Mr Giovanni Di Giovanni

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Viewing 20 posts - 1 through 20 (of 42 total)
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  • in reply to: Pump spray mirror silvering kit #623419

    It must be admitted that Prof. McKim knows more than the devil. Thanks for the valuable information, Prof. I really didn’t know about the inverted mirror and other procedures you mention. Nor did I know about the possible effect of an atmosphere polluted by sulphur dioxide and hydrogen sulphide. And concerning this, the various attempts at silvering I made in the chemistry lab of the high school in the city where I teach (physics), a very industrialised city. I will not attempt to silver again, but I will at least theoretically explore the topics presented by McKim, to whom I extend my thanks. Thanks also to those who have considered my intervention.

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    in reply to: Pump spray mirror silvering kit #623243

    Good morning everyone. I am a bit surprised to find this topic, I didn’t think the problem of silvering the telescope mirror still existed. And even more I didn’t know about that silvering kit. The first mirror silvering I commissioned from a well-equipped glassmaker, who did a very good job. The only major problem was the minimal durability of the Ag deposit, which began to oxidise and yellow. After a few months (max 6-8 months) it had to be removed and re-done. Then I tried to work on it myself by buying Ag nitrate, ammonia, H2O and more. Very bad result! Longer life (up to a year) but silvering with dark spots, uneven deposit, minimal adhesion so cleaning impossible, and other defects. Everything has made me prefer mirror aluminisation. However, here in Italy, aluminisation is made by very few companies and costs a lot. So I gave up the resolution power of a 200 mm and opted for a smaller (90 mm) catadioptric that is very handy and inexpensive. Nevertheless, the D200mm dream still haunts me. I would kindly ask for your opinion on what I have reported. I am a self-made astrophile, and as a basis I have the manual: Procedures in Experimental Physics by John Strong.
    Thank you and greetings to you all

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    in reply to: Is ANYONE getting clear nights any more? #623050

    My enthusiasm for astronomy is ebbing away.
    Concerning the weather, I think something is happening perhaps beyond what the researchers are reporting. Here, in central Italy, we have had a winter very different from previous ones. In my mountains (Gran Sasso d’Italia), snow was always abundant from the end of November to the end of April. On the Campo Imperatore plateau, at an altitude of 2100 m, where the astronomical observatory is located, at least 1 m of snow. By contrast, last winter was disastrous for skiers and for all tourist activity. The attached photographs are a comparison between the normal winter situation on the plateau and that of winter 2024. All taken in the first week of February. During the winters of the past years, we have always had frequent very clear and cold nights down to -10 C. Using the telescope on the moon and planets was a delight. This year, on the other hand, cloud cover was more frequent than usual and the sky was less transparent, so there were very few night frosts that we did not have to use antifreeze spray on our car windows. The month of May allowed only a few observations. This morning I went out with my two dogs and wore a padded jacket because of the black sky and cold air. Summer had already broken out in the past. All this together with light pollution (from my terrace you can read the newspaper in the middle of the night) is dampening my passion for observational astronomy. No more shopping for telescopes, ccd cameras, go to’s, eyepieces, mounts, filters, mechanical work and as many other accessories as we want.
    Alan, I agree with you.
    I can’t take it any more! I have decided two things:
    1) I will devote myself only to the study of Astronomy;
    2) better enjoy that money by inviting a beautiful woman to dinner. Just tell me I’m wrong.

    in reply to: Is ANYONE getting clear nights any more? #623041

    Here in the beautiful country (Italy), lights are scattered everywhere and directed almost randomly, even upwards. They mostly use illuminating globes and LED spotlights directed towards everything that can be illuminated. Not only are the neighbour’s lights dazzling and annoying, the public lighting is also bad. A 120×100 car park, 200m from my house is lit by 54 street lamps of 250 W each. In this climate, the absolute indifference of private individuals and institutions reigns. The anti-pollution law is not even in the administrators’ drawer. The motorist who forgets to dim his headlights is fined, but the headlight of the certain shop is ignored, or the headlights of the supermarket and the motorway that point towards the road and dazzle all night long. What if one appeals? You get a good chuckle. Summary: the problem of light pollution does NOT exist here.

    in reply to: Is ANYONE getting clear nights any more? #623031

    Alan, I agree with you, the effect caused by planes is certainly not minimal. I too have observed many aircraft contrails in the air. The phenomenon has become more frequent since about a year ago. And I will tell you that I am now doing research to find out two things: 1) the photodissociation time of the combustion products ejected by planes into the atmosphere; 2) the floating time of the same in the air. The vast majority of discharges occur at the upper limit of the troposphere (10-12 km altitude), where the atmosphere (close to the stratosphere) is on average rather static. Therefore, the ground deposition time of long-lived photodissociated products will certainly be of the order of months to a couple of years. Unfortunately, the vast majority of people do not understand this. As you say, it is enough for many to eat, drink and watch the stars (the stars as it were) on television. This thoughtlessness is leading us to an irreversible situation, and afterwards those who want Christ pray to Him.

    in reply to: Is ANYONE getting clear nights any more? #622966

    I am not too surprised by what you say about the frequency of cloudiness in the sky, I have always known that in the UK clouds and rain are frequent and inclement. However, even here in Italy some worsening variation seems to be happening, skies more often cloudy and above all less and less transparent. I am neither a visual observer nor do I take photographs, but for several years I have been observing, with a camera, the colours of the sky at sunset and sunrise. Well, for about a year now, the number of clear evenings (i.e. followed by clear nights) seems to have decreased; from an average of 6-8 clear nights per month, we seem to have fallen to 2-3.
    Another thing I have noticed is the decreasing consistency of the snow in the Gran Sasso chain. Until a few years ago, one climbed the highest snow-covered peaks (over 2500 m altitude) with a boot and crampons, sinking a maximum of 10 cm. For a few years now, people have been sinking down to their knees and beyond, and the avalanches (and unfortunately also the victims) have increased. It’s the effect of climate change, agreed. But I can’t help but wonder if this is the only cause or if there is an external cause.

    in reply to: Dark Skies and Satellites in the News #621791

    I always hoped for their title.

    What a beautiful sky, all black. Back then, the sky was filled with clusters of stars, which you could touch with your hands, even from the cities. Remember?

    Unfortunately today our starless sky is all white. I see white, it’s over!

    in reply to: Dark Skies and Satellites in the News #621604

    I have carefully viewed the articles posted by Mr Christopher. They are very interesting, well laid out and equally well developed topics. I am interested in their content, and for this I thank the author for making them available in this forum. For a few years now, I have been interested in sky transparency and observing sunrise and sunset light in order to detect the ‘optical depth’ parameter. I have a small archive of data from about 300 observations. I will try to identify the possible existence of a correlation between the theory Christopher applies and the one I use for my observations. I hope this will provide good guidance for further experiments and studies. Thank you Christopher.

    in reply to: map of light pollution trends #621460

    The Astronomical Observatory at Campo Imperatore, today 30 minutes after sunset.

    in reply to: map of light pollution trends #621459

    I read these remarks of yours with great interest, and I am actually amazed that such educated and reasonable people exist. You speak of respect for animals even with enlightenment. How nice it would be if it came to that in my region too. Here, in Gran Sasso, wild animals of various kinds abound, but there is no consideration or respect for them. The fox is bad because it plunders hen houses, the wolf is the bad wolf from the Little Red Riding Hood tale. Not to mention the poor bear that even enters some villages in the national park and arouses keen interest among tourists. Two months ago, a bear with two cubs approached the fence of a house; the owner shot it twice in the back. The poor animal left the two cubs at the mercy of anyone, even wolves. Imagine if our administrators, our politicians, our technicians and how many others would dwell on blue light pollution and the effects on mammals (including humans) and insects. In my city, the old sodium-vapour street lamps have been replaced by LEDs. In an unused car park of 100X80 m2 there are 54 of them! Many point at 45°. Some lampposts also stand radiantly in the forecourt of the astronomical observatory at Campo Imperatore. Are we talking about a starry sky? For many it is something that does not exist. Faced with this marasmus, one should only do two things: be ashamed and correct oneself. But who does?

    in reply to: map of light pollution trends #621434

    Unfortunately, when it comes to light pollution here things are getting worse by the day. Surely you are familiar with the cycling event called Giro d’Italia Giro d’Italia. You also know that the cyclist who wins a stage will wear the ‘maglia rosa’ (pink jersey). The finish of the stage on 11 May 2024 will be in Prati di Tivo, a ski resort at an altitude of 1600 m above sea level just below the slopes of Corno Grande. The picture is the Corno Grande seen from Prati di Tivo. Corno Grande belongs to the Gran Sasso d’Italia mountain chain, it is the highest peak (2912 m) on the peninsula, populated by foxes, chamois, bears, wolves, snakes, wild boars, mice even on the peak you can see, lynxes, a wide variety of birds (eagles, crows, buzzards etc.). Well, brilliant idea from the organisers, guess what it is? Illuminating the whole of Corno Grande in pink! If this is done, there is no doubt that it will only be the first timid step towards an even worse process of not only light pollution of the mountain. Are we stupid or reckless enough?

    in reply to: Light Pollution Consultation and CPRE Star Count #615791

    Years ago, a proposal was made in Italy for a national law against light pollution. All kinds of discussions were immediately raised. Television programmes were flooded with chatter on the subject. Presenters improvised themselves as experts on the problem. Interviews were conducted with lawyers, with technicians who only then knew about the problem, with poets and painters who described the stars (perhaps without ever having looked up at the sky), with storytellers and people from the street. Olympic wrestling champions were asked if they would feel safe after ‘switching off’ the lights in the city, they answered no. In short, everything contributed to confusing people’s ideas. Epilogue? The bill was never considered by the Chamber of Deputies, it was rejected by the pre-chamber committee. Current situation? there are many regional laws and laws that no one is complying with. Just like the ‘Manzonian cries’. 1st chapter of ‘I Promessi Sposi’ by Alessandro Manzoni.

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    I cannot remember if I have already posted this image. Certainly, my location is the worst for observing the sky. Such trouble I wouldn’t wish on my worst enemy.

    in reply to: Mars Occultation #614447

    Dear fellow amateur astronomers
    I thank you all for the consideration you have given to this note of mine. My sky has been very bad, overcast with black clouds. For my study purposes I will use the sequence taken by Mr Ian, to whom I offer my compliments and ask for one more piece of information: What is the instant of the start of the shot (UT).
    My compliments for the photograph taken by Nick. I would not have been able to make such a shot and photograph.

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    in reply to: Mars Occultation #614355

    Alex, thank you very much. I would need the images of the occultation, from there I would extract the nmeric data I would use. From my location the weather is bad, so I probably won’t be able to observe the event. Ciao.

    in reply to: Partial solar eclipse of 2022 October 25 #613265

    Hi Nick, I will do a thorough processing and study of the images I extracted from your You Tube film. Thanks to you I was able to follow the whole phenomenon. You will hear from me soon. Thanks again. Regards.

    in reply to: Partial solar eclipse of 2022 October 25 #613262

    Dear friends, I present to you my photographs of today’s solar eclipse. I have just one question for you: How much would you have bet that the cloud would not move for the duration of the phenomenon? Is this a statistically significant phenomenon? It went wrong for me, very wrong. Best regards to you all.

    in reply to: Partial solar eclipse of 2022 October 25 #613224

    Skies with high but thin clouds are also forecast for my locality, I hope well. However, for my study of the phenomenon it is only necessary to have the cusps of the solar sickle visible.

    in reply to: Partial solar eclipse of 2022 October 25 #613221

    Dear Nick
    I saw the solar disk on the page. I download images every 2-4 minutes. I have a few things to ask you:
    1) Does the image come in real time? What is the phase shift?
    2) The disc image would be fully suitable for my study of the phenomenon. The only small problem is that the disc is too big, it is not entirely included in the picture.
    3) If the disc remains stationary within the frame, it is not easy to establish the North-South direction. To do this, it would be necessary to bring (for example every 15-20 minutes) the disc close to the east side of the frame and NOT chase it until it reaches the west side. In this way, the alignment of the various images will make it easy to establish the North-South line on the painting itself. Can you make these breaks?

    This is the procedure I will follow with the camera (nikon) on my telescope:
    – Entire disc in the frame;
    – Periodically interrupt the tracking and take 3 or 4 images until the solar disc starts to leave the frame.
    Here (L’Aquila near Rome the weather should be permissive)

    Thank you and good observation

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    in reply to: Partial solar eclipse of 2022 October 25 #613216

    Greetings everyone, I am looking for a few amateur colleagues who can collaborate in observing the phenomenon. More precisely, to establish the timing of the contacts and the maximum phase, together with the contact angle (clockwise from the north). For arrangements
    Thank you and greetings to all.
    Giovanni (Italy)

Viewing 20 posts - 1 through 20 (of 42 total)