Astronomy Cafe – Monday September 21st 2020

Posted by as Astro Cafe, Meetings

FDAO Virtual DAO Star Party Saturday September 19th 2020

The Friends of the Dominion Astrophysical Observatory are hosting a Virtual Star Party on Saturday September 19th at 7:00PM. Robert Conrad and Andrew Krysa from the Vancouver RASC are speaking on Mars. Click the link for details: https://centreoftheuniverse.org/events/2020/9/7/virtual-star-parties-equinox-to-solstice-mars-opposition-edition

Astronomy Cafe – September 14th 2020

Posted by as Astro Cafe, Meetings

Transcript video of meeting – Phil Groff portion

This is a special edition with guest speaker Dr. Phil Groff, the Executive Director of RASC. Phil gave an overview of RASC from a National perspective and took questions from Victoria Centre members.

Edmonton Contributions relayed by Dave Robinson

The Cygnus Wall, a portion of the North American Nebula (NGC 7000) in Cygnus. By Abdur Anwar Sept 6
Using ASI1600MM Pro with ZWO LRGBHa filters RGB: 30 mins each L: 74 mins Scope: 8″ f3.9 reflector
Abdur writes: Capturing the Cygnus wall was one of my goals for this year since Cygnus is almost overhead right now. Really happy with how it turned out. I didn’t take any Ha subs for this target as I prefer the more natural colours of RGB. Due to a lot of Ha emissions, the red would overpower everything else with Ha data.
Above Neptune with Triton: total exposure about 1 hour
both photos by Massimo Tori using a 10″ Newtonian f/4.7 and a Canon XSi.
Below Moons of Uranus: total exposure about 2.5 hours

Great Martian Details by John McDonald

At 2AM on September 11th John McDonald captured amazing surface details on Mars. Using his C-8 SCT with a Barlow he used lucky imaging – 1000 frames in R, B, G and IR(for luminance) with a ZWO ASI120MM camera.

President’s Message September 2020

Posted by as News, President's Message

I don’t know about you but I am not ready to change the calendar to September just yet. The uncertainty introduced by the pandemic and the political drama unfolding south of the border distracted me from making the most of the Summer. The restrictions of Covid 19 produced a Star Party deficit and deprived the Victoria Centre of the social interaction enjoyed when sharing the night skies with others. But the constellations march on and they are indifferent to our plight. So enough snivelling and it is time to count our blessings.

On the Covid front, whether it was our favourable geography, good governance or good fortune, so far Vancouver Island has experienced relatively few cases when compared to other areas. On the weather front, relatively cool conditions have reduced wild fire smoke and presented favourable observing and imaging opportunities. On the technological front, Zoom and our tireless hosts, Chris Purse, Barbara and Kurt Lane and John McDonald have kept the doors to Astro Cafe open during the summer months. This allowed us to remain connected and share our techniques, images, sketches and enthusiasm. These sessions were all captured on video by the kindness of Joe Carr and posted on the Astronomy Cafe web page. One antidote to the pandemic was the visit by the beautiful comet C/2020 f3 Neowise. Editor Bruce Lane went the extra mile and prepared bonus issue #420 of the Victoria Centre newsletter, SkyNews, that showcased images and sketches of comet Neowise and conveyed the joy it generated. Bruce also provided a colourful history of comets of yesteryear and their relationship leaders of the day.

The National RASC response to Covid was remarkable. There were so many web offerings that they have developed a very useful weekly email entitled “What’s happening at The RASC?” which alerts you to regional and national presentations. If you are not already receiving this email then I encourage you to subscribe here. In particular they had developed a series of Zoom webinars related to the Explore the Universe program. These and other presentations have been captured and are available on the RASCanada YouTube channel for viewing at your convenience.

As we head into September, the number of Covid cases are on the rise and the rooms at UVic will remain closed. Instead of having a special monthly meeting on Zoom, we plan instead to have one Astro Cafe session each month with an invited speaker. The first presenter, Dr. Phil Groff, executive director of RASC, will attend our Astro Cafe Zoom meeting on Monday September 14th at 7:30 PM. It is a great opportunity meet Phil and share your thoughts with him.

As the nights continue to lengthen I do hope that you will find time to step out, look up and marvel.

Useable Skies

Reg Dunkley

Astronomy Cafe – August 31st 2020

Posted by as Astro Cafe, Meetings

Video transcript of meeting

Sketch of fading Comet Neowise by Bill Weir

Bill writes: Using Stellarium as a guide, with my 15X70 binoculars it was an easy long star hop from Arcturus to the precise area where I should be able to see the comet. Due to the 1/4 Moon being maybe only 25° away and even though I had the Moon blocked by a tree the comet was invisible through binoculars so on to the f/3.3 508 mm Dobsonian scope. Bill’s persistence allowed him to glimpse and sketch comet C/2020 f3 Neowise.

What’s happening at The RASC?

Not all members of the Victoria Centre have been receiving this valuable email which provides information on weekly RASC online offerings such as the Explore the Universe and some regional Zoom presentations. To subscribe to this interesting message click here.

Impressive Images of Mars from Edmonton RASCal Abdur Anwar

Abdur Anwar dusted off his old Celestron 8 inch Schmidt Cassegrain Telescope and put it to good use using a lucky imaging technique to capture some amazing images of Mars. On August 25th Abdur experimented with the program WinJupos which can remove the blurring effect caused by rotation. Check out the before and after images below.

Mars on August 25th Image uncorrected for rotation
Same image as above with “derotation” corrections from WinJupos applied
Abdur’s derotated image of Mars taken on August 28th using Celestron C8 with 2X barlow and an ASI600MM camera with zwo RGB filters and a CG5 mount using 1/60s exposure time and a gain of 175. Images were stacked in Autostakkert, wavelets applied in Registax, and derotated in Winjupos.

Speaking of Mars check out this 4K video

The video in this link displays a collection of high resolution images taken on a number of Martian space missions. It is 12 minutes well spent.

Observing

Astronomy Cafe – August 17, 2020

Posted by as Astro Cafe

Video transcript of meeting

Robotic Telescope Editing Contest

Want to put your image editing skills to the test? Now you can, with the RASC Robotic Telescope image editing contest.

In collaboration with SkyNews, each month the RASC Robotic Telescope team will release the data for an image for the public to edit. Judges from the team will pick a winner out of those submitted. Click here to learn more: https://skynews.ca/introducing-the-rasc-robotic-telescope-editing-contest/

Deep Sky Images from an Edmonton RASCal

Edmonton RASCal Abdur Anwar Captured the Cacoon and Bubble on August 9th

Abdur writes: Finally had a clear night last week and I spent most of my imaging time on the Cacoon Nebula (IC 5146) and the Bubble nebula. I got about 2 hours of data on the Cacoon and about 1.5 hours on the Bubble nebula using an ASI1600mm and an 8″ reflector. Really happy with how they turned out 🙂

Equipment and capture details for each target in order:
ASI1600MM Pro
ZWO LRGBHa filters
Ha: 12 mins (Cacoon) / 27 mins (Bubble nebula)
RGB: 20 mins each / 10 mins each
L: 60mins / 30 mins
Scope: 8″ f3.9 reflector
Mount: EQ6R Pro

Cacoon Nebula (IC 5146)
The Bubble Nebula NGC 7635 …Caldwell 11

Rho Ophiuchi Cloud Complex by Dan Posey

Bill Weir encouraged Dan Posey to visit the Pearson Site. The result was at stunning photo at this link: https://rascvic.zenfolio.com/posey/head1949f#hebe220b7 This file is large but the click is worth it! Check it out.

Dan writes: “Thanks to Bill kindly hosting last night, as the conditions at Pearson provided that opportunity I have been waiting for. The result isn’t perfect but that just means I’ll need to revisit in the future; I know where I need to be to take a longer stab at this target next year. This is 48.5 minutes (97x30s) using my Sigma 105 at f1.4 and my Canon Ra at iso 640.”

A Lunar Album from Mike Nash

Victoria RASCal Mike Nash captured images of the Moon 9 nights in a row. Watch the features change as the terminator crawls across the surface. Check it out in mouth watering detail at the following link: https://www.westcoastcaptures.com/Lunar-and-Planetary-Imaging/Aug-7-Aug-16-9-days-of-Luna/n-8j7f2Z/

Dr Doug Johnstone Presents at UVic Open House this Wednesday

You are invited to the UVic Open House which starts at 7:30PM on Wednesday August 19th. The zoom guest link (with password embedded) is:
https://zoom.us/j/97173236268?pwd=V2hhYTAwVVY5cXl5eEFoOUxSYmZGdz09

Title: Peering Into the Darkness with the JCMT: Witnessing the Birth of Stars

The birth of stars remains shrouded in mystery. Stars form inside thick puddles of gas and dust located primarily along the spiral arms of the Galaxy. Astronomers use infrared and radio telescopes to peer into and through these murky puddles to witness the birth of stars. For over 25 years the JCMT has been leading investigations to uncover the formation of stars in the Galaxy. In collaboration with the Spitzer Space Telescope, the Herschel Space Observatory, and the ALMA Observatory in Chile, the JCMT has transformed our understanding of stellar birth. Join me on an adventure to uncover nearby stellar nurseries.

Astronomy Cafe -August 10, 2020

Posted by as Astro Cafe, Meetings

Video transcript of the meeting

Presentations and Discussions

  • Mars and the Moon – David Lee
  • Colour Filters for lunar observing – Randy Enkin
  • Yellow Filters and how human sight works for lunar observing, then seeing colour when observing nebula – Dorothy Paul
  • Space Educator’s Institute -3-day online conference – Lauri Roche & David Lee
  • Perseid meteor shower and other observing hints – Chris Purse
  • Discord chat service being used by RASC National for Perseids observing group – Bill Weir

A Medley of Lunar Images by many RASCals

Edmonton RASCal Alister Ling recorded a wonderful Coho Salmon Moonrise time lapse on August 3rd-4th. Enjoy the YouTube video here: https://www.youtube.com/watch?time_continue=28&v=jC8eZOwmEnk&feature=emb_logo

Victoria RASCal Mike Nash captured 70% Waning Moon on August 9th. Check out the following link: https://www.astrobin.com/rbewkl/0/?real=&nc=WestCoastCannuck If you Zoom in you can glimpse Hadley Rille.

David Lee captured the conjunction of the Moon and Mars on August 8th together with a wonderful foreground shot taken from Rithet Bog.

Some Great Planetary Detail

On August 4th Edmonton RASCal Arnold Rivera captured martian suface details. Arnold writes: I managed to observe and image Mars this morning starting at around 6:00 am from north Edmonton. Seeing conditions at the time were above average and the surfacefeatures on Mars included the dark prominent area of Syrtis Major on the north hemisphere and the rapidly shrinking south polar cap:
Equipment and details: Celestron CPC1100 (in alt-az mode)
Camera: ZWO ASI120MC-S 9.7ms, 2500 frames, processed in Registax
John McDonald captures Jupiter, this time in fairly good seeing shows fair detail. Date 08-08-2020. 8″ Edge SCT on AVX mount. ZWO ASI120MM-S camera with filter wheel and TV Powermate barlow to give focal ration f/25. Captured 1000 frames in R,G and B filters. Stacked best 45% in Astrostakkert. Post processing in Images Plus and Photoshop.
John McDonald writes: My best image of Saturn to date. I had fairly good seeing as the image shows. Date 08-08-2020. 8″ Edge SCT on AVX mount. ZWO ASI120MM-S camera with filter wheel and TV Powermate barlow to give focal ration f/25. Captured 1000 frames in R,G and B filters. Stacked best 45% in Astrostakkert. Post processing in Images Plus and Photoshop.

Lucky Imaging of Planets and the Moon

If you want to learn how to capture wonderful images like the above perhaps you should attend the following webinar!

Tuesday, August 11th – 7:00pm ADT / 6:00pm EDT / 3:00PM PDT
Nova East 2020 – Lucky Imaging: Astrophotography of the Moon and Planets
Lucky imaging is a technique used to capture high resolution images of the Moon and planets. It involves taking as many images as possible, often several thousand, with a high-speed “video” camera and using specialized software to identify and stack only the sharpest images. The talk, presented by David Hoskin, will cover the equipment, software and processing workflow used in lucky imaging.

Click the following to register: https://zoom.us/meeting/register/tJcvd-isqDopGNaC-bUKGBgFgl2NkMkVl4hv

Noctilucent Hummingbirds from Edmonton

Edmonton RASCal Mark Zalik – captured this remarkable sequence on August 4th which closely resembles hummingbirds. All Edmonton content kindly relayed by Dave Robinson.
Mark writes:
Wonderful NLC display tonight! Nice arrays of billows formed way down near the horizon, where the twilight imparted a beautiful cinnamon colour on the NLC. A bit earlier in the display, the clouds formed an ethereal hummingbird.

Observing

Astronomy Cafe – July 6, 2020

Posted by as Astro Cafe

Transcript video

Views from Doug Hardy’s Deck

Doug used a Canon 60Da and a Sigma 10-20 zoom at 10mm looking eastward from his deck in Downtown Victoria. He captured a nice conjunction of the Moon, Jupiter and Saturn. A red light from Trial Island is visible.
Doug then turned around and looked almost straight up there were very interesting clouds tangled up with the dipper. Since the shot was taken at 1:30 AM those clouds are not illuminated by the sun. They might resemble noctilucent clouds but are probably much lower cirrus cloud illuminated by the Moon.

David Lee’s Creamsicle Moon

Could Creamsicles overtake Viva Puffs to become the favourite Astro Cafe summer treat? Penumbral Eclipse July 4. 2020 Billed as a subtle eclipse the penumbral shadow is subtle. What David didn’t expect was the orange ball that emerged from the horizon. A nice creamsicle colour! Camera: Nikon Z6 with FTZ adapter Lens: Nikkor 300/4 AFS with 1.4 x TC Effective 420mm cropped. Sensor ISO: 1600. Exposure: 1/100 sec at f/5.6
Processing: Adobe Photoshop CC 2020

Martian Citizen Science: Zoom Webinar at 11AM Tuesday

Meg Schwamb (Queen’s University Belfast) will be speaking about “Exploring Mars with 150,000 Earthlings.”

Planet Four (http://www.planetfour.org) and Planet Four: Terrains (http://terrains.planetfour.org) are citizen science projects mining Mars Reconnaissance Orbiter (MRO) images to explore how the south pole of Mars is sculpted by the never-ending cycle of freezing and thawing of exposed carbon dioxide ice. In the summer, carbon dioxide jets loft dust and dirt through cracks in the thawing carbon dioxide ice sheet to the surface where winds blow the material into the hundreds of thousands of dark fans observed from orbit. Planet Four enlists over 136,000 volunteers to map the sizes, shapes, and orientations of these fans in high resolution images. Planet Four is creating an unprecedented wind map of the south pole of Mars in order to probe how the Martian climate changes over time and is impacted year to year by dust storms and other global-scale events. Planet Four: Terrains, aims to study the distribution of the jet process across the south pole and identify new targets of interest for MRO. Over 12,000 people have helped identify the channels and pits (dubbed araneiforms) carved during the jet formation process. In this talk, I’ll give an overview of Planet Four and Planet Four: Terrains and present the latest results from these projects.

Zoom info: Meeting ID: 954 6636 7375 password: DAOseminar

Please click this URL to start or join. https://monash.zoom.us/j/95466367375?pwd=cVJpdEZjVW1kaHAyWGo4Um9NOWxkZz09

Astronomy Poem inspires Mystery Novel: from Marjie Welchframe

“Though my soul may set in darkness, it will rise in perfect light;
I have loved the stars too truly to be feaful of the night.”

From poem The Old Astronomer
Sarah Williams/S.A.D.I.
English poet/novelist, 1868

Novelist Ian Rankin titled his Inspector Rebus novel Set in Darkness after these lines. The poem is written from the perspective of an aged astronomer on his deathbed bidding his student to continue his humble research. The lines have been chosen by a number of professional and amateur astronomers as their epitaphs. Entire poem:
https://en.wikisource.org/wiki/Twilight_Hours_(1868)/The_Old_Astronomer

Astronomy Cafe – June 22, 2020

Posted by as Astro Cafe

More Noctilucent Cloud Sightings from Edmonton’s Alister Ling

From Ramsey Heights Park June 20
Noctilucent Cloud and Stunning City Scape From Saskatchewan Drive

UVic Open House Presentation: Using Telescopes as Time Machines

Be sure to catch the following UVic Webinar that begins at 7:30PM on Wednesday June 24th: Using Telescopes as Time Machines by Nishith Eluri and Jonathan Ranallo

“The telescope is perhaps an astronomer’s most useful tool, allowing them to study and understand things billions of lightyears away, in places we could never dream of visiting in person. With only a small telescope and a dark view of the heavens, anyone can see with their own eyes the beautiful planets and moons of our Solar System, faraway spiral galaxies dancing and interacting with each other, the nebulous death throes of ancient stars, clusters of young stars just leaving their nurseries, and a myriad of other celestial wonders. This week, our volunteers Nishith and Jonathan will delve into the history and inner workings of telescopes of all types, from Galileo’s first hand-made refractor to the Earth-sized telescope used to image a black hole, and everything in between.”

The zoom guest link (with password embedded) is:
https://zoom.us/j/97173236268?pwd=V2hhYTAwVVY5cXl5eEFoOUxSYmZGdz09

Meeting ID: 971 7323 6268 Password: 554555​

Observing

Telescope Price Fixing Legal Dispute

Chris Purse shared this CBC story on a legal dispute regarding price fixing of amateur telescopes.

Christopher Go Planetary Imaging Tutorials

Zoom has allowed accomplished members of the astronomical community to share their expertise in a Webinar environment. These sessions are often posted on YouTube to replay at your leisure. There are so many postings, however it is easy to miss some valuable talks. In the following three links acclaimed planetary imager Christopher Go shares his expertise. These sessions may help some local planetary and lunar imagers to further hone their skills. These sessions were hosted by Woodland Hills Camera and Telescopes in April 2020.

Planetary Imaging Essentials Part 1: https://www.youtube.com/watch?v=C5ctZoqOi20

Planetary Imaging Essentials Part 2: https://www.youtube.com/watch?v=-b1rO38Snh0

Planetary Imaging Essentials Part 3: https://www.youtube.com/watch?v=UJTCDLljNYU

President’s Message June 2020

Posted by as News, President's Message

President’s Report June 2020

The abrupt onset of the pandemic introduced a wave of uncertainty. There is a growing realization that the impacts will continue for some time. Most Victoria Centre activities including monthly meetings, VCO observing sessions and Saturday Night Star Parties at the DAO have been cancelled. Astro Cafe has established a virtual presence on victoria.rasc.ca and a weekly Zoom webinar. The Island Star Party, Merritt Star Party and the Mount Kobau Star Party have been officially cancelled. The Saanich Fair is morphing into some online entity. UVic has announced that lecture halls will be closed until at least January 2021.

This has left us staring into a void. But by suddenly escaping the treadmill of everyday life many were given an unexpected gift of time. This has allowed RASCals more opportunity to step out into the stillness of the night, look up and savour the arrival of starlight. While the days of the week became less relevant, our awareness of the rhythm of the Solar System became more pronounced. RASCals have been sharing wonderful images and sketches of the lunar cycle as well as evening and morning dances of the planets. 

Zoom webinars have proven to be an effective tool that helps reduce the sense of isolation and allows us to share our enthusiasm, knowledge and imagery. As a result the Victoria Centre has acquired its own Zoom Pro license which will increase our capacity to meet on line. During this pandemic the astronomical community has rallied and is posting a rich source of offerings on the internet. RASC National frequently hosts interesting webinars which are usually archived on the RASCanada YouTube site. This site will also be used to live stream a virtual General Assembly event between 11AM and 2PM PDT on Sunday June 7th. Dr. Sara Seager and Bob McDonald will be delivering presentations. UVic has moved its Cafe Scientifique online and is also hosting an Astronomy Open House webinar every Wednesday in the summer at 7:30 PM.

During a recent Victoria Centre Council Meeting we explored options of what to do while we wait for a vaccine. We are currently in the process of sending the VCO 16 Inch RC scope for repair and may have an alternate scope available in the mean time. If activities resume at the VCO, however, attendance will initially be restricted to a very small number. This would enable the site to be safely used more for observing/imaging activities than social interaction. Active Observers would be required to bring their own eyepieces to avoid spread of CoVid19. 

This eyepiece issue may be problematic when Saturday Nights at the DAO resume. One alternative to sharing an eyepiece is to try Electronic Assisted Astronomy (EAA). This technique is “casual astrophotography” that enables a camera to automatically stack images on the fly and display them on a tablet or monitor. It avoids complex post processing and would allow fainter deep skies objects to be viewed by the public without lineups. With an internet connection EAA has the potential to share live imagery to a meeting or webinar. The challenge of CoVid19 has served as a catalyst to explore this option. An interesting overview of EAA is found on this link.

While we are waiting for face to face outreach to resume we could set up static astronomy displays showcasing our astrophotography. David Lee recently delivered an astronomy orientation course using Zoom and similar programs might be considered. In the mean time, if you something that you would like to share on the Virtual Astro Cafe please send it to president@victoria.rasc.ca. In closing I would like to thank hosts Barbara and Kurt Lane, Chris Purse and John McDonald for agreeing to extend the Astro Cafe into the summer season.

Wishing you good health and useable skies this Summer

 Reg Dunkley

President’s Message May 2020

Posted by as News, President's Message

President’s Message May 2020

During the early dawn of February 16th I obtained a glimpse of the future. After months of almost perpetual overcast, skies finally cleared. While looking northward towards Cassiopeia I noticed a long precession of fairly bright evenly spaced satellites moving from left to right. It took about 10 minutes for this parade to pass. I realized that this must be the Starlink Constellation that had been mentioned in the news. When I searched the Internet to learn more I was in for a surprise.

Starlink is a bold ingenious project with an ambitious mission to deliver high speed broadband internet to locations where access is unreliable, expensive, or completely unavailable. It plans to achieve this by deploying a vast constellation of communication satellites. The parent company SpaceX was founded by Elon Musk in 2002 and has developed a remarkable capacity to launch Falcon 9 rockets and successfully land them for reuse. This greatly reduces the launch costs. The communication satellites are stacked aboard the Falcon 9 in two columns of 30 and they gradually drift apart once they reach orbit. Each satellite is powered by a single solar panel which gently unfolds. The satellites are maneuvered by ion jets using Krypton. This elaborate scheme sounds unwieldy but when Starlink V0.9 was launched in May 2019 it actually worked! 

Satellites are usually expensive “one off” devices that take years to build but by employing the manufacturing expertise that Elon Musk honed at Tesla, Starlink can assemble 6 satellites a day at their Redmond Washington plant. This production rate allows Starlink to launch 60 satellites every two weeks! At that launch rate Starlink can place 1584 satellites in a shell 550 km about the Earth by the end of 2021. They will be placed in 72 orbital planes inclined at 53 degrees. 22 satellites will occupy each plane and when in position they will form an exotic mesh surrounding the globe. Animation of this configuration reveals that the concentration of satellites is greatest between latitudes of 50 to 53 degrees. While this network will provide coverage over most of the globe, two additional phases have been approved by the FCC to increase capacity and speed. Phase two will add an additional 2800 satellites in a 1125 km altitude shell and phase three will add 7500 more satellites in a lower 340 km altitude shell. 

When completed an additional 12000 satellites will be in orbit! This exceeds the 9000 satellites that have been launched during the last 50 years and the 5000 that are still in orbit. The first batch of 60 operational satellites were launched on Starlink 1 on November 11th 2019 and the sixth Starlink mission occurred on April 22nd bringing the total to 420. While Starlink obtained the necessary frequency approvals from the FCC to prevent interference with radio astronomy there was no governance regarding visual and infrared ground based astronomy. The initial Starlink v0.9 group was much brighter than anticipated and generated alarm from visual astronomers. Elon Musk is embarrassed about this oversight and is working with the Astronomical Community to mitigate the impact of this massive network. On April 27th Musk announced VisorSat, an innovative sunshield that may significantly reduce the albedo of the satellites. Some of these shields will be tested during the next Starlink launch. 

The satellites must be illuminated by the Sun to be visible. Due to the low altitude the Phase 1 cohort will only be visible near twilight. The higher altitude Phase 2 will remain visible longer. Satellites are brightest when just launched but will become dimmer as they ascend to operational altitude. Since twilight lingers into the late evening near the Summer Solstice the presence of this constellation will be most pronounced in the area of highest density over Canadian skies this summer. So keep on the lookout for this new swarm of satellites while stargazing this summer. Please share your observations on the Virtual Astro Cafe web page or during the Astro Cafe Webinar which will take place every Monday evening at 7:30 PM. In someways the unintended consequence of this mission resembles an outbreak of a “stellar virus”. And it could get worse as SpaceX has requested permission to place another 30000 satellites in orbit! Let’s hope that the Starlink team creates a stellar vaccine soon and that skies will remain useable.

Wishing everyone good health and useable skies

Reg Dunkley