80ED and DSLR....

[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]

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.

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]

the 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!!!!     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.

Basically 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.