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Posts Made By: James Robinson

January 3, 2005 07:39 PM Forum: Birding Optics and Photos

LCD screen focusing aide

Posted By James Robinson
Hi, I have difficulty seeing the LCD screen in the sunlight, partly because of the light and partly because I should be wearing reading glasses. I found a handy aide for both problems, Google for "jayandwanda" dot com and look under photography for "Coolpix LCD Shade ". Describes adapating a slide viewer. It works great for me.

February 17, 2005 02:55 AM Forum: Telescope Making

Help with 80mm f/6 mystery lens

Posted By James Robinson
Hi, I have an 80mm f/6 lens that I picked up sometime ago. It was represented to me as a University Optics ED glass lens. I never got around to doing anything with it but have lately grown curious about it. Is there anyway to verify the type of glass? I read somewhere once that you could do a test for ED glass with a laser but can't find the reference.

The air spacing on this lens is so tight that I thought for a while it was cemented. I took it out of the cell (not a UO cell, an Apogee) to clean it and discovered it was air spaced.

I'm trying to decide if it is worth the bother and expense to make a scope from this lens, like I don't have enought projects already.

Thanks

Jim

March 6, 2005 07:58 PM Forum: Binoviewers

Matching eyepieces

Posted By James Robinson
Hi, I'm new to bino viewing. Occasionally you see ads on astromart advertising "matched pairs" of eyepieces. Does this imply choosing 2 from a large set of samples that are the best match? Are manufacturing tolerances sufficient that just buying a pair of the same brand/type/fl is enough? Finally, do you try to buy them at the same time so you hopefully get them from the same manufacturing batch? I already have a large collection of eyepieces, would I be able to order one or two that match what I already have or is that not reccommended? I guess I don't know how much variation there is in precise focal lengths and how much that matters.

Thanks

Jim

March 11, 2005 12:02 PM Forum: Beginning Astronomy?

Re: Filter Question

Posted By James Robinson
Here's a fun way to find out if you like this sort of thing. Order the cardboard spectrometer kit, or better yet the plastic assembled one, from these folks. www-dot-starlab-dot-com. Calibrate accoring to their instructions and just check out your filters. I have one of these, they are not precision instruments but do show the peaks on my filters quite nicely. The O-III filter should show a single peak.

Jim

March 12, 2005 08:00 PM Forum: Telescope Making

Tripod question (leg clamps)

Posted By James Robinson
OK, not a telescope question, but scopes need mounts.
Does anyone know a source for tripod leg clamps? I'm referring to the clamps at the bottom of the top section of an adjustable set of legs, typically with a large thumbscrew which tighten down to lock them. I've done all the usual web searches and can't find any. I know there are other options, but having this simple piece of hardware would greatly simplify construction.

Thanks
Jim

March 26, 2005 10:08 PM Forum: Birding Optics and Photos

Common Meganser

Posted By James Robinson
Not a great pic, taken through a 3.5" Mak. Soliciting any photoshop or other advice for getting good, or improving afterwards, shots in a small aperture long FL instrument. I really like this scope as a birding scope and want to make it work as a digiscope as well. The challenge of course is getting enough light to get the shutter speed fast enough for wildlife.

To get the shutter speed up to something usable I pushed my Coolpix to ISO 400 which is the max. I've been considering a digital SLR for a while, for most I note you can set much higher ISO settings. Would this be helpful with a slow system like a small 3.5" Mak?


March 27, 2005 12:54 AM Forum: Equipment Talk

Mak newt diagonals -- why so small

Posted By James Robinson
I recently picked up a like new Intes MN-56. Best purchase I ever made. To me it's a nearly perfect 5" scope, I'll concede a 5" APO is probably better, thus I say nearly perfect.

It's got me curious though, why can you get away with a smaller central obstruction in a MN as opposed to a Newt? A f/6 newt would require a much larger secondary, especially accounting for the fact that this scope has a very high focuser profile. What's the secret, or maybe there isn't one and MNewts are just designed for less illuminated field.

I got this BTW because I was feeling APO aperture fever and I can't afford such a disease right now. Mak Newt aperture fever will be easier to deal with, happy with th 5" right now.

March 27, 2005 02:35 AM Forum: Birding Optics and Photos

SLR advice for bird scoping

Posted By James Robinson
I've concluded I like to take pics of birds and am interested in upgrading my equpiment. Currently I am using a Coolpix 995 and either a Ranger, C5 or Questar Field model. I've had a lot of fun with it but would like to try prime focus photography with an SLR. I'm thinking of getting just a body as I probably don't have funds for the type of lens I would want. For now I'll use one of my scopes.

What is the best entry level SLR? Actually that's too open ended, are there any to be avoided? Some of the digital rebel models are attractively priced. Any "gotchas" I should look out for? I can get specs off the web but any first hand experience you could share would be appreciated. I have bought new eqpt in the past to find out a week later that it wouldn't do some critical thing I hadn't thought of.

Thanks,

Jim

March 31, 2005 04:15 AM Forum: Birding Optics and Photos

Help with Falcon ID

Posted By James Robinson
My mom took this pic out her window at a falcon that has taken up residence in her front yard. He has a large nest in a tree there. The location is Knoxville (east) Tennessee. Is it a juvenile peregrine? I don't see the dark sideburns. Got me stumped.

Jim

April 1, 2005 12:24 AM Forum: Birding Optics and Photos

Mergansers and Buffleheads

Posted By James Robinson
Most of the wintering sea ducks will be leaving us in Massachusetts soon. Any creature that "winters" in the ocean here has my respect. I got out today to try for some parting photos.

Heres a group shot, red breasted Merganser and 2 buffleheads. You don't realize buffleheads are so small until you see them with something else. That's part of the reason I never get a good photo of a bufflehead I guess.

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