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Posted by A R Pratt at 11:31 on 2013 Feb 12
Hi Marlyn,Yes, I agree that the presenters stressed the dangers of solar observing. Unfortunately, the programme didn’t discuss the pros and cons of solar projection, which was the only method available to me in the 1960s and ’70s, when my mentor was Harold Hill. Since then I have made – and purchased – a number of solar filters.I was concerned that a member of the Flamsteed Society used a home-made mylar filter that was loosely seated inside the rim of the dew shield of his refractor. We didn’t see the filter secured in place.A few years ago a member of a local astronomical society mentioned that he’d made a solar filter for his 20cm SCT, but it gave very dim and blurred images of the Sun. I inspected his mylar filter, which was well made and was tightly secured over the front of his ‘scope. Then I noticed his design flaw – the mylar aperture was in the centre of his cardboard disc, sitting precisely in front of the secondary mirror obstruction! No wonder he couldn’t see the Sun through it. :-)Clear skies, Alex.
Posted by David Strange at 23:25 on 2013 Feb 11
Edward,I think Richard has already given you the answer! I can only add that it was a sequence of 30x20s exposures with a C8 @ f/2 in hyperstar mode and SXV H9C CCD. Hope to get 2012 DA14 with the same set up on Friday if the skies clear.David
Posted by Richard Miles at 22:51 on 2013 Feb 11
I wonder – Could this difference be related to the tilt of the Earth on its axis projected on the sky.Note that the P.A. quoted is measured through East on the face of the Moon from the north point of the disk and NOT from the North Pole of the Moon.Richard
Posted by Richard Miles at 21:46 on 2013 Feb 11
Edward,That’s a nice time-sequence which David captured.My reckoning gives the centre of the image at R.A. 03:34:18.9, Dec. +13:41:40The date and time must be close to 2012 December 16 20:00-20:12 UTCheers,Richard
Posted by Marlyn Smith at 09:41 on 2013 Feb 11
Here’s a few more images from Solar Section observers during February
Images by Brian Woonam, Mick Nicholls, Peter Paice and Dave Tyler.Posted by Marlyn Smith at 09:30 on 2013 Feb 11
Of course you are quite right with your warning that the Sun should be treated with respect and any method of observation should be well checked out and made completely safe.I watched the programme and thought the presenters did emphasise the dangers. Many solar observers use a mylar/cardboard type filter (including myself on occasions) as it’s the cheapest method for direct solar viewing. A good fit is essential and the filter should not be loose or "flapping about". The presenters commented on wind blowing the filter loose and suggested sellotaping the filter to the telescope tube as a precaution. I thought this was entirely sensible as the filter is light and any additonal method of securing it to the telescope would enhance safety. I didn’t get the impression of a "Blue Peter" type fix!Solar projection is a very safe method for solar observation but of course the observer still has to "find" the Sun safely. During projection, the telescope is NOT "safe" and there is always the risk that someone will try to look through the eyepiece. At least with a filter in place, this danger is eliminated. Solar observing is a very rewarding aspect of astronomy but the observer must be aware of the dangers and take proper precautions. I wouldn’t recommend any method of solar observation as safer than any other and I have no criticism of the Sky at Night team.
Posted by Edward Sawyer at 02:42 on 2013 Feb 09
David, Can you give a date or RA and dec of that super image.Ed
Posted by TonyAngel at 08:18 on 2013 Feb 08
I am sorry that we will not get to see Richard’s. Let us hope that he will change his mind.
Posted by Sheridan Williams at 14:16 on 2013 Feb 06
Just noticed your post. I will check and get back to you.
Posted by Paul A Brierley at 20:20 on 2013 Feb 04
Thank you Nick.I watched them all yesterday. They are very good. It’s also nice to see what I’m paying for with my BAA subs.
Posted by Nick James at 00:43 on 2013 Feb 03
Jeremy and Stewart’s talks uploaded the members’ only video page.http://britastro.org/baa/index.php?option=com_content&view=section&layout=blog&id=16&Itemid=196Richard McKim’s talk was very good but he didn’t want me to upload it.Nick.
Posted by Richard Miles at 23:46 on 2013 Jan 21
I’ll just mention that I have had 3 laptops out in my observatory these past 9 years. They are switched off when not observing. The reason why they have all survived is that the volume inside the enclosure is about 1 cubic metre and I always have loose silica gel exposed on trays, etc. to keep the relative humidity of the air low. I also have about 50W or so residual heating by way of three eyepiece-type heating tapes. (That reminds me with not having observed for about 6 weeks now the humidity will be approaching unacceptable levels so I’d better reactivate the silica gel when I get a chance.)So humidity is the key factor when it comes to electronics. Surface leakage currents across insulators play havoc. Silica gel of the indicating variety is the magic solution provided it is frequently regenerated by heating in an oven.
Posted by Americo Watkins at 08:18 on 2013 Jan 18
I have another lap top now running windows xp. Seems to be running ok except that after about an hour it shuts Sky X down saying that it has encountered a serious problem. Able to Re-load again but continues to repeat after about an hour. Sent of the automated microsoft report format. reply advice is something about either driver not fitted or that it shuts down to protect from possible damage due to a driver?I also bring the lap top in after use.cheers
Posted by Nick Atkinson at 19:33 on 2013 Jan 14
Now is a good time to buy a new lap top or mother board for your tower. Maybe the problem lies in buying a reconditioned computer with aging integrated circuits. I have used my lap top out doors in sub zero temperatures but always bring it indoors when The observing session is over.
Posted by Paul A Brierley at 17:39 on 2013 Jan 14
Yes they are. Especially with the Sun at such a low elevation. Peter has done a wonderful job.It is nice seeing Sol, active once again.
Posted by Marlyn Smith at 13:10 on 2013 Jan 14
Pete Lawrence has posted these 2 amazing images of the Sun on 13th January 2013 showing AR1654 in all its glory
