Search found 11 matches

by M4rc
Wed Aug 23, 2017 1:09 am
Forum: Great American Solar Eclipse August 21 2017
Topic: Eclipse outreach activity in the park
Replies: 5
Views: 4142

Eclipse outreach activity in the park

I hosted an eclipse party at our local park. I set up a Hydrogen alpha telescope, a small refractor projecting an image onto a screen and a pinhole setup. Here we had only a 32% partial eclipse. I had about 30 people go though. I enjoyed sharing the sun with all these people, who would not otherwise...
by M4rc
Sun Aug 20, 2017 10:29 pm
Forum: Great American Solar Eclipse August 21 2017
Topic: Is this Eclipse Viewer still safe?
Replies: 2
Views: 3238

Re: Is this Eclipse Viewer still safe?

I doubt that anyone will go out on a limb and state that this filter is safe. Look at the filter carefully. Any signs of scratches, punctures or discolouration and I would conclude that the filter is not safe. Look at a bright light bulb with it, if you see any light getting through the filter, the ...
by M4rc
Wed Aug 02, 2017 6:43 pm
Forum: This is SolarChat !!
Topic: The Sun in a pinhole — solargraph
Replies: 5
Views: 1191

Re: The Sun in a pinhole — solargraph

Very nice results. I like the wide field view, you nearly captured the whole path of the sun. It is tricky aiming the camera just right. Instead of doing a 1 year long exposure, I suggest limiting the exposure to 6 months (solstice to solstice) to avoid having the suntrails overlap. Also having it o...
by M4rc
Thu Oct 20, 2016 12:26 am
Forum: This is SolarChat !!
Topic: A PS question
Replies: 13
Views: 2138

Re: A PS question

Using GIMP, I think that I see the effect that you describe. The selection is displayed as as series of dotted lines. In certain sections, the dots seem farther apart. I think this is simply the way the program shows the selection. This effect is there at zoom levels of 100% and 200%. The effect see...
by M4rc
Wed Oct 19, 2016 4:40 pm
Forum: This is SolarChat !!
Topic: A PS question
Replies: 13
Views: 2138

Re: A PS question

Can you confirm if your image of the Sun perfectly circular? Although it should be circular I imagine that you might have an ellipse if the imaging plane of the camera is not perpendicular to the optical axis. If you rotate the image by 90 degrees and repeat the same processing steps, do the flatten...
by M4rc
Mon May 09, 2016 5:42 pm
Forum: This is SolarChat !!
Topic: Invitation to time the transit of Mercury
Replies: 3
Views: 891

Re: Invitation to time the transit of Mercury

I observed from 48.929 N, 55.658 W using a Lunt LS60THa telescope. The timing was trickier than expected because of the poor seeing conditions and the occasional cloud. The first contact was observed at 8:43:24 NDT or 11:13:24 UTC. That was the point where I was certain that Mercury was on the limb ...
by M4rc
Sun May 08, 2016 2:30 pm
Forum: This is SolarChat !!
Topic: Invitation to time the transit of Mercury
Replies: 3
Views: 891

Invitation to time the transit of Mercury

The transit of Mercury can be used to determine the astronomical unit. Different observers from around the world see the transit at a slightly different time. I intend to perform careful timing of the 1st, 2nd , 3rd and 4th contacts. If I can convince other solar observers to do the same, then it sh...
by M4rc
Sat Nov 21, 2015 6:19 pm
Forum: This is SolarChat !!
Topic: Ringed filament over time plus intruder
Replies: 9
Views: 1734

Re: Ringed filament over time plus intruder

The main reason that we are getting different results is that we are using different values for the elevation of the sun. I used 42 degrees while you used 53.2 degrees. This difference may explain why your value was larger than expected. I came up with the 42 degrees using this calculator http://www...
by M4rc
Fri Nov 20, 2015 9:29 pm
Forum: This is SolarChat !!
Topic: Limited sunspot activity at present
Replies: 9
Views: 1078

Re: Limited sunspot activity at present

I commented on the altitude of the plane in http://solarchat.natca.net/viewtopic.ph ... 77#p174277

Marc.
by M4rc
Fri Nov 20, 2015 9:29 pm
Forum: This is SolarChat !!
Topic: Ringed filament over time plus intruder
Replies: 9
Views: 1734

Re: Ringed filament over time plus intruder

In this post http://solarchat.natca.net/viewtopic.php?f=4&t=18177&p=174275#p174275 you wondered about the altitude of the plane. Since it deals with this image I thought it best to post my reply here. You gave enough information to find the angle of elevation of the sun (42.07 degrees). Usin...
by M4rc
Sun Apr 26, 2015 1:02 pm
Forum: This is SolarChat !!
Topic: Sun April 21 arching prominence
Replies: 5
Views: 920

Sun April 21 arching prominence

As soon as I set up my scope on Tuesday, I knew that I was in for a treat. A very bright prominence consisting of an arch and a detached part nearby. I enjoyed the view, then noticed that the prominence was fading fast. So then setup the camera. I got the arch but by that time the detached part was ...