![sun spotter with mirrors sun spotter with mirrors](https://i5.walmartimages.com/asr/29922066-8797-4f17-8052-ec70210075db_1.a495a08aec4f3b0ee98fee48cedfa77c.jpeg)
I suspect that the explanation for this is tube seeing that quickly builds up after the start of the session when some inner parts of the telescope are absorbing light (despite the front ERF) and getting warmer. When I am taking a sequence of a dozen or so CaK videos, after processing the best image almost always proves to come from the first or second video. I've been experimenting with a Mewlon 210 with a front ERF for some weeks now. Thanks Alex, very informative, in particular the IR images! I had later a chance to observe with the de-coated mirror in better seeing conditions. Here, the first pics in bad seeing and bad wind conditions, in KLine with no coating on the primary. So, I went for removing the primary mirror coating.
![sun spotter with mirrors sun spotter with mirrors](https://i.pinimg.com/736x/fa/08/9c/fa089ca70cf56fc442990891c9aebe0b.jpg)
The clouds were leading to temporary cool down of the equipment.Īn other fellow made a similar test in St Veran, with a different optic and he also had trouble getting high resolution imaging.Īfter one additional trial, I came to the conclusion of instrumental turbulence due to the local heat of some telescope parts, despite the system was fully open (made out of a truss system). Now, I remember that I could get the former Halpha "reasonable" results only when clouds were passing. We checked the temperature in the system with an IR camera.Ĭertainly, we don't know the emissivity of the filter surface, nor from the surrounding material, but it looks that hot parts to have are about 10☌ higher than the surrounding.Įven the focusser side is getting warmer, sign of energy passing through the filter and heating the setup the system behind Christian detected filigrees on my first image in KLine.įinally, getting further progress was difficult.
SUN SPOTTER WITH MIRRORS FULL
Very full of hope, I went to the St Veran Observatory site, expecting for further progress. Here also, I could get some results, but not easily. I could get better granulation pictures, in the red domain. So, I went out of the city for further trials. In my area, a small city suburb, surrounded by streets and houses, I could get some granulation. I tried with a blue "ERF" and a red "ERF" aiming for CaK and Ha Then I went for the final version, a 50mm filter. I experienced also a returning flux against the carbon truss they started then to generate smoke. In this picture the flux is reflected back toward the body of the telescope, leading to a local heating. This is one of the indirect danger of the application. The wished color (blue here) passes through the filter. I tried also to partly target the filter, so to have one side "cold" and the other side "hot". A blue interference filter suffering the full flux
![sun spotter with mirrors sun spotter with mirrors](https://i.pinimg.com/originals/45/64/f2/4564f28f68995c5e5a972a8b95dca574.jpg)
You can figure what will come into these fingers. I started with various trials, measuring temperatures, etc. Here the ERF would be as big as the secondary, thus about 50mm in diameter, located in front of the secondary. So the idea of a smaller ERF set into the system.
![sun spotter with mirrors sun spotter with mirrors](https://i.etsystatic.com/6029295/r/il/2d64ad/1876125694/il_fullxfull.1876125694_9rzb.jpg)
A 300mm front ERF doesn't cost a few thousand of Eur, but several thousand of Eur. We all know that there big front ERF filters are difficult to make and also very expensive. The scope is of newton type, thus a big part of the heat is concentrated on a circle of about 50mm in diameter at the location of the secondary mirror, then further concentrated to the focus and forth. The amount of solar power collected by the mirror is estimated to 90w. In the here trial, a 300mm aperture scope, with coating, is used. "anyone doing this should take all necessary precautions." I can not take any responsibility for any action you would do in solar observation, especially with modification.Ĭertainly never put an eye in a moded scopeĬonsidering again the dangers, expected and unexpected, I'll take over word by word the comments posted along my previous post: If you don't know what you are doing, if you are not mastering your working process, strictly refrain for any solar scope action. Dangers are direct (ie direct viewing), indirect (ie reflection), affecting equipment (ie reflection aside, heat-up / burning parts), etc. We are clearly in a zone, where we should know what we are doing and where the dangers are. The here subject copes with the use of the full aperture of a telescope, partly without pre-filtering. But solar observation still remains dangerous. There are solutions for reducing the danger: front filter, Herschell prism, de-aluminized mirror, etc. Warning: Solar observation is dangerous, we know it. The here subject cover the observing with aluminized mirror, thus having high flux suitable for Ha / Cak imaging.