Posts Made By: Richard Keppler

David McGough said:

Hi,

In ad 768077 for an old 5" f6 NASA glass triplet, there is mention of "VERY beginning amount of crystalline structures in the lens".

What is this referring to, devitrification of some sort? Is this something peculiar to this old NASA glass and that those of use with later EDTs and the like never need to worry about?

Dave

Can you see it? Then you don't have to worry about it.

Tom Nigrelli said:

Does any one know where i can obtain the rubber grib material that is used on focus wheel of binoculars.
Seems to be a generic item that is glude onto focuser wheel.
Thank for any help.
Tom Nigrelli

It is probably liquid latex. The object to be coated can be dipped into it with multiple layers to build it up. Be sure to clean any metal parts with hot water and soap and thoroughly drying followed by acetone before applying the latex. Do NOT use acetone on most plastics! Once you start applying the latex, let it dry between coats. Drying time varies depending on humidity, temperature and brand/viscosity/thickness of applied layer.

You have to make a flat by shooting a short number of frames towards the center of the sun, slightly out of focus so that sunspots are not in focus and the whole image area is fairly evenly illuminated. Stack this and save it as a flat, hen divide the image by the flat using software. If you you the most recent registax, it has a facility for doing this. Check out registax for more on it.

Timothy McDougall said:

Got to be on the old 180 list though...good luck to those who are...

http://www.astro-physics.com/index.htm?whatsnew/whatsnew

Yeah, it's too bad. After years of saying that the "large lens list" or 180 list was put to bed, they pop up with this. It would have been an excellent opportunity to start a brand new list, and then draw a name off of it whenever a scope was finished and ready to go. Can you imagine the excitement and anticipation each time, as well as the hope that a person actually had an opportunity to purchase an Astro-Physics scope? Instead of that, it goes back to a list of dusty names from 15 years ago.

Ah well . . .

I thought I had found something but it turned out to be the wrong gender. I don't know a thing about the Lunt, but is the male threaded portion actually machined from the diagonal block or is it a threaded in gender changer? The reason I ask is that my Baader Herschel Wedge has the male portion threaded in to the block and it can be removed leaving a female T2 threaded hole.

Steven Sterner said:

I'm working toward using a 2" powermate in front of my Lunt BF1800 diagonal , however : I need to locate a T2 to T2 connecter (both pieces are male t2). Does anyone know of a source for these . So far my searching has turned up nothing .

THX ,
Steve

Actually, I have been looking a bit more closely and I think that this will be what you want, a T-2 Conversion Ring (10mm thick, 49mm OD) (# T2-34).

http://www.alpineastro.com/eyepiece_adapters/eyepiece_adapters.htm#Threaded%20Couplings

I looked on Anacortes but could not find a listing for it.

Rick.

John Stewart said:

I plan to fly with my new Celestron Nexstar 6 SC.
Question...
Does anyone have experience traveling with their Schmidt Cass as checked luggage only?
Is it preferable to carry on board the OTA ?
What equipment cases(s) and special precautions are other astronomers using these days to protect their...loved ones?

Thanks
John Stewart

If you are flying with any sort of telescope as checked baggage it had best be in a super durable hard shell case with at least 2 inches of firm foam surrounding it. Personally I wouldn't do it. I would chose the second option you mentioned and carry just the OTA and optical accessories (diag, ep, finder, etc) with the mount and tripod in checked luggage. You will be charged per bag of checked luggage and it cannot exceed 50 pounds total weight per piece without incurring some significant over-weight charges. Most airlines are getting very restrictive on the size and amount of carry-on luggage you can take, usually one regular size carry-on bag and one smaller laptop sized carry-on. Also, on some regional carriers, the jets or turboprops are small, both underseat and overhead compartments are smaller than usual, and the larger carry-on ends up going in the baggage compartment as well.

The stars look good across the frame and I definitely like the dust cloud detail you managed to get. Now a 180 f/9 with TCC? Which TCC did you use? For some reason I thought they are focal ratio dependent.

Barry Yomtov said:

I will be flying to Arizona this January and I would like to take a small C4 SCT scope with me for observing and imaging. My plan was to pack the C4 with the SE mount in my carry on, and put the tripod into the check in luggage. Are there any procedures or restrictions that I need to be aware of for going through security?
Thanks

It all depends on how large your carry-on is and the airplanes you will be traveling on. The small regional jets don't have a large amount of space for carry-on so if it won't fit under the seat, you may have to check it at the gate. I always put the mount and tripod into my checked luggage and carry the OTA (Sky90 or similar), or just the lens cell (AP130 - the tube goes in my luggage too), with eyepieces in my carry-on.

That is a tough choice. The net light throughput gain will result in a slight improvement to image brightness and slight increase in limiting magnitude but the image might be considerably better due to the improved coatings, quality of figure and aperture. I don't know that the scope will be any lighter weight-wise, but if it is due to improved lightweight construction techniques, it will also be a bulkier overall too. It definitely won't be a hugely noticeable change at the eyepiece but if you like to tinker . . .