Upcoming CCD nights #3

[Amar Sharma]

Hello Folks, I am 2 nights already in my set of CCD nights # 3. I will be utilizing the next whole New Moon week. This time its going to be my longest span, covering atleast 8-10 nights. My errands for the nights are going to be the following: A) On the personal side, perform or attempt functions in fine tuning the mount; like CCD drift alignment, periodic error correction using PEMPro. Additionally- i) learn auto-guiding of the CCD guiding chip (somehow I am not able to initiate this successfully) ii) taking CCD Flat and Bias frames and applying them to my images (I have no clue how I will successfully do this) All this when done should relieve my ongoing burden immensely. B) On the community side, carry on some scientific work. I have developed some more serious new-found interests (not my personal interests per se, but in duty towards contributing to the community). They are- i) CCD imaging of Variable stars - for generating light curves ii) CCD imaging of asteroids (apart fainter comets which I would in any case) - for any data reduction later on iii) Time the asteroid occultations of stars, IF any for our latitude - which is going to provide considerable data about these objects iv) Supernovae hunting - yes! I would be taking several galaxy shots based on feasibility, and later blinking them to spot possible candidates C) And for pleasing the eye, I will add to my album, several aesthetic shots of celestial objects you would not have heard before. This is the part you will enjoy the most. Its like a CCD revolution happening with me! I have spent the last couple intense occasions delving into attempting and analyzing some scientific softwares like Maxim DL, AstroArt and Astrometrica. Ending by saying --- Going by law of probability, the more you are out under the night sky, the more you stand a chance to discover a celestial object. I had a tingling few days back like the several other times I've had. Watch out! This time it was for an intuition in grabbing a new supernova (or an asteroid? Anyway in more probability than comets)! I head on with endless faith...rest is upto Nature. Hoping for the best. Thanks, Amar.

[Amar Sharma]

ISSUE !!! Doc, Ajay, Nikolas et al. plz help. After I wrote the email and connected the CCD I was faced with a drastic problem. All these weeks while fastening the camera's nose piece into the focal reducer I used to take precaution to 'extra' tighten the threadings by rotating little more than needed. Now over the long term its given way and only today has it happened that the threadings have worn out... When I fasten the nose piece of the camera into the focal reducer it tightens and then slips with just a little more rotation. I now have the CCD with its nose piece "dangling" from the focal reducer. I always would have to go near it, and for EVERY object slewed place my hands below the camera and play catch-catch, incase the worst happens. I can do it one or at max two nights all through. But how can it be forever?! What do you do when the threadings of the accessories wear out over the years? In my case its just within weeks. Moreover, how do I know which is the culprit of the two pieces? It wont be possible to purchase another focal reducer! I can try at most getting a simple nose piece from the company. This is disgusting. Its like a bad spell cast on the forthcoming week night outs I had planned. :-( :-(

[Suresh Mohan]

Dear Amar ,

 I'm sorry to hear this happen to u, I'm afraid there is no fix but try a thin twine on the thread of the nosepiece, hope this helps

Sent from my iPhone

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[Akarsh Simha]

On Thu, Feb 16, 2012 at 10:07:18PM +0530, Suresh Mohan wrote:
> Dear Amar ,
> I'm sorry to hear this happen to u, I'm afraid there is no fix but try a
> thin twine on the thread of the nosepiece, hope this helps

Usually, if threads are loose, the typical solution is to use Teflon
Tape.

Regards
Akarsh

[Arun Venkataswamy]

On Thu, Feb 16, 2012 at 9:57 PM, Amar Sharma <amar_u...@yahoo.com> wrote:

What do you do when the threadings of the accessories wear out over the years? In my case its just within weeks. Moreover, how do I know which is the culprit of the two pieces?

You can try and use a `Teflon' tape on the male thread (the one which has threads on the outside wall). Wrap the tape 2 times around the threads and then try to mate the two. You can get Teflon tapes in most engineering hardware shops.

http://en.wikipedia.org/wiki/Thread_seal_tape

For some reason, it is called Teflon tape in India!

Regards,

Arun

 

[Akarsh Simha]

It's called Teflon tape even in the US

--

[Arun Venkataswamy]

On Fri, Feb 17, 2012 at 1:00 AM, Akarsh Simha <akars...@gmail.com> wrote:

It's called Teflon tape even in the US

Yeah, my mistake.

I confused PTFE with something else... 

DuPont's PTFE is branded Teflon.

Regards,

Arun

 

[Hemant Hariyani]

Use Teflon tape like everyone has suggested and make sure that you have a backup support in case the camera falls.

Regards
Hemant

--

[Rakesh Nath]

Not recommended, I am pretty sure you will screw up your calibration with this.

I know this is really crappy but I think over long term you should plan to get a new reducer or rethread it.

-- 
Thanks and Regards 
Rakesh Nath
"It is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring." 
Carl Sagan

[Akarsh Simha]

> Not recommended, I am pretty sure you will screw up your calibration with this.
>
> I know this is really crappy but I think over long term you should plan to get a new reducer or rethread it.

Yes, Teflon is a brand name for PTFE.

Certainly, with Teflon tape, there is always some amount of error in
the angle introduced in any thread. But that should not be a problem.
It's just as though your mirror were slightly out of collimation, so
you'll have to recollimate it a bit. You might see some different
distortions etc, but the angle will be so small that unless you have a
very short focal length, just recollimating should fix all problems.

Regards
Akarsh

[Rakesh Nath]

On 02/16/2012 02:55 PM, Akarsh Simha wrote:
> Yes, Teflon is a brand name for PTFE.
>
> Certainly, with Teflon tape, there is always some amount of error in
> the angle introduced in any thread. But that should not be a problem.
> It's just as though your mirror were slightly out of collimation, so
> you'll have to recollimate it a bit. You might see some different
> distortions etc, but the angle will be so small that unless you have a
> very short focal length, just recollimating should fix all problems.
>

Bounce me off a little bit on ideas here. Lets use Amar's discomfiture
to have a good discussion. So essentially because the camera doesnt sit
flush with the focal reducer you will have the optical axis being
slightly offset.

I think this will impact the focus and ur calibration. So the
calibration is a function of stray photons etc. I think with the
introduction of a tape you will be creating air gaps to have more
background light to filter in. Now in Amar's case he's looking for
incredibly faint light, so his new photons will kind of screw up his
results.

I don't think this will be a HUGE impact but it could mean the couple of
hrs between a new discovery and missing it.

[Amar Sharma]

Yesterday after letting the CCD stay on the imaging train, because I didnt visually see it dangling, I proceeded with slewing the telescope. At 45* altitude it stayed put, so I was confident and slewed to zenith, keeping my hands below it. Before I even realized, due to gravity, the $2500 worth CCD banged on the metal floor from a height of 3 feet with a thud !!!!! The power was still on and it was running, but I was just frozen in my shoes. I had to be hopeful that such costly advanced gadgets will be designed taking this into account. My stars...the instrument was SAFE and working even after that. That means for the whole week what I had claimed to do, I CANT. Not only that, till the solution comes up, I cant do anything ! Having just forayed into the scientific world with Aditya Ravi, when I saw a bright week of activity ahead, its all chopped from the root. And for me, any single hour of the night lost, matters everything, especially when the season is not going to hold on for longer. I am feeling very distraught, till some option comes up.

--- On Thu, 2/16/12, Amar Sharma <amar_u...@yahoo.com> wrote:

ISSUE !!!

[Suresh Mohan]

Amar the next time u drop it maybe the last time , pls buy the new connector , u were simply lucky

Suresh

Sent from my iPhone

--

[Akarsh Simha]

On Thu, Feb 16, 2012 at 03:02:13PM -0600, Rakesh Nath wrote:
> On 02/16/2012 02:55 PM, Akarsh Simha wrote:
> > Yes, Teflon is a brand name for PTFE.
> >
> > Certainly, with Teflon tape, there is always some amount of error in
> > the angle introduced in any thread. But that should not be a problem.
> > It's just as though your mirror were slightly out of collimation, so
> > you'll have to recollimate it a bit. You might see some different
> > distortions etc, but the angle will be so small that unless you have a
> > very short focal length, just recollimating should fix all problems.
> >
> Bounce me off a little bit on ideas here. Lets use Amar's discomfiture
> to have a good discussion. So essentially because the camera doesnt sit
> flush with the focal reducer you will have the optical axis being
> slightly offset.

Yeah, that's what I think.

> I think this will impact the focus and ur calibration. So the
> calibration is a function of stray photons etc. I think with the

What exactly do you mean by 'calibration'? Do you mean the darks,
flats and bias? Bias should be unaffected, same with the darks. The
flats will certainly need to be redone. In fact, AFAIK, it's best to
take a fresh set of flats, darks and biases for each imaging
night. (biases and darks, I'm told, are temperature dependent, whereas
flats are dependent on collimation, alignment etc)

> introduction of a tape you will be creating air gaps to have more
> background light to filter in. Now in Amar's case he's looking for
> incredibly faint light, so his new photons will kind of screw up his
> results.

Well, the gaps should be very very minute. Anyway, you have more light
leakage from the surroundings into the telescope OTA, and that should
be more of a botheration, I'd think, since it's collected from such a
large aperture. Of course, if you shine a flashlight right at the
CCD's threads, you'd have light leakage, but you should be really
stupid to do that when collecting incredibly faint light.

> I don't think this will be a HUGE impact but it could mean the couple of
> hrs between a new discovery and missing it.

I don't think so.

Regards
Akarsh

[Amar Sharma]

After the CCD incident couple days ago and it's adapter's threading going bad, I was cast in a bad state of depression for the entire day or two (happens every now and then), fearing the thought its the end of my CCD activity for the month (till the new adapter could be ordered only by next month). I could not have afforded missing out the clear dark skies of New Moon that I have overhead me for all the various and scientific work I had just awaited to do. It was so grim with me, that this time I had decided to stop writing on b-a-s for couple days! But where there is a will, there is a way. Some new person who came along to the site for general visit, suggested to simply use Araldite. He stuck the focal reducer and nose piece together saying it's like welded now, and is one piece. That option came in as a saviour, for me. The first time I attached the CCD to the scope and it slewed around, I had this burning paranoia that it would fall down. The view of the CCD falling the first time was etched in my brain. But it would not fall this time. First night I used it as it is. Yesterday I additionally gave it extra support by tying the camera around with a string on multiple rounds, to the handle of the telescope. Will use it like this for this set of days. Now since I am back with a light heart, I will post my activities of the whole week in different reports. Hope you enjoy.

--- On Fri, 2/17/12, Amar Sharma <amar_u...@yahoo.com> wrote:

Before I even realized, due to gravity, the $2500 worth CCD banged on the metal floor from a height of 3 feet with a thud !!!!! The power was still on and it was running, but I was just frozen in my shoes.

[Akarsh Simha]

> But where there is a will, there is a way. Some new person who came along
> to the site for general visit, suggested to simply use Araldite. He stuck
> the focal reducer and nose piece together saying it's like welded now, and
> is one piece. That option came in as a saviour, for me.

Araldite is such a stupid solution. How will you detach it if you ever
want to use it without the focal reducer now? You'll either have to
use some sort of a liquid that can dissolve Araldite and thereby
sacrifice the focal reducer, or saw the nosepiece away and therefore
risk saw dust falling on the shutter or the focal reducer.

If you had only taken the trouble to go to SJP road and buy some
Teflon tape, that would have hopefully made the threads tight
(although not tight enough to obliterate the need for some external
support when pointing to the zenith), but also made your CCD portable
enough to be used on other telescopes, or at least fixable.

Now, how will you ever use the CCD on other telescopes where you don't
need a focal reducer?

Regards
Akarsh

[Amar Sharma]

Haha. Good concern Akarsh. You think I would have permanently stuck up some accessories and not realized that fact ?? The nose piece and focal reducer is dedicated for use on this telescope. If I have to use my CCD on another telescope, like the planned Aditya's 8" f/5 SW, I will have to just order another nose piece before next Amavasya. The nose piece should slide into the focusser I guess like an eyepiece end does. I would not be needing this 0.62x focal reducer and spoilt nose piece anywhere else. Who knows if the threading of the focal reducer is also bad, that is both accessories' threadings are out?! Hence I did not panic sticking it forever, since I will not be needing them elsewhere. My site is off Hosur, and there is NO way I could head to SJP road to experiment, that too after previous night being awake and commencing activity the succeeding evening, in the new moon period.

--- On Wed, 2/22/12, Akarsh Simha <akars...@gmail.com> wrote:

Araldite is such a stupid solution. How will you detach it if you ever want to use it without the focal reducer now?

[Akarsh Simha]

On Tue, Feb 21, 2012 at 11:38:41PM -0800, Amar wrote:
> Haha. Good concern Akarsh. You think I would have permanently stuck up
> some accessories and not realized that fact ??
> The nose piece and focal reducer is dedicated for use on this telescope.
> If I have to use my CCD on another telescope, like the planned Aditya's 8"
> f/5 SW, I will have to just order another nose piece before next Amavasya.
> The nose piece should slide into the focusser I guess like an eyepiece end
> does. I would not be needing this 0.62x focal reducer and spoilt nose
> piece anywhere else. Who knows if the threading of the focal reducer is
> also bad, that is both accessories' threadings are out?! Hence I did not
> panic sticking it forever, since I will not be needing them elsewhere.
> My site is off Hosur, and there is NO way I could head to SJP road to
> experiment, that too after previous night being awake and commencing
> activity the succeeding evening, in the new moon period.

Oh wow, okay. I didn't know that the nose piece is a replaceable
thing. That makes sense. Awesome.

Jugaad (but undoable) fixes to save new moons are totally worth it!
Remember my telescope's Altitude bearing?

Regards
Akarsh