Posts Made By: Barry Simon

A good refractor on a good night should easily handle the oft quoted 50 to 60x per inch of aperture (roughly 2x per mm). Assuming good optics and good seeing many have maintained good image fidelity at up to 80x to 100x per inch.

However it has also been authoritatively written that eyepieces in combination with telescopes that yield anything smaller that a .5mm exit pupil will not produce an image that has any more detail (this works out to 2x per mm). In essence the image gets bigger, but it degrades. In most cases on most nights, anything smaller than a 1mm exit pupil will not give a better image, just a bigger one.

With the Pronto that would mean that a 6.8mm eyepiece would give you a 1mm exit pupil and a 3.4mm eyepiece would give you a .5mm exit pupil. The respective magnifications would be: about 70x for the 6.8mm and about 140x for the 3.4mm eyepiece. Something like a 2.5mm eyepiece giving 192x would yield impressively larger images of the Moon, Jupiter and Saturn and of course any other bright object you may want to view, but your ability to resolve fine detail will not be improved and will very likely to use your terms "be too grainy".

Barry Simon

I have both a Gibraltar and a TAK FS78. As the TAK clamshell for the FS78 is too wide for the Gibraltar, I had to get a TeleVue clamshell for the TV102 and build it up on the inside with felt to work with the Gibraltar. A set of Parallax rings also work.

I feel that the FS78 is close to perfect with the Gibraltar. Both the TV102/101 and the FS102 are really a little large for this mount. Re - your question on "tracking problems" - what do you mean, this is not a motor driven mount? With a 4 or 5mm eyepiece you will have to nudge the mount along every few seconds.

Barry Simon

I did not like the orientation of the mount in relationship to the legs with the CG5 either. By placing the front of the scope and the declination/counterweight shaft between 2 legs as opposed to over one it is more susceptable to being tipped forward and over when in the so called "resting position". I cannot speculate as to why this was changed when the more traditional and stable position had worked for years with the Vixen Super Polaris, SP-DX, Great Polaris, GP-DX, the CG4 and early CG5's.

I changed mine too. I used a hacksaw and cut off the declination post. I then repositioned it in the correct place to put the front of the mount directly over a leg. It was reattached by tapping it and connecting it from the bottom with a threaded bolt. I also reinforced the surgical site with some JB Weld.

Barry Simon

Joseph,

The only Pelican case that would be large enough for your C9.25 would be the Pelican 1660. It will cost you close to $250 discount. I have the 1650 for another scope. It does not have quite enough depth to accomodate the C9.25.

Another alternative would be a storage bin. Rubbermaid makes one that I believe is their 31 gallon size. The pre-cut foam that comes in the box that your C9.25 was shipped in will not fit. You would have to cut it down somewhat, however I would not recommend using that anyway as you really want to save that along with the original shipping box in the event you ever need to send your scope in for service. The C9.25 with Losmandy dovetail attached will no longer fit in the original foam packing anyway. I would recommend cradling your scope with a Coleman sleeping pad and scrap pieces of foam (locate better grades that don't have any outgassing problems).

Barry Simon

The eyepiece pictured is likely a surplus military eyepiece sold in the 50's, 60's and 70's by Jaegers or several other companies. The 2" adapter for it is not original and could have been an add-on by surplus dealer or by an earlier owner of this eyepiece.

For years Jaegers sold a 38mm erfle which was also marketed as a kodachrome viewer as you could put it right on top of a 35 mm slide for viewing it. I have a 38mm Jaegers from 1978 but mine does not have the diopter adjustment.

Barry Simon

The bodies on the new FMT-SX2's are similar to the old. The lower rubberized objective cell skirts look a little different. The bodies still have a leatherette type skin. The chief difference seems to be in the prism top plate (where the binocular identification information is found). It looks to be a rubberized plastic or composite of some kind, not metal like in the regular FMT-SX (which have been available for at least 11 or 12 years, if not longer. Additionally the trademark yellow highlight pinstripes on the eyepieces are not visible in the promotional photos.

Markus mentioned a 10x50 model, but I have not been able to find anything about that. Does a 10x50 truly exist, or was that a mistake?

Pricing in Europe seems to be approximately 25% higher than the older models.

I have attempted to post a promotional photo of the 16x70 model.

Barry Simon

If you are a cat or a Great Horned Owl the 7.5 mm exit pupil 8x60 binoculars will be right for you. However for most people the large exit pupil will result in wasted aperture. 12x is a good magnification balanced for 60 mm objectives as they will give you a still large, but more appropriate 5 mm exit pupil. A 5 mm exit pupil is great for astronomy and more than large enough for any daylight use.

For most people, an 8x42 or 10x42 is the largest you will need for daytime use for most applications.

For astronomy I would not drop the magnification any lower that 10x with 60 mm binoculars. My personal preference based upon my days with a 7 mm exit pupil being years in the past.

Barry Simon

Ed,

As you know there is a fair amount of controversy in respect to this subject as we have both read and participated in it on the "Binocular Astronomy" Yahoo Group. I do agree that binoculars will enhance the view of extended objects, that is not questioned. I can personally attest to how much brighter and even dimensional objects like M-27 or the Andromeda galaxy look in binoculars.

Perhaps the fact that I am amblyopic (lazy left eye, with patch on the good eye as a kid, exercises, etc.) is part of the problem. Today my distance vision is excellent in my right eye at 20/10, it is about 20/30 in the left eye. I do have problems fusing bright point sources such as Sirius and the brighter planets. I have no problem with the Moon, and with stars dimmer than 1st magnitude. However my suspicion is that this amblyopia could play a role in why I can perceive no increase in brightness of point sources when using binoculars in comparison to telescopes.

One advantage of this amblyopia is when I do observe thru a telescope, I do not have to squint or close the other eye. In effect I look thru a telescope with my good right eye, and just leave the weaker one open. This is not distracting to me and is probably an advantage while looking thru the telescope.

I compared my University Optics 80 mm f/6.25, fl. 500 mm telescope on a Gibraltar mount and utilizing a 26 mm TV plossl for 19.2x and also a 17 mm plossl for 29.4x with TV Everbright diagonal to my Miyauchi 20x77 binoculars on a Bogen tripod. A pair of Miyauchi 30x eyepieces was also used along with the stock 20x pair.

My target was an easily findable grouping of stars immediately east of the star Pollux in Gemini. Space does not permit a description of this group of stars. I will add a second post about that. Curiously I coud personally not see any improvement in two eyed viewing with the binoculars vs. using just my better eye in one half of the binoculars at a time, try as I might. There was a marked improvement in the visibility of these faint stars when I switched to the 30x eyepieces. The "visible now, not visible then" disappeared, while still faint, I could always see them.

After using the binoculars, I switched to the telescope and found that the faint stars were immediately and very clearly seen as sharp, well defined points at 19x. While 29x helped, it was not necessary. No averted vision here, moving away from them and then back and they were easily seen again. In fact the telescope found another faint star below the southernmost of the 8th magnitude stars. It was faint and distinct. Moving back to the binoculars this star was hard to see, but eventually I did. It kept fading in and out.

As always, your mileage may vary, but I personally can see no advantage in terms of pulling in fainter stars, with two-eyed observing. Extended objects are seen to advantage in binoculars.

Regards,

Barry Simon

It so happens that I have both the FCT 76 and the FS 78. As you know the dewshield diameter and threads on the dewshield and the respective lens cells are the same for both scopes.

When I ordered my SolarMax 60 I ordered an adapter for the FS 78. The adapter received is a one piece machined aluminum part which replaces the dew shield. Accordingly it is internally threaded to screw on to the objective cell. It, in turn, is threaded at the other end to accept either the SolarMax directly or the T-Max with the SolarMax attached. This has the same thread pattern as the end of a TeleVue 76 or a TeleVue Pronto. Of course for a SolarMax 40 the diameter here would be different.

Unfortunately I found that the objective cell is just a little bit different for the FCT 76. In short, the part that actually houses the objective is just a little bit taller, maybe 3/8" to 1/2" on the FCT 76; so when you try the adapter designed for the FS 78, the adapter does not come down quite far enough, it's inside (ceiling) hits the top of the FCT objective cell before it can engage the threads. If Coronado can machine for you essentially the same adapter, but just a little longer, it will work with both scopes. Better measure and have them make you an adapter with the additional length as measured by you.

Note - someone had an adapter on AstroMart for the TV Genesis and the Solar Max 60. I bought it and modified it by mounting it on an extra FS 78 dewshield cut down to the proper length so that the Coronado part is close to the top of the FCT 76 objective cell, but not quite touching it. The two parts were fastened together using JB Weld. It works perfectly on the FCT 76.

Barry Simon

Sammie,

Everyone is posting on the Binocular Astronomy Yahoo Group this morning. You may want to check that out.

Temporary lulls are commonplace. Give it time or post something provocative and plenty of fish will bite on the hook.

Barry Simon