I've often wondered why it is that when you look at Jupiter through the telescope, for the first few seconds it often appears very bland, then dark bands appear, then maybe after 10 or 15 seconds you realise the Great Red Spot is also visible.  I've never read a good explanation for this.  What I've read is 'Keep Looking' and your eye needs to be trained or become acustomed to the view.  I think this is true but doesn't explain why details become visible.

I've always thought it is somehow related to persistence of vision.  That's the effect you get when you look at a venetian blind (horizontal blinds) and turn away.  You retain the image of the blinds for up to a minute in some cases.  Likewise glancing at a bright light bulb does the same.  Persistence of vision is why we see movies, when in actual fact we are only being shown still frames, flashed rapidly one after the other. 

Processing my Mars video the other night I was struggling to wring more detail out of my bland low contrast unprocessed image and it occured to me that indeed it is persistence of vision that allows our eyes to reveal detail very hard to capture in photos.  Here's the proof.  When you play your Mars or Jupiter video clip (assuming it is of reasonable quality) you see planetary details, polar ice caps, surface marking, etc.  But if you pause the video and advance frame by frame, you will see a hopelessly noisy low contrast image, often completely (on my low price camera vidoe clips anyway) devoid of detail.  But as you watch these stills flashed rapidly in front of your eyes, you suddenly see a wealth of detail that doesn't exist on any of the individual frames.

Your eye/brain is effectively stacking images on the fly just as we do when using Registax to arrive at a final stacked and clearer image.  How bizzare!  And how great!  Of course I have no research to prove this and its pure conjecture, but when the data fits, use it!  Looking through a telescope is highly subjective, but not so much with a video clip - it is real data that can be exactly repeated.

Wonder if anyone else has considered this phenomenon? 

Thursday 9th October, 2009, 3.00am.  In just 90 minutes time, NASA was to crash a lunar probe LCROSS into a permanently shadowed crater (Cabeous) at the Lunar South Pole.  Actually the upper stage of a Centaur rocket would hit the moon first at 6km per second  followed 4 minutes later by the LCROSS probe itself.  LCROSS was to fly through the plume sent up by the first impact and measure hopefully, water vapour.

The impact time and site were carefully chosen to allow all the big scopes - The Keck - CFH - Palomar - Hale - etc, in the West of N.America to focus on The Moon with a barage of imagers, spectrum analysers and the like in the hope of securing both scientific proof of water on The Moon and to provide a spectacle for the public.

The Result?  Well the Jury is still out on that one, but it was great to know that we were watching the Lunar South Pole at the same time as most of the major observatories in Western N.America! 

My alarm went off at 3.00am and I immediately checked the sky conditions.  The sky was 80% cloud covered.  But The Moon was in the clear sector.  I made some breakfast and checked again at 3.30am.  The sky was clearing fast so it was a green light to set-up the scope in the backyard. 

I gave my wife Debra the clear sky report at 3.45am.  Outside at 4.00am I began aligning the ASGT Mount - I didn't want the scope to drift too much when I was videoing the Moon at high power.  I looked up and there was now 80% cloud cover again.  The sky conditions were changing so rapidly it was hard to keep up.  There was some low fast moving cloud racing across the face of The Moon as we aimed our scopes skyward.

At the last minute I realised the hand controller for the C8-ASGT was missing from its case!  My cell phone showed 4.25am and I raced into the house trying to figure how the HC could be missing?  Finally I found it in my backpack *&^%  I had taken it to London Drugs to look for an RS232 Cable to connect to the PC.  I dashed back to the scope, plugged in and did a 'Quick Align'.  My cell phone showed 4.29am - time was evaporating - as I slotted in a 7.5mm E.P. with my Pentax Optio E30 (pocket digital) attached.  I zeroed in on the South Polar Region at 271x but couldn't quite decide what crater was cabeous ... 

The video was running as I again glanced at my cell phone and saw 4.32am.  The Impact had happened!  I stared at the 3" screeen on the back of the camera as the video continued to record.  There was no sign of a plume, no flash or sign of any kind of movement.  I had seen SMART-1 hit The Moon a couple of years ago - it was the briefest fleck of light - so I expected something more ...  I continued to video the impact area hoping a plume might develop but I later learned even the 200 inch Hale Telescope saw nothing!

Finally at around 4.45am I slewed away from The Moon - Orion was calling ...  I split The Trapezium for the first time with a C8.  It was the biggest view of The Trapezium I've had and I had to remind myself the cloud in the FOV was Hydrogen and not the low thin cloud in the sky above me.  I slewed over to Mars and found a small squidgy yellow blob.   I went back to The Moon and shot some video of mountains and craters near the terminator. 

I Looked up once more at The Moon around 5.45am and thought to myself, we came, we saw, errr, nothing!  But, if a plume had developed, if it had been front page headlines the next day, how mad would we have been if we had missed it?  I was glad to be pointing my scope along with the Hale, The Keck, The Canada/France/Hawaii Telescope at The Moon! 

A short note about the mishaps that have befallen my trusty Canon 300D (Rebel).  I had the camera at prime focus on my Celestron Omni 150 XTL.  I'd just taken some nice shots of Orion.  I turned the camera to remove it from the T-Ring and for some reason it would not come undone.  It turned O.K. but just would not release.  I carefully tried about four times to remove it - but no deal.  So I let go and Wham! the Canon dropped about 4 feet onto concrete!!!    I thought the Canon was toast, but I picked it up to discover only the small settings window on the back was cracked.  Murphy's law - the camera would not come lose but the moment I let it go - hey presto instant release!!!  To stop Your camera doing the same, hook the strap around some part of the scope.  Simple enough, whish I'd thought of it earlier

The second near disaster was with a 250mm IS lens attached.  I thought I'd save some extra baggage by putting the camera with lens attached into my sturdy backpack instead of bringing the camera bag.  But as I got into the car the pack pack bumped off the centre console.  I thought nothing of it.  But later I tried to take some pictures and the camera would not operate.  I examined the camera to discover an alarming gap between the camera and lens.  Yikes ... I took off the lens to discover it had nearly been ripped of its mounting ring.  The ring was plastic and had broken away from the securing screw revealing some wiring and other lens internals.  It didn't look good for my $350 lens, but I got out my small screwdriver set and managed to take out the retaining screw and force the warped ring to seat back into place.  I retightened the screw and attached the lens to the camera and it worked - whew!!  Lesson two - always use a camera bag (a well padded one), instead of your back pack, jacket pocket, floor of the car, glove box (I'm guilty of all of these).

Well the camera is looking a little beat up now, but its 8 years old, still works perfectly and still takes great deep sky shots.  This would be good grounds for a new Canon T1i and I'll put that case to the wife soon I'm sure.  But for now just being a little bit more careful with the old battle torn Canon!

Just wanted to relate a glitch and solution.

New scope, the C8 on CG5-GT - been great so far.  But a couple of days ago I was viewing the Moon in the afternoon.  I left the mount tracking and turned out it was about 3 hours later I got back to the scope.  It was semi-dark so I decided to a star alignment.  I chose to send the scope to the 'Home' position using the option under the utilities menu, but I accidentaly chose the first option 'Set Home Position'.  Didn't think much of it.  But after powering off and beginning alignment, the initial stars were way off (more than 20 degrees away).  Weird I thought, Its been quite accurate until now.  Then I remembered accidentally resetting the home position.  It should have nothing to do with alignment - just a convenient position you choose in which to park the scope.  I tried a few more alignments and all were way off.  Then I realised how slow the motors were running and realised I was nearly out of power - even though the Power Pack reported 'ready for use'. 

Next day with a fully charged power pack I tried a virtual alignment in the garage.  I stepped outside to check the real position of the rising Moon.  Then I did a quick align (carefully pointing the mount north and levelling it) and picked 'Moon' from the GoTo Menu.  The scope slewed in the general direction, but was way off again - about as far off as before.  I tried two more times with no luck. (I also tried setting the 'home' position again with the scope and mount pointing north - but this seemed to have no effect on goto's).

I decided to do a factory reset as this would also reset the 'home' position (which I still suspected had something to do with the missed goto's).  After the reset I 'Quick Aligned' again and this time the mount hit the target very close.  Later that night I did this for real and hit the Moon and Saturn dead on with just a quick align (I do use the polar scope to set the mount).  Since then the initial alignments have been very accurate. 

Don't plan on setting the 'home' position again anytime soon!

Hope this helps anyone who runs into the same problem.

James

I know its tempting fate so early on but as they say at mission control - "Confidence Is High!"  After being plagued by technical issues with my HEQ5 (with Antares 200mm Newtonian), I finally picked and bought a replacement.  The Celestron CG5-GT with C8 on board.

After the first couple of outings I'm very impressed.  I had always been a little wary of buying an SCT because of scary stories about mirror shift and soft focus, blurry stars, etc ...  Well so far, No, No, and No!  The scope is razor sharp, rock steady, and the focuser easily beats anything I've had before - with light action and almost no image jiggle (that may not be the accepted technical term) when focusing at high power.  Oh yes, high power - I accidently put my Antares 4.3mm eyepiece in the focuser and glimpsed Saturn at 463x  Yikes! talk about a big planet - the seeing was poor and their was high haze so the power was ridiculous for the night, but just the same Saturn looked huge, I could see the ring plane and a moon.  The image was also bright enough to hold the power.  I can't wait for a night with clear air and steady seeing. 

Since I've been crawling about on the ground (often the beach) lately trying to get under the polar scope, I've just read (yes finally read the manual after 3 outings) about the CG5-GT's Polar Align routine!  Well knock me down with a polariser (please excuse the British and Canadian spellings) if that works out, my knees will be writing a letter of thanks to Celestron.

Love'n it so far - ready to try the polar align routine and fire a couple of DSLR shots of M57 The Ring, and M13 in Herculese.

One question if anyone has noticed - when aligning the scope - the motors seem to surge a little - the speed sounds uneven.  Is this normal?  Only seems to do this on alignment and not when slewing afterwards.  I'm not too worried as a 2yr warranty helps me sleep easy! 

So far so brilliant!

James

(picture of first driveway outing)

Just read an amazing piece of science in Astronomy May 2009.  Apparently when light encounters another materioal, i.e. glass, the atoms in the glass absorb the original photon and emit a photon in return. 

This process causes a delay that results in the photon appearing to travel slower through the glass.  As a result the light bends - the way a spoon in a glass of water appears to be bent.  So the amazing part is that light from Andromeda, after travelling for 2.4 million years strikes your telescope lens just a couple of feet from your eye.  It's then a photon from the glass in your telescope lens that you see and not the original photon from Andromeda! 

Can anyone confirm this is correct?  The source is Astronomy, May 2009, Bob Berhman's column 'Light Fantastic'.  If true, its amazing and really makes you think.

Yes runaway scopes - that's what I'm talking about!  I just spent 3 months with an HEQ5-PRO (two of them actually) and random slewing was the main party trick.  I bought this scope because it had an excellent reputation for accurate tracking and reliable operation.

I've had GOTO scopes before and have never seen this behaviour.  I persevered and tried to work out the errors but 3 hand controllers and 2 mounts later I had to return it to the dealer.  Since them I've been really surprised to hear similar accounts from other makes of GOTO systems ..

I can't help wonder how much hardware/firmware is shared between manufacturers and could this be the reason this is cropping up across platforms.

I'm no electronics guy (a computer guy actually) but it seems that biggest issue is that the programming (normally on ROM firmware) is being corrupted during operation.  Once that happens the hand controller is toast.  You can re-flash the handcontroller but the basic problem remains that the program will be corrupted again.

So I'm now looking around for another GOTO platform. I've owned and LXD75 in the past and its was totally reliable.  It did develop too much play in the gears and I'm not that handy at taking things apart - I usually have some parts left over!  So I wasn't up for following the online guides to stripping down the mount.  Despite the play it was still acurate in GoTo's and tracking.  I did part with it to move on though.

So now looking at the CG5-GT.  Its less pricey than both the HEQ5-PRO and the LXD75.  I'm surprised to see its payload is higher than both.  I won't be asking it to carry anything bigger than an 8" Newtonian, and probably will purchase the C6 to go with it.  I'm hoping Celestron's electronics don't have the same source as Skywatcher ..

Now if only the Canadian dollar can climb back up the hill a little ways I'll be on the phone placing my order.  Ahh remember the halycon days (just last year) when the loony ($CDN) was worth $1.10 U.S. that was astro parts heaven for us Canucks.  I think everyone north of the border is holding on to their orders until the dollar comes back a little.

Any comments on the CG5-GT would be appreciated!

Top marks to Celestron for streaming 'Around The World In 80 Telescopes' during 100 Hours of Astronomy.  Many people in our Astronomy Club immediately got online and watched fantastic coverage of the great observatories and ongoing scientific research.

There so much interest from many club members who are not online that I've set about recording the archived files so that they can see the coverage they missed. 

I totally loved the short introduction films from each observatory. They are so well made its like Science Meets Art!  I could easily watch all of those films back to back.

I realy have to get down to planning a trip to a great observatory - I'm thinking Kitt Peak.  Its brilliant that these observatories, which were a short while ago the premier facilities on the planet, are now welcoming the public with open arms and running programs that include observing and imaging with these historic instruments.  I have to go there - its like the scopes are calling me ....