Jupiter - Still Struggling

[neil phillips]

Hmm, I've deleted these files from the capture laptop, unless they still exist in Gimp on my home computer - possible, though unlikely.    I do however have the session browser dat file from firecapture.   

Looking at this the gamma is set at 100 for all these captures. Gain set to 950 for LRG and 962 for B, exp 0.4ms for L and 1.2 for other channels, Histogram peak 210 for L to 157 for G (81-61%), noise is a very stable 18-19 throughout all channels.      

Maybe I did something odd in AS!2?, though rarely tinker other than AP size and amount of frames to stack.

You may well have done something during processing perhaps. Did the new images come out of the stack with a much darker background can you remember this ?

Either way your on the road to some good images. you've done well here. what a turn around. Perhaps talk to others about the noise issue as I have no experience with the cam. But the images look fine at the moment.

[Space Cowboy]

Its not a brilliant idea lol. it will dew up the primary Stuart. At least any heat used in the  dryer will

It would take several hours to do that Neil half my OTA is open and I've not had the primary dew up over a 2-3 hour session.

[neil phillips]

It would take several hours to do that Neil half my OTA is open and I've not had the primary dew up over a 2-3 hour session.

No I meant what you said here

If I had a solid OTA newt I'd lop a hole in the side just below the secondary and shove a hair drier in. Now someone tell me thats not a brilliant idea!

SOLID makes all the difference I found out the hard way many years ago

[Space Cowboy]

If the drier is pointed upwards it can't effect the primary. Obviously if you blow down into the OTA bad things will happen.  It takes me just 5 secs to blow the secondary clear and Jupiter goes fuzzy for a few seconds and then settles down back to normal after 30 secs.

[neil phillips]

If the drier is pointed upwards it can't effect the primary. Obviously if you blow down into the OTA bad things will happen.  It takes me just 5 secs to blow the secondary clear and Jupiter goes fuzzy for a few seconds and then settles down back to normal after 30 secs.

I tried many years ago blowing in from the side ( not down ) I aimed the dryer sideways into the focuser only. The primary was completely dewed up after doing it

 warm air does make its way down to the bottom in a closed tube. Well it did with mine. I cant think why that would have been a one off. Though I would like it to be, as I could cure dew on the secondary in seconds if it worked. Have you actually tried this in a closed tube ? I would be interested to know how you stopped the primary from dewing. if you have

[Space Cowboy]

The problem with blowing through the focuser is the air flow wil be deflected down onto the primary the same route as the light bounces up onto the secondary where as blowing from underneath the secondary the air is deflected to the side and up not down.  Nope, I've never used a solid tube and in my hands it would not stay solid for long.

[SnakeyJ]

Just like to say thanks to everyone, especially Neil, Stuart, Chris & Freddie for their input to this thread.    I started this quite frustrated with my lack of progress this time around on Jupiter, especially after last years first attempts and some pretty respectable results on Saturn in the spring.     It was intended more as a cathartic rant, to let of some steam, but has developed in to an extremely useful and wide ranging discussion - my apologies if a lot of this was old ground recovered for the more experienced PI'ers.  

Not venturing out tonight as feeling rather shakey, but will follow through on all of this over the weekend and hope to identify and strike out some of the gremlins - and no doubt that better images will follow shortly

[neil phillips]

The problem with blowing through the focuser is the air flow wil be deflected down onto the primary the same route as the light bounces up onto the secondary where as blowing from underneath the secondary the air is deflected to the side and up not down.  Nope, I've never used a solid tube and in my hands it would not stay solid for long.

That rules me out, im not about to test the idea with a hole in the side. Sounds a bit unpredictable to me ?

[neil phillips]

Just like to say thanks to everyone, especially Neil, Stuart, Chris & Freddie for their input to this thread.    I started this quite frustrated with my lack of progress this time around on Jupiter, especially after last years first attempts and some pretty respectable results on Saturn in the spring.     It was intended more as a cathartic rant, to let of some steam, but has developed in to an extremely useful and wide ranging discussion - my apologies if a lot of this was old ground recovered for the more experienced PI'ers.  

Not venturing out tonight as feeling rather shakey, but will follow through on all of this over the weekend and hope to identify and strike out some of the gremlins - and no doubt that better images will follow shortly

you know what Jake I reckon you could go up a bit in focal length. Not to go crazy But 5000mm should be doable. Personally I would keep that heater off. What will be interesting is if you do keep it off. If you start to get more consistent images over a longer period. ( ruling out seeing as being a one off ) reason I say this. Even under really poor seeing my images do not fall below a certain quality level. And from what ive just seen here. its like a totally new telescope.

That first image was poor beyond belief. looks more than just seeing effects to me. Time will tell. Or some testing switching it off and on. But I am the kind of person where if something keeps working I don't really care if I understand it too much or not. Its the images I am interested in. A lot less hassle.  I suspect theres quite a few of us out there like that. just my 2 cents. Well done Jake. Going to be watching with interest

[SnakeyJ]

Cheers Neil - 5x on standby, though I get a little room to vary this with the qhy's 1.25" concentric design. It certainly gives a more solid image train.

typed on my mobile with Tapatalk

[Space Cowboy]

That rules me out, im not about to test the idea with a hole in the side. Sounds a bit unpredictable to me ?

Somebody must have tried

[Space Cowboy]

Stuart - a little odd and intriguing, I think the USB Traffic setting may not be consistent for all filter profiles, but would only be in the range 0-2.    It runs very happilly with traffic set to 0 for any of the ROIs, but 12 bit full frame does need a small tweak.    My preview drops to 15fps during capture, I shall drop this right down to see if it makes a difference.   I am using an older HP625 AMD based laptop for capture (Win7x64, 8GB RAM, Hybrid hard disk - which seems to work well for capture, but not great for processing).   I suspect that dark frame subtraction and, probably the ephems calcs may be slowing things a little?

Noise levels from the FC log files are between 16-20 for 8 bit capture, though this was with dark frame subtraction.     Here's one of the files for a red channel capture:

FireCapture v2.3 (beta 15) Settings

------------------------------------

Observer=Jake Gully

Location=Bembridge, Isle of Wight

Scope=SWExp200P

Camera=QHY5LII

Filter=R

Profile=Jupiter

Diameter=43.84"

Magnitude=-2.53

CMI=203.9° CMII=349.7° CMIII=143.4°  (during mid of capture)

FocalLength=3280mm

Resolution=0.24"

Filename=2013-11-21-2333.8-JG-R.ser

Date=20131121

Start=233353

Mid=233434

End=233515

Duration=81s

Frames captured=6000

File type=SER

Binning=no

ROI=640x480

FPS (during start of capture)=74

Shutter=4.237ms

Gain=950

Brightness=0 (off)

USBTraffic=0

HDR=off

Contrast=0 (off)

HighSpeed=on

Gamma=100 (off)

Histogramm(min)=0

Histogramm(max)=167

Histogramm=65%

Noise(avg.deviation)=15.38

Limit=6000 Frames

Focus issues were just the in out travel restrictions.   Pretty similar for the two Revelation barlows, but the zoom barlow seems a little different and I don't have the infocus to use this outside of the FW - works fine on the inside, once I was able to find enough bits to get the spacing right.   Certainly not an elegant or particularly solid solution.    I need to get a lower profile male T thread to 1.25" EP / compression adaptor,  so I can reclaim some travel and move this back outside of the F/W.   This will keep the weight of the FW hard against drawtube and should be considerably more business like.

I have previously used the nosepiece adaptor to give increase extension beyond a barlow to increase focal length, but predictably it limits reduction of focal length.     Prefer to keep it all closed/sealed to keep the sensor clean as the finish on the nose-piece is not great and tends to flake from the internal threads.

Not sure Dark frame subtraction is necessary Jake I've not heard of that being used for planetary imaging?  Your laptop is much more powerful than my 2 gb Netbook.  I'd try backing off on the gain as you should still get a very good frame rate and you wont need to stack so many frames.

I think using a 5x barlow (assuming your scope is 1200mm fl) would be too much with the cmos sensor. I've just tried a 3x barlow with extension tube which is roughly 4.5x in good seeing and the result was much softer than just the 3x with the cam extended out on the nose piece (I know what you mean about getting dust on the sensor already had to clean mine).

[SnakeyJ]

Hope to get a run in tonight if the sky stays clear. Native focal length is 1000mm and can use the x5 to get 4200+, so is useful. I shall have a play at lower gain without dark frame. I can always do some image calibration post capture.

Sorry Stuart, a terse response as I had to go and get the kids ready for bed!

I'll start at 4200 and see how I can push this tonight, all depends on the seeing I guess but will give it a good go and will do some tests with the heaters later on to see if they are introducing any electrical noise or thermal distortion.    However, keen to grab some more data first and see what the views like
 

[Kokatha man]

Far too much here in your thread for me to come in late on and say much of any real value Jake, but a couple of things I'll put 2-bob's worth in fwiw...  

Yes, I agree with Ralph - a glass or 2 of Bushmills or any other good spirit would always be of some benefit!

Like Neil I'm a "no heaters" believer, although there's plenty who seem to do fine using them!

Like Chris...err, I've forgotten what Chris said that Neil differed on but there was something I had similar views as Chris on....!    

Got it!!! Do a star-test...it really is easy to target a star and bring it up on your screen...defocus until you see diffraction rings (a central dark space with alternating bright & dark rings and that way you can get a proper collimation and also see lots of other things going on, like whether the seeing is worth imaging for starters!!!

Also, heat plumes manifest themselves very obviously to indicate if the scope is sufficiently cooled for imaging...

Even if your confidence/experience of star-test collimating isn't great it's much easier looking at a screen as you tweak collimation screws - as long as you turn the laptop screen to face you in the position you have to be to tweak those screws!  

Initially for folks with not much confidence herein and who want to image regardless of the seeing conditions just to get some "under your belt" practise I's suggest just trying to get a nice round donut where the bright band around the central black space looks nice and even in width all around.....as you get more confident you go further of course!

Hope any/all this isn't irrelevant but maybe someone might find it worthwhile.....and those later images in this thread look pretty reasonable and a great improvement!!!      

....oh - and like Simon I'm not a fan of iR-RGB images but that's just a personal taste, they can certainly "lift" image outcomes as iR nearly always performs better in poorer seeing and ultimately it's whatever any individual desires imho!  

[SnakeyJ]

I was out of action on Friday night, Saturday was lost to cloud and Sunday lost to failure of the QHY5L-II (now located as laptop problem).    However I did get out this evening - pushed the focal length out to 4650mm, which was a bit beyond the seeing - however was able to check the effects of running the dew heaters.   There does seem to be a small effect from electrical noise, rising from a fairly stable 12-13 to 16.4 when I turn the heater on and returning to normal afterwards - though this was a couple of runs both ways and may not be conclusive and the effect is quite small.    I only let the heaters run for 10 mins, looking at the preview there seemed to be quite a marked effect, though I will need to re-run this again and save some capture for proper checking.

Nothing better than my run from Thursday night, but very happy that things seem to be working properly for the time being.

[SnakeyJ]

Far too much here in your thread for me to come in late on and say much of any real value Jake, but a couple of things I'll put 2-bob's worth in fwiw...  

Yes, I agree with Ralph - a glass or 2 of Bushmills or any other good spirit would always be of some benefit!

Like Neil I'm a "no heaters" believer, although there's plenty who seem to do fine using them!

Like Chris...err, I've forgotten what Chris said that Neil differed on but there was something I had similar views as Chris on....!    

Got it!!! Do a star-test...it really is easy to target a star and bring it up on your screen...defocus until you see diffraction rings (a central dark space with alternating bright & dark rings and that way you can get a proper collimation and also see lots of other things going on, like whether the seeing is worth imaging for starters!!!

Also, heat plumes manifest themselves very obviously to indicate if the scope is sufficiently cooled for imaging...

Even if your confidence/experience of star-test collimating isn't great it's much easier looking at a screen as you tweak collimation screws - as long as you turn the laptop screen to face you in the position you have to be to tweak those screws!  

Initially for folks with not much confidence herein and who want to image regardless of the seeing conditions just to get some "under your belt" practise I's suggest just trying to get a nice round donut where the bright band around the central black space looks nice and even in width all around.....as you get more confident you go further of course!

Hope any/all this isn't irrelevant but maybe someone might find it worthwhile.....and those later images in this thread look pretty reasonable and a great improvement!!!      

....oh - and like Simon I'm not a fan of iR-RGB images but that's just a personal taste, they can certainly "lift" image outcomes as iR nearly always performs better in poorer seeing and ultimately it's whatever any individual desires imho!  

Thanks Darryl - extremely useful information here,and much re-enforcement of the sound advice already received.   You also reminded me that I forgot to do the star test tonight, though much cloud when I started this evening and was desperate to catch some data and prove that the camera and improved image train is working well.

Hopefully the weather will permit a another go tomorrow evening and I can try and tighten up on some better data.

Much appreciated - Jake

[neil phillips]

Just to be clear on what I was saying Darryl. Of course I am not suggesting people shouldn't star test. ( I did enough myself over the years ) what I think I was saying is, for me using a Newtonian. And someone who's Laser checks out nicely with other collimation devices procedures. ( both Cheshire and glow in the dark collimation cap ) For me there is little point in Star testing.

By the time I have the primary and secondary aligned (  and use glow in the dark colli cap for primary too) star testing would not produce any benefit. The glow in the dark colli cap for example is SO precise in getting the primary aligned. That even a tiny movement of the primary away from from the spot being dead centre, is obvious. Probably or nearly as accurate as a diffraction ring. under good seeing at high power I believe

The same accuracy using star testing would be both time consuming ( something I never have a lot of with 2 hour setups already ) and for the most part difficult unpredictable and with the seeing in the uk. likely not as accurate as the methods I already use.

Cooldown and heat plumes for star testing. Again I employ two fans one at the front, and one at the back. and I cool to the point of obsession.

There has been occasions where the scope may not be cool. as I did a rush job to setup, and try and catch something before the clouds came in. Or Jupiter moved too far over my house roof. Further cooling in those situations was desirable. But I have two choices. Catch some images. End with no images and a cool scope.

Ill let others choose the choice.

Star testing for heat plumes at this point is moot for me. The old saying. Is there anything I can do about it. Answer NO. Then I don't need to worry about the problem.

 Same for dew shields. I cool my shields by putting them in a freezer for a while. then leave them out to raise back to ambient. In such situations. I don't like using shields full stop. But I have no choice. ( or its heaters again lol ) again seeing the shield influencing the image during a star test for me is moot.

Is there anything I can do it about ? Answer NO.

Then I don't need to worry about it no more. Meaning star testing.

Don't forget Darryl SCT users collimate using stars. So all SCT users will look at life like that. But for Newtonian users very accurate collimation can be achieved in the field. using Glow in the dark collimation caps. lasers, and Cheshires.

 In fact I would challenge anyone with the rather unstable air here in the winter. To collimate my scope better, or as precise as is needed, using stars, compared to my methods that i use with no stars. Ill put the collimation way off. And away you go. See how long it takes, and how accurate, once checked with 3 different methods.

Ill bet, the collimation will likely still need tweaking,  when checked with the 3 methods I use.

Of course I know star testing is supposed to be the most accurate method. But with the unstable air and time constraints I often have here. That ideal will nearly always not be realized. And is far too time consuming and unpredictable for me. with very little gain.

There is a case for doing a star test for me,  perhaps if I have moved the spider during collimation. Or if I have tried a new material for a dew shield. But other than that, for me its all moot.

SCT users on the other hand  have really little choice. So of course will look at star testing from there viewpoint. I get that.

As for checking seeing. Using a star test,  If the stars are going wild twinkling. sometimes I wont bother. If not. By the time it takes me to get rolling. ( at least two hours to get everything setup collimated running ) I will take some images regardless. Just cloudy here for weeks a time sometimes. So yes I will take some images regardless of what I am going to get. Is there anything I can do about  about ? Answer NO

Then I don't need to star test and see things are not ideal

As I said to Chris I think we are all on the same side here Darryl. but maybe circumstances. And equipment differences. Are making our choices rather different perhaps.

Star testing is also more important when first starting out imaging perhaps. It does get the new imager around to the idea of what things affect the telescope profoundly. But beyond that I believe  all my choices suit me just fine.

[neil phillips]

Btw Jake if you can get a glow in the dark colli cap they really are pretty darn good. I don't think the laser Barlow method will be any more precise, as you can easily see when the primary central sticker is dead centre of the colli cap hole. Even just a small movement of the primary shows, when its not dead centre I find.

All you need is a light source to make it glow. and you will get some time to centre the primary inside the collimation cap 2mm hole (  it may be the other way around, but you get the point )

 They are good and fast. If anyone hasn't tried one, I would suggest its worth a go For Newts. My laser coincides exactly when I use the cap. The Cheshire cross hairs right in the middle. It all backs each other up nicely. Showing that each device is working correctly and in tandem. A great star test collimation from someone experienced at it under calm air and high power ,  would likely show similar collimation as my method I believe. Star testing may well be the best method for experienced users. under good seeing with care. But my method could be achieved in seconds after a night out on the booze. Though I wouldn't recommend it, unless its cloudy of course. Ill have a pint of Abbots mmmm

[Kokatha man]

You've gone to great lengths to defend your position Neil and that's fine by me  .....I have no interest in changing anyone's opinions whatsoever and merely express my own opinions like yourself and anyone else: as to star-testing for collimation there is quite simply (IMHO!!!) no better way than to collimate with the imaging train you are using, whether it be SCT or Newtonian etc...you simply cannot insert any one mechanical device to collimate and then remove it and insert an entirely different device in and expect it to duplicate the collimation of the previous device(s) - this is most applicable when said device is a filter wheel + barlow & camera unit where this unit taken as a whole quite likely has orthogonality issues.....obviously the ideal is a scope & system where everything is concentric & orthogonal but that is often idealistic so collimating where these fine nuances can be "self-corrected" to a relative degree is a better approach - remembering that "fine nuances" in collimating are really not that fine at all when it comes to considering how fine good collimation is.....

I've no interest in getting into any bunfights about this except to say the above is my own  consideration of the matter (and many others' also - particularly re the most accurate methods)...and that it is possibly more likely the "less experienced" (not yourself, just "in general") that the sellers of these devices are targeting, if you'll excuse the pun..!

But ultimately it boils down to whatever any individual is happiest with...heat plumes & appraisals of the seeing are moot points and NOT the main point of my comments re star-testing: Chris & Jake both gave me "brownie points" and liked my previous post.....but if (say) Ralph thinks there's nothing except Bushmills and takes exception to my suggestion that "any other good spirit" is in any way comparable I'll just have to accept that also and say "sorry Ralph, but I think there are other drinks just as pleasurable!"

[neil phillips]

You've gone to great lengths to defend your position Neil and that's fine by me  .....I have no interest in changing anyone's opinions whatsoever and merely express my own opinions like yourself and anyone else: as to star-testing for collimation there is quite simply (IMHO!!!) no better way than to collimate with the imaging train you are using, whether it be SCT or Newtonian etc...you simply cannot insert any one mechanical device to collimate and then remove it and insert an entirely different device in and expect it to duplicate the collimation of the previous device(s) - this is most applicable when said device is a filter wheel + barlow & camera unit where this unit taken as a whole quite likely has orthogonality issues.....obviously the ideal is a scope & system where everything is concentric & orthogonal but that is often idealistic so collimating where these fine nuances can be "self-corrected" to a relative degree is a better approach - remembering that "fine nuances" in collimating are really not that fine at all when it comes to considering how fine good collimation is.....

I've no interest in getting into any bunfights about this except to say the above is my own  consideration of the matter (and many others' also - particularly re the most accurate methods)...and that it is possibly more likely the "less experienced" (not yourself, just "in general") that the sellers of these devices are targeting, if you'll excuse the pun..!

But ultimately it boils down to whatever any individual is happiest with...heat plumes & appraisals of the seeing are moot points and NOT the main point of my comments re star-testing: Chris & Jake both gave me "brownie points" and liked my previous post.....but if (say) Ralph thinks there's nothing except Bushmills and takes exception to my suggestion that "any other good spirit" is in any way comparable I'll just have to accept that also and say "sorry Ralph, but I think there are other drinks just as pleasurable!"

No that's fair enough, and you do make some interesting points. Its something I have thought about. Perhaps using self centering devices. For slop in the focuser. But for me personally. I think we are talking primary collimation here. If a laser is aligned well. And care is taken to average out slop in the focuser. Then secondary collimation for me is best done in the field with a laser.

So yes I agree there could be a case to adjust the primary on screen with the imaging train setup. But with my rather cheap setups. My primary cells do have slop. As such not only does the primary move from position to position. But often as the angle of the scope changes. So does the primary collimation. So going from even a close star ( close to Jupiter ) then onto Jupiter. might well change the primary position slightly.

Then getting Jupiter on screen with the imaging train still intact. would likely be difficult to impossible, without first removing the camera putting in a eyepiece centering Jupiter on screen. And we are back to the problem of slop again.Destroying the collimation that was just done.

Do you know of any software that could collimate the primary using Jupiter as a source perhaps ? If so I would certainly be interested in perhaps trying something like that

You know Sometimes. ( seems to happen more and more for me lately )

By the time ive setup cooled down. And got going, I've only managed about 3 or 4 runs. Before Jupiter hits my roof. Causing heat problems for the images. And having to stop.All that work for 4 so so images.   Time is something I just don't have if I want to get some runs most often. When we get  a clear night ALL NIGHT. Then yes I can plan for longer perhaps. Those with Obs are certainly lucky. Two hour setups after waiting for the clouds or rain to clear. Doesn't often leave me long here Darryl. So my procedures may well be the best for me personally.

I haven't disputed that star testing is regarded as the best method. Ive disputed it might be for me. Or even others with similar problems.

[Kokatha man]

Fair enough Neil   - I'd be trying anything I could to eliminate/minimise that movement in the primary mirror although I think there's some misunderstanding re collimation Vs optical concentricity etc between us - for me it's the actual degree of collimation that is applicable for whoever (ie, the visual obber through the ep) or whatever (ie, the cmos/ccd sensor of the imaging device.)

As I said above it's important to get both right if you can but providing there isn't enormous axial problems then collimating for the person or the device is going to be the most salient imho...

I'd have to put my thinking cap on tight to try and devise a very secure primary cell from one that's not doing the job properly...apart from tighter springs and ensuring the clips etc are set correctly I suppose a decent "after-market" cell would be the most expedient: I haven't tested it in the field as yet (it will happen!!! ) but the Orion VX16 looks pretty nice in that respect...

I had a devil of a time with the C14 on this score and led to me using the threaded holes in the mirror assemblage & rear casting (used for transporting new scopes) to turn the primary into a fully-supported & locked unit and "think" this has been a major enhancement for when I did it before this year's Saturn apparition and a big reason for my images at the time...

The only other thing I'd say was something I said on CN to someone this morning: we have a "Golden Rule" about always collimating as accurately as we can with a star-test before EVERY imaging session and the few times we've not done so have nearly always been to our detriment...that "saving time" haste we'd occasionally decide upon has always bitten us on the backside except possibly when we were the first AA'ers to produce those images that showed Saturn's hexagonal polar storm shape - we only got one rgb set in before clouds swamped the entire sky and if I'd collimated beforehand we'd have missed that grab; but that's the only time this year I'd say expediency wrt that has paid off..!

[michael.h.f.wilkinson]

This has been a very interesting read. Nobody can doubt the excellent results you lot are getting, so evidently, there is no single "right" way of doing it. I must say I am generally fairly cavalier in my attitude to collimation, as my C8 seems to hold it very well indeed. On the other hand, my results to date aren't anywhere near as good as yours, so I might well pay more attention (once the clouds have buzzed off (some time after the next 14 days according to the current forecast).

[SnakeyJ]

Every time I go to reply someone adds more info to digest - this has turned out to be a detailed and extremely thought provoking expansion on collimation and how to eek the finest out of often less than perfect conditions and equipment.    I'll read the latest post and then take up....

[neil phillips]

Every time I go to reply someone adds more info to digest - this has turned out to be a detailed and extremely thought provoking expansion on collimation and how to eek the finest out of often less than perfect conditions and equipment.    I'll read the latest post and then take up....

Jake hope you don't mind my long winded takes on all this. I worry about going on so much, on others posts. Hope you find some good info in and around the discussions

[michael.h.f.wilkinson]

Jake hope you don't mind my long winded takes on all this. I worry about going on so much, on others posts. Hope you find some good info in and around the discussions

I really like these lengthy discussions, it is nice when people take the time to make things clear