PeterW

I’ve used the mvh501 to 100x, but as I said I always move it with the handle and lock it down. There is some jiggle, but I’m sure that’s the manfrotto190 tripod it’s on, hence the query about more stable tripod. Peter

I have a mvh501 manfrotto head and use it with an 80mm refractor or70mm binoculars. I need a more stable tripod to go under it as things weren’t as stable as I’d have liked when I mounted a Mak127 recently, so the opposite issue you have. I don’t rely on the fluid balance force, I move the head and the lock it into place firmly. I wonder if Benro do a suitable carbon version as I’d like the tripod to be closer to 2kg and still super solid. @Marian M I have thought the same for “adding some angle” to help make near zenith observing easier, I reckon a 3D printed wedge with plates bolted on would work. If you extend one tripod leg a bit more and reverse the head you can get pretty close to the zenith, risking a little unbalance so you need to be careful. Peter

Any reviews, seems solid and allows adjustment to different eyepieces and phones. Saves me having to make several 3D printed adapters for scope/phone combinations… if it’s rigid enough? Peter

You ain’t seen what Chroma filters cost… they recently put up their not insignificant cost a bit…. Peter

It’s more that at night your eyes are colourblind and although the sensitivity rolls off away from the green, if you have a nice bright bit of light pollution and attenuate it 99.5% it’ll still be bright and possibly swamp your faint nebula. With your eyes being logarithmically sensitive it matters if you have 0.1% or 0.01% or better away from the transmission. Narrow transmission and good blocking give the best contrast enhancement, though this can kill the stars off pretty severely too. Baader are doing a lot of innovating in this space, keep them in mind too. Peter

The other thing that’s little notes is the amount of blocking that filters provide away from the transmission line, the degree they block the light pollution and thus the resulting contrast. Even a fraction of a % can affect thingsZ very few companies publish the data, more expensive filters are likely to do better. Peter

I can confirm that visual use of a CaK filter is a waste of time…. Modern cataract surgery adds back UV filtration, so that won’t help. As noted anything in the visual range should work fine, just a matter of how narrow the bandwidth is and thus what effect it will have one the contrast. I’ve used 5.5nm hydrogen beta filters on some binoculars to make some galactic nebulae visible from an urban location. Christopher Hay has done comparisons of h-beta and OIiI for visual observing and the narrower tend to do a better job, even though conventional wisdom would advise such filters are only for big scopes and dark skies…. https://www.cloudynights.com/topic/722322-pushing-the-filter-envelope-observing-galactic-nebulae-with-handheld-binoculars-under-suburban-skies/ Peter

My problem with non-RACI is the bit that’s dropped… I could lose the RA bit and do the physical gymnastics, but I’d prefer to keep the CI bit, so I can easily map the view to the naked eye one… avoiding the mental gymnastics for the scope view. Peter

The ability to flip/rotate the field of view can really help you hop to the right location. It’s surprising what you can see from less than ideal skies. peter

As noted you can we many stars in a finder scope. If you’ve got a friend, then I’d use binoculars and a laser. A decent pair of binoculars will let you find your object location quite well, unless you’re moving to the most directly light polluted part of London. Then you point the green laser at the object location (being careful as always), your friend then sweeps the scope to align to the beam. Another option would be to find the location with binoculars and then punting the laser down the eyepiece of the normal Finder and put the beam on the memorised object location. Of course I’ve also use Mr Spocks jumping, but sometimes there aren’t enough stars or it’s a long hopping exercise. Which bit of London are you joining? Peter

Another one to keep an eye on and from a company that we know has a track record in astro hardware, cameras and software, unlike some other options. As with the other options, this will succeed or fail on the software and how easy it is to achieve good results. These could be very useful for outreach. Peter

Convergence for closer objects. For really close views you need the “reverse porro” designs like the Pentax papillon so the lenses are closer and thus the fields can continue to overlap for really close objects. Peter

Christopher Hay has done a lot of testing of these types of filters, not always from good locations as you will have read. I caught a glimpse of the California neb from my streetlight infested SQM 19skies. I did have very good stray light blocking around the eyepieces so I could well dark adapt (these filters let little light through, you’ll be looking at a reflection of your eyes if there is any straylight about) and some long dew shields to cut out the local light pollution. Not got them under better skies yet. h-beta are your best bet for galactic nebulae and give them the largest exit pupil (brightest view) you can, two eyes giving a calmer view than one. For reflection nebulae you want a blue CCD filter, ie one that fully transmits upto a given cutoff wavelength, not an older written type that has a Much less distinct transmission spectrum. Peter

Twilight would be mesopic, when you’re observing faint nebulae it’s scotooic and rods only. They will saturate as the light levels increase. I’d use a hydrogen beta filter as most hydrogen nebulae have emission there and the eye is much more sensitive to it. https://www.freunde-der-nacht.net/filterexperimente/h-beta/ (use translation) has a review of different h-beta filters, if you want to go after galactic nebulae. Peter

The Pentax papillon binoculars focus to 50cm and are great for bugs and the like. Hopefully you’ll find a cheaper way to get such close in views. Peter

But I got a few more carefree years for my 12x36II(probably pushing 20yrs old then), then I’ll have to decide if I get a newer model. Interesting to see the 15c and 18x are not going anywhere soon. thanks peter

Had a quick bit of visibility, so I know where to look from a few local areas, will help over the next fortnight. Peter

Anyone got a narrow sodium filter and going to go looking for the sodium tail - 11-16april should be the right part of the orbit for it be visible. Peter

For helping match to what is there at this moment, with correct shadows etc, nasa dial a moon is very helpful. https://svs.gsfc.nasa.gov/5048 Peter

Depends on the glass. Went to Rye Nature Reserve recently, lovely big visitor centre with seats round the edge. Tried using my spotting scope through the window… ugh, not crisp at all, had to go back out into the wind to get the best views. However I’ve enjoyed lunar views with my 12x binoculars whilst lying on the sitting room floor through a window. peter

Ouch, spending too much too quickly. Good to hear that the UK space activity seems to be in much better overall health. Be interesting to see what happens in the coming years Peter

Anyone making large aperture etalons already has the kit and skills for getting the flatness sorted….. Peter

Great to hear you found the jelly, for extra challenge there is more nebulosity “behind it”.. find a deep image, looks like a clawed hand. I’d give Lowers Nebula a look if you’re “in the area”. My toes felt cold just looking at that image… Peter

Happy to ask, not sure what’s currently used, think Dave has retired. They measured some ultra flat ceramic disks I had some years back on a zygo. You can use a liquid surface if it’s big enough. Met a chap from PTB once who had an autocollimator that could measure the earths diameter from the curvature on a cup of water….. Peter

Uses the same LRO data as the 21st century atlas. My only grumble is the contrast/brightness level chosen can make some rima/wrinkle ridges hard to see. Look for rupes/rima Cauchy for example. The hand drawn ones do better here, but fail on the actual, realistic detail. the duplex is a solid, useful atlas to have. Peter