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Re: [APML] Teleconverter advice

I was planning to use the lens on a simple tripod.  For the annular eclipse, there won't be a corona so the exposures will be fairly short.  The December eclipse in Australia will be short in duration (less than 30 seconds) and at sunset so I suspect atmospheric extinction will make it difficult to photograph the outer corona.  The short duration will make taking a full range of corona shots more difficult also, so I'll probably go for Baily's Beads, prominences, and maybe some inner corona shots up to 1/2 second or so.  For longer eclipses I still plan to use the Vixen scope on the GP mount.   The next reasonably accessible total solar eclipse of moderate duration will be in 2006; in between will be the annular in June and short total in December of this year, and a short total in 2005.
 
The corona composite on your Web site is very impressive, especially considering the relatively short focal length and non-tracking mount.
--
Alson Wong
Riverside Astronomical Society
  http://www.rivastro.org/
Visit my Web page at <http://home.earthlink.net/~alsonwong/index.htm>
----- Original Message -----
Sent: Friday, March 01, 2002 1:10 PM
Subject: RE: [APML] Teleconverter advice

Hi Alson,
 
Stick with the TC-301 combined with the Nikkor 300 f/4.
 
Although I have not used this combo for eclipse shots - I have only used the 300 f/4.5 EDIF AI-S at 300mm in order to have a wider coronal composite shot  - I have used the TC-301 in combo with this same lens on daytime images with very good success.  While not quite as sharp as the TC-14B 1.4x converter, the 2x nevertheless is very good.  I have used it in situations like bear photography when you don't want (or can't) lug a heavy 600mm lens into the field.
 
For the eclipse, I would caution you to think out your shutter speed/aperture exposure combinations carefully.  For instance, are you going to have the lens on a tracking mount?  Or just on a tripod?  If just a tripod, you will certainly need to use the lens more open than f/8 or f/11 at 600mm.  One of the reasons I photographed the 1998 eclipse at only 300mm was the problem of exposure time needed for the outer cornoa vs. having a motion blurred sun/moon, since I used a fixed tripod (no clock drive).  I struggled with what focal length to use - 300mm; 420mm (with the TC-14B 1.4x converter) or 600mm (with the TC-301 converter).  In the end I was very happy with the results at 300mm (photo on my web page if you're interested).
 
Take care,
 

Scott

website:  http://www.rsiphotos.com/
email:  ireland@gate.net

-----Original Message-----
From: owner-astro-photo@seds.org [mailto:owner-astro-photo@seds.org]On Behalf Of Alson Wong
Sent: Saturday, February 23, 2002 8:20 PM
To: astro-photo@seds.org
Subject: [APML] Teleconverter advice

I'm going to be traveling to Mexico this June for the annular eclipse and to Australia in November for the total eclipse, and instead of bringing my Vixen 102-ED and GP mount I'd like to bring a more compact setup.  I have a Nikon 300/4 ED lens which is quite good and a Sigma 400/5.6 that I haven't been too impressed with.  I'm thinking about getting a TC-301 to use with the Nikon lens to get me to 600/8 for closeup eclipse shots.  I don't plan to do night sky work with it, but I'm wondering how well it would work for eclipse and daytime shots at f/8 or maybe stopped down to f/11.
--
Alson Wong
Riverside Astronomical Society
  http://www.rivastro.org/
Visit my Web page at <http://home.earthlink.net/~alsonwong/index.htm>