Posts Made By: John Biretta

Post some pics when you are done!

I always enjoyed stopping by Company 7 if Bruce was on-duty -- we'd often spend an hour chatting, he'd show me the latest new stuff, make useful suggestions, etc. Even sell me a couple eyepieces or scopes now and then. My wife would sometimes show up there looking for holiday or birthday presents, and she'd remark how helpful and patient Bruce was. All-around good guy!

Very nice!! What lens / camera?

I grabbed a couple 2" diagonals and did a quick eyeball measurement with a ruler. I got 45mm clear aperture for Astro-Physics, 44mm for TeleVue, and 41mm for William Optics. In all cases the restriction is at or near the internal safety stop (i.e. near the base of a 2" eyepiece). These are all older diagonals (5+ yrs old), so I can't say whether current production might be different.

For typical F-ratio scopes it will only impact the very edge of the field of view, and the light loss there won't be noticeable to most folks. In any case it will be difficult to get 100% illumination at the field edge if you've got a 46mm field stop in 2" barrel -- lots of light rays will end up hitting the inside of the eyepiece barrel either before or after the field stop -- the illumination at the field edge is already compromised by the eyepiece design. Of course, it would be nice if the diagonal did not contribute further light losses, but in practice if the eyepiece has 45% light loss at the field edge already, and the diagonal increases this to say 50% loss, its not going to be perceived as a large impact.

Another approach I have used for my Vixen mounts is to use a 12v batery pack (available at most auto stores, Walmart, etc. -- for jumping cars). And also get a 9v car adpater -- it will plug into the battery pack and drop the 12v to 9v -- get one that has interchangable plug tips -- probably Radio Shack will have them.

Also check the polarity of the connector before using it with the mount -- you need to get the correct polarity for the center pin of the connector -- either + or - voltage -- you can check it with a volt meter on the old battery pack, and then make sure you get the same polarity on the 9v adapter. I recall that some Vixen mounts have center - plugs, which is different from nearly all other power plugs.

I presume the scope has a shroud or solid tube already? That would certainly help.

I try to park the scope horizontally when not actually observing, and aimed away from the beach, so junk blowing off the ocean is less likely to settle on the mirror. Get some sort of water-proof cover and keep the scope covered as much as possible (though it will need to be uncovered to cool around sunset). A canopy or something similar will help keep the sun off the scope during the day, so it will need less time open to cool in the evening.

Could you fashion some sort of cover for the front of the mirror? It might allow you to cool the scope at sunset, while keeping the mirror protected a little longer. My Meade LightBridge had a mirror cover, and that seemed to help.

I've not had serious problems with mirrors collecting stuff -- not to the point of damaging the views. But my experience is limited to 1 week stays near the beach, so I am not sure whether I would have much worse problems at 2 or 4 weeks.

Would it be possible to fill a spray bottle with distilled water and spray off the mirror after observing sessions (i.e. spray with some force to dislodge stuff)? Followed by pouring more distilled water over the mirror to rinse -- hopefully the poured water will sheet-off leaving it nearly dry. I have seen fellow observers at the beach doing something similar, though I've not tried it myself. It will depend whether you can easily reach the mirror, and if your scope structure can tolerate being wet.

I suppose with the refractor you could get a protective clear filter to put over the front. Or perhaps carry the scope farther from the water when not observing. But otherwise the refractor lens will be similarly exposed to the stuff.

I am aware that Newport Glass Works lists achromat glass kits from 4" to 8" on their website.
http://www.newportglass.com/angwcat.htm
and scroll down the left menu until you reach achromat kits.
I don't have any recent experience ordering from them.

I like:

a) Most of it works ok

b) Good search capability and old ads with photos. Good for researching old telescope equipment.


I hate:

a) The way my web browser (IE8) freezes for 12.6 seconds while the Facebook "Like" thing at the upper
right loads. No one has ever clicked on the "Like" thing even once all these months its been on there
for most of the pages. The "Like" rating is 0 for most of them. Yet it causes a 12.6 sec delay every time
I load a page with it. Can't we just assume no one will ever click the "Like" thing and take it
off the pages? Maybe leave it on the home page if you really need it somewhere.

b) If you navigate to "account menu" then "unused ratings" and then click on one
of the ads to remind yourself what it was, you are stuck there on the ad. It displays the
ad, but the browser "back" button won't function. You have to start over at the top menu
to get back to where you can leave the rating.

c) If you go to give someone a rating and click "cancel" nothing happens. OK, OK I guess
I could just close the page instead.

It seems the programmers did something to the Facebook "like" rating thing, but the web browser freezes I'm
getting are now MUCH WORSE than before. I'm seeing timings up to about 37 seconds for the Astromart
web pages to load. Probably it must be related to using IE8 browser on Windows XP. Some particular timings:

http://www.astromart.com/ -- 25 seconds to load

http://www.astromart.com/news/ -- 33 seconds to load

http://www.astromart.com/classifieds/ -- 33 to 37 seconds to load

http://www.astromart.com/auctions/ -- 29 seconds to load

It does appear they took the "like" thing off some of the pages. Thanks.

This sounds like the problem I reported yesterday.... Guess I'm not the only one.

http://www.astromart.com/forums/viewpost.asp?forum_post_id=805258