Jupiter May 13 845AEST

[matt]

Seeing looks OK tonight.

It's still only early but wanted to post this anyway.

Jupiter about 45 degrees above horizon.

Quick run through Registax. No other processing.

Think the moon's having a bit of an impact.

Did a Mitchell 150% resize rather than resample. Not sure the data's quite up to it, but I like the scale.

I'm looking forward to midnight and GRS, and hopefully the seeing will get better.:thumbsup:

[[1ponders]]

Looking promising Matt :thumbsup: Good luck. It's lights out here tonight.

[Lester]

Good luck Matt.

[asimov]

Good luck mate.

[matt]

Thanks fellas

I'll try and get a goodun' for ya;)

[beren]

Looking good Matt hope it holds for you and you can get some great sequences :thumbsup:

[Dennis]

Hey Matt

Looking better than Brisbane. Break a leg!

Cheers

Dennis

[davidpretorius]

i like the colour in this one.

well done!

[Robert_T]

nice one Matt:) ... so how did it go later on?

[matt]

Cheers guys

Rob, sadly, Canberra's fantastic track record for crap seeing remains intact. Conditions just got exponentially worse within a couple of hours.

I'm just about sick of it, actually. I've been hauling myself out there for 6 months straight with the 9.25 and don't feel like I'm making much headway.

I've little by little fixed those areas which are under my control (collimation, dew, etc) but my images remain disappointing. I might have to concede defeat.

I'm at that point where I'm wondering whether further expenditure is going to leave me even more depressed?

Sorry mate, but you asked:lol:

I can feel a clearance sale coming on. Expressions of interest are welcome.

[Robert_T]

Hey Matt, I can understand that. I've had a few patches when I thought like tossing it in as I wasn't getting anywhere, and that's with Brisbane seeing which I suspect, given our more sub-tropical locale, is likely to fare better over the year than Canberra (I could make all sorts of jokes here about hot air, but I'm sure you've heard 'em all before).

Maybe the winter is when it all comes together for Canberra? Reckon I'd struggle with it though... I'm still imaging up here in a T-shirt, though I've been forced to wear jeans instead of shorts the last couple time out - it's hell!:P

Anyway, hope you can stick it a while longer - it only takes one night of good seeing to get you going again and make those mountains into speedbumps ;).

cheers,

[matt]

Thanks Rob

Not sure what you mean about Winter being when it all comes together here in Canberra????

If you mean massive temperature differentials, humidity over 75% by 10pm and 98 % by early am... smoke from thousands of fires and seeing that looks like it's rarely above 3-4/10... then yeah, it's all coming together nicely.

[Robert_T]

well I did say, Maybe ;)

you've talked me out of moving:D

Anyway Matt, hope those conditions can leave off for you for a couple of nights sometime soon - like to see you score at least one night of 8+/10 seeing, keeps you going for weeks.

Good luck!

[Dennis]

Hi Matt

In 6 months, you have achieved a lot, you really have; it took me 6 years to get an image of Jupiter only half as good as the one you attached in this post. You've taken on a BIG challenge and so far have been doing a great job in mastering the equipment and techniques required.

Keep at it and the holy grail of 8/10 will come visit you one incredible, mind blowing night. Your skills will be ready for her warm, enchanting and captivating embrace and those long, cold, lonely nights will be banished.

Cheers

Dennis

[matt]

Thanks guys ...

Dennis - haven't you only had the 9.25 for about the same time as me?
Didn't you get yours late last year? Same for Rob T.

And Asimov has had his even less time.

We've all had the same scopes for about the same time, but compare results. What can I say...

I'm going to sit down and have a long hard think about it all.

Thanks anyway:)

[Robert_T]

Hi Matt, yeh I've only had the C9.25 a while, but had 9 months of planetary imaging prior to that with the Mewlon and 6 inch acromatic... My best results 6 months in ain't pretty though. :) Asi the same I think.

cheers,

[matt]

OK rob.

Just really bummed at the moment:(

I'm sure you're right. Just need a night of good seeing to lift the spirits.

It's tough, though... never having seen good seeing. At least if I'd seen it I would be encouraged by knowing it does exist;)

This is, of course, assuming the trouble is above my head and not with the gear I'm using.

But good seeing would certainly narrow down the culprit!!!!

[Dennis]

Hi Matt

I've been punishing myself for over 6 years with astrophotography in general, from 35mm film to CCD, Meade LIP and now the ToUcam. All the stuff I learned, equipment foibles, seeing, software, etc during that period was available to me when I started with the C9.25 and ToUcam approx 6 months ago.

If you have started from ground zero with a C9.25 and ToUcam - I take my hat off to you. It is a big piece of glass with a long focal length and can be very unforgiving. My first Jupiter’s were with the Meade LPI and a 4” f9 (918mm focal length) refractor, which was tough, but quite forgiving and manageable.

I would not have liked to start my Jupiter career with a C9.25 and a ToUcam.

Cheers

Dennis

[asimov]

Hi Matt.

We all feel this way at times. Just before I sold the refractor & bought the C9.25, I was contemplating getting the hell out of astronomy. I certainly haven't seen too many nights with good seeing since I took up astrophotography...4 nights I think, 1 night with the C9.25 in over a year.

I have been in this game for over 30 yrs now, & as much as I've ranted & raved & threatened to sell the whole shooting match & just forget all about it/take up another hobby etc, I found it impossible to do. It's in my blood. The fascination to see, & now to photograph the heavens is overpowering.

It takes a person with a lot of patience to do what we do; never one of my strong points :) Hang in there Matt! Your opportunity is just around the corner, guaranteed. :thumbsup:

[matt]

Thanks Asi...

We must share the same "Patience gene":lol:

Yeah... astronomy's also in my blood, but gee ... you sometimes wonder whether a "hobby" needs to be such a pain in the derriere!

I know... I know .... it's a challenge, a learning curve, part of the fun is the thrill of the chase:rolleyes:

but honestly...

Anyway, those are nice words. Especially seeing it's your special day. Nice of you to take the time to think of someone else on your birthday.

You're a nice fella:thumbsup:

[[1ponders]]

Hang in there matt.

The seeing will visit you sooner or later. Just follow the golden rule "Don't you ever let a chance go by" (sound like a good name for a song :P ). Get out there every chance you can. The seeing may look like garbage but you never know you might just get that 5 minutes of absolute perfection appear out of nowhere one night and all the effort will feel worth it.

Besides it can't hang around over Dennis and Rob forever. :lol: Have a look at the results they are putting out and have a look at the results I'm putting out (none) and I only live a hundred clicks away. It can't all be seeing. I found out last night that part of my problem was my collimation has been just a tad out, and that has been enough to make most of my captures pretty much a write off.

Plus there are some (not me :sad: ) who just seem to have that extra something that tells them quietly without them even knowing it "This is what I need to do to get this shot right". Sorta like a green thumb. Mike, bird, DP, Dennis and Rob are good examples, but not the only ones. You and me, mate are going to have to work a bit harder. We just have green thumbs in other areas. Doesn't mean we can't learn though.

[asimov]

Think nothing of it mate!:thumbsup: We must stick together.;) ..& console each other in rough times! >:D <

[matt]

Paul.

If it's a collimation issue then I'm really buggered, because to my eye the out of focus star tests look spot on. Nice round concentric circles with a pin-point airy disc at the very centre using the 10mm and 5mm eyepieces:shrug:

Looks about the same as the diffraction patterns in my well collimated newt.

If it's out by a fraction, and that's what you say makes all the difference, I'm not sure I can tweak it any finer??? I simply can't see where I can improve it or make it better, with the skills I have??

It would be great to hear from someone who had their SCT very close to perfectly collimated and then took it that one extra (quantum leap) step and got it "bang on".

How did you achieve/gauge it? What difference did it make to your scope's performance?

By the way, Paul. Did you fix your collimation?

[[1ponders]]

I'm just about ready to post a couple of images of before and after. Just running them through registax as we type. Watch this site.

[davidpretorius]

i obviously can't comment on your collimation as i haven't looked thru your scope, but your description sounds spot on.

i put it down to seeing. canberra, hobart and adelaide sound like hell holes of seeing. I think hills in adelaide and hobart play havoc with the air and temperature drops in canberra sound atrocious. Launceston also has these large drops, but the presence of the oceans helps to moderate temps and conditions

This is only a gut feel, but if you compare the seeing i have got to birds, I feel I have had better runs of weather than bird. Both of us are controlling our temps. I would also say I have got better seeing than everywhere apart from brisbane. Then again, i am out most nights to report on what the seeing was like.

I am uploading 500 frames from the 26th april to the ftp area. (should be finished soon)

They have been quality sorted by ppmcentre, but if you have broadband, download the rar file. it is 80mbyte. If not, i can send them on cd. Then load them into registax and watch the program flick each image up. The purpose of this is to get a feel for great seeing. Then ask yourself, have any of your vids stayed steady like one. IF yes, we then have to work on collimation or processing.

Have a go at processing these bmps to see what you can get out of them.

On SCP, peter posted an image of jupiter that i was able to extract quite a bit more detail out of.

A few thoughts anyway. It is frustrating, but i have a horrible feeling canberra is not "seeing friendly"

[davidpretorius]

http://www.iceinspace.com.au/uploads/dp_jup_060426_1147_500frames.rar

80 mbytes = 500 frames

seeing was 9/10

[matt]

Davo.

you're a champ:thumbsup:

Where's the ftp area, by the way?

[[1ponders]]

Ok these two images were taken about an 3/4 hour apart and if anything the seeing was worse for the second one as I was shooting over the roof of my house.

The collimation still wasn't spot on but the small tweak I did made a surprising amount of difference. Capture settings should have been the same and I've kept the processing the same. Maybe I'm wrong that it was seeing improving that made the difference, but looking on the laptop screen while taking this shot was what decided for me to pack it in as it didn't seem to be getting any better seeing wise.

[davidpretorius]

nice example paul,

I have often thought to collimate, take a video, untweak collimation and take another.

Matt,

http://www.iceinspace.com.au/forum/showthread.php?t=9879

is the thread to the new ftp are, you will need a password from mike to post there, otherwise, guys that post there just give a link to it like i have.

This is a crucial read re collimation I believe with examples

http://damianpeach.com/simulation.htm

[matt]

Hey Paul. Nice comparison.

How exactly did you tweak? Do you colllimate visually or on a computer screen using a webcam?

What did you observe to suggest collimation was out? How could you tell? And what adjustment did you make?

Was it an out of focus star test? How much was the central obstruction shifted away from centre for that degree of improvement?

[davidpretorius]

hey matt, can you please delete all unimportant private mail ie from mike and the mods and only leave the spammy important ones from me and asi.

your 200 limit is blocking my reply to your pm to me. :D

[matt]

Already done, Davo ol' son:)

[davidpretorius]

hey matt,

airbag packed and ready to go with my "home made" video!!

paris hilton has nothing on this one!

[[1ponders]]

There is a bit of a story involved (as there usually is with me :P )


But I'll shorten it :D

I've been getting a fair bit of heavy "blue around the limb" over the past couple of weeks and I thought it was coming from my barlow (but the blue was always on only one side :shrug: ). I assumed I must have knocked a lens out of alignment in the barlow or something. So I switched from negative projection using the barlow to positive projection using an eyepiece. Still not good but better, so I accepted that and moved on thinking I would get myself a powermate after this Jupiter apparition. (I had taken the diagonal out of the equation which could have been affecting things as well)

Now in the mean time I'd been noticing that while Dennis and Robert were getting what to me looked like fantastic seeing, me living only 100km away was getting crud all the time. This made doing an effective star test on collimation all but useless. Normally I collimate with a 6mm eyepiece, but I just couldn't get the stars to stop flaring out one side and put it down to seeing.

Well last night I gave it another go but I used the laptop and ToUcam with positive eyepiece projection instead of negative projection with the barlow. Spica looked like a mass of jelly in an earthquake, but I tried to see something. Nah, useless. Then I swung over to Beta Centaurus and noticed something. Even though it was jumping around all over the place I could definately identify flaring to one side (this was all done defocused). So I started to try to adjust the flaring out. It only took a couple of minor tweaks on one screw and the flaring seemed to centralize around the defocused star. Focusing on the star I could only make out minor differences. When I slewed back to Jupiter I noticed a considerable difference.

In the three images, the first darker sample is as bright as I could go with gain and gamma without the blue being unprocessoutable, so to speak. It was taken on the 27th of April. The second image is from the start of the night last night. I had collimated between the 27th and last night but obviously not well enough. The third image is from when I slewed back to Jupiter and noticed a difference from earlier in the night so I used the remaining "blue limb" and the flaring on one of the moons to guide me in a final small tweak.

It may not be the proper way to do it and is as rough as guts, but it sure as hell made me happier than the results I've been getting over the past few weeks.

[matt]

That's very interesting Paul. I've never heard of anyone using the colour separation at the limb as a guide for collimation.

If it's working for you, good for you I say.

As for this:



Positive/negative.... I do not understand that at all.

But I'm definitely going to try and tweak my collimation using the webcam.

If it's good enough for you, Dennis and other experienced folk, well I'm in!

[matt]

Cheers Dave

and I'm sure I have no idea what you're refering to ... as far as Ms Hilton's concerned?? Video? What video?:lol:

[[1ponders]]

Negative projection and postivie projection are just different ways of increasing the FL and there for the magnification of your imaging system.

The 4 main types of imaging. Afocal; Yep we've all been there and moved on quickly :lol: Prime focus; wacking the camera/toucam without their lenses, in where the eyepiece is supposed to go. Negative projection; using a 2x telecoverter with a camera or a barlow with a webcam. This effectively increases the focal length of your telescope by the multiplication factor of the converter/barlow, which I'm sure you already knew.

Positive eyepiece projection is a bit different. You place an eyepiece in a tube (I use a meade variable Tele-extender) and then attach your webcam to the other end of the tube. The tube then usually screws onto the scope. What happens then is that you get the normal view through the eyepiece but it is projected onto the toucam chip. To get a handle on the idea, get a torch and hold it about a foot from the wall. The wall represents the chip and the lense of the torch the lens of the eyepiece. Now move backwards. The image ie the circle of light gets bigger. The same thing happens by mounting the toucam away from the eyepiece. And the further away you get the chip the larger the image. With my variable extender and a 2000mm natural FL of my scope, if I get the toucam chip about 145 mm away from the eyepiece, this will give me an effective focal length of 12 500mm when using a 20mm eyepiece. With a 15mm eyepiece; 17 333mm FL, 5mm eyepiece; 56 000mm and with a 1mm eyepiece a whooping 288 000mm, as if that will ever be useful :rolleyes: But effective FL of 5 000 mm to 10 000mm are definately useful to me.

If you can get hold of the book Astrophotography for the Amatuer by Michael Covington, he explains it really well.

[[1ponders]]

BTW using the 20mm eyepiece at 145 mm with a 2000mm fl scope give me a magnification of around 630X

[davidpretorius]

[quote=matt]
Positive/negative.... I do not understand that at all.

But I'm definitely going to try and tweak my collimation using the webcam.
quote]

firstly paul, it makes sense what you are saying. Chris go collimates on the moons of jupiter to make sure he can get the sharpest image. Mind you, his seeing conditions are fantastic and obviously the c11 is easier to collimate whilst tracking a moon of jupiter than my dob with a dob driver.

secondly, i have heard guys say, do not collimate with the toucam and i was believing this, but, the blue limb issue is something i have noticed too.

If i am to view thru the eyepiece, then collimate to that, but if i am to image, then collimate to the toucam seems to make sense to me!!

Matt, as for positive and negative, this televue charts helps me ( http://televue.com/engine/page.asp?ID=243 )

[[1ponders]]

Dave if you or I were imaging through a refractor I would have said it was chromatic aberation. But SCT and Newts shouldn't suffer from that. So my thinking was that if I was getting blue on a limb it either had to be in my barlow or something was acting as a diffraction crystal. The only thing I could think of was a miscollimation. I dont know if I was right , but the blue limb is largely gone now.

Matt if you are interested I have an excel spread sheet that I made up that does all the calculations for you.

[matt]

Sorry guys.

Just wanna make one point clear. When I said I don't understand the positive/negative projection thing, that wasn't a slight on you in any way Paul. Just meant I don't understand how it works.

More research for moi;)

Now, here's a question. I understand the perils of collimating a SCT with a diagonal in place if I'm not going to use a diag when I'm imaging.

But when I have been collimating my scope I've been doing so by eye with the ep straight in the visual back. No barlow ... no Powermate.

But when I image, I use a powermate.

Sooooooo ... could that be contributing to any type of collimation error????

Should I be collimating with the barlow or powermate in place, if that's the optical train I'm using when I capture???

Or does that not present the same mis-collimation issue as a diagonal??? the

[[1ponders]]

This Excel sheet may give you an idea of what you can do with Extended Eyepiece Projection (another name for positive eyepiece projection)

It is made up of two pages. You only need to fill information on your scope and eyepieces on the first page onlyThe first page is for afocal photography but the various parameters are linked onto the second worksheet.

For EEP all you need to do is fill in your Telescope FL, your various eyepiece FL and your telescope objective (towards the bottom of the worksheet) on the first worksheet. If you are interested in the afocal option you can also fill in the camera lense FLs as well. Just delete any existing eyepieces and camera lens FLs.

If you then go to the second worksheet the top table will give you the various magnifications of the system (apply this magnification to the "normal" magnification of the system ie 1000 mm FL with a 20mm eyepiece gives 50 X. Multiply this 50 X by the magnification factor from the top table.)

The second table will give you your effective focal lengths based on how far the chip is from the eyepiece

And the third table give you your f/ratios at the various chip distances and eyepieces.

If you have any problems give me a yell.

BTW the grey areas on each table are where the most useful ranges are. This will probably be incorrect as I initially set the work book up to use with an SLR camera.

[[1ponders]]

None taken :thumbsup:

I would hope that there isn't a problem with a powermate. Not at those prices. It's mainly the diagonal

[Dennis]

Hi Matt

I have always collimated with the x2.5 Powermate in place, using a 20mm Plossl (medium magnification x235) followed by a 9mm Vixen Lanthanum (x522) and then I remove the eyepiece and plug in the ToUcam and eyeball the inside and outside focus position on the notebook display and it looks the same as looking directly through the 'scope.

From memory, my experience has been that although I check every 4 to 6 weeks, I have only tweaked it once originally, followed by two minor tweaks in the 4 or 5 months I have been collimating.

Cheers

Dennis

[matt]

Great. Thanks Dennis.

And all you guys for your help and encouragement.

Well, I'm all set up and have been since 5pm. Scope nicely chilled. Did a quick check of collimation in the 10mm XW and it looked sweet.

Even with a 5mm in the back (470x) the rings are concentric and the airy disc is centred.

Just had a quick look at jupiter with the 10mm XW (235) and the detail is very encouraging. Swirls, knots, festoons... the works! I'd put the seeing around 6/10 and getting better. Even the jetsream map looks good, not that that's proven a winner of a form guide lately:mad2:

So I'm getting right back in the saddle, digging the spurs in, and taking this pony for another ride:lol:

See you when the mud dries. Yeeeehaaaa!!!!!!!