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Messages - Cesar Lawhorn

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Light Pollution Topics / Re: LP Solution: LIGHT-EFFICIENT COMMUNITIES
« on: February 09, 2018, 07:48:45 AM »
Husky1, Education is definitely the key,I should say proper unbiased education;because too many ridiculous claims have  been made for  solar and wind power ,CFL bulbs,etc. Most of the rural security lights are utility installed  on the utility  side of the meter and billed at a fixed monthly rate;the customer cannot turn the light off if he wanted! The street and highway lights are mostly utility installed and the governmental body pays a lease fee.Two local communities  actually operate their own city electric utility ,buying power wholesale and then installing,maintaining, and billing .THOSE   are  installing some LED  streetlamps as the incentives ,economic and political must be stronger. The other area  lights mean pressuring local politicians to change contracts with  companies headquarted far away. (I am not a fan of the 1980s deregulation here which led to consolidation of so many industries,such that we lost our local gas and electric companies,our local banks,etc.An executive in some large metropolis cares little for us hicks except as  a profit source.)I neglected to mention the local economy is being propped up these last two decades by casino gambling.Casinos and their  environs are very brightly lit! And of course so must be the roads  leading there.Because of the number of jobs AND the huge boost in local tax revenue,criticism of casino operations in even mild form is met with hostility.A truck driver complained to me last week that the new LED headlights in his company trucks fail to make enough heat to melt off  accumulated or even keep snow from accumulating on those headlights.A reminder that one solution does not fit all situations.The people in an area may be strongly opinianated  for or against  something to the extent changing their minds is a Quixotic  AND Herculean task.Not sometyhing I feel up to at the moment.I have educated the county council in the past.A animal (really,people) control ordinance was passed  AFTER having been approved by the county's own lawyer;but I appeared at council with 14 pages of citations showing said ordinance conflicted with state and federal laws including the U.S. Constitution! The ordinance was rescinded and redrafted  to be less onerous and in agreement with higher law.For my trouble I received  a screaming tirade from the original ordinance supporters and a unsigned,typed letter wishing me and a local official both DEAD!(Local officials did nothing with the letter but I did state in open session that I would defend myself if necessary.)It may be of mild intereset to know I was an early  would-be adopter of CFL-and sorely disappointed by the short lifespan  and extended warm-up times of lamps costing $8 -13 ,when the ordinary incandescent  at 4 for $1 worked better and longer.I have bought at least two dozem CFL and the only ones giving good service  have been left on continuously .Early LED replacement lamps at $5 each provided barely more than a spot of light.On the other hand,heavily discounted prices after Christmas make strings of LED in red or white useful  cheap and effective  for pathway lighting.Anyway I am not convinced outlawing incandescents is the solution as much as simply directly proper levels of illumination where it is needed.

I am hoping to have a bigger bucket for collecting light in, this coming Messier season: If I can add another 27 to my list of "seen" I'll be well pleased! And as you say, it is a great test of one's observing skills.

Three hats, a couple mohair scarves over my nose and mouth, loose thin layers all over, a wind breaker jacket with a hood, and a couple sleeping bags arranged in a kind of baggy cloak/cone was what made my 2016 early April post-snowstorm marathon moderately comfy. Hilltop, snow, some tart little breezes zinging through, minus I don't know how many degrees, but cold enough to send me down into the sleeping bags to use my breath to warm me up, several times. Also big baggy converted sweaters-slippers on my feet, with several socks underneath.

Half the fun for me was staying warm -- I'm also a snowshoer and I love the challenge of winter cold.

I'm wondering if this is a common thing to do? Do people use low magnification wide angle eyepieces as finders without using any external finder scope? What type of eyepiece would you recommend for a 690mm / 106mm refractor (AT106LE)? Thanks

My 17.5" f4.1 dob finder eyepieces are:
2" 40mm 70deg AFOV University Optics MK-70 Koenig
2" 30mm 82deg AFOV Meade 5000 UWA
2" 20mm 100deg AFOV Explore Scientic

My ST80mm finder eyepiece is:
1.25" 18mm 82 deg AFOV Meade 5000 UWA
1.25" 24mm 68deg AFOV Televue Panoptics

My Denk II finder eyepiece/OCS(s)/Power Switches are:
two 1.25" 24mm 68deg AFOV Televue Panoptics
1.0x Newtonian (38mm clear aperture) OCS or 0.89 Multipurpose (45mm clear aperture) OCS with
Low Newtonian power switch and Low Reduces Power Switch in series.

Reflectors Telescopes Forum / Re: Moonlite + Paracorr type 2 vs SIPS
« on: February 09, 2018, 01:42:07 AM »

The Paracorr lens does blur the shadow of the primary's center marker when the image passes through on its way to the Tublug screen.
This is just another reason I think the separate Paracorr is better:
1) it's removable and usable in multiple scopes, so only one purchase.
2) it's usable in any focuser
3) it parfocalizes all your eyepieces.
4) it's easier to dial in the correct position in the system the first time
5) it removes the risk of long accessories like 2" barlows hitting the lens
6) it's threaded for filters which makes it possible to change eyepieces without transferring filters.
7) it's easy to remove for collimation
8) it's easy to remove for ultra high power on planets in a tracking scope (less scatter)

All these 8 points you mention sound very reasonable. On point 3 you say "it parfocalizes all your eyepieces". What I understand is that I can change my Ethos 21 with my Ethos 10 and I dont have to adjust focus like I do now. Do I understand well?
Thanks a lot
Parfocal never means EXACT, but it does mean very close.
if changing from a 21 Ethos (setting A) to a 10 Ethos (setting H), you'd simply unscrew the tunable top to the maximum out setting before inserting the 10mm and the amount of refocusing necessary would be maybe 1 or 2mm, but it would be close to good focus when you insert the 10mm..
So pre-dialing the tunable top to the correct setting for an eyepiece means that, when you insert it, that eyepiece will be close to being in perfect focus.
And the pre-dialing of the tunable top means every eyepiece in your entire collection would be close to exact focus when it is inserted. The focuser barely moves.
In contrast, with the SIPS, when moving from the 21 Ethos to the 10 Ethos you'd have to move your focuser out 18mm (0.7") to achieve focus.

On the Ethos line, the 21mm and 17mm use the all-the-way-in setting A, while the 13mm, 10mm, 4.7mm, and 3.7mm use the all-the-way-out setting H.
The 8mm and 6mm are used as 1.25" eyepieces using the adapter, in setting B. I modified my 8mm and 6mm to use setting H like the others so I'd only have to remember two settings for the Paracorr and i could adjust it in the dark with no light.

Given what the software can do with images, I would have guessed the ideal mount for differential photometry would be any alt-az mount. The reasons would be related to their mechanical simplicity andstabilitymore than anything else.

Beginners Forum / Re: My first Telescope.
« on: February 08, 2018, 06:15:56 PM »
I observe primarily under red-zone skies with an 8" SCT on a manually-operated equatorial mount. There are several characteristics about this setup that, in my mind, make it a compelling choice for urban observing:(1) The long focal length of SCTs increases contrast especially under light polluted conditions (for more, see Rod Mollise's Urban Astronomer's Guide -- http://www.springer....k/9781846282164 -- a very worthwhile book for urban observers). (2) Especially at high magnification (i.e., when doing planetary and globular cluster observing), having only one slow motion control to work to track an object is a big advantage. You could have battery-powered motorized tracking do this for you, but I really like the simplicity (and cost savings) of a manual setup. With a Dob, I find the constant nudge-nudge in order to keep an object in the eyepiece is a less than pleasant, although not completely bad, experience.(3) I make full use of the setting circles on my Orion AstroView EQ-3 mount. While my 8" SCT is a bit too heavy on that lighter-weight mount (I wish I had an Orion SkyView Pro EQ-4 mount for that scope), I can most often find what I'm hunting for by using the setting circles to get an object in my 8x50 finder scope. When I use my 10" Dob in the city, I find that my ability to starhop is seriously hurt by the light pollution. My 10-incher is better used under darker skies. Indeed, it's my scope of choice when I drive out to a darker-sky site. At bottom, I really enjoy the challenge of finding an object manually rather than having a computer do it for me. And I like the cost savings that not having a computer entails.It's very true that a 10" Dob would be a great choice for getting the most aperture for the dollar. But I personally prefer using SCTs in urban settings for the reasons I mention above.Also, the NexStar 6se package that GaryCurran suggested is very compelling. It offers lots of gear for the price. But I've heard that the accessory package isn't the greatest. Personally, I dislike Plossl eyepieces in their shorter focal lengths (15mm and below) -- way too little eye relief.Here's another setup you may also consider piecing together:- Celestron C6 OTA (http://www.highpoint...etail-91010-xlt): $389. - Orion SkyView Pro equatorial mount (http://www.telescope...c/34/p/9829.uts): $330. - GSO 8x50 right-angle finder scope ( $70. - A decent ~$70 eyepiece in the 16-18mm range -- possibilities include those listed at ( - A good 2x Barlow lens around ~$70 -- check out Celestron 1.25" 2x X-Cel LX Barlow Lens ( Your total would be around $930. Using the supplied 25mm eyepiece, an additional eyepiece in the 16-18mm range, and a 2x Barlow would give you four well-spaced magnifications. One compelling advantage of the Orion SkyView Pro mount is that you could add on motorized tracking and a go-to computer if you found you wanted to do so in the future.Considering that you will *double* the light-gathering ability if you get an 8" SCT over a 6" one, it may very well be worth your while to hold off on a purchase and save around $300 more for the bigger scope. The Orion SkyView Pro mount would also be able to handle that larger OTA.

I got another Celestron 30mm Ultima. It's not going anywhere if I can help it. Great in f/5 scopes to f/13 scopes which I had in the past using 30mm Ultima and 30mm Pre-Ultima eyepieces.


Yes, I would love to have an observatory! At this time, I can't build one. In another year or two, I will be at a point where I can start building one.

Stelios and Dr. who have nice recommendations. George is correct on the GM811G on being a nice lite mount.

Jeff's photo gets me going on mount envy every time!!! lol (If I could find a used late model AP900 that probably would be the way to go for me. The AP900 could then become a pier mount later for me.)

I do agree with others that the Meade LX850 is a nice platform, just waayy to heavy for me to use for a portable system.

Any other thoughts???

General Astronomy & Observing / Re: Swearing off the hobby...
« on: February 03, 2018, 07:21:53 AM »

These threads come up now and then, and the usual advise is "DON'T SELL YOUR EQUIPMENT." Yeah, if you've got a telescope farm in your living room, you might want to thin the herd, but don't do it when your enthusiasm is down.
Me? I have slow, inactive periods when all I do is run out with binoculars or naked eye for a quick look at the night, but I've been using the same scope for 40 years, and I'll NEVER sell it. If my kids don't want it, THEY can sell it when they're disposing of their late father's stuff. Sooner or later, the DSO's start calling...

The DSO's start calling when we pass? I like that alliteration.
Well, a number of old legends have us walking the Milky Way...

For me it is the Astrotrac: it is very light to move around, its size/payload is well matched to the 100/740 refractor, and can engage the tracking when required; plus can be "transformed" quickly into an alt/az mount by detaching the declination axis, so can decide at the very last how to use it (and even switch among alt/az and eq while observing, albeit it would take few minutes*)

I have a long-time fascination with the Astotrac, so feel right to underline that it is a quite inefficient solution when all things are taken onto account (price, size, features, etc..) and has some quirks (among them, a blind spot); and, truth be told, with a it of habit think that any decent mount will end by seeming "natural"*can be done without wrenches if the declination module is screwed through its 3/8" hole

General Astronomy & Observing / Re: Solutions For High Humidity Conditions?
« on: February 03, 2018, 12:51:12 AM »
A little time and effort can save you some big bucks. I made my own dew shield out of a closed cell foam mat, a 3 way dew controller out a RGB LED dimmer switch, and various dew strips out of nichrome wire and duct tape. Total cost for the controller and as many dew strips as I will ever need was under $40.

The following link is the best I found for theory. (so you'll know what your doing)


Now the above site promotes multiple wraps of nichrome but that is unnecessary. If you do the math you can pick out the correct gauge wire to do one wrap, which is easier. For instance I wanted one for an 11" SCT with a length of 39". Well 38" of 22 gauge nichrome wire was near perfect. I think it was 28 or 30 gauge that worked perfectly fore my ED80mm. Here is a link to what I find to be a proper selection.

Lastly here is a link to understand using a RGB dimmer as a dew controller. There are also examples on u-tube. I did not use a project box and got the RGB LED dimmer switch from amazon for $14. Could not find this or nichrome locally.


I had a few RCA cords and duct tape around so I didn't need to purchase these. You will need some female RCA jacks if you go with the RCA.  Gotta think there's something better that RCA out there but they do work fine. I been using this set up for about a year with a small battery pack and it works quite will.

I'm building this simple one before I do the Arduino based dew controller. These are simple and as long as you monitor the temp on them and don't set them too high you're fine so I like the inexpensive nature of this particular build and trust that I cold get the temp right.
From the article you posted:
"there is no straightforward way to calculate the appropriate temperature of the dew heater band to achieve this, nor the power needed to attain that temperature."

The plans below detail an Arduino board that employs a humidity sensor and a temp sensor and calculates the dew point. It also has temp sensors in each heat band and monitors that keeping the band about 1 degree hotter than the ambient temperature.
not sure if it will work since Dew point and dew on the corrector aren't exactly the same thing but I believe some tweaking of the software from the plan here might be doable to achieve the desired results. The beauty of this one is that it only uses exactly the energy you need and nothing more. While guessing on this is sure to require adjustments periodically during the evening, the Arduino unit will probably not. But this is quite an undertaking compared to the plans you posted above and I want dew control sooner rather than later.

ATM, Optics and DIY Forum / Re: filling the hole in my life
« on: February 02, 2018, 11:30:43 PM »
your cell looks good; any update?

i need some time on the foot pedal; the pistol grip controls are intriguing

ATM, Optics and DIY Forum / Re: Source for Long Focal Length Achromats
« on: February 02, 2018, 07:35:22 PM »

SurplusShed sometimes has achromats, used to have a supply af Jägers.

I always kick myself for not getting some of those. Last time I remember checking, they had none left. Jens Jacobsen has a 80/1200 that he bought from SS, which is extremely sharp, with wonderful contrast.Clear skies!
Thomas, Denmark
Indeed Thomas! Vintage 3in (76.2mm) f/16 or more modern 80mm f/15 achromats are really little gems able to work 90% of the times despite almost any seeing conditions. Many vintage objectives are known as being able to reach theoretical optical limits easily, making their owners really proud! thes 76 or 80mm f/16 or f/15 achromats are fantastic scopes for observing plantes, doubles and the Moon. Able to go up to 100x per inch for the best objectives and 80x/in for good ones. That's quite a feat! Some will say that with an instruments like these you'll never be able to explore DSO. Well, I live 3 block form Maracanã's soccer stadium here at Rio de Janeiro, with a sky with #8.5 on Bortle scale... yes I know: ouch! ;-( but depite of this, yesterday I easily spotted M3 (Bootes) and M13 (Hercules) easily with 60-70x with my 76.2 f/16.4 old timer. I know these globular clusters are not DSO objects and that only appear as diffuse white blobs, but considering all factors, the 3in f/16 is giving amazing views! You may even use a binoviewer like I do. Moon images are fabulous and help quite a lot with eye floaters! So... if you find one of these long beauties, grab it without thinking twice!
Regards, Andy.

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No, the mirror being off-center would affect its relationship to the corrector, but would be compensated for in collimation.
Especially with such a tiny error. 0.5mm on one side translates to 0.25mm off center. Negligible.

ATM, Optics and DIY Forum / Re: Wall Hypochromatic version 2017.
« on: February 02, 2018, 03:33:50 PM »

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