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ZEISS DTI thermal imaging cameras. For more discoveries at night, and during the day.

Canon 450D + Skywatcher 80ED (1 Viewer)

Thanks !

Eyepieces are no good for birding then i take it.

The MAX dslr is next to buy, and a 2" ED Barlow then. Yes, sorry - i forgot about you using the barlow housing as your ext tube. I'll have a go at that before i waste money on ext tubes

I may have to wait till some of my gear gets sold off - I blew my main wedge on the above, but i should get a decent price for my 500 sigma - assuming someone wants it.

I've also emailed jwpone, who appears to have not posted here in months, but have read that he used an AF confirm chip - i really need to pick his brains to find out how this works with a scope
 
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The eyepieces will be ok for birding. he 20mm will give 30X and the 5mm will give 120X.

I'm not sure if the 90° diagonal accessory that you have is a mirror or a prism. If it's a mirror then the image will be the correct way up but will not be correct left to right. If it's a glass prism then it will be correct all ways. It's not too much trouble with a mirror and you get a good quality image but just remember the left/right thing. The prism ones are cheap enough on ebay though if you wanted one.

Paul.
 
Thanks again Paul

As i have zero experience, i dont know how having a diagonal will help or not help me.

If i find they're a good thing, and its a mirror type, i'll hunt down a 2" prism angle viewer :king:

I have now ordered and paid for a 2 " MAX Dslr for my EOS from scope n skies !!
 
Without the diagonal the image will be upside down if you just put an eyepiece in the back of the scope. This is fine for astronomy but for daytime use we use the diagonal to get the image the right way up.

For photography however the image is the right way up without the diagonal.

Paul.
 
I presume you are talking about short, medium and long eye relief. Not sure what your eyepieces are but the 20mm is probably medium and the 5mm probably shorter. Can't see you ever having a problem using a barlow with the eyepieces. I use the GSO with a long eye relief eyepiece and it works fine.

The Televue Powermate on the link you posted isn't of much use to the digiscoper. The quality of photograph from them isn't anything special, certainly no better than the GSO barlow and they only offer one fixed magnificaton. With a barlow you can move it further away from the camera and gain considerable increase in magnification. This is done by inserting a macro tube between the camera and the Max DSLR. Unless you plan on looking at very distant stars then Powermate isn't really worth spending the £225 for the 2" one.

Paul.
 
Musoman said:
Ok noted - cheers.

With regard to eyepieces, what length is considered short, medium , long ?

I'm asking because of this:

http://www.televue.com/engine/page.asp?ID=42
Click to expand...

There is no rule but the average range of the length (focal length) of the eyepieces is between 2mm and 30-40mm. So probably the short is 2-10mm, medium 10-20mm and long 20-40mm.

Paul, please can you post a link to the GSO 2" ED barlow? I try to buy one and since there are different names in different shops, the better way to identify it is visually. Thanks .
 
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Thanks you guys

I wouldnt buy a Power mate, because of the price, And you've already stated that the ED GSO is pretty good for what it is. I would have preferred a 1.4x / 1.5x rather than a 2x but i cant seem to find a 2" GSO ED in anything but 2x

The link was really to see what you thought of those guys talking about the problems of adding a TC. An ED GSO is what i'm after - and the ED glass will of course match the ED glass in the Evostar - nice :)

I'll figure it all out in the end, i suspect, like i did with DSLR photography, but of course i only did that by picking people's brains and then trying stuff out, so i'm well on my way with Digiscoping, thanks to you two :t:
 
Musoman, screwing the GSO barlow element into the Max DSLR will make it around 1.5X anyway. This is because the distance to the film plane isn't all that much and so magnification of the barlow is reduced. You can vary the distance of the barlow from the film plane by inserting macro tubes between the camera and the Max DSLR. The longer the tube you add in then the greater the magnification.

Paul.
 
Looking at some old experiments I did you can get the barlow up to around 6X magnification (3600mm equivalent) before it stops increasing.

Paul.
 
Excellent :)

I've read here that someone used Kenko extension tubes.
Presumably, they are just a tube that slide fits , rather than being threaded ?
 
valy said:
There is no rule but the average range of the length (focal length) of the eyepieces is between 2mm and 30-40mm. So probably the short is 2-10mm, medium 10-20mm and long 20-40mm.

Paul, please can you post a link to the GSO 2" ED barlow? I try to buy one and since there are different names in different shops, the better way to identify it is visually. Thanks .
Click to expand...

Here's a link to the GSO one. Note, this is the new version as I have the old version. The new one has the added light baffle in front of the element to reduce ghosting or stay light issues that I suffered with on the older model. Get the new version if possible or you will have to baffle it yourself. On the link look at the enlarged photo and note the ring just in front of the glass. On the old model it is shiny black and about a 45° angle but on the new model it is now not shiny and it's 90°.

http://www.agenaastro.com/GSO-2-2x-ED-Barlow-Lens-p/obar-gs-gs22b.htm

Paul.
 
Musoman said:
Excellent :)

I've read here that someone used Kenko extension tubes.
Presumably, they are just a tube that slide fits , rather than being threaded ?
Click to expand...

Macro tubes are a bit like empty teleconverter tubes and they fit together with the same bayonet fitting as the camera. On the cheaper ones they screw together but have the correct bayonet fitting at each end which means it takes a little longer to change the length as you have to screw all the bits together. The more expensive ones are a nice matt black inside while the cheap ones are shiny black. Shiny black is just a source of unwanted stray light that can decrease the contrast of the photo.

Paul.
 
Gotcha

So if you say the cheaper ones screw together, what do the quality ones do ? Surely all tubes must have a bayonet mount each end ?


Would these be the quality ones

http://cgi.ebay.co.uk/Kenko-Auto-Ex...ItemQQptZLens_Accessories?hash=item439b93a1f1

and these the cheap ones .. but they're not screw, they're EOS bayonet, just like the very expensive Kenkos

http://cgi.ebay.co.uk/Macro-Extensi...ns_caps_hoods_adaptors_ET?hash=item45efbec087

I cant see what the difference is. They're just tubes, and as long as the inside is matt black , where's the extra £80+ been spent on the Kenkos?
 
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Well this is where camera gear just gets pointlessly expensive. The Kenko ones are a series of separate tubes each with their own bayonet fitting so it's very quick to link them together or take them apart. They also relay camera information back to the camera via electronic connections so you can still auto focus, take meter reading etc.

The cheap ones don't relay any information to the camera and don't allow auto focusing etc. Plus because they only screw together they take much longer to to take apart, change the length by removing or adding a section which has to be screwed/unscrewed and then screw the bayonet back on. I've got a couple of sets of the cheap ones and they are ok as long as you don't mind the points I made. For digiscoping they are fine because you only really need them as a sort of extension between the camera and the barlow.

Paul.
 
The cheap ones are 55mm plus the bayonet at each end gives around 60mm. That will take the barlow to around 2.5X magnification. Two sets takes it to to 5X and then the magnification really tapers off. I've tried a third set which only gave me around 6X so the extra 1X isn't much for the added 60mm of extension or the 180mm overall which is quite a lot. One day I'll get another GSO and because the GSO barlow lens cells are threaded they can be screwed together easily.

Paul.
 
Ok thanks - noted.

Without any Ext. tubes, you mention the 2x GSO would be approx 1.5x ... when adding one 55mm Ext. tube, you approximate, with bayonets = 60mm and would give 2.5x, but is that taking into account that the barlow is actually starting off at about 1.5x without a tube ?

Tricky stuff this scoping lark, isnt it ? ;)
 
Yeah, that's with all that taken into account.

The way I personally work out the magnification is to shoot a stationary object with the scope at 600mm and no barlow. Then I use the barlow with a macro tube to increase the magnification and take another photo. In Photoshop I overlay the 600mm one onto the magnified one and make the 600mm one semi transparent by adjusting the layer transparency. Then using the percentages I increase the 600mm in size until it matches the photo taken with the barlow. The transparency allows you to see when they perfectly match. The percentage needed to get them to match up is your finial figure for the magnification.

For example if you had to increase the 600mm photo by 350% to match up with the barlow one then you know it's 3.5X bigger and the barlow in that position is giving 3.5X magnification. It's harder to describe than to actually do. ;)

Paul.
 
Its pure magic :)

Anyways - all appreciated. The seller has told me that the courier has already picked up the scope kit - its on its way :eek!:
 
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