heads up for cheap new sammy 2000 on fleabay £36 inc

[SkySpy]

Ok. Lets get some facts straight here folks.  

Yes. The seller told me he cannot service his trading account as he is in Thailand and has little or no internet access.  He apologised for this but said that he cannot guarentee to supply the camera for at least another two weeks (I had already waited two weeks).  However the eBay ad is still showing a Buy It Now and delivery estimate of 3-5 days.   As a a buy-it-now you are paying up front as I did and I was thinking of saving other community members woes - not my own...  

So if passing on up to date information which may concern other members is being over the top, then that's not my definition.. and certainly in future I will keep my mouth shut if this is the kind of negative commentary it is going to generate.

SkySpy

[JamesF]

I think he's way out of line.  It's not acceptable to advertise stuff for sale in that way when you know you can't deliver.  If he's capable of emailing you then he's clearly capable of emailing anyone who has bought from him to explain the situation and of taking down the listing.  That's nothing more than common courtesy.

Once or twice I've had ebay sellers email me saying for whatever reason their despatch was going to be delayed and whilst it can be irritating if you want something in a specific time-frame there are times when stuff "just happens" and we all have to give and take a little.

I'm not suggesting that anyone here is at fault.  What appears to be a good deal, appears to be a good deal and is worth posting about.

I wonder how the vendor will feel when he receives a load of negative feedback?  Were it not for the fact that he has a history of selling similar items I'd be wondering if it weren't a scammer trying to drag things out in order to get as much money as possible out of it.

James

[SkySpy]

I owe an apology to JamesF.  I misread your comments and thought you were suggesting it was me who was "out of order" for passing on the critique!  

...the joys of the english language   

[JamesF]

That absolutely wasn't my intention  I do apologise if I was excessively vague.

James

[stash_old]

I still stand by my opinion . i agree that bad communication is not acceptable or that it can be highly infuriating to see x available when in fact they have sold out - Ebay does not have real time stock control.

I totally agree that passing information to be wary is great and would never discourage anyone from trying to that but one persons experience doesn't mean he/she is a bad "ebayer". 

Unless there are many others in the wings about to put negative feedback into ebay the person has had no negative feedback in 12 months and if he/she is in Thailand (probably his source for goods) it is probably a fair 1 off excuse.

At least you are protected by Ebay so you have nothing to loose.

This not meant to offend anyone - sorry if it seems too !

[shirva]

Can be a hit and miss with ebay ..been lucky had ordered a camera and seller was slow to respond to emails ect worked out ok eventually.. thought I was on to a winner couple of weeks back,I bought a samsung ultra high resolution cctv monitor £22 delivered bargain alas no power lead and when I got one and tried it ..it didn't work..so much for tried and tested..got full refund but a waste of time and effort

[SkySpy]

Found  a good starter article for those (such as me) wholly new to the subject of video astronomy

so thought woud share:

http://www.astrosite.co.uk/my-first-tentative-steps-into-video-astronomy/

(apologies if this has been posted before but still thought it worth a mention)

SkySpy

[HiloDon]

SkySpy,

Thanks for the link. I had not seen this one before. It illustrates the opportunity to get into EAA cheaply. I'll never forget the first time I saw the Horse Head with my Sammy. There's a whole thread on CN that talks about a DIY board cam that will open a whole new world to the user. Forums like this help spread the word.

Don

[stash_old]

SkySpy,

Thanks for the link. I had not seen this one before. It illustrates the opportunity to get into EAA cheaply. I'll never forget the first time I saw the Horse Head with my Sammy. There's a whole thread on CN that talks about a DIY board cam that will open a whole new world to the user. Forums like this help spread the word.

Don

do you mean this ?

http://www.cloudynights.com/topic/497530-diy-astro-ccd-16-bit-color-6mpx-camera/?hl=ccd

if not have you got a link for diy board cam- thanks

[SkySpy]

With reference to the last article link I posted  http://www.astrosite.co.uk/my-first-tentative-steps-into-video-astronomy/  the guy is clearly a very experienced amateur, so am sure he knows his stuff, but I just wanted to run something he said in his article with other people.   

With the matter of the stock Infra-Red filter installed in the Sammy 2000 he is suggesting that it is only necessary to remove the filter if you are using the camera with a refractor.   He states in the article:

"...If your not going to use the cam with a refractor, then you do not need to worry (about taking out the stock filter) as relectors don't have the same issue with focusing IR light"

So, firstly is this true?  

Second what about Maksutov-Cassegrain's (which is what I have)?

and finally... would it not be the case that replacing the stock cam filter with a true a astronomical one be a better bet anyway?

Any thoughts?

Thanks...

SkySpy

[Dragon Man]

Spy, he is actually incorrect.

The built-in IR filters in the Samsung cameras (and even some Astro dedicated Video cameras!) are nothing but blue glass with the IR cut-off point in the wrong place in the spectrum.

They are designed for Security, and cut off at around 600nm which is still in the Visible light range. That means it cuts off the stuff you want to see. But what do they care. They are just security cameras, not dedicated Astronomy cameras.

To obtain 'Astronomical' use out of an IR filter it needs to be strictly designed to cut-off at around 675 - 700 nm (in the Infra-red range).

Like this: http://www.astronomik.com/media/produktabbildungen/astronomik/transmission/full/astronomik-l-uv-ir_trans.png

found here: http://www.astronomik.com/en/photographic-filters/l-filter.html

I think you misunderstand the bit about the Refractor. He actually says: 

"In order to make the cam sensitive to the red end of the spectrum (produced by many emission nebulae), you need to remove the IR filter that’s built-in – this is an easy process that’s documented in several places on the web – google will help you here… You then need to replace it with a higher quality astronomical one that allows more of the ‘good’ stuff through but still blocks the wavelengths that cause the problems.  If you’re not going to use the cam with a refractor, then you don’t need to worry, as reflectors don’t have the same issue with focusing IR light".

That is correct information. Refractors have trouble focussing all the colours at the same point, causing bloated stars. Adding a good quality IR filter sharpens the stars into pinpoints.

Notice he also suggests replacing the crappy one with a good one if you are going to use one at all.

Apo and ED Refractors are happy to use an IR filter, but to help improve the quality of 'Achromat' Refractors which suffer bad Chromatic Aberrations, the use of Wratten #8 or #12 yellow filters fix the problem, making Achromats ideal for Video Astronomy.

I covered that here: http://astrovideoforum.proboards.com/thread/1079/using-achromats-video

Scopes without Refracting elements don't need an IR filter but some people use them anyway. 

I hope this helps 

[JamesF]

I think you want an IR filter all the time.

There are two issues here.  One is that different wavelengths of light will be refracted at different angles through any glass.  Whilst some optical components will have been designed to bring the visible spectrum to focus at the same point that's not the case with all, and they probably won't bring IR to focus at the same point even then.

Also, camera sensors are often quite sensitive to IR so if it reaches the sensor then it can affect the image in ways you might not want.  If it's blocked by the green and blue filters on the sensor but not by the red ones for example, you'll end up with an image that is biased towards the red end of the spectrum.

I also think there's merit in replacing the stock IR filter with a proper astronomical filter.  Stock filters are often cheaply-made and not necessarily optically flat or subject to high levels of QA.  That has the potential to result in distortion in the image.  It may not be sufficient that you notice it of course, or you'd only notice it if you had two cameras side-by-side.  A decent filter isn't that expensive however so it seems like a false economy not to use one.

James

[AstroAdam]

With reference to the last article link I posted  http://www.astrosite.co.uk/my-first-tentative-steps-into-video-astronomy/  the guy is clearly a very experienced amateur, so am sure he knows his stuff, but I just wanted to run something he said in his article with other people.   

With the matter of the stock Infra-Red filter installed in the Sammy 2000 he is suggesting that it is only necessary to remove the filter if you are using the camera with a refractor.   He states in the article:

"...If your not going to use the cam with a refractor, then you do not need to worry (about taking out the stock filter) as relectors don't have the same issue with focusing IR light"

So, firstly is this true?  

Second what about Maksutov-Cassegrain's (which is what I have)?

and finally... would it not be the case that replacing the stock cam filter with a true a astronomical one be a better bet anyway?

Any thoughts?

Thanks...

SkySpy

SkySpy - Unfortunately, you read that wrongly, and you inserted words which changed the meaning of the sentence...!  (plus you misquoted me my misspelling "you're" as "your" but I'll forgive you for that )

The bit you inserted (in brackets), was wrongly assumed.  What I meant is that if you're using a reflector, you don't need to add an astronomical IR/UV filter once you've removed the little blue stock one, as reflectors don't have the problem with differential focus of the IR causing bloated stars etc.  To be honest Id still add one anyway, as keeping that pesky IR away is always a good thing, and it also acts as a dust shield for good measure! 

In short - you ALWAYS need to remove the stock filter, as it's a pile of pants   

Cheers for pointing out the ambiguous wording though - I'll  reword it on the site for good measure anyway! 

Spy, he is actually incorrect.

The built-in IR filters in the Samsung cameras (and even some Astro dedicated Video cameras!) are nothing but blue glass with the IR cut-off point in the wrong place in the spectrum.

They are designed for Security, and cut off at around 600nm which is still in the Visible light range. That means it cuts off the stuff you want to see. But what do they care. They are just security cameras, not dedicated Astronomy cameras.

To obtain 'Astronomical' use out of an IR filter it needs to be strictly designed to cut-off at around 675 - 700 nm (in the Infra-red range).

Like this: http://www.astronomik.com/media/produktabbildungen/astronomik/transmission/full/astronomik-l-uv-ir_trans.png

found here: http://www.astronomik.com/en/photographic-filters/l-filter.html

I think you misunderstand the bit about the Refractor. He actually says: 

"In order to make the cam sensitive to the red end of the spectrum (produced by many emission nebulae), you need to remove the IR filter that’s built-in – this is an easy process that’s documented in several places on the web – google will help you here… You then need to replace it with a higher quality astronomical one that allows more of the ‘good’ stuff through but still blocks the wavelengths that cause the problems.  If you’re not going to use the cam with a refractor, then you don’t need to worry, as reflectors don’t have the same issue with focusing IR light".

That is correct information. Refractors have trouble focussing all the colours at the same point, causing bloated stars. Adding a good quality IR filter sharpens the stars into pinpoints.

Notice he also suggests replacing the crappy one with a good one if you are going to use one at all.

Apo and ED Refractors are happy to use an IR filter, but to help improve the quality of 'Achromat' Refractors which suffer bad Chromatic Aberrations, the use of Wratten #8 or #12 yellow filters fix the problem, making Achromats ideal for Video Astronomy.

I covered that here: http://astrovideoforum.proboards.com/thread/1079/using-achromats-video

Scopes without Refracting elements don't need an IR filter but some people use them anyway. 

I hope this helps 

There we go - I think it got cleared up there anyways

[AstroAdam]

Actually - SkySpy makes a good point.... What about Maks? (and SCTs)?  Never really thought about them as i don't have one any more (though wish I did again now I've taken up the video astronomy - sold my C8 not long ago!)

I'm guessing as they include a corrector (i.e, a refracting component), then an IR filter would be needed?

[JamesF]

I always use one with my Mak and SCT, both because they include refracting optics and because I don't necessarily want IR reaching the sensor at all.

James

[Dragon Man]

You don't 'need' an IR cut filter in SCT's, but they do help. The sensors we use are very sensitive to IR and will pick up any IR in the object. We can't see it but the camera does.

But again, many people don't bother with an IR filter. They are happy to have slightly blurred stars to capture the IR in Galaxies.

IR filters can be a real killer on many galaxies as much of their light is in the IR.

If you want super pinpoint stars, use an IR filter. If you want to see super faint super distant galaxies, or faint Galaxy arms, don't use an IR filter.

Isn't it great to have choice 

[HiloDon]

do you mean this ?

http://www.cloudynights.com/topic/497530-diy-astro-ccd-16-bit-color-6mpx-camera/?hl=ccd

if not have you got a link for diy board cam- thanks

Stash,

That's not the link I meant, although that's an interesting one, too.

Here's the one I was referring to. Should have included it in my first post.

http://www.cloudynights.com/topic/488625-diy-camera-for-eaa-better-than-ln300/

If you have any questions about this board cam, just post them in this CN thread. David B in NM will probably answer them quickly.

Don

[SkySpy]

Thanks to everyone who has chipped in regarding the technical elements of IR filters.  Much appreciated 

SkySpy

[AstroAdam]

You don't 'need' an IR cut filter in SCT's, but they do help. The sensors we use are very sensitive to IR and will pick up any IR in the object. We can't see it but the camera does.

But again, many people don't bother with an IR filter. They are happy to have slightly blurred stars to capture the IR in Galaxies.

IR filters can be a real killer on many galaxies as much of their light is in the IR.

If you want super pinpoint stars, use an IR filter. If you want to see super faint super distant galaxies, or faint Galaxy arms, don't use an IR filter.

Isn't it great to have choice 

I didn't realise there was that much IR in some galaxies.  Well, just starting out along the road on this branch of astronomy, so am learning stuff all the time!  All helps!  Will actually do a bit more rewording on the article - that's useful info.

Thanks!

[Dragon Man]

Adam, not only does a crummy cheap factory fitted IR filter block the infrared in objetcs, it also blocks around 75% of Hydrogen Alpha which is what Emission Nebulas are seen in.

If you want to get the best of both worlds (sharp stars and H-alpha) there are specific filters which still block IR but allow the H-alpha through.

The Astronomik filter I linked to above cuts off the IR but leaves the important H-alpha line in place. This results in sharp stars, and great Nebula, but at the loss of most IR objetcs.

There is always compromise.

To give you an example of hoW a factory fitted IR filter makes a huge difference to Emission Nebula, have a look at the comparison of M42 with a factory IR and without.

This comparison was done using a Canon 350d DSLR:

Reference: http://cheapastrophotography.vpweb.co.uk/Mission-Statement.html

The most notable change in the two images is the H-alpha in the Emission Nebula. By using an Astronomik UV/IR 'L' filter will allow that same Emission Nebula to reach the sensor but sharpen the stars better on the sensors we use for Video Astronomy. The above images are done with a DSLR where star bloat isn't as obvious.

Here is the Astronomik Filter graph showing how the H-alpha line is still visible and not cut-off:

[shirva]

Nice info ken

[SkySpy]

Help!  I have now got the Samsung 2000P camera and removed the stock filter.  I thought I would try a daylight test of the camera, so duly set up with my scope, debut capture software etc.  

I have perfectly good images... except only in Black and White.   When I switch to colour I get blue and yellow bands static bands up and down the screen.  

I have looked for any necessary adjustment in both the capture software and the camera set up and can see no obvious reason for it.   

Unfortunately I did not see the advice about not buying cheap capture devices until after I got one (which I now know is chinese rip off of the EZcap) and I am wondering if it is down to this?

** Also I am getting sharp horizontal lines darting across the screen every so often... maybe the cable I am using is no good too? **

Any hints?

Thanks 

SkySpy

[Pan Euro]

It's alright I did the same. Buy the Ezcap and it will sort it out.

Ed

[shirva]

Try linking camera to a tv. This will eliminate a bad usb grabber..I have the true ezcap and knock off copy and have no problems with them.. if problem is still there recheck camera internals

[SkySpy]

Thanks to Shirva and Pan Euro for suggestions.  I tested the camera direct to a TV and no issues at all, so its definitely the usb grabber which is causing the problem.

So.. a genuine EZCap.TV 116 ordered direct from the manufacturer is on route....

and the chinky one is in the bin!

Oh well.. that's another lesson learned ! 

SkySpy