*
Monday and it's sunny again. Though a bit milky around the edges. So I'm not rushing out there before morning coffee. It always takes a little while for the sun to gain enough altitude to sharpen up and lose its initial thermal "boiling."
I have a 2", ST, UV/IR blocking filter for the solar prism coming in the post today. It may not be strictly necessary but why take the chance? Having the new filter will give me greater freedom to compare the effects of using the SC [green] filter and viewing without it. I saw the Solar Continuum as a mild blocking filter and extra insurance for my eyes.
IR and UV are quite "sneaky."[technical term] Being completely invisible then can cause eye damage without any apparent extra image brightness or pain. Lacerta recommended using such a filter for larger apertures. My 180mm [7"] refractor is a bit larger than most amateurs use for solar, white light viewing. Hopefully I shall enjoy the advantages of greater resolution once the sun rises far enough to escape the worst effects of the turbulent atmosphere. That said, higher solar altitudes produce more ground warming. Leading to increased thermal effects. There is a belief that limited apertures [~120mm] provide the clearest solar views more often.
I'm hoping my raised observatory will distance me from the worst ground currents. Though placing myself in a dome is supposed to make matters worse. So called "dome seeing" can produce its own thermal problems with image agitation. A white dome would have helped reflect the sun's heat away but I don't want the attention.
I do have the option of opening the ground floor doors. To hopefully induce a strong chimney effect. There are also the double doors to the veranda. Which can be opened if there is a westerly breeze to flush the dome of warm air.
I do have the option of opening the ground floor doors. To hopefully induce a strong chimney effect. There are also the double doors to the veranda. Which can be opened if there is a westerly breeze to flush the dome of warm air.
I have considered adding louvers to the dome to block direct warming. There is also the option of an adjustable shutter screen to stop the sun from entering the observing slit. Not easily done but possible. It has been known for decades that an opening to en enclosed space leads to solar warming. There is no need to add glass to warm the interior.
10.50am 48/45F [Out/in] nothing visible on the disk in WL.
10.50am 48/45F [Out/in] nothing visible on the disk in WL.
Prom on the bottom of the sun at 7.00 in my view. Showing as 10.00 on GONG H-a.
11.20am I have cut out another stiff, black foam, light shield for the eyepiece itself. This blocks the bright, peripheral dome interior from my field of vision. The main shield blocks the direct sun from reaching my face. Both shields contribute to the contrast in H-a. You'd think the sun was bright but not in H-alpha. Which is a deep red to which the eye is less sensitive than to brighter surroundings. It's much like trying to see the night sky with overhead street lamps.
The dark filament, surrounded by the large, lighter, disturbed area, from several days ago, continue to cross the disk. Some other darker markings on the disk [on Gong] worth looking out for.
12.15pm I tried a 15mm for 80x but had to return to the 20mm for 60x.
The TS items have arrived in the post. There wasn't quite enough room to add the IR blocking filter below the polariser. Fortunately there is a shoulder stop to prevent damage to the prism. The small standoff won't affect anything so I have ignored the slight projection. The three, rotation locking screws provide security enough.
I also ordered a T2 > 2" eyepiece adapter for the prism thread in the hope of greater support for a binoviewer. A sturdy bit of kit, too, with a good bit of weight to it. If I want to use it on top of the Lacerta prism it needs to be a really solid fitting.
Another week has passed since I sent my last email. So I have reminded TS that they still owe me a response about the binoviewer misalignment.
11.20am I have cut out another stiff, black foam, light shield for the eyepiece itself. This blocks the bright, peripheral dome interior from my field of vision. The main shield blocks the direct sun from reaching my face. Both shields contribute to the contrast in H-a. You'd think the sun was bright but not in H-alpha. Which is a deep red to which the eye is less sensitive than to brighter surroundings. It's much like trying to see the night sky with overhead street lamps.
The dark filament, surrounded by the large, lighter, disturbed area, from several days ago, continue to cross the disk. Some other darker markings on the disk [on Gong] worth looking out for.
12.15pm I tried a 15mm for 80x but had to return to the 20mm for 60x.
The TS items have arrived in the post. There wasn't quite enough room to add the IR blocking filter below the polariser. Fortunately there is a shoulder stop to prevent damage to the prism. The small standoff won't affect anything so I have ignored the slight projection. The three, rotation locking screws provide security enough.I also ordered a T2 > 2" eyepiece adapter for the prism thread in the hope of greater support for a binoviewer. A sturdy bit of kit, too, with a good bit of weight to it. If I want to use it on top of the Lacerta prism it needs to be a really solid fitting.
Another week has passed since I sent my last email. So I have reminded TS that they still owe me a response about the binoviewer misalignment.
Click on any image for an enlargement.
*
No comments:
Post a Comment