Rusted

Quote: QOTD #18: "Astronomers, like burglars and jazz musicians, operate best at night." - Miles Kington As a practising solar imager [4th Class] and Nyctophobic [White Belt] I take exception to being so excluded. It takes all sorts! Good post, BTW.

When the Hyades are as near as the Moon we'll have more than a bit of frost to contend with. A. Pedant

I'm a martyr to the 1%.

And then they started reproducing... to the point where the Earth grew dark and increasingly frosty!

It seems a bit extreme putting so many satellites up there just to provide a few sunspots for impatient solar imagers. My sun is a magnet for airliners. Hardly a day passes when one or two do not fly across "upside down." "Fasten your seatbelts," takes on a whole new meaning! Returning to the subject matter. Who pays for the Internet when the "advertising bubble" bursts? What happens when the cost of the bandwidth for ads, trackers and cookies greatly exceeds global income from all advertising sales? Supersaturation by ads is already highly stressful for many browsers despite add blockers. Myself included! Trackers and cookies are running into the tens of thousands, per day, for quite ordinary, Internet users! I am so sick of ads that I will never buy anything [ever again] which is spammed onto my screen.- Not without my personal invitation and button confirmed permission. Time for a Freedom From Advertising Movement!

Commercial filters usually have the advantage of greater neatness and hopefully easy fitting and security against falling off in the wind. The solar foil filters are considered to be optically superior to glass filters provided the foil is slightly wavy. Commercial or DIY, you don't want a perfectly smooth, foil filter. Baader tells you this in their instructions. I found suitable donor objects for supporting my foil, over suitably large holes and they have lasted for years. My 180mm has a modified, aluminium baking pan which fits over the objective cell with foam lining for security. The 90mm is just a detergent bottle cut short [100mm/4"] and the foil taped over the outer end. It slips over the dewshield. When not in use I keep them both standing foil upwards in clear plastic food containers. That way I can see how ugly they are but can't lose them! Hold the filter up to the sun before use and move it about to look for pinholes or damage. Pinholes won't blind you but will lower contrast in use. I like to be reminded how small the sun is in the sky and whether there are any naked eye sunspots. It's probably an age thing.

You are much too modest. Nice capture!

I believe that such foil needs an air gap of at least an inch [25mm] to function correctly as a radiant reflector. Placing it tightly against metal [or anything else] will only form a thin conductor or thin insulator depending entirely on the properties of the material. In building work it is usually [or should be] sandwiched between well spaced battens to provide the necessary air gap. No air gap means no reflectance. It would be like expecting our reflecting telescopes to work with the mirror cover still in place.

You seem to have it all nicely worked out. Notwithstanding your thoughtful response and without wishing to push you any further in this direction: Have you asked your blacksmith if he can source thin aluminium sheet? It is readily available online in all sizes but delivery to a private address can be quite costly. Metal sheeting, which is insulated from below, is likely to become even hotter. Baking your timber structure may reduce its lifespan. Which aluminium will avoid.

Nice build! Despite being "shiny," galvanized steel soaks up a lot of heat from the sun. As does shiny stainless steel. I did some tests of shiny samples of metal sheet in the sun. Aluminium was by far the coolest and lightest. I had a shed with a 4-6" thick, concrete roof which was unbearably hot in summer. Leaked in the winter. So I laid flat sheets of thin aluminium from a scrap yard on top and fixed it down around the edges. This tamed the heat problem immediately. Nor did it ever leak or drip with condensation again. Rubber pond liner, which Gina mentioned, is affordable, UV stabilised and long lived. No idea of its thermal qualities but I have used it as a flexible dome skirt. I second Peter's concern on wind lift in "mid flight." You need hooked retainers to stop lift.

Very crisp!

All me own werk, Guv! A frustrating afternoon trying to capture 500 frame videos with the 90mm Vixen f/11 and the 180/12 iStar. ASI120 & 174 respectively. I was using the SharpCap gain and exposure sliders constantly as the cloud streamed across the sun. Mostly just gaps in the clouds with the solar surface detail only becoming visible before complete overcast. Registax keeps crashing on Alignment so this is a rare effort in AS!3. I still don't know how to use it properly and can never find the stills afterwards!

I captured lots of 500 frame videos in white light. Only at the very end was I seeing convection cells. This is probably going to be my best. Complete overcast now.

I'm capturing 500 frame videos during gaps. No chance in H-a.

That was yesterday. Full sun all afternoon but a bit breezy. Thought I might hang some heavy shade netting over the slit. Leave a gap to look out but protect the telescopes from being buffeted by the wind. Well, it's a plan!

6" f/10 PST, ASI174, SharpCap, PhotoFiltre7.

This was earlier today:

Tell me about it! 42F and I'm frozen in the dome even with only a small gap to peak out through the shutters. Enjoying early lunch. With the sun shining on the dome now.

"Thick" is the only technical term I need for today's cloud. The sun keeps teasing with brief brightness. Though I couldn't even define the limb in the H-a 6" during one of these "flashes."

It has clouded over here now but the sun is still just visible at 12:20. I have plenty of prom captures to get on with but it's not the same.

Lovely proms at 2, 4, 8 and 10 o'clock. I just need some guy lines to stop the telescopes blowing about.

Despite two dire national forecasts for solid, grey overcast I am off to capture some proms under a clear, blue sky.

I don't usually use FireCapture and still much prefer SharpCap. FireCapture still seems totally opaque compared to SharpCap. SharpCap has experimental monitoring for auto-guiding but doesn't actually guide. PHD2 was denied a connection by ASCOM. When I finally managed to get a Solar image in PHD2 it proved impossible to reduce the exposure. I was using my Vixen 90 with 1000mm F/L and solar foil. I should probably try a filtered finder next. I was hoping to use my 120MC for auto-guiding with PHD2 and SharpCap. Must try harder at this. At least I have options to play with instead of watching the clouds tomorrow. There's something rather magical about auto-guiding. As in: "Look, no hands, Mum!"

And guess how we know this? We had a lovely, sunny afternoon today. Capturing loads of prom videos over a couple of hours. The forecast for tomorrow is still determinedly grey and overcast over here. Sunny for most days after that too. Sniff! Blah!