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Old Dec 30, 2003, 5:05 AM   #1
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Default Spotting scope MC

What about a Mack-Casse spotting scope for digiscoping as this one?

SKYMAX-127 (EQ3-2) MAKSUTOV*
450 euro *
*

127mm (5") f/1500 Maksutov-Cassegrain
Magnification Range: x60,* x150
Diameter of Primary Mirror: 127mm
Telescope Focal Length: 1500mm (f/11.81)
Eyepieces Supplied (1.25"): 10mm & 25mm)
Red Dot Finder
90 Diagonal
EQ3-2 Equatorial Mount
Built-in Polar Alignment Scope
Aluminium Tripod with Accessory Tray

I could not find any ETX-90 for less than 300 U.S. dollar or 550 euro here in Europe. The SKYMAX-127 (EQ3-2) MAKSUTOV* is nearly the same as the ETX-90 but it offer a bigger primary mirror (more light) and a focal lengh similar to the ETX-90 (1250 for the ETX Vs 1500 for SkyWacther SkyMax)

Please help me in hurry!! Thanks and happy new year!!
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Old Dec 30, 2003, 6:36 AM   #2
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I wonder what depth of field you would get with this set-up ? From my limited experience of looking through mirror scopes I got the impression that the depth of field may be a problem....
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Old Dec 30, 2003, 10:46 AM   #3
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Sorry totoro ita, didn't respond to your question earlier in case you thought I was stalking you. (I'm stalking Graham really, he he.) You didn't reply to my last post on the Add-On Lenses forum here so thought you may be fed up of me...

The US prices you may have heard about for the Meade ETX90 were so low partly because Meade is a US company and their goods are cheaper over there, but even more perhaps because the item quoted was the ETX90RA which was a model in the process of being discontinued. As far as I know, it comprises the same OTA as the later models (and is hence as good for digiscoping) but has a much simpler mount without the electronic gizmos to help astronomers find and track objects.

You may have seen an earlier thread in which member Geordie was in the same situation as yourself and I suggested the Lomo Astele and Skywatcher models as possible alternatives (though wasn't considering anything as big as 127mm or might have suggested the Celestron C5). In the end he went with the safe route and puchased the 90mm Meade.

Don't know if you tried birdforum.net. There have been a few posts there from people who have gone down the Mak Cass route with example pictures. Generally Andy Bright there doesn't recommend using astro scopes having himself had the luxury of using top terrestrial ones. However the Jay of the jayandwanda.com site I mentioned earlier is a member there and would probably be more than happy to answer any questions you have. Like this site, birdforum.net has a PM facility you could use if your need for info is urgent. Mind you, reckon it'd be best not to rush if you can help it. Lots of pros and cons to consider.

Regards.
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Old Dec 30, 2003, 11:19 AM   #4
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I was considering the Mak-Cas Synta SkyWatcher 127 (1500mm FL - 127 mm aperture) because i found it second hand here in Italy and because the ETX-90 is not in stock in the USA on-line stores (in Italy it cost 600 euro).
I could spend the 350 US dollars for the ETX90 spotting scope but none of the shop have it in stock. My friend - who is in USA for a trip - is going to return in Italy in a few days, before the shop can obtain the ETX-90; Icould not afford to pay shipment, taxex, VAT, ect and I don't trust international shipment.
The ETX-125 cost too much and it's a 1900mm focal lengh!!!

The C5 is the best choice but it cost nearly 800 euro in Italy (600 US dollar in USA) and i could not find it second hand.

Is there something wrong with the MC SkyWathcher 127mm?
I think is quite similar to the ETX-90 for the focal lengh (1250 vs 1500) but the MC SW 127 has a bigger mirror so i can gain more light and keep the shutter faster... is this right?
Thanks
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Old Dec 30, 2003, 1:25 PM   #5
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Sort of
You get your F-stop ratio by dividing the scopes focal length by the apature.
So your Fl1500mm/d127mm = F11.8
the Meade etx90 is a Fl1250/d90mm = F13.8
the Meade etx125 at Fl1900/d125mm is a F15.2 scope, the slowest of the bunch .
I use a Skywatcher newt Fl1000mm/d200mm = F5
and a Skywatcher short refractor FL400mm/d80mm also = F5

This gives you the F-stop or speed of the main scope.

To get magnification devide the focal length of the scope by the focal length of the eyepiece so my fl1000mm with a 25mm eyepiece gives 40x, my fl400mm with the same eyepiece gives 16x.

Now that I've confused everyone, it is true the larger mirror or lense apature the more light the scope gathers and the dimmer objects it can resolve, for instance my d200mm maxes out at ~400x and a magnitude 14.2 object is about the faintest it can resolve.

(to get the 400x i'd need a 2.5mm eyepiece smallest I've been able to comfortably use is a 6mm).
With a 2x barlow (a negative lense that effectively doubles the focal length of a scope and unlike a camera teleconverter can actually can imporve a scopes performance) turns the scope into a F10 or the eyepiece into a 3mm. Getting me to 333.3x which needs real steady seeing conditions to use but that is another story.

Anyway for afocal photography you want a bigererer eyepiece like a 40mm to reduce vignetting. and with a 40mm eyepiece with the scopes discussed you get

1900mm = 47.5x @ F15.2
1500mm = 37.5x @ F11.8
1250mm = 31.25x @ F13.8
1000mm = 40x @ F5
0400mm = 10x @ F5

One big thing is weight & portability, my d200mm on its mount weighs in at 36kg so not many plans to take it in the field . The d80mm comes in soaking wet at 2kg and can mount on my manfrotto tripod.

Hope this hasen't muddified things too much.

Oh then you need to figure in whatever camera&lense you are using to look into it
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Old Dec 30, 2003, 4:18 PM   #6
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Are you primarily interested in daytime digiscoping of birds/other wildlife (tripod over shoulder, trudging along ankle deep in mud, that sort of thing) or astronomy?

If you are interested in astronomy the 127mm Mak might be worth going for. If not, can't help but wonder whether might be worth looking again. For daytime digiscoping you'll probably want a different support setup from the one you mention and the magnifications with the provided eyepieces are really too high. A Mak Cass may be of a "delicate disposition" compared to a birding scope, slow at f10+, and its long fl means that even with a 40mm eyepiece, as Peter shows, you're still getting highish magnifications. If you need to zoom the camera lens to avoid vignetting then mag goes up even more. (And by trying to use very long fl eyepieces in a Cass Mak perhaps there is a risk the central obstruction will become visible in your pictures.) Problems with camera shake, atmospheric haze etc etc mean that the best quality daytime digiscoped pictures tend to happen most often at lowish magnifications rather than the highest feasible ones.

If photographing wildlife was my interest and I could afford a S/H version of the scope you mention, I might be tempted to wait until a reasonably price S/H ED glass birding scope came along (at 80 or so mm something like a S/H Opticron 80ES (a bit new), Nikon ED78 (just discontinued) can be picked up new under 500 at the moment here in UK while a 60mm ED scope might well be available for less.) If you are interested in terrestrial and modest astro work, how about saving up for a Pentax PF80ED (400 S/H from dealer here in UK). Of course must remember to budget for eyepiece, support, possibly an eyepiece to camera lens adaptor.......

You can see why most digiscopers still are those who happened to have most of the kit already (keen birders). It's a lot of hassle and expense to get there starting from scratch
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Old Dec 31, 2003, 3:18 AM   #7
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Ciao Totoro,
I'm also writing from Italy and had exactly the same problem.
At the end of the story I purchased an ETX90 on e-bay for 149 USD from Handsonoptics (they are good seller)
I purchased only the tube that was removed from an RA mount and also a 32mm plossl was included.
The tube comes with 2 standard 1/4" in the bottom part, so you can use it on any tripod.
I paid an extra 50 Eu for VAT and import fee.
I'm very happy with the final result, especially if compared with the 2000 Eu to have a Swaro HD or something similar.
By the way this kind of the set up (I have a CP990, also purchased on ebay and shipped from US) is also very easy to use on the field because the camera is mounted above the scope, resulting in a very well weight balanced combo.
After that I put everything on an astro Alt-Az head with micro screw (also purchased on ebay).
Final note:as you can see, at least in my experience, shipping from US is safe and never had a problem
Bye
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Old Jan 12, 2004, 1:23 PM   #8
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Corvus, Geordie et al, any chance of making public some of your best pictures of terrestrial subjects done with mirror scopes? Must be difficult for someone to judge results they themselves might get based solely on the strength of Lin's three photos of fox cubs, American robin and starling.
Just a thought.
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Old Feb 12, 2004, 8:43 AM   #9
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Greetings. I have just joined this forum. I was very interested to see the disscussion on digiscoping with mirror scopes. I've been using the Meade ETX-90ra with a 32mm Orion Highlight Plossel eyepiece and Nikon Coolpix 995 for digiscoping for a few months now. I am very pleased with the results I am getting, especially considering the amount of money invested. I have posted a number of photos taken with this combo on birdforum.net under the user dendroica46. I would attach an example image if I could figure out how. Thanks.
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Old Feb 12, 2004, 8:50 AM   #10
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rick_0620:
If the site your images are on allows direct linking you use the img tags

[ img ] picture url [ /img ] (leave out the spaces between the keywords and the [ ]'s

If it dosen't you can either upload them to a photohost that does allow direct linking or post them using the [ url ] tags

EDIT:
I just tried to view your images and that site only allows viewing of thumbnails without joining, you will need to find a storage site.

There is a forum just for finding storage sites here http://www.stevesforums.com/phpBB2/viewforum.php?f=12
I myself am using www.photobucket.com
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