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Posts Made By: Joplin Motisher-Chittenden

May 11, 2003 06:49 PM Forum: Equipment Talk

Opinions re: SV 85S APO

Posted By Joplin Motisher-Chittenden

Gregory,

I've got a Vixen FL80S (80mm F8 fluorite apo) that I am very happy with. I routinely use it with a 3.6mm eyepiece for 178x on the planets, moon, and double stars. I have watched Io transiting Jupiter (the moon, not the shadow) on at least one evening with near perfect seeing. These scopes still obey the laws of optics and physics though, anything more than 60x per inch of aperture is going to yield diminishing returns on the planets. My advice is to get the Vixen/ Orion 80mm fluorite listed in the classifieds if it is still available - great scope at a great price. You would get 94% of the aperture of a TV85 for half the price. Another good option that would save some $ is the Borg 76ED at less than $900 new. It doesn't have quite the color correction of the TV85 of Vixen fluorite but it is a featherweight scope that can be mounted to almost anything. The borg with a Nexstar 80 mount would be a very sweet combination.

Joplin

May 11, 2003 11:13 PM Forum: Wildlife Photography

DragonFly

Posted By Joplin Motisher-Chittenden

That is really neat - interesting to see how it stows its legs while in flight. Reminds me of a program I saw a while back about a guy who was using high speed cameras running at hundreds of frames per second to document dragonfly flying techniques.

Joplin

May 12, 2003 08:13 PM Forum: Equipment Talk

Mosquito Remedies.... hmmmmm.....

Posted By Joplin Motisher-Chittenden

That's hilarious - I have found that one of the best defenses against mosquitos is humor. I did try wearing an old long sleeve shirt that I sprayed with DEET based repellant last night, it seemed to work quite well. Of course you to make sure you get it all off your hands and avoid getting on equipment since it melts plastic, paint, coatings, etc.

Joplin

May 13, 2003 05:48 PM Forum: Equipment Talk

Pentax K-1000 T-Ring... help...

Posted By Joplin Motisher-Chittenden

You need the K-Bayonet style t-ring. It will fit the bayonet flange on the camera. The univeral or "screw mount" style works with older Pentaxes like the Spotmatics.

Clear Skies,

Joplin

May 14, 2003 07:47 PM Forum: Equipment Talk

1rpd AstroBuffet 30mm ST80 Eyepiece

Posted By Joplin Motisher-Chittenden

See the thread over in the eyepiece forum. One note - the version he is sell now for $99 is the same as the BW Optik 30mm 80 deg. eyepiece sold by Anacortes for $99. I have confirmed that both eyepieces are threaded for filters and have blackened lens edges. The previous version is now reduced in price.

Joplin

May 14, 2003 08:29 PM Forum: Film Astrophotography - Imaging and Processing

Lunar Eclipse Photography with OM-1

Posted By Joplin Motisher-Chittenden

You can do it, the multiple exposure part will be more tricky than with some cameras though. To do multiple exposures with the OM-1 you need to wind the film fairly taught with the rewind crank on the camera, take your expossure, then hold down the rewind button while you advance the film. If the film counter moves then you are out of luck and the film has moved. You will need a somewhat wide angle lens to capture the entire event without moving the camera. If you start with umbra first contact and end when the umbra leaves the moon, the moon will have traveled 46deg. in azimuth and 15deg. up in altitude. That is just outside the reach of a 50mm lens, a 35mm would be a better choice. If you try to start with penumbra contact and end with penumbra last contact, it will travel about 75deg. in azimuth, necessitating about a 24mm lens (which would make for a really tiny moon on film - 1/5mm ). The other option is to use a longer lens but come up with some sort of grid or plan to reposition the moon to the correct place in the frame for each shot.

Joplin

May 14, 2003 08:39 PM Forum: Film Astrophotography - Imaging and Processing

Lunar Eclipse Photography with OM-1

Posted By Joplin Motisher-Chittenden

James,

I'm afraid I have to disagree with you on this. The "hat-trick" works great for deep sky shots but it isn't fast enough for lunar photography - even during a total lunar eclipse. At an average camera lens F setting like F4 the proper shutter speed for the totally eclipsed moon is going to be about 1/4 second with 200 speed film. No one has hands that fast and even if you stopped the lens down to say, F16 - the partial phases of the eclipse would end up overexposed.

Joplin

May 19, 2003 09:11 PM Forum: Equipment Talk

90 mm f/10 decent?

Posted By Joplin Motisher-Chittenden

I have a 10" newtonian and an 80mm apo refractor. The 10" will handily beat the 80mm on the planets on any night when the planets are worth observing. The 10" does need to be cooled down and collimated properly. I do prefer the views through the refractor for double stars on all but the most stable nights and for low to middle power observing of the moon (higher contrast image). The refractor also serves as my daytime terrestrial and solar scope. If you want the extra versatility of a refractor I'd say go for it, just don't expect it to outperform a collimated 10" dob (with good optics).

Clear Skies,

Joplin

May 22, 2003 05:40 PM Forum: Equipment Talk

Inside Condensation

Posted By Joplin Motisher-Chittenden

I would think that moving dry (filtered) air through the scope would be the most effective way of removing the existing condensation. I would see about getting or making a plug for the scope that has a silica gel or similar dessicant pack in it to absorb moisture so this doesn't happen again. I noticed that Astro Pro products plans to introduce a product like this, you may want to contact them.

Joplin

May 22, 2003 07:07 PM Forum: Wildlife Photography