You never came across Barlow lenses?
Originally Posted by Larry.Manuel
Correct - a Barlow lens is just another name for a 2X teleconverter.
Originally Posted by Q.G.
Good morning, Wayne;
While I have a "GoTo" telescope also, I am now trying to set up a fairly good "German Equatorial Mount" for use in astrophotography. It will easily work with either film or a digital sensor camera. I am doing this for the learning experience, mainly. It would probably be more cost effective to just buy a mount already set up for this work, than to make the conversion myself, but that probably would not be as much fun.
A workable tracking mount for astrophotography -- not just visual observing -- will start at about $ 2500. A really good one such as the Software Bisque Paramount ME will be about $ 10,000. That is for a mount for the optical system; it is not the price for a telescope. These prices may seem unusual until you remember that this is a precision electro-mechanical system that must work precisely for hours during a long exposure in temperatures that may well be below freezing. I also want to build an auto-guiding system for this mount -- that is actually my main goal. I had hope of having this ready for use this summer, but they will not be shipping some of the parts to me until the end of June, so it is going to take longer to get it done anyway. So many things seem to work out that way. Well, the skies are more clear in the wintertime anyway, aren't they, and the viewing time is longer each night then. At this time, approaching the Summer Solstice, the stars really do not come out until almost 2300 or 11:00 o'clock at night our time.
One group I can recommend is RoboScope on Yahoo Groups. I am learning a lot there.
Others have provided references to books on astrophotography. Getting your telescope to do what you want it to do while trying to take photographs of the stars is an entirely different and separate challenge.
Ralph Javins, Latte Land, Washington
When they ask you; "How many Mega Pixels you got in your camera?"
just tell them; "I use activated silver bromide crystals tor my image storage media."
Alternately, you could get your feet wet with something like the AstroTrac TT320X (google it) and an SLR with a long telephoto for some wider field stuff.
Or for the ultimate in bang for the buck, make your own Scotch, Haig, or barn-door mount. Dave Trott's variation has better guiding for longer times.
Thanks Ralph and Lee. Interesting project your doing there Ralph. Are you going to blog it?
In my research to get a setup hopefully by years end I'm coming to appreciate the whole genre of astro-photography. It certainly isn't for the faint hearted. Unfortunately it appears as concerns camera systems a D might be the way to go.
My brother has a 4-5" reflector telescope out in AZ. I would like to get a clockwork mount for it for observational use, but I've not studied the abilities of the scope for photography since I'm in FL. We did at one time observe Saturn's rings which was neat when it was here in FL, land of ever present clouds in the summer. Once I'm out there in Dec I'll be looking to mount it on a German Eq mount till the funds are available for a better scope.
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Apropos mounts: are there cheapish clockwork (don't mind if it is electric either) mounts available that anyone can recommended?
The AstroTrac TT320X looks fine, but the price tag ...
Here are the names of other products of which I'm aware that are designed for wide field astrophotography:
Purus - German made mechanical clockworks drive - out of production AFAIK, and in the lower price ranges - needs to run for a full minute without adjustment to reach a correct stable drive rate before the exposure is begun
Byers Cam Trak - discontinued, sought after, made by a premier maker of professional telescope drive gears - electronic
Kenko Skymemo - still available new for about the same price as the AstroTrac TT320X - electronic
Kajers 7700 - discontinued AFAIK - electronic
Takahashi Teegul Sky Patrol - available around US$1000 - electronic
Astro Kits ( http://www.company7.com/library/astrokit.html ) - out of production, few sold, around $125 new - 4 AA batteries or DC supply
Orion Min-EQ Tabletop EQ mount
- needs one of two available electric motor drives (with or without hand correction paddle) to track for photography. Base unit about US$60, and motor setups at US$45, or US$73 with hand paddle.
Jim Ballard - Handbook for Star Trackers: Making and Using Star Tracking Camera Platforms, Sky Publishing - appears to be out of print, but used copies around
Of course you can also find a number of new or used equatorial telescope mounts that have, or can be fitted with drive motors. You'll have to do your own research on the suitability of these mounts for photography. The important features are some way of polar aligning accurately, and a drive system with a proper tracking rate and as little periodic error as possible. (Google 'periodic error' so that I don't have to write a long explanation here.)
I have used a hand built straight bolt drive, an Astro Kits motorized curved bolt drive, and a Synta EQ-6 telescope mount for my own wide field astrophotography, all with very good results when used within their limits. The Astro Kits and Synta work well with up to 15-20 minute exposures with my 180 f:4 and shorter lenses. That's getting to the limit for sky fog where I typically shoot anyway.
The current trend in amateur astrophotography is DSLRs with computer driven and timed multiple short exposures (up to about 5-10 minutes), then stacking in the computer.
Lots of leads to follow.
The Orion looks good, and quite affordable.
I should add that much of this kind of equipment trades in the classifieds at astromart.com , where people know what they're selling and buying. That and the rest of the internet killed the former print classifieds newsletter, The Starry Messenger. Some equipment reviews can be found at cloudynights.com, which often include comments on suitability for astrophotography. Sky & Telescope also publishes equipment reviews, and may be in your local library. They have a yearly index in the Dec. issue, and I think 6 month indices in both June and Dec issues, perhaps depending on publishing date. They also used to have a Gleanings for ATMs column, ATM = Amateur Telescope Maker.
Last edited by Lee L; 06-20-2009 at 01:14 PM. Click to view previous post history.
I will have a look, read reviews first, than see what is on offer.