For those of you with telescope apertures of 200mm or greater and not easily frustrated, now is a great time for observing and imaging Mercury in the eastern dawn sky.
Tomorrow morning, the planet presents a 40% crescent phase with an angular diameter around 8.4 arc seconds (about 2" greater than Mars appears at present). It will be at Central Longitude 177 degrees presenting a view not imaged by spacecraft previously. If the seeing is exceptionally good then you may see some fleeting low albedo surface markings. A red Wratten filter #25 or #23A will help improve contrast and will work well for an image if you're game to try. I'd be interested to see any results (no matter how bad) from forum members. Of course tomorrow morning is not the only opportnity as good observations can be made into the month of May however the planets apparent size is shrinking daily.
I'll start when the phase gets to 50%, my problem is not so the resolution but more the surface brightness, which is usually too low during day time with crescent phases to make decent images.
I'll try to get 4 or 5 observations in this apparition.
Knew you'd be in there boots'n'all..at least that's two of us chasing the elusive. I hope we can get a few more invloved.
Drop me an e-mail outlining your intended imaging days so we can perhaps image and compare probable features captured.
Had a very good morning on the 22nd and just got around to processing the results today (see below). Just a primer for now and still have to do a grid overlay. Still have a dozen or so 15 second AVI's to get through but the local seeing started to decline at about 32 degrees above the horizon.
BTW, I was looking at the Planet Position diagram on page 19 of Astronomy 2005 Australia tonight (what else is there to do during full moon?), and noticed that Pluto is coming into the best time of year for viewing in the period May/June/July. How hard is it going to be to see in my scope? Any tips? I've got the LX200 with GOTO, just concerned I may not be able to work out which one is Pluto!
Cheers mate (oh, and keep the great books coming....your text on Exploring the Moon is a recent addition to my shelves!)
Whew...Pluto huh!? And here was I thinking Mercury had the rather limited appeal in this post.
Well, you have enough aperture to visually detect Pluto from a moderate dark sky location with a 10-inch but its a very, very faint target with a magnitude of around 13.8 and it is difficult to detect among the other surrounding background stars. If you have a GOTO system then you're well under way to narrowing it down in the eyepiece. If you're a star-hopper like me using setting circles then the task of ensuring you have it centred in the correct surrounding star field carries with it a little more uncertainty. A low power eyepiece yielding about 1/2 a degree view is perhaps your the best option and a detailed star chart with low magnitude stars (probably generated with computer software) will allow you to positively identify it.
If you are not intending to take a long exposure photo or image then make a drawing plotting the confusing array of stars in the field. Note also the directions (at least North and East) on the drawing. If you have good software you can work out which one is most likely Pluto by comparing your drawing to the software map. But for true satisfaction of certainty, go out again one or two nights later and compare the view with your drawing (and make another drawing) to see if the star-like Pluto has moved. If so you've done it.
If you have an integrating digital camera you could take two exposes over consecutive nights and do a blink comparison using a image-processing program to detect any wanderers. You will of course need to try your best to orient the camera the same on both nights so that the stars register correctly (or use registar).
Hi Steve, I don't think its as much as limited appeal (148 viewings after all) as a realization of what a challenge this subject is, and that everyone is hanging on yours and Erwins every word to find out how best to go about capturing this ellusive planet. I know I feel lucky if I see it, let alone image it.
Folks, if Erwin's image doesn't inspire a few of you to have a go I don't know what will.
It's amazing to reflect on what was once hardly achievable in the days of conventional photography to what is now amazingly possible using low cost imaging devices so readily available to amateurs. And of course a little trial and error experimentation and shared advice.
Terrific image Erwin - if that's a rough composite then weather gods were truly kind in Brisbane. Look forward to seeing it processed futher.
I usually image between when Mercury sits between 30 and 40 degrees altitude, thus a fair bit after sunrise. I hope that together with Steve's hight quality stuff and hopefully some other participants images we can make quite a nice observing round.
I'll try again to observe tomorrow, here's the unsorted 6000 frame stack of yesterday, again, decent processing (sorting, 16 bits finishing) will be done after this apparition.
Cheers,
Last edited by ErwinvdVelden; 30-04-2005 at 05:20 PM.
How high will Mercury get? I have to work out if it will rise above the trees in the East before I attempt to image it
Also, at only 2500-3000mm FL my image is going to be very small compared to yours and Erwin's, but if I can capture a phase i'll be happy
Mike,
If you want to do some serious imaging towards the Eastern Horizon the best place by far (within our locale) is at Crackneck Lookout at Bateau Bay. Not sure if you know where it is, but it is a superb place for planetary observing/imaging towards the east at dawn. It is right on the ocean with an altitude of about 400 feet above Sea level and gives unobstructed views to the east. There are concrete structures to use to sit equipment on as well (laptops and adaptors etc). The seeing to the east across the Tasman Sea at dawn is usually excellent considering the low altitude of the targets.
I would be happy to take you up there during daylight hours to familiarise yourself as a 1st time visit at night is not advisable
I know the place, have been there with the family once or twice.. have also thought it would be a good spot to observe from. Will definitely give it some thought for AM imaging if I get up early enough to take the gear out there.
I know the place, have been there with the family once or twice.. have also thought it would be a good spot to observe from. Will definitely give it some thought for AM imaging if I get up early enough to take the gear out there.
Thanks for reminding me about it!
It's a great spot to observe from between 2am and dawn.
Ving picked it in one, "Romance is in the air", if you go there prior to 2am on a Thurs, Fri,Sat or Sun night. That alone wouldn't worry me but they keep driving in with their headlights on
Keep in mind though that for imaging Mercury during the day time you need to keep your scope out of the Sun because of heating issues. The best place is one that has a flat obstruction to the east of about 15 to 20 degrees high. This way you can image Mercury at around 35 degrees altitude while still sitting in the shade.
On another note, I'll increase the gamma of the colour image tonight, it's a bit hard to see the fainter bits
Cheers,
Last edited by ErwinvdVelden; 27-04-2005 at 01:24 PM.
Mercury Observing
Chasing the Elusive
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to find out how best to go about capturing this ellusive planet. I know I feel lucky if I see it, let alone image it. 
