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Friday 1st: 34/35F in/out, very windy. Lots of racing cloud with blue patches is teasing me again. The bright moments are fleeting. So I am filling the cloudy periods with text. The telescopes are tracking on the sun so I can dash over to the eyepieces at the first sign of brightening. I left the foam sleeves over the 7" tube and dewshield and the objective dewing is absent so far.
The low sun provides a very long path for clouds to obscure the view even when it is bright blue overhead. This is also the reason why seeing conditions are usually much poorer with lower objects in the sky. There is more air to affect the image quality over the much longer path length.
The relatively narrow observing slit in the dome makes it difficult to see the cloud upwind of the sun but certainly helps to protect me from the wind. Which is getting quite noisy and gusty now! I have had to remove the extended foam dewshield because it was catching the wind. As the sun moves westwards I should escape the easterly wind more and more. It did indeed became more comfortable as the slit moved away from the wind direction.
The low sun provides a very long path for clouds to obscure the view even when it is bright blue overhead. This is also the reason why seeing conditions are usually much poorer with lower objects in the sky. There is more air to affect the image quality over the much longer path length.The relatively narrow observing slit in the dome makes it difficult to see the cloud upwind of the sun but certainly helps to protect me from the wind. Which is getting quite noisy and gusty now! I have had to remove the extended foam dewshield because it was catching the wind. As the sun moves westwards I should escape the easterly wind more and more. It did indeed became more comfortable as the slit moved away from the wind direction.
11.30: 34/36F Still no sign of any surface detail in the brief and often partial clearances. 32mm for 68x in the 7" provides good image scale but the disk still doesn't fill the field. I have the 20mm in the 6" for h-alpha for a similar disk coverage. It is surprising how little cloud it takes to make the sun completely invisible through the heavily filtered telescopes. It's not like watching the Moon come and go behind thin cloud. It is literally is on and off with the sun.
12.00. Getting cloudier and windier by the moment. I've bought more door bolts to stop the shutters from closing and opening in the wind. I might as well fit those instead of waiting for the non-existent sun to show itself! Wind is forecast at 16mph steady with gusts to over 25mph. I can well believe it!
Where to fit the sliding door bolts continues to elude me. They can't go between the shutters or they won't close. They will be trapped. The same goes for inside of the outer shutter ribs for the same reason. The dome and shutter ribs contact, flat against each other, at both ends of their range of travel.
Problem solved. I added 40mm square battens to the bottoms of the shutters Then marked and drilled the battens as a location for the noses of the bolts. Now the shutters are secured in either open or closed positions independent of each other. A series of holes would allow full adjustment in slit width. Or even offset to one side in windy conditions. The battens move out of the way along with the shutters so they don't change the sill height. Another job done. The drawer slides are still providing free movement of the shutters.
13.30. Brief clearing but no surface detail. Gong H-a shows only a darker smudge on the disk.
13.45. Clearing but I have to go in for lunch.
14.15 Back out again to more cloud and wind.
14.30. 35/38F. First sign of surface detail. Only briefly though before full overcast arrived. Returned indoors at 15.00 to warm my feet. I really should make a habit of wearing my walking boots. However clumsy they feel on the stepladder and in the dome.
12.00. Getting cloudier and windier by the moment. I've bought more door bolts to stop the shutters from closing and opening in the wind. I might as well fit those instead of waiting for the non-existent sun to show itself! Wind is forecast at 16mph steady with gusts to over 25mph. I can well believe it!
Where to fit the sliding door bolts continues to elude me. They can't go between the shutters or they won't close. They will be trapped. The same goes for inside of the outer shutter ribs for the same reason. The dome and shutter ribs contact, flat against each other, at both ends of their range of travel.Problem solved. I added 40mm square battens to the bottoms of the shutters Then marked and drilled the battens as a location for the noses of the bolts. Now the shutters are secured in either open or closed positions independent of each other. A series of holes would allow full adjustment in slit width. Or even offset to one side in windy conditions. The battens move out of the way along with the shutters so they don't change the sill height. Another job done. The drawer slides are still providing free movement of the shutters.
13.30. Brief clearing but no surface detail. Gong H-a shows only a darker smudge on the disk.
13.45. Clearing but I have to go in for lunch.
14.15 Back out again to more cloud and wind.
14.30. 35/38F. First sign of surface detail. Only briefly though before full overcast arrived. Returned indoors at 15.00 to warm my feet. I really should make a habit of wearing my walking boots. However clumsy they feel on the stepladder and in the dome.
Click on any image for an enlargement.
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