最大的0.8米反射镜观星，日后也能继续用来研习天文。

随后会在这里继续分享更多测试报告。

After completing final collimation and optical alignment during the pre‑commissioning night last week, the 0.8 m reflector was transported yesterday to the Galaxy Research Society’s observing base at HKFYG Tai Mei Tuk, for the first official activity session. There, more than forty students from the Hong Kong Academy for Gifted Education (HKAGE) participated in a six‑month astronomy training program.　

The site is located by the sea, with often remarkably stable seeing, the best I have encountered in my years of visual observing. At the beginning of last night’s session, the Moon stood about 40° above the horizon. Using a TeleVue Ethos 8 mm eyepiece (350×) and later switching to a TMB Supermonocentric 5 mm (550×), the telescope’s tremendous light‑gathering power and resolution revealed the knife‑edged contrast of the Theophilus crater peaks on edge of Mare Nectaris. Though the atmosphere was not perfectly still, such steadiness only an hour after sunset was extraordinary.

Next came Saturn, at an elevation of just over 30°, slightly affected by seeing, yet the almost flattened rings cast razor‑sharp shadows across the planet, a level of contrast surpassing even my former TMB 203 APO refractor, which cost HKD 300,000 for the optical tube alone. The view recalled my earlier sight through the TMB 304 APO binoculars at Xichong Observatory. Five Saturn moons were directly visible; a sixth lay beyond the field of view. Under better transparency and with star‑chart assist, I’m confident that, ten or more moons can be detected.

Then we turned to the Orion Nebula (M42). Using the Ethos 21 mm, 13 mm, and 8 mm eyepieces in succession, the Trapezium’s four main stars and the fainter E and F components (>10 mag) were clearly seen, far easier than through the former TMB 203 APO. (In 2010, I also visually observed the Trapezium through China’s then‑largest 2.4 m RC telescope at Gaomeigu Observatory.) Regrettably, I didn’t have time last night to revisit Sirius B, the faint companion of Sirius, which I seemed to glimpse the other day from the Shing Mun River before it was obscured by thick clouds. As on previous nights, the green hue of the Orion Nebula was obvious, but this time I could clearly perceive its red component, something I had only barely suspected years ago with a 40 cm Dobsonian under ideal conditions. What struck me most was that the green now appeared different from the pure green seen through smaller telescopes, back in my youth, even a 10 cm reflector on the balcony could show that color. Now, instead, the tone was a blend of green and red, shifting gradually outward from the Trapezium’s aqua‑green core to a soft pink ring, and finally to a reddish‑brown outer transition. I happened not to have a visual light‑pollution filter or the proper adapter at hand, but by holding an Antlia RGB Triband Ultra filter by hand in front of the coma corrector, the nebula’s filamentary structure suddenly surged into view, and the contrast improved dramatically. Two decades ago, while alternating between a Starmaster 24‑inch Dobsonian and a TMB 254 APO in Germany, I could only imagine this level of nuance. Now I look forward to the coming summer to observe the same set of deep‑sky objects, especially the M57 Ring Nebula and M27 Dumbbell Nebula with their richly layered gas, and to catch sight of the pre-white‑dwarf at the heart of M57.

As the sky began to haze, I still aimed at Jupiter. The Great Red Spot was squarely in view, and even through intermittent thin cloud its color saturation surpassed that of our Celestron EdgeHD 14 in the observatory. Jovian details, festoon, white ovals, and dark barges, can be rendered with ease. Ganymede’s disk appeared clean and well defined; under steadier air, its surface shading would certainly be more distinct than in the TMB 203APO or the Obsession 18UC with a Mike Lockwood primary. Which I imaged before with the TMB 203APO

Despite an extremely tight schedule (the Galaxy Scientific Group often runs 5 to 8 outreach programs per weekend, and yesterday dozens of students were being assessed on their first‑phase science reports), I insisted on bringing the telescope out before the rainy season to complete field testing. The goal was to tune up the computerized mount pointing and tracking, verify precise collimation and the coma‑correction backfocus, all of which performed beautifully. The results were highly satisfying. This telescope’s intrinsic optical precision is exceptional, its full‑thickness primary mirror achieves a research‑grade RMS accuracy of 1/30 wave. Combined with accurate mechanical assembly, careful alignment, and excellent seeing conditions, its visual performance has surpassed that of any telescope I have previously owned.

It also challenges the long‑held belief that a fast f/3 reflector cannot deliver high‑quality planetary and lunar views, and the initial trials have even demonstrated promising potential for planetary imaging. It is time to "bring out of retirement” my long‑stored, full‑focal‑range TMB Supermonocentric and Aspheric Ortho eyepieces worth over HKD 100,000, and see how this mirror’s lunar and planetary imaging compares to the Celestron EdgeHD 14. Of course, I also mentioned to the students how fortunate they were to begin their journey in astronomy with the opportunity to observe through Hong Kong’s largest 0.8 m reflector telescope, and that they will have the chance to continue using it in their future astronomical studies.

Further test results and observation reports will be shared here in due course.