Mercury Observing

[videoguy]

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. :astron:

[ErwinvdVelden]

Hi Steve,

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.

Cheers,

Erwin

[videoguy]

Hi Erwin

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.

Cheers

[Rodstar]

Thanks for that info Steve. I will give it a try.

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!)

[iceman]

I got up to try Mercury this morning, but clouds ruined any chance of an image.

Very nice shot Steve!

[videoguy]

G'day Rod

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).

Hope this helps.

[ErwinvdVelden]

Hi Steve,

Here's my unsorted 4000 frame mess from this morning, decent processing will follow after this apparition.

Cheers,

Erwin

[[1ponders]]

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.

Oh and btw, :welcome:

[videoguy]

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.

Thanks for the feedback & welcome Paul.

[iceman]

Great image Erwin!

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 :D

[ErwinvdVelden]

Hi everyone,

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,

[iceman]

Nice colour shot! What focal length are these taken at?

[ving]

I am so not a morning person!
but I am inspired to look at your great pics!
thanks guys.

yes I am very lazy...

[ErwinvdVelden]

A bit short shorter than the Jupiter ones, this time around 6100 mm.

By the way, I didn't get up very early, I just wen't to bed very late...

:zzz2:

[toetoe]

Nice pic Erwin.

[ausastronomer]

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

Here is an arial view of Crackneck.

http://ccparagliding.com.au/images/dunsty.jpg

CS-John B

[iceman]

Hi John.

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!

[ving]

sounds romantic! ;)

gunna have a go at it mike!
we need some pics of mercury for dob users :D

[ausastronomer]

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 :)

Clear Skies
John B

[ErwinvdVelden]

Mike,

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 :computer:

Cheers,

[ErwinvdVelden]

Steve,

If you want to compare the colour image with Johan's Warrel map made with the old SVST, this map is available at

http://www.astro.uu.se/planet/planet/MERCWWW/DISKMAPS/map_global.jpg

My image has a CM of roughly 180, the map is orientated North so you have to rotate my image 180 degrees to make a comparison. As far as I can see the features are matching pretty well, so I think the dark zone near the terminator just south of the equator is real.

Cheers,

[ErwinvdVelden]

Hi everyone,

Just for your information, I changed my colour image of Mercury in this thread to a higher gamma, the terminator looks pretty straight so the details should be reasonable reliable. To be sure however I have to handsort 6000 frames, a thing I'll leave until after this apparition.

I put the SVST SixMaps.jpg version (Johan Warell's SVST images with Rehling's coordinates) next to my latest rough image of Mercury:

http://members.dodo.com.au/~erwinvandervelden/SVSTvsVelden.jpg

Cheers,

[videoguy]

Thanks for the link Erwin. In fact I have already been using that image from the Swedish Vacuum Solar Telescope as a reference.
I've attached an image from this morning made up of R(G)B + I filters..still rough but the features appear consistent with those in your pic above with a little shifting in longitude of course.

My eye's are going square with all the image sorting and processing.:-)

Cheers

[ErwinvdVelden]

Looks pretty good to me Steve! :2thumbs:

After 3 mornings of rain and clouds :cloudy: I had another session this morning and finished up with 8000 frames. Everything look pretty well focused and exposed, a 300 frame stack shows already the crater ray system. :cool:
My computer is chewing on the data for the rest of the day, probably tonight I'll have the complete unsorted 8000 stack ready and can chuck everything on CD so I can empty the harddisk for the next session... :help2:

Which makes me wonder, I noticed that the unsorted stacks give results as sharp as frame selected stacks, only the unsorted one needs a bit more sharpening. I tried this a few times with Jupiter, and if I compare two separate images shot a few minutes apart the unsorted stacks show not only the same amount of detail as the sorted ones, but their detail is also more consistent.

With al these unsorted stacks of Mercury I start to notice the same thing, if I stack 60 very crappy frames together, Mercury's disk still shows up with a sharp edge, as long as the telescope is exactly focused. :confuse3:

Cheers,

[iceman]

I'm hoping to try and grab Mercury tomorrow morning - it's been clear most mornings this week, but it hadn't risen high enough by the time I needed to leave for work. Tomorrow morning = no work, but the weather is also predicted to take a turn for the worse this afternoon/tonight.

So we'll see.. :shrug:

[ErwinvdVelden]

Hi everyone,

Here's the unsorted stack of 8000 frames made this morning.
Looks familiar? :party:

The big spot just above the centre is a big crater ray system, in both Steve's as well as my image it shows up blue, which indicates fresher material brought up from deeper layers!

Cheers,

[videoguy]

Thanks for posting the latest image Erwin. It looks good and adds credence to the exciting possibility that there may be a large ray crater at that longitude. More confirmation images are certainly required however. I did some imaging this morning but the seeing was really poor compared to earlier runs and not really worth the processing effort at this time. I certainly doubt I'd be able to make out the bright spot in them.

I understand there is a U.S team that will be using the IRTF at Mauna Kea from today until the 5th of May using a mid infrared spectral imager so hopefully something to confirm our suspicions may turn up from that.

In the meantime any more images we can get (including anyone else in this forum or elsewhere) will be really useful.

[ErwinvdVelden]

Steve,

This morning there were too many high clouds over Brisbane, this afternoon I'm going to clean my corrector plate and try again tomorrow morning.

Cheers,

Erwin

[toetoe]

Nice shots guys, keep em coming.

[ErwinvdVelden]

These :tasdevil: clouds! Drive me absolutely nuts! Tomorrow maybe before I go to work.

@#$%^%! :mad2:

Grmpf,

[iceman]

Clouds for me today too :/ Maybe tomorrow.

[videoguy]

Don't feel too disheartened guys..the other morning I'd stayed up all night and took the attached Mars snapshot in preparation to check the status of the general seeing which was looking good. As the Sun began to rise and I had Mercury nicely focussed ready to start imaging, a strip of cloud running North to south-east developed right across the rising path of Mercury while there were huge clear skies everywhere else.

Yes, that strip of cloud could have formed anywhere else across our vast sky but today it was going to ensure I didn't take any pictures of Mercury. Even as Mercury rose higher, so too did the annoying strip of cloud and it even grew thicker. Since then it's been either poor seeing or cloudy skies.

[ErwinvdVelden]

At least you have a nice Mars shot! I leave that until after Mercury has gone, there are just too many planets around. :juggle:

Cheers,

[iceman]

Nice Mars Steve!

Went out to image Mercury this morning, but there was clouds.. on my drive to work the clouds went away and by the time I was at work, it was beautiful and clear and Mercury was just staring at me, taunting me :bashcomp:

Oh well, maybe tomorrow :D

Also, Mars was quite close to the moon at about 3am this morning, would've made for a nice shot.

[ErwinvdVelden]

Hi everyone,

Did another seesion with bad seeing this morning and intermittent clouds. Currently there is a blowing South-easterly, but at least it's better than the last few days. Here's the 6003 frame stack, but I need a confirmation tomorrow morning. Sorry about the weird colour, I'll correct that with the final processing.

Cheers,

[iceman]

Very nice Erwin.. another cloudy morning for me here.. I don't know what it is.. get up, check the weather, cloudy.. come to work, by the time I get to work, clear.

It's very annoying.. i'm just going to have to start later tomorrow.

When are you going to tackle Mars?

[iceman]

Hi guys.

Finally had a clear morning, so as promised here's my Mercury. Also as promised, it's nothing compared to yours and Steve's. :P

The seeing was shocking, 3/10, and my image sacle is just so small at 3000mm FL with a 2.4x barlow. Mercury was only at 19deg elevation, so the individual frames have horrible atmospheric refraction as you can see by the single frame in the image below. Thank goodness for Registax RGB shift!

Details:
- 10" dob with ToUcam
- 5th May 2005, 5:45am
- 10 fps
- 1/33s, 0 gain

Out of 653 frames, only 3 were worth stacking @ 95% quality. Is there any special (coloured?) filter you use for Mercury to make it stand out more against the ever increasing blue background as the sun rises?

Anyway, it's my first ever image of Mercury and it clearly shows a phase, so I'm happy :D

http://www.iceinspace.com.au/images/images/planets/20050505-mercuryall.jpg

[ErwinvdVelden]

Congratulations Mike, especially if your Dob hasn't any drive!
Seeing gets much better when you wait until Mercury is upto 30 degrees, and the dispersion will also be much less.

I tried myself this morning, the clouds were too numerous to get a good shot.

Yesterday I got 6 minutes through a suckerhole filled with thin clouds, and got some confirmation of the much sharper image made the day before.

I really need a clear morning! :help3:

Cheers,

[ving]

yay mike!!

go team dob :D

[videoguy]

Well done Mike...this is what it's all about...Having a go and you've done a real nice job for a first attempt at Mercury. God knows my first attempt in 1995 as a shocker compared to your first result.

Lot's more to be done over the next few weeks guys so get those webcams going and post your results.

[iceman]

Thanks for the comments guys. Erwin or Steve, do you use a filter to image Mercury as it comes into daylight? I've heard that a red filter is useful.. is that true?

[ErwinvdVelden]

Mike,

I image with a colour chip, so I'm using an IR+UV blocking filter only. With a monochrome camera a long red pass filter is very useful.

Cheers,

[ErwinvdVelden]

Hi everyone,

I've been up every morning to check the weather. :prey2: Last Thursday was cloudy, on Friday I went way west to escape the clouds, clear most of the night but cloudy early in the morning. :cloudy: The same on Saturday, did a lot of deepsky imaging :astron:, but... overcast on Sunday morning, with only a few glimpses of Mercury before sunrise. :doh: I got back on Sunday and cloudy on Monday, as wel as today :tasdevil: And the forecast for this week really stinks, for me at least. :rain:

:help2:

The more attentive reader should have noticed a hiatus in this emoticonical essay by asking himself what happened last Friday.

I'll let you know more about that one late tonight... :evil:

Cheers,

[ErwinvdVelden]

Hi everyone,

Here as promised the Mercury shot of last Friday. It's a stack of 8000 frames made under a very transparent sky with a reasonable seeing, the latter doesn't happen that often when imaging Mercury.

This image shows the suspected Skinakas Basin as a dark area in the Southern Hemisphere.

The skies should clear by Friday, hopefully I can pull another observation in.

Cheers,

[Dennis]

Wow Erwin - that is a stunning image. Good job!

Cheers

Dennis

PS - Now tell me that you didn't sort the 8000 frames manually!

[iceman]

That's an awesome shot Erwin, the image scale is fantastic. 8000 frames! Holy cow! Do you image at 10fps?

How many frames did you capture, to stack 8000 of them? Can you post a stack of say 500 framesto show the difference? Is it just grainier?

[ErwinvdVelden]

Hi folks,

Handsorting this amount of frames would be a solid 6 hours of work, which I used to be quite happy to do. The gradient selection in Registax however works pretty well nowadays, this compared to the older selection functions that weren't capable of making any sense out of the low contrast day time images.

I noticed however that as long as the AVI is shot exactly in focus, better results are being obtained when using all the frames. I tried a selection of 2900 frames, but the result is just much noisier.

I'll post a 500 frames stack tonight for comparison.

The 4 AVI's are shot at 5 fps, 2000 frames each.

I also put the scientific version on the web, see

http://tinyurl.com/bysvy

It contains a comparison of the two different data sets.

Cheers,

[videoguy]

Well done on the Friday image Erwin - glad you finally got some good weather. That's a nasty band of cloud hovering around the north.

I've attached below a animation showing both our recent images and the relative movement of surface features.

Also obtained some rough results through thin cirrus cloud this morning which (when I get around to it) will add nicely to this animation.

[ErwinvdVelden]

Hi Steve,

Looking very good! It is definitely rotating! Saturday is going to be clear here, maybe I can add another one.

Cheers,

Erwin

[iceman]

Very nice images, Erwin and Steve!

[rumples riot]

Very nice images gents, a very difficult target and one that presents a little too much danger for me. Been flashed by the Sun once and have learnt my lesson. I know that Mercury is quite a distance from the Sun at present but am glad that you guys are doing this. Keep those great images coming.