Return to the Cloudy Nights Telescope Reviews home page


Telescope Specific Forums >> Celestron NexStar

Pages: << 70 | 71 | 72 | 73 | 74 | 75 | 76 | 77 | 78 | 79 | 80 | 81 | 82 | 83 | 84 | 85 | 86 | 87 | 88 | 89 | 90 | >> (show all)
Maverick199
Postmaster
*****

Reged: 02/27/11

Loc: India
Re: IC1805 new [Re: ghataa]
      #5511270 - 11/09/12 09:19 AM

Wonderful image George!

Post Extras: Print Post   Remind Me!   Notify Moderator  
Skip
Starlifter Driver
*****

Reged: 01/23/08

Loc: Fort Worth, Texas, USA
Re: IC1805 new [Re: ghataa]
      #5511728 - 11/09/12 01:56 PM

Hi George,

Very nice "Heart"! Glad to hear you finally got your power back. Hope you didn't have any/much damage from Sandy!


Post Extras: Print Post   Remind Me!   Notify Moderator  
Tel
Postmaster
*****

Reged: 03/31/06

Loc: Wallingford England
Re: IC1805 new [Re: Skip]
      #5514011 - 11/11/12 05:56 AM Attachment (22 downloads)

First time "out" in the dome in literally ages !

Very clear skies last night although with some turbulence particularly from rooftop heat emissions making focusing difficult; (when isn't it with planerary imaging) ?

Nexstar 8i @ f/30 (i.e. X3 Barlowed) on a Skywatcher HEQ5 Pro. using a Philips SPC900NC webcam. 120seconds at 30fps.
Stacked in Registax. Processed in Registax and Photoshop CS2.

The image lacks fine detail.

Thank you for viewing.

Best regards,
Tel

Edited by Tel (11/11/12 05:59 AM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
Maverick199
Postmaster
*****

Reged: 02/27/11

Loc: India
Re: IC1805 new [Re: Tel]
      #5514334 - 11/11/12 11:50 AM

At f/30 and achieving focus with X3 takes some doing. Great shot!

Post Extras: Print Post   Remind Me!   Notify Moderator  
Tel
Postmaster
*****

Reged: 03/31/06

Loc: Wallingford England
Re: IC1805 new [Re: Maverick199]
      #5515511 - 11/12/12 05:14 AM Attachment (14 downloads)

Many thanks, Haseeb.

The one thing in both our favours when trying to focus planetary images, is that with a decent wormdriven, no backlash GEM, at least one doesn't have additionally to contend with too much drift on the LT screen when carrying out this operation.

I therefore have every respect for the skills of those imaging from the standard Alt./Az. mount having once found it intensely difficult myself.

I've also taken a look at my Jupiter image, (above), to see whether I could tease a little more detail from it. Here's the result.

All comments invited.

Best regards,
Tel


Post Extras: Print Post   Remind Me!   Notify Moderator  
Peter9
Post Laureate
*****

Reged: 10/30/08

Loc: Yorkshire - Born & Bred
Re: IC1805 new [Re: Tel]
      #5515517 - 11/12/12 05:37 AM

Thats a wonderful image Tel.

You've certainly captured, and brought out through processing, much more detail than is normally seen in such images of Jupiter. A credit to your skills.

Thanks for posting.

Regards. Peter.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Maverick199
Postmaster
*****

Reged: 02/27/11

Loc: India
Re: IC1805 new [Re: Tel]
      #5515520 - 11/12/12 05:50 AM

Definitely looks a bit more natural than the first one.

Btw, how does one go about achieving focus with a Barlow at prime? I have taken lots of images but still find focusing a hassle. Any suggestions or method?


Post Extras: Print Post   Remind Me!   Notify Moderator  
Tel
Postmaster
*****

Reged: 03/31/06

Loc: Wallingford England
Re: IC1805 new [Re: Maverick199]
      #5515581 - 11/12/12 07:53 AM

Hi Peter, Hi Haseeb,

Many thanks for the comments and appreciation. It's very kind of you both.

In response to your question, Haseeb, on focusing, I take it we're talking "Barlowed" webcams or an equivalent multiframe planetary imager ?

If so, one prime requirement is that the 'scope should be checked for colliimation and, if necessary, adjusted to achieve the best one can before undertaking any planetary imaging.

Webcams and their like, normally equate to the type of short focal length EP, (e.g ca.6mm),traditionally used for fine collimation. Thus if your webcam or other planetary imager is sufficiently powerful enough to pick up a bright single point of light, (i.e. a bright star), you can use it to collimate your 'scope on your LT. Otherwise collimate with a short focal length EP.

(N.B. The use of any Barlow lens is irrelevant. What you're seeking to do at this stage, is merely to optimise the alignment of your 'scope's optical components).

Once satisfied that you can do no more to improve collimation, then, apart from opting to image when the planet in question has reached sufficient altitude so as to have minimised the effects of atmospheric turbulence, you are now pretty well in the lap of the Gods !

Even having ensured both collimatiion and altitude requirements, I find some in and out of on-screen frame focus, (boiling), still inevitable, though a motorised focuser helps enormously in obtaining the best possible "crispness" to the image.

Additionally and particularly when imaging Jupiter, keep the frame exposure period relatively low, particularly when "Barlowing". In the above instance, I chose only 120 seconds at 30 frames per second. Extend the capture time too much and Jupiter's rapid rotation will impart extra unwanted blurring to the image.

Finally though, end processing is all important as evidenced by the two images I submitted above. Altough radically different in appearance, they result from the SAME capture sequence.

Hoping this is the answer you required,

Best regards,
Tel


Post Extras: Print Post   Remind Me!   Notify Moderator  
Maverick199
Postmaster
*****

Reged: 02/27/11

Loc: India
Re: IC1805 new [Re: Tel]
      #5515830 - 11/12/12 11:30 AM

Hi Tel,indeed I meant the Neximage imager. I find without Barlow, framing and achieving focus is a simple task. When Barlowed with TV X2, sometimes the said Planet just snaps into view but more often than not, I need to keep tweaking and tweaking. Sometimes some adjustments in Sharpcap like gain / gamma does the trick. I don't seem to have so much issues when using a DSLR barlowed for instance. In other words this issue is more pronounced with Neximage. Could be the 6mm that you speak off.

So I thought I could pose this question on some doable method wherein a Neximage barlowed can be brought into focus on the AmCap or SharpCap screen.

I always check collimation of the scopes with a star test and find them concentric and round both inward and outward. Planets to can be seen in all their glory even at high mags. Is it therefore safe to assume, once the object in question is within the focal plane unbarlowed, there is a plane shift when barlowed? In other words, would I be better off trying to change what could possibly be some kind of 'slop' in the train? Sorry for asking so many questions but after seeing your beautiful images, couldn't help ask, especially considering you are at a much longer f/l than I.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Greyhaven
Carpal Tunnel
*****

Reged: 05/11/04

Loc: Greater downtown Maine
Re: IC1805 new [Re: Tel]
      #5516306 - 11/12/12 04:38 PM

Tel
You sure were able to bring out quite a bit of the cloud action in the zones. I hope I get a chance to try another go at Jupiter tonight. Keep shooting and thanks for all your help.
Be Well
Grey


Post Extras: Print Post   Remind Me!   Notify Moderator  
Tel
Postmaster
*****

Reged: 03/31/06

Loc: Wallingford England
Re: IC1805 new [Re: Greyhaven]
      #5517295 - 11/13/12 05:34 AM

Hi Haseeb,

I don't profess to be at all well aquainted with optical physics, but my simple experience tells me that, given a well collimated 'scope, it is significantly more difficult to bring an object to focus under high magnification, than it is to do the same at low power. Indeed to me and I'm sure others feel the same, the difficulty in performing the task, is exponential. Thus, combine this with a high frame rate and magnified atmospheric turbulence, and it's easy to understand how these factors conspire to make high magnification focusing, arduous.

In practical terms therefore, (and I, incidentally, use Stark Labs. "Craterlet" software), this amounts in my case, to firstly placing the planet in the centre of my ca. 26mm EP, which I "borrow" from my finder scope. This is introduced into the 1.25" visual back. No diagonal nor Barlow lens is used.

Now having centralised the planet, (Jupiter in this case), I then remove the EP and replace it with the X3 "Barlowed" webcam.

Moving to the software, it is quite possible that absolutely no sign of the image appears on screen, so I then begin to adjust both shutter and gain until I can at least see something.

Next, back to the focuser, (a motorised unit in my case), whereupon I start to try to achieve the best focus I can on screen. It may also be necessary to stop midway and adjust such other features as brightness, contrast and saturation. (I was taught at one stage to leave the "Gamma" control on zero).

Eventually a reasonable image will emerge although there is no doubt it will very probably be slipping rapidly in and out of focus according to local atmospheric conditions. Sometimes indeed, the image will appear to fluctuate in focus so badly as to warrant a step down in magnification; (i.e. to a X2 Barlow), which, although producing a smaller image, will likely sharpen the picture to something more acceptable.

At this point, I will normally make my capture.

Obviously on the night, I will repeat captures several times over and may even try the effect of both X3 and X2 "Barlowing".

As to processing, in similar vein, I use Registax to stack and process and Photoshop to "tweak" the image that much further as required.

Using Registax, I tend to look at the "Stack List" individually to find the best reference frame I can before carrying out the "Align", "Optimise" and "Stack".

If you are using Registax 6, I was once advised that instead of appointing a Quality Percentage to the final "Stack", the feature at the left bottom corner of the "Align" screen provides an option to select "Best Frames". This, I do find preferable.

Finally, to cover you mirror slop idea, if I read this correctly you are perhaps talking of the effects of mirror shift and/or mirror flop. (?)

To avoid mirror shift, final focusing should be undertaken in an anti (counter) clockwise direction.

Lateral flop may or may not occur, depending on the position of the OTA at the time, but cannot in essence, be avoided. On the other hand, I believe the influence of both is minimal when one considers all other conspiring factors involved but equally the large frame rate when making planetary captures !

One last tip which I'm sure I've stated before somewhere : if your image does begin to drift "off-screen" during capture, set your slew rate to a minimum and merely bring it back to the screen centre. Sure you will lose a few tens of frames to blurring, but these will be excluded by Registax during processing.

Hoping to have given you the explanation you require but if not, do please let me know.

Best regards,
Tel


Post Extras: Print Post   Remind Me!   Notify Moderator  
Tel
Postmaster
*****

Reged: 03/31/06

Loc: Wallingford England
Re: IC1805 new [Re: Greyhaven]
      #5517301 - 11/13/12 05:42 AM

Quote:

Tel
You sure were able to bring out quite a bit of the cloud action in the zones. I hope I get a chance to try another go at Jupiter tonight. Keep shooting and thanks for all your help.
Be Well
Grey




Many thanks, Grey, for you kind words and comments. I hope the "Shoot" went well last night and I look forward to viewing the results !

Best regards,
Tel


Post Extras: Print Post   Remind Me!   Notify Moderator  
Maverick199
Postmaster
*****

Reged: 02/27/11

Loc: India
Re: IC1805 new [Re: Tel]
      #5517397 - 11/13/12 08:04 AM

Hi Tel, I do follow the steps with regard to placing the eyepiece first and then the barlowed Neximage. In fact I insert the Neximage first, see the Planet in question and then barlow. Upon barlowing is where the 'shift' occurs so the 'slop' I was referring to is the focuser slop or the visual back alignment. The TV X2 barlow has a long barrel so perhaps this could be one reason? Once I figure this out then hopefully getting a planet framed and focused should be easy. I don't discount the possibility of minute adjustments to do with collimation and something I should check the next time I am out observing.

Thanks again for your great tips and suggestions which I am sure others too will find invaluable.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Tel
Postmaster
*****

Reged: 03/31/06

Loc: Wallingford England
Re: IC1805 new [Re: Maverick199]
      #5517540 - 11/13/12 09:25 AM

Hi Haseeb,

If you think the "flop" as you put it is occuring either from use of the long tubed Barlow or within the visual back, why not assess this by using a diagonal ?

This will place the whole camera/Barlow assembly at right angles to its original position and, with luck, identify where the exact nature of the problem lies. If then, in future it proves better to use a diagonal, then so be it. I'm sure you'll find that you won't even notice any slight light loss due its reflected from the diagonal's prism or mirror.

What do you think ? Does this make some sense ?

Best regards,
Tel


Post Extras: Print Post   Remind Me!   Notify Moderator  
Maverick199
Postmaster
*****

Reged: 02/27/11

Loc: India
Re: IC1805 new [Re: Tel]
      #5517687 - 11/13/12 11:11 AM

Hi Tel, that never occurred to me or perhaps I assumed ( wrongly ) that the Neximage with barlow may not work with the diagonal. Now that you say, I think I will give it a try once I get some clear skies. Thanks.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Tel
Postmaster
*****

Reged: 03/31/06

Loc: Wallingford England
Re: IC1805 new [Re: Maverick199]
      #5517800 - 11/13/12 12:09 PM

Hi Haseeb,

Given the large range of the C6-SCT focuser, I'm fairly sure the Neximage can be used with or without the use of a diagonal, including a Barlow, although of course you will need to check this out.

What I don't understand though, is why I don't have any problem in this respect but you do ?

I'll keep thinking !

Best regards,
Tel


Post Extras: Print Post   Remind Me!   Notify Moderator  
Uggbits
sage


Reged: 04/28/10

Re: IC1805 [Re: Tel]
      #5517817 - 11/13/12 12:23 PM Attachment (13 downloads)

Hey guys, I managed to get through a little bit of data from the summer last night.

This is 2h50m of 10m exposures with a QSI 583c through a Televue 127is mounted on a Paramount ME. It was guided by a Starshoot Autoguider through an Orion 80mm 'apo'. If you remember the Iris nebula I posted this is from the same week, so right after we worked out the tracking kinks for 10 months (I cringe remembering the amount of work that took).

Hope you like it! (It's the Bubble Nebula, but I figured you all could tell :P).


Post Extras: Print Post   Remind Me!   Notify Moderator  
Maverick199
Postmaster
*****

Reged: 02/27/11

Loc: India
Re: IC1805 [Re: Tel]
      #5517825 - 11/13/12 12:27 PM

Quote:

Hi Haseeb,
What I don't understand though, is why I don't have any problem in this respect but you do ?

I'll keep thinking !

Best regards,
Tel




But that's why we have chosen you as "The One".


Post Extras: Print Post   Remind Me!   Notify Moderator  
Maverick199
Postmaster
*****

Reged: 02/27/11

Loc: India
Re: IC1805 [Re: Maverick199]
      #5517829 - 11/13/12 12:28 PM

Uggbits, that image is great and the first time I have seen a brown nebula. Something different.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Uggbits
sage


Reged: 04/28/10

Re: IC1805 [Re: Maverick199]
      #5517850 - 11/13/12 12:36 PM

That's the issue with using the QSI - the colour rendition it produces is... questionable.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: << 70 | 71 | 72 | 73 | 74 | 75 | 76 | 77 | 78 | 79 | 80 | 81 | 82 | 83 | 84 | 85 | 86 | 87 | 88 | 89 | 90 | >> (show all)


Extra information
14 registered and 16 anonymous users are browsing this forum.

Moderator:  Brian Risley, panhard, mayidunk 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 86913

Jump to

CN Forums Home




Cloudy Nights Sponsor: Astronomics