Anonymous
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I'm deciding what telescope to buy, and I would like to do some film astrophotograpy with it - I have a nikon FE2 and a mamiya 645. I'm leaning towards a Mak Cass (the orion 127) and if not that, then a 3 or 4 inch refractor.
My questions -
1) Do Mak Cassegrains work for film astrophotography? I know they're slow, so there might be adapters to make them faster (like I say, I'm very new). Also, I haven't seen them with 2" diagonals, which leads me to question 2.
2)Is a 2" diagonal necessary for film astrophotograpy? I read somewhere that 1.25" will cause vignetting, again I don't know if adapters are available.
3) what is the minimum recommended GEQ mount for film astrophotography? In my dreams, I'll be doing DSOs, but the reality could fall short of that.
Thanks!
Chuck
Thanks
3)
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Suk Lee
Post Laureate
Reged: 10/07/03
Posts: 4315
Loc: Pleasanton, CA
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Hi Chuck:
> 1) Do Mak Cassegrains work for film astrophotography?
You can do it, but a 3 or 4 inch refractor would be much better. With a Mak, you're stuck with a long focal length, and hence a small field of view/high magnification. Widefield vistas are out, you're limited to DSOs and planetary work. Combine that with the slow optical speed and film and it's pretty limiting.
> 2)Is a 2" diagonal necessary for film astrophotograpy?
I wouldn't recommend any diagonal at all - you need that for visual but for astrophotography it's just another surface to scatter light. You definitely want a 2" focuser, a 1.25" will vignette. Actually a 2" focuser will also vignette a 35mm frame, but it's *much* better than a 1.25".
> 3) what is the minimum recommended GEQ mount for film astrophotography?
I'd recommend a Losmandy GM8. Combine that with a 4" refractor and you've got an excellent imaging combo.
What refractors have you been considering?
Suk
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http://www.siliconvalleyskies.com
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Anonymous
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Suk,
Thanks for your input!
What refractor was I considering? the Orion 80ed for its price and portability. It's a bit slow, though, f 8.5, I think. The 4" apos (TV, Tak) seemed a little big for carrying on airlines, so I reduced my target price, and I started leaning toward the ~80mm.
I got a bit of aperature fever, so I started thinking about a Mak. Additionally, a mak might be more comfortable for viewing, and a 5" mak is quite portable. I will be doing alot of backyard viewing from the city, so what I see will be limited unless I trek out to the country.
Chuck
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Suk Lee
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Reged: 10/07/03
Posts: 4315
Loc: Pleasanton, CA
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Chuck:
I really like Mak's for visual - I have a 3.5" and used to have a 7", but they're pretty long/slow for astrophotography.
You should check out what Chris Cook was able to accomplish with a TV85 and flattener:
http://www1.chapman.edu/oca/ai99/cook.htm
Very transportable.
Good luck,
Suk
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http://www.siliconvalleyskies.com
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wilash
Fairy Godmother
Reged: 09/30/03
Posts: 5746
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What is your budget? The Takahashi FSQ 106 is heavy but not long. You can also consider the Pentax 100SDUF II. That scope is designed as an astrograph, but it can be used visually. Both these scopes have an image circle large enough for your Mamiya - whether a camera adapter is available is something you will have to check.
The other thing to think about is telephoto lenses. They can perform better than telescopes. ebay can have some good deals on nice equipment. The FSQ has a focal length of 500mm and the Pentax, 400mm, so telephoto lenses are very good solutions.
If you like Maksutov Cassegrains, Intes Macro makes 5" and 6" F/10 scopes that have a 2" focuser and can take Meade/Celestron accessories including their focal reducers. I have a 5" Intes Macro and the vignetting is not bad on a 35mm frame - I have not put a focal reducer on it, but reducers will have more vignetting.
I would recommend two books - Astrophotography for the Amateur by Covington and Wide-field Astrophotography by Robert Reeves. While neither author really understands photographic technology and say some pretty silly things, their comments are mostly harmless. Covinton tends to go overboard with math, but for the most part it can be ignored. Reeves work does not cover lunar or planetary imaging - its basic emphasis is on deep sky. I perfer Reeves approach for getting started in this hobby. If you want to photograph the planets and moon (or sun), Covinton will have that information.
Suk Lee is right, the GM-8 is an excellent mount. Takahashi EM-10 is also very good. When considering a mount, the wieght of your equipment and the focal length you are working at must be taken into account. I would not load the mount to its limit for photographic use. It would be better to get a mount that is too big than too small. It's accuacy or how smooth it moves becomes more important with focal length.
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Anonymous
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As far as telephotos go, is there any way to increase the magnification, aside from teleconvertors. Could just be the reason I need to buy a nice long lens for birds. I guess the telescope offers that option with eyepieces.
FS 106 is intriguing, but way beyond my budget. Haven't looked at pentax. Since I could lose interest in astrophotography, I'm wary of dumping alot of $$ on a setup for it.
It's possible I'll have alot of fun once I get a decent EQ mount doing piggyback deep sky shots. For a while, I was just considering the mount with no telescope, but I like looking through the scopes.
The Intes maks are interesting. I'll have to think about them. sounds like they're better suited to photography than the Orion 127 mak cas.
Thanks for your comments!
Chucky
One thing I'm looking forward to with an equatorial mount
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wilash
Fairy Godmother
Reged: 09/30/03
Posts: 5746
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Chucky:
It sound like you want to do deep sky photography. Magnification is not an issue there. There are quite a few objects that have a greater angular dimension than the moon. (Eyepiece projection is used for planetary and lunar work mostly and increases the effective aperture very easily.) Check out the wide-field section on this web site:
http://starmatt.com/
Most of this is done with fairly common photographic lenses. If this is the stuff you would like to try, I would get Robert Reeves book Wide-field Astrophotography. He makes it quite simple. Many mounts cheaper than a Losmandy GM-8 or Takahashi EM-10 can be used. It does not require the investment that good telescopes like the Takahashi or Pentax require.
As far as Intes Micro go, ITE is a US dealer and will give you a test report with your scope. The owner is happy to answer your questions. They have a web site.
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Anonymous
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Quote:
Chucky:
Many mounts cheaper than a Losmandy GM-8 or Takahashi EM-10 can be used. It does not require the investment that good telescopes like the Takahashi or Pentax require.
How low can you go, as far as GEQ mounts are concerned, for Wide Field astrophography?
Thanks,
Chuck
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Suk Lee
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Reged: 10/07/03
Posts: 4315
Loc: Pleasanton, CA
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Chuck:
If you stick with really widefield, say 85mm and below on 35mm film, you can go REALLY low, like <$100:
http://home.att.net/~lee.suk/root/equipment/barndoor.html
I also have an Orion AstroView that I use for widefield imaging, around $250 (not including STV  )
http://home.att.net/~lee.suk/root/equipment/orion.html
Cheers,
Suk
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http://www.siliconvalleyskies.com
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wilash
Fairy Godmother
Reged: 09/30/03
Posts: 5746
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Chucky,
Since I live in Japan, I'm not able to really give prices which would be reasonable in the US. Suk Lee obviously can (nice barn-door tracker by the way). But I would also look at Astromart for second-hand mounts. Other mounts to consider used would be the Vixen line - SP (Super Polaris) or GP (Great Polaris). I'm sure Meade, Celestron, and Orion have mounts that can be used for Wide-field astrophotography.
You would want a mount with at least a single motor. Many people prefer a dual axis drive. A polar scope is very helpful. Maybe a cheap guide scope and a reticle eyepiece to drift align the mount as well. I use a Chinese 80mm f/5 scope which is also used for visual astronomy. The guide scope will let you make longer exposures and longer focal length lenses.
The great thing about this hobby is there is always something you can spend your money on. Or as my wife might say, it is not just a waste of time...
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Suk Lee
Post Laureate
Reged: 10/07/03
Posts: 4315
Loc: Pleasanton, CA
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Will:
I travel every month or so to Japan on business and am always wonder how people do astronomy/astrophotography near the big cities, particularly since I grab the mags while I'm over there and there are some really fine Japanese astrophotographers.
For example, on my last visit to Yokohama, the only thing I could see in the sky was Mars.
Do you live outside a metropolitan area or do you have to travel far?
Suk
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http://www.siliconvalleyskies.com
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wilash
Fairy Godmother
Reged: 09/30/03
Posts: 5746
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Dear Suk:
You could see Mars from Yokohama! They usually only let the moon out! Japanese skies are guranteed to be at least mag. -6.0 or better. Otherwise we would never even see the sun.
The photgraphers that work in the cities are doing mostly digital work. One of my colleagues does deep sky imaging next to his house. The street lights let him read his star charts. He never sees the targets he images, but uses a computerized mount to point and then a lot of processing afterwards. Quite an achevement considering he has an 8" Epsilon - not your average urban imaging device.
The film photographers head to the mountains (or Hawaii or Australia). Although there are many mountains in Japan, the tree line is very high. So even the highest point in Tokyo, a rugged mountian topping 6,000 feet, is still covered in trees. There are some nice spots in the Japanese alps that draw a number of imagers, but the season is short and the weather very unstable.
I live near Osaka. And the skies are a shade better than Yokohama. Getting around Japan with a scope and mount is not as simple as in the States. Puplic transportation is the best way to travel - I can get to dark skies in five hours on two trains and one bus which makes it an overnight trip. I've been working on a portable setup and hope to try it out this summer.
- Will
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Suk Lee
Post Laureate
Reged: 10/07/03
Posts: 4315
Loc: Pleasanton, CA
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Will:
Good luck with the portable setup this summer.
Suk
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http://www.siliconvalleyskies.com
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Anonymous
Unregistered
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another astrophotograpy question - i'm leaning towards a refractor now, orion ed 80 or stellarve nighthawk.
Do achro refractors "work" for prime astrophotography, or does one need to go the apo way?
Thanks!
chuck
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Suk Lee
Post Laureate
Reged: 10/07/03
Posts: 4315
Loc: Pleasanton, CA
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Chuck:
Achro's can be made to work acceptably via filtering, but you're best off with an APO for astrophotography work.
Suk
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http://www.siliconvalleyskies.com
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Anonymous
Unregistered
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Suk,
Well, in that case....
Can you loan me three thousand dollars!
Seriously, if I wanted to go down the apo astrophotography road, what would you recommend as bare minimum, scopewise. Anything cheap to recommend?
I know sturdy mounts are critical - losamandy, maybe vixen, regardless of apo or achro, so what else would I be looking at.
Thanks!
Chuck
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Suk Lee
Post Laureate
Reged: 10/07/03
Posts: 4315
Loc: Pleasanton, CA
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Chuck:
As Will said, the Vixen GP line of mounts is very good, and the Orion ED80 is getting rave reviews at $500.
I'd also look at the Vixen line of APO telescopes.
Suk
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http://www.siliconvalleyskies.com
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