Posts Made By: Randy Roy

Wayne,

It is hard to tell what it is, could be slight oxidation. Have you tried cleaning it lately? Could be residues from your cleaning.

Nevertheless, from your description, it does not need recoating. Place the mirror on a table in a room with moderate lighting. Step away from the mirror about 3-4 feet. Does it look normal at this angle, from this distance, without an intense light shining directly on it?

If so, avoid the desire to give the mirror multiple cleanings, place it back in the tube and enjoy it a few more years.

Randy

I have a couple of Televue caps and as nice as they are, the king of hats has to be the Coronado hat. It is lightweight, but has the long sun flap in the back to protect your neck. It doubles as a sun hood, but turning it around and letting the flap drap in front of your face shielding the Sun and increasing contrast. It is beautiful, durable and functional.

The TV caps are, however, really cool!

Randy

David,

If the world were perfect and everyone measured Strehl universally the same way, I would want a Strehl ratio of at least 95%. This is because the Strehl of the total system is impacted by the central obstruction and to a degree, diffraction of the spiders. A central obstruction of 20% (by diameter) would give a perfect mirror a Strehl of .96. Add to that the effects of the spider and you are probably down to .92-.94 (and this you can't do much about). Following this reasoning, a mirror of .95 Strehl in a newt with a 20% obstruction would have a total Strehl of about .87-.89--comfortably above the generally accepted level for the diffraction limit of .80 for Strehl.

I agree with Gary, however, and that is Strehl can be misleading due to the various ways it is measured and reported. A manufacturer could report a high Strehl ratio, for example, where a mirror of lower Strehl, could be smoother and provider better contrast. Like one of the other respondents wrote, the true test is in the observing. I would keep a mirror without a test document or with a any Strehl ratio listed on a test document over a 99+% Strehl, if I were satisfied with the image contrast and overall quality.

As far as effects of atmosphere, my own experience convinces me that excellent mirrors outperform mediocre mirrors in any seeing. Sorry, but that has been my experience consistenly over the years. Others feel differently, but just take note at the different star parties under different conditions and I think most would agree.

Best wishes,

Randy

I know of three mounting plates that will work:

Stellarvue
Losmandy GM-8 Universal plate
Astro-Physics 7" (SB0800)

Mount your rings to one of these plates and these plates are drilled to mount to a TV head. BTW--The Losmandy and Astro-Physics plates can be purchased from Anacortes.

Randy

Doug,

You have the right idea. I've shipped SCTs many times and never had a problem. Of course, the original shipping material is usually best. If you don't have that, bubble wrap around the OTA and dense foam to isolate the whole rig from the sides of the box is good. The main thing is to make the pack job on this box nice and tight. Be sure to turn the focuser (usually clockwise) so that the primary mirror is all the way back and whatever you do, double box the whole thing. Make sure there are no loose parts--tape everthing down firmly.

Take a few quick pictures of your pack job, insure the package for the replacement value and don't sweat it once it leaves your hands.

Best wishes,

Randy

Hi Paul,

My name is Randy Roy--perhaps a distant Confederate cousin, by marriage:>)

I go to Blanchard Springs Park quite a bit. While visiting there you could enjoy the beautiful caves and local hiking trails. A few miles down the road outside the tiny town of "56" Arkansas is a campground named "Gunner Pool" which enjoys a beautiful mountain spring year round. Still a few miles farther down the road is Barkshed, an excellent and dark campground. All these sites are part of the Sylamore trail system in Arkansas and follow a beautiful mountain stream with high rock bluffs, waterfalls and incredible vistas. If you are into fly fishing, you can harvest trout during the day and observe the stars at night.

No, I'm not employed by Arkansas' dept of tourism. In fact, I live outside of Memphis where things are more 'civilized' (a.k.a., light polluted).

Best wishes,

Randy

I'll go along with the crowd recommending the 24mm Pan. If you had a 2" focuser I would recommend the 22 Nagler. My reasoning is the 24mm Pan will give 62X at with an exit pupil of 5.1mm which is very comfortable for most of us and with optimal throughput for most of us as well. A larger ep with a longer focal length will give a wider FOV but at the expense of placing it in the pupil of your eye. If you had a 2" focuser a 22 Nagler would give you approximately 67X with an exit pupil of 4.6mm.

Perhaps an even better reason to switch to a 2" focuser is so that you can use a Paracorr with your scope. I have an F4.3 dob and would not consider being without one for use with my low power eps.

Randy

Phil,

I have the Maxscope 40 and a TV85 and have been able to observe through both setups. I believe it is a question of personal preferences only. I do enjoy having the Maxscope ready to go at all times. I especially like to use a lighweight Bogen tripod and pan head for almost daily quick peeks of the Sun. This setup is way too light for the TV85 which is over twice as heavy. But, I also like mounting the MS40 atop of the TV85 on my Tak EQ mount, especially at public events where I can show white light filtering through the 85 to give context to the Ha.

One consideration: I used to travel by air a lot and take my scope with me. If I were still doing that, I would prefer the SM40 to prevent taking multiple scopes.

Many will tell you the Maxscope is optimized for Ha, but in my comparisons, the views through the SM40, even through pretty cheap scopes, was comparable to my MS40.

Best wishes with your selection.

Randy

Jorge,

The difference in today's Telepod, Panoramic and Gibraltor heads is the little sticker on the end of the altitude bearing that bears the name of the mount.

The old style Gibraltor head was not drilled for eyepiece caddies and had a slightly larger azimuth bearing.

There also is a new Gibraltor 5 head made specifically to accommodate the NP127.

Post a pic of the head you have and about a thousand folks here can tell you which you have.

Hope this helps.

Randy

Darrell,

Thanks for letting us dream along with you. If I had your opportunity, I would also consider:

10" Ritchey-Critien on a Titan mount
16" Parallax Newt on their mount
16" Parks F5 Observatory setup
C14 on Titan mount plus 4" TMB guidescope

Whatever I did--if I had the cost of a Meade 16 GPS to spend--I would start with an excellent mount--at least the Titan, Mountain Instruments, Tak NJP, Paramount, etc. Then I would buy the best OTA that suited my needs with what was left over.

Best wishes with your move and observatory.

Randy