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80ED and DSLR....

Started by Les R, Aug 24, 2013, 11:07:35

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Les R

After several unsuccessful attempts to buy a refractor, I am now confident on collection of a skywatcher 80ED with 2" diagonal, finder and aluminium case next saturday. (As Vinnie Jones once said..... "it's been emotional".... lol)

Anyway, the guy selling, mentioned the setup he was going for and camera he was going to buy (supersonic or something like that and doing some mod to the telescope which brings the F stop to F2 or below - I can find out the full details)

He has a modified Canon 1000D which is obviously an older model - but with less than 1000 clicks and comes with the 18-70mm (or whatever it is) lens, + 2 spare batteries, remote shutter and T mount. BUT..... the external LCD isnt working - which I'm guessing wont matter at all? Price is £150

It sounds reasonable enough - but is it something I should be investing in? (ie does the LCD screen matter or relatively low pixel count.)

I've got a week to let him know.

In the meantime... I did get the HEQ5 out last week and get it aligned fine (and 9x50 guide now accurate - but the Telrad steamed up again so thats still out!) However - I ended up needing to use the hand controller to align in the end - possibly because I wasnt sure how to use EQMOD! Is there an easy description anywhere on EQMod alignment using the PC?

Cheers


The Thing

Hi Les,

I use a 1000D. Is it modded? I would think so if the LCD is not working - probably broke the connector. Otherwise for £150 it's seems a reasonable buy.  Ideally the pixel count should match the arsec resolution capability of your scope/ focal reducer/flattener combination. There is no point having a zillions of pixels if the scope can't provide the detail to make use of them all. That's partly why there is still a good market for small chip CCD cameras.

The lens is irrelevant unless you are going to have a go at wide field imaging. I don't have any canon lenses for my 1000D or 350D and it's never been a problem! You can control all that's needed with Canon software and something like Astro Photography Tool so the screen is pretty much irrelevant as well. I'd go for it as a way into imaging and learning the ropes.

Most important -  see a good -flat- image taken with it recently so you can check it's clean.

Hope that helps

Duncan

Les R

Thanks Duncan... Yes it is modded and I appreciate the lens wont be used - but it has value (and I do have a couple of canons already) so saying it as Im asking about the price as well as usefulness.

I hadnt thought about the pixel count in respect of the scope details. So I guess a 10MP camera is fine for an 80ED. I dont have a reducer, but will eventually.

I assume you are talking about a recent image taken attached to a telescope and unprocessed? I will ask for this - but so I explain myself well, what should I specifically ask for?

The Thing

Hi Les,

A FLAT is an image taken with a plain illumination either with an electroluminescent panel or a diffusser over the scope. This records optical defects, vignetting,  dust, blotches, fingerprints etc. and which can then be used to correct the LIGHTS (also called SUBS) which are the actual pictures of the object. You also need DARK and BIAS/OFFSET frames. (lots to learn).

The flat you want will be taken with a diffuser (can just be two or three sheets of paper) over the lens mount hole (no lens) with the camera on A mode. The resulting image will show if there are any marks on the CCD or the filter/glass covering it (depending on which mod he did). A couple of marks near the edges aren't really a problem as you are likely loose the edges in processing. The image will be pinkish on a modded camera. BTW You should find out if it's Baader, Hutech or plain glass. You may need to stretch in a photo editor the image to see what there is esp. if initially it looks totally clean.

Duncan

Mac

Hi Les,

Have a quick read of this.
http://forum.orpington-astronomy.org.uk/index.php?topic=6334.0

It will give you a rough and ready overview of what to expect.

Mac.

Les R

Quote from: Mac on Aug 24, 2013, 12:48:19Have a quick read of this.
http://forum.orpington-astronomy.org.uk/index.php?topic=6334.0

It will give you a rough and ready overview of what to expect.

Thats excellent. Thanks for that..... I will give it some attention this evening.

Les R

I will ask him to do an image Duncan.

Actually its reminded me I need to check my 550D as Ive noticed a couple of dark spots that have appeared on images.

As far as I know, he said a filter had been removed. Nothing had been added - so not sure what "Baader, Hutech or plain glass" even means!

Carole

Quotethe external LCD isnt working - which I'm guessing wont matter at all?
to be honest for astro imaging the LCD can be a bit of a nuisance especially if you're imaging around others as sometimes you can't get the screen dim enough as I found out to my cost once at Kelling Heath when I got shouted at!!!!   :oops:  I now have it on the dimest setting and cover it with a jacket or something just to be on the safe side.  So I wouldn't be concerned about that and if you're only going to be using it for astro-imaging the replacement of a Baader filter or glass won't matter as focus is done manually.  

That's a real bargain of a price, it cost me £200 just to have mine modified without the cost of the DSLR in the first place.  

So long he says it's in working order I would definitely go for it.

Carole

Les R

Thanks Carole. So the addition of a filter is just so it can be used in daylight and to do with focusing?

I wouldnt be using it for anything other than attached to a telescope - or maybe some night time wide angle shots / time lapse.

Carole

I believe that's the case Les. 

Carole

MarkS

If the filter was removed and none put back then in most astro-imaging situations you will want a IR-cut filter to prevent star bloat.  Except if you are using a reflecting telescope - then you won't need it unless also using a correcting lens.

If you always use the camera with a laptop (to download the images) then the lack of an LCD is of no consequence.

Les R

Mark.... So was this filter needed to be put in when it was modified?


MarkS

Either an IR filter is put in when modified (e.g. the Baader IR replacement filter) or you simply put an IR filter somewhere in the optical path when imaging.

For instance, my modded Canon 350D always has to be used with an IR filter.

Les R

Mark, I got the reply back regarding the filter.... Hopefully it makes sense!

He is going to send over the flat image you suggested and the image count. Have to say, he is a nice guy to be dealing - unlike the previous two attempts.

QuoteBasically you have 3 main mods and many smaller ones. Two of them are that the filter which is removed is replaced by either the Baader/Hutech glass or a plain glass. This allows autofocus to still work. Autofocus isn't required in astrophotography unless you are using a camera lens for widefield imaging otherwise it is the telescope focus that needs to be adjusted.

The third is what mine is which is where nothing is replaced by removing the glass. Both have their advantages and disadvantages. The advantage this way is that without replacing any glass or by replacing with a clear glass, you actually allow the absorption of a much higher spectrum of wavelengths. The Baader and Hutech allow increased sensitivity to Ha compared to not removing the filter inside but not as much as you get by replacing with nothing or plain glass. I hope this makes sense. The disadvantage is that autofocus does not work when nothing is replaced. The clear glass is quite expensive so for the sake of autofocus for widefield (which I didn't need) I didn't replace it with anything just removed. Bear in mind that there is a second filter which still remains in the camera and protects the CMOS sensor which itself has a protective coating. In my opinion the Baader and Hutech are only worth it if you need autofucus to work.

So as you've said, I need an IR filter, which can be anywhere? Which would you recommend? Going on what Carole mentioned earlier to me, Im looking at one of those Clip in CLS filters also.

The Thing

Hi Les, 
Unless you live in another country you will need an Astronomik CLS-CCD clip filter which fits in the camera body to deal with the light pollution. I don't know if this includes a IR-cut element, my 1000D has a glass replacement so I don't need one.


Les R

#15
Quote from: The Thing on Aug 25, 2013, 19:36:51
Hi Les,  
Unless you live in another country you will need an Astronomik CLS-CCD clip filter which fits in the camera body to deal with the light pollution. I don't know if this includes a IR-cut element, my 1000D has a glass replacement so I don't need one.



OK.... so what would be the price you would expect to pay for a 1000D with this glass replacement? Bearing in mind the CLS appears to be approx £70 secondhand. I did mention above I knew this was needed.

OK had a reply back re flats. (Its a .cr2 image so cant upload. I will see if I can find a host to upload to...

Edit.... the cr2 upload.... https://docs.google.com/file/d/0B5FA5HhvEEi7RjJWNVpJaW1CSk0/edit?usp=sharing



But this is the image count..


MarkS

Les,

Be aware that there are two types of Astronomik CLS filter.
The standard Astronomik CLS filter does not cut out IR. 
The Astronomik CLS CCD filter does cut out IR.

So if you are using an ED80 (or a lens) with a modded Canon 1000D without Hutech/Baader replacement then you need
Canon + IR filter

If you want a light pollution filter as well then you need:
either:
Canon + CLS + IR
or:
Canon + CLS CCD

Currently I use a modded Canon 350D with no Hutech/Baader replacement so I very frequently image with both a CLS filter and IR filter screwed together because my Astronomik filter is not a CLS CCD.

The other thing to be aware of is that if the Canon 1000D has had its original filter removed then it affects the focal plane and it might mean that standard lenses may not be able to focus to infinity i.e. distant stars.  It may be the case, it may not be.  It was certainly the case with my 350D.  However it will focus OK on a telescope.

Mark

Les R

#17
Mark

So it sounds like I would need a CLS CCD... Ta for that. -

EDIT.... Ive spotted a non CCD at a decent price... is it worth grabbing that and adding an IR filter? How does that fit together?

I'm not intending on using it for anything other than with the telescope, so not sure why the lens part might be relevant. Would there be a use with with a lens attached? (I can only think of it being usinged on a tripod for star trails or similar. Is there anything else?)

Did you have a look at the image I posted above that you suggested asking him for? Im not sure what I would be checking for with it!

Cheers

Only 3 days to go for the 80ED and camera (if I buy that!)

MarkS

If you go for a CLS CCD you could buy a clip in filter for Canons.

If you buy a CLS you will need an IR filter that doesn't clip in - you can't clip both into the camera.

I don't use clip-in filters but use a 2" IR filter screwed onto a 2" CLS filter (the screw threads are compatible) and then the whole thing screws into the camera adapter.  But check the camera adapter for your ED80 to check it has a screw thread for filters.

I mentioned lenses because I thought you might also try widefield shots of constellations, Milky Way etc.  If you don't intend to do this then don't worry the comment about the lens focal plane.

Les R

#19
Cheers Mark.

So it would be option 2 I am likely to go for. (I hopefully have a clip in CLS sorted) That said, I'm not sure how best an IR filter would be connected. (Purely because I've not seen how it fits together. I assume it just fits screwed between the camera and telescope.)

That said.... I just reread his email and it does say that one filter is still in the camera - and from what I have read, this is for IR and UV - so the CLS (not CCD) would be OK?  (And if so, that would completely put my mint at rest with buying the modded 1000D - which cames with the standard lens (obviously surplus to requirement), 2 spare batteries, charger, remote release and T ring for £150) Not bothered about no autofocus as Id never use it with a lens and no working LCD isnt a real problem and in some ways useful! - But would I still be able to use the magic lantern firmware mod?)

Yes... I do intend to try for some wide angle shots, but dont really need a modded camera for that so would use my 300D or 550D. (Would that be ok with the CLS clip in and IS lens)

PS.... was this "flat" ok?   https://docs.google.com/file/d/0B5FA5HhvEEi7RjJWNVpJaW1CSk0/edit?usp=sharing

Carole

Confused, a modded camera would have had the IR filter removed.

If it has been removed you can put the CLS clip filter in the front of the camera and any other filter can screw onto the end of the nose piece you are using.  I've never done it this way but according to Mark this is what to do.

I couldn't open the flat file it said it was corrupt.  I'd ask him for another version, maybe put into dropbox or something.

Carole

Les R

Quote from: Carole on Aug 29, 2013, 12:44:15Confused
Haha... You and me both!
Quotea modded camera would have had the IR filter removed.

Reading through on some sites that mod, they do say there are 2 filters and the IR one is at the front and is left. i could of course be mistaken! (Which is a frequent occurence!)

QuoteIf it has been removed you can put the CLS clip filter in the front of the camera and any other filter can screw onto the end of the nose piece you are using.  I've never done it this way but according to Mark this is what to do.

Thats what I figured- but I'm guessing the size will be large and more expensive this way?

QuoteI couldn't open the flat file it said it was corrupt.  I'd ask him for another version, maybe put into dropbox or something.

Oh poo! He did send as an email - and it was me that uploaded. I'll see if I can email it direct if thats ok?

MarkS

CCDs respond to a much broader range of wavelengths than the human eye.  So the internal IR filter in the Canon is very severe because it attempts to match the human eye (otherwise photos would include extra wavelenths and appear unnatural).  As a result it cuts out most of the all important H-alpha.  After removing the IR filter the problem is that the camera is now sensitive to a very wide range of IR.  But lens design is a compromise and they are generally not optimised to focus a wide range of IR light onto the same focal plane as visible light.  So the IR wavelengths beyond H-alpha appear defocused through lenses and refractors - one of the effects of this is that stars appear bloated.  So an IR filter that cuts out the IR beyond H-alpha is needed.

Whoever did the 1000D conversion may or may not have left in a secondary filter that cuts some of this unwanted IR light.  But I've heard mixed reports about how effective this is.  That's why I recommend using additional IR filtration to be on the safe side.  A standard CLS filter does not do this additional IR filtration but a CLS CCD filter does.

Hope its clearer now ;-)

Carole

Quotethe size will be large and more expensive this way?
I can see why you want to try to do things the cheapest option - if there is one - but I am afraid imaging is not a cheap hobby if you want to do it correctly.  I have 7 x 2" filters LRGB, Ha, Oiii, Sii imagine how much that little lot cost, plus the filterwheel, also a CLS filter and a LP filter for the QHY8L.

Your DSLR is already a really cheap price, so spending a little on filters to get it right will be no more expensive than getting a modded DSLR elswhere (with filter replacement) which might not be so cheap.

There is a chap who advertises modded DSLR's on Astrobuysell, check out his prices to compare.

Carole

Les R

Quote from: MarkS on Aug 30, 2013, 08:43:01Whoever did the 1000D conversion may or may not have left in a secondary filter that cuts some of this unwanted IR light.  But I've heard mixed reports about how effective this is.  That's why I recommend using additional IR filtration to be on the safe side.  A standard CLS filter does not do this additional IR filtration but a CLS CCD filter does.

Hope its clearer now ;-)

As clear as mud! lol

Anyone want to test the camera? Picked it up yesterday, along with the 80ED. Had a quick play with the telescope last night. Very quick alignment this time, but cloud cover put paid to any real used. Plus I only have a 28mm 2" eye piece for it (and not enough time to attach the computer). I can see the advantage of having an observatory and permanent set up!

Carole, I would still need a CLS filter even if I did buy another camera. Not sure why a new camera and CLS is a better option than what I have and buying just a a CLS CCD filter which seems to be about £30 more. Or have I misunderstood something?

Carole

Glad you got them both Les, he sounded a genuine chap.  Got a bit lost with all the permutations, but hopefully you are sorted once you have whatever filter you need.

Just need to practice using it all now.

Carole


Les R

Quote from: Carole on Sep 01, 2013, 20:51:30
Glad you got them both Les, he sounded a genuine chap.  Got a bit lost with all the permutations, but hopefully you are sorted once you have whatever filter you need.

Just need to practice using it all now.

Yeh, he was a nice guy. I'm going to wait until a CLS CCD filter comes up secondhand. No rush. I've spent enough in the last 6 weeks as it is! (Plus a new 5 man tent that arrived on friday.... But I'll start another thread for that!) lol