PeterW

Plenty of stereotypes missed out, we need a second episode!! Peter

For zenith objects I enjoy lying on the ground, saves the neck and more protected against the wind. always good to get real SQM data, though new LED lights might give some errors. peter

Noted, I can use a mains extension in the garden, but I’d have greater location flexibility if I could “cut the cord”, so that skywatcher unit looks like an option. Thanks Peter

I have a generic camera 680nm IR and the Altair 685nm, as I want to maximally purge light pollution, but some people are praising the 642nm... maybe I should get the shorter one, though I don’t get to dark skies often. Peter

https://en.m.wikipedia.org/wiki/Einstein's_Blackboard put that board rubber away. peter

21.4 is probably near the best you’ll find apart from places where others don’t live anywhere near..., Wales, Scotland.. peter

Some work a while back showed forward (mie) scatter from light emitted “close to the horizontal”, so full cutoff (and hopefully better fixtures) will constrain the light into a pool below them, rather than spreading it all the place. If it’s going straight up, almost none will come back. There will be reflection and scatter off the ground, which can add a bit Another study I saw modelled the sky glow spread and showed that fitting full cut off fixtures in a city would drastically shrink the light foot print and improve the skies around. when you walk about the place how many streetlights are shining in your face even though they’re miles away and so can’t possibly provide any useful light at your location?? the focus has to be on penalising any fixtures that spray light outside of the area where the illumination is needed.... efficiency and safety (less dazzle). Justify why your light has to illuminate my bedroom?! The new LEDs near me are essentially invisible from only a short distance away, no dazzle and yet the ground underneath still has the right level of light. Of course then we can discuss that the light he tends to be bluer, which introduces additional issues. peter

With an illuminator everyone see where you are... not very covert! NV picks up IR security floodlights very well too. peter

IR?? Never used the one on mine! Outdoors there is always plenty of light as the night sky is rich in NIR, indoors I was disappointed as you were. With the filters added you’ll kick it up a notch! Mark, I need to try some of those other filters to see if it’s worth me investing.... Peter

“Achromat”... I meant Chroma.... auto correct is beginning to drive me nuts. t With such narrow band filters, when you have lots of light at other wavelengths even 0.1% could be an issue. Normal filter transmission plots are with a linear scale, so you can t tell 0.1% from 0.01%. It’s quite common for these filters to have regions where they are less blocking, but you won’t know unless they provide a logarithmic plot in ND units (which I think Chroma do). If you add a 12nm to a narrower one then the loss of hydrogen alpha will be trivial compared to the additional blocking of those undesirable wavelengths. I haven’t done a lot of testing as if I filter too heavily the image starts to get hard to use. Maybe in the coming months. peter

A chap in the US recently stu he’s together the Apollo hand drawn charts, don’t cover the extreme limb regions, but good to be able to move between them with a realistic projection. https://www.cloudynights.com/topic/711469-whole-moon-lac-chart/#entry10245763 virtual moon atlas 7 is now out too, lots to play withhttp://ap-i.net/avl/en/start peter

I’ll wait till I see what the achromat does with my grey haired system, I fear it would kill the brightness too far.... I have a 12 and 7nm and a smaller 6nm astronomik. Sometimes I stack them to help keep the out of hand transmission down, especially if there’s a lot of lig about. Peter

Interesting, but only the adapter?! Need to see if it could work on another ep I have that might be suitable. Peter

Merge seen a lot of better cut off LED lights, which may be a missed opportunity. I feel that if we could reduce the lateral spread of light from cities we could bring darker skies closer for everyone. PEter

Can’t hurt to put light pollution back on the political agenda. More efficient lighting can only be a good thing and maybe we can reduce light pollution, though accurate measurements are needed. Peter

Heat will soften epoxy, though it’d be a pain to get the residue off to the bare glass. Norland UV adhesives are popular, but as said, once stuck-always stuck. Hopefully you can get the muck out and get some better index matching stuff in there, hopefully make the scratches less visible. Peter

If you move jupiter about round the edges of the field of view in many bins (especially wide old Porro), you’ll find it goes off elongated bird shapes, highlights that the edges are for your peripheral vision. Move the bins not your eyes, unlike with a telescope. Must say I’ve not tried looking through focus, I could try and see what my reasonable, collimated ones do. If you get a single view of a bright star in the centre of the field then the collimation isn’t far off. peter

Many people are happy with the normal ones... it’s just some people have tried the more expensive ones and they do a bit better. Have a look at comparison posts. I reckon if you never compare yours against the chroma you’d probably never worry... but like not having a 5000FOM tube (if they existed). Peter

Get internal measurements and a block of foam, so you can customise an oversized case to fit the job... won’t help if the case is too small 😉 Peter

I made a pushfit adapter to hold a 2” over the front of the 1x, fits the 3x with another adapter. Then 2” will fit on the 55mm plossl. 6nm is pretty good, the high spec tube people like the narrower Chroma filters, but they cost a bit more. A 685nm long pass is the other one you’ll want (especially from town). I had a nice session looking at Milky Way structure (found B312), with 1x/3x from a local park. peter

Nothing that can’t be wiped off. Make another cover that doesn’t squish the eyecups (the lid of the case should stop dust getting in. I think I lost one of the caps for my old 15x70. Mine stored eyecups down... downward surfaces don’t collect dust so easily. peter

Depends on ease of carrying and “value” (actual or perceived). I have “rehoused” several binoculars in Pelicases, mainly to protect them. The other reason is that finding a close fitting replacement case is nigh on impossible so the customisable goal in a pelicase works well. Not the lightest or most comfortable to carry. If you can find a padded case that would fit id probably go with that. Peter

On other lights I made a small conic shield for the light so when you tilt the red light downwards... for charts and walking about It is not visible (and Thus does not dazzle) other people. Nice little lights. Peter

We used to use ceramic lined uniters for high power stuff as they were more precise than the metal lines ones... when you don’t want any light to “miss”... remembering you are lining up 8micron diameter “pipes”. Replacing “burnt” connectors is a pain, blowing fibres up “mission impossible style” is fun, but expensive! if the LED launch is working i’d stick with them, if you get fibre coupled lasers, be careful to ensure the power levels are kept down and don’t get them too close to your eye (or eye view with any optical instrument)... that way the light will spread out such that your eye shouldn’t be able to take in and focus a dangerous amount (be careful with LED as hey can damage retinas like laser can if powerful enough). Having bought some “5mW” pointers only to measure tham at 10x that I’d advise caution. peter

Multi mode gives more area to collect light into, brighter stars. I would guess the OM2 are the same. My experience was for FC where UPC and APC were different colours to stop you trying to grind an angled end into a flat end. peter