Package just arrived...APM 100-90 ED APO BINO

Here is the place to talk about all those equipment(Telescope, Mounts, Eyepieces, etc...) you have. Not sure which scope/eyepiece is best for you? Trash it out here!
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rlow
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Re: Package just arrived...APM 100-90 ED APO BINO

Post by rlow »

So is the "False Pupil" an issue when observing? Last night and tonight, I tried the Pentax XW 20mm and Panoptic 24mm on the rising moon, my personal findings on first impression is that there is not an issue for me on ghosting or veiling glare etc whether I place the moon on axis, at the edge of FOV or just outside the FOV of the Pentax XW 20mm.. The field stop of XW 20mm is 24mm, wider than the bino's 23mm rear aperture. This is seen in an urban condition with light pollution. I will check again when we head out for dark sky observing this weekend.

I find a little glare using the Panoptic 24mm on the moon. The Panoptic 24mm has a field stop of 27mm. Whilst the Panoptic 24mm does give the widest true field, and show sharp pin-point stars almost up to the edge of FOV, but there is visible darkening of the outer portion of FOV due to vignetting, and the fieldstop is blurred and not sharply defined. There is also some pin-cushion distortion. Eye relief is a bit short for some people, especially those wearing glasses. I tend to view binoculars without glasses but I still need to wear glasses for aiming and starhopping.

The Pentax XW20mm and XW14mm gives sharp edge of fieldstop, no vignetting but the stars start to lose that pin-point sharpness halfway out to the edge and gradually worsen towards the edge of field. The XW 20mm works excellent on my Denk II PXS binoviewer but I wont use the XW20mm and XW14mm for this bino. I will try to check on Vixen LVW 22mm eyepieces in two weeks time. Doctors are on the way, hopefully to arrive by next week. :)

The Zeiss EPL 10x/20 (25mm) microscope eyepiece is able to reach focus, and the Nikon MC-II zoom (7mm to 21mm) spotting scope eyepiece, with 1.25" custom-made adapter, just managed to reach focus. I also tried the ZAO-II 16mm and 10mm which worked great. I tried the ZAO-II 6mm which gives 91.67x and the bino image alignment is still fine, but the short eye-relief make viewing quite uncomfortable. I have not tested the ZAO-II 4mm yet. All these eyepieces give excellent high-contrast clear views with minimum light scatter and with stars sharp to the edge similar to the XWs, but with relatively narrower FOV compared to widefield eyepieces like XWs and Delos.
Richard Low
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rlow
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Re: Package just arrived...APM 100-90 ED APO BINO

Post by rlow »

Airconvent wrote:Congrats Richard for your new Bino ! Looks like you are giving Gavin a run for his money! I wonder how the Omega Centauri would look like with this :)
Thanks Rich1.

I post this thread so we can share our experiences, and learn from each other. I learnt more from others in the various forums than finding out myself by trial and error. This is not intended to "give anyone a run for his money". Gavin has a very nice 100mm binocular telescope too.

Anyone is welcome to take a look through this APM 100-90 ED Apo bino.
Richard Low
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rlow
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Re: Package just arrived...APM 100-90 ED APO BINO

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Just return from overnight observing at Sedili. I have interesting findings to report later.

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rlow
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Re: Package just arrived...APM 100-90 ED APO BINO

Post by rlow »

Hi folks

I like to request from our Singastro members if I may borrow any of the following eyepieces for testing on the APM 100-90 ED APO Bino this weekend. I already have one of each, so I just need to borrow the 2nd eyepiece:

1. Ethos 8mm
2. Ethos SX 3.7mm
3. Pentax XW 14mm

A note of thanks and appreciation to our fellow Singastro friends who are helping me to try out or lend these eyepieces:

Mooey - Radian 18mm pair, Radian 14mm pair, Radian 8mm pair, LE 30mm
Malcolm (Mariner) - Pentax XW 7mm, RKE 28mm

If anyone wants to try out or lend other pairs of eyepieces on the APM bino, please bring it to Science Centre Observatory area this Friday 5 Feb 2016 at 8pm. I will bring the APM 100-90 ED APO bino there for everyone to view and enjoy.

If anyone want to join us for the overnight observing at Sedili this weekend 6-7 Feb 2016, please let me know. I have space for another three persons.

Note: I am testing different kinds of eyepieces to see which eyepiece type and which focal lengths are suitable for the APM bino before I commit myself to buy a pair. The APM bino poses a few challenges: (1) eyepiece able to reach focus, (2) off-axis performance in this fast f/5.5 refractor, (3) vignetting due to 23mm clear aperture, (4) light baffling and control of false pupil reflection, hence I need to test all kinds of eyepieces under dark sky condition to assess and evaluate the eyepiece/bino performance.
Richard Low
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rlow
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Re: Package just arrived...APM 100-90 ED APO BINO

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rlow wrote:Just return from overnight observing at Sedili. I have interesting findings to report later.
Last Saturday 30 Jan 2016 my wife and I went for an overnight observation trip to our regular overnight stargazing site at Tanjung Sutera Resort in Sedili Besar, Malaysia. It is about 100km north of Singapore, a 1.5 hours drive away. On a night of clear transparency, the Milky Way is clearly seen naked eye stretching almost across the whole sky and the Coalsack Nebula is clearly defined.

That night the sky transparency was very good and this was our first time looking through the APM 100-90 ED APO bino under dark skies. I inserted and pair of Pentax XW 20mm and took a first look at M42 Orion Nebula almost overhead. Wow! ...the binocular sharpness and contrast is incredibly superb, and makes the view so spectacular! The XW20mm showed me an image that has sharpness, clarity, and high-contrast. The sharpness is out to about 75% to the edge only. The fieldstop is clearly defined and there is apparently no vignetting visible.

I realised that the XW20mm works well on the APM 100-90 ED APO bino. This is in line with the good comments made by Rich V, and others, saying that XW20mm is "ideal" or "good match" for the APM 100 ED APO bino. This is because when we view through a binocular or binoviewer, our eyes focus only on the central 58 degree portion of the field of view, which is sharp in the XW20mm. Beyond the 58 degrees the image is usually not sharply defined, unless you redirect your view towards one side. But it is tiring on both eyes to focus on the top or bottom of FOV, and even more tiring or almost impossible to view the extreme left or right edge of FOV. Hence, most of the time I just focus on the central 58 degrees and let the outer portion beyond the 58 degrees "frame" the view.

When I scan around the sky, I noticed the "false pupils" first highlighted by Mr Bill. The main one is the semi-circular chord of light similar in shape and position to the "chord-shaped false pupils" at 5 o'clock position in the exit pupil photos I posted earlier in this thread. It appears when a bright 1st magnitude star is hidden about 0.5 degrees beyond the fieldstop at the 11'oclock position of the left eyepiece. Those exit pupil photos I posted earlier were taken of the left eyepiece. For the right eyepiece, the "false pupils" are in the mirror-image position compared to the left eyepiece. Fainter ghost of the "chord-shaped false pupils" may appear at the 11 o'clock position if the bright star is hidden at the 5 o'clock position. There is also another artefact that looked like a tight double star that may appear under certain condition. These appeared when my eyes are slightly off-axis. They don't seem to be present on-axis. When a bright star is right at the edge of fieldstop, there is some veiling glare across the field. At first all these artefacts were a bit disconcerting when I scan around the sky, as the artefacts suddenly appear like a thin crescent moon or micro-meteor, but after a while I got used to it, ignored it, and just simply enjoy the high-contrast views. I realised that under urban conditions, these artefacts may not seem so obvious due to poorer image contrast, but it is still there.

I tried the Panoptic 24mm (just one piece) and the view didn't quite appeal to me, due to lower contrast, fuzzy fieldstop, and the vignetting and pin-cushion distortion around the edge. Stars are sharp almost to the edge of fieldstop. I see slight degradation of sharpness visible at the edge. The Panoptic 24mm is small and lightweight, and are a good match for Nagler 13mm and the other Type 6 Naglers. I plan to take a look with my friend's LVW22mm sometime this week, if the arrangement works out.

Next I tried the pair of Zeiss E-PL 10x/20 (25mm equivalent) microscope eyepiece with APM 1.25" adapter. Fantastic view, very sharp, with clarity and high contrast. Sharpness is almost to the edge, with slight degradation visible at the edge.The AFOV is not too wide but appears wider than the standard field of 50 degrees and quite comfortable, as I had attached the Baader winged rubber eyeguards. So different from the Panoptic 24mm.

Finally I tried the Zeiss Abbe Ortho-II 16mm pair and again I observe the similar clarity, sharpness and high-contrast similar to the Zeiss E-PL 25mm and XW 20mm. Sharpness is almost to the edge, also with slight degradation visible at the edge, similar to the Zeiss E-PL 25mm.

I am borrowing from some of our Singastro friends a few eyepiece pairs to test on the APM 100-90 ED APO bino for the next Sedili overnight observing session this weekend 6-7 Feb 2016. The current eyepiece list to review comprise of LE30, RKE28, Zeiss 25mm, XW20, Radian18, ZAO-II 16, Radian14, ZAO-II 10, Radian8, XW7, ZAO-II 6, ZAO-II 4.
Richard Low
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rlow
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Re: Package just arrived...APM 100-90 ED APO BINO

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We did a public outreach session tonight with the APM 100-90 ED APO Bino at the Singapore Science Centre Observatory. We also have first light for a pair of really exceptional eyepieces that arrived separately today from two different countries.

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