10500 replies to this topic

[jragsdale]

I would need at least a 13.5" OD outer ring for my 10" and I would be very nervous about the interface with the dovetail bar being robust enough for a 45 lb scope. But what a great idea.

Yes, there's a very real limit to the size that you can build these, once the pressure on the ball bearings starts deforming the surface of the inner chases, it is all over. The Rockwell hardness and impact strength of the printed material becomes very important, you can overcome this by increasing the interface surface area so using a cylinder instead of a ball bearing for the interface shape.

[CHASLX200]

I needed to 3D print some tube ends for a Parks 6" f/6 Newtonian. The original plastic ones had cracked and were really cheap plastic. So I reprinted the top cap:

 

20250530_203100_copy_600x482.jpg

 

But on the bottom one I printed 4 little ears that I installed threaded brass inserts:

 

20250601_110840_copy_646x766.jpg

 

Then I designed a 92mm fan holder with built in 12V power (3x18650s) and a toggle switch:

 

20250601_104531_copy_602x630.jpg

 

This connects with 4 thumb screws to the back cap so can stay with the scope full time:

 

20250601_104447_copy_583x593.jpg

 

Easy on/off, long lasting battery life (~30 hours of viewing), vibration isolated, easy to pop off to recharge the batteries or collimate. Super stoked with how this turned out!

 

20250601_104603_copy_646x673.jpg

Never needed a fan stan here where i live. More like need heat as my lows avg 78 to 84f in the am as my optics gotta warm up from my 78f house.

Edited by CHASLX200, 02 June 2025 - 06:07 PM.

[jragsdale]

Never needed a fan stan here where i live. More like need heat as my lows avg 75 to 84f in the am as my optics gotta warm up from my 78f house.

Yeah, I built the fan for where I live, not for where you live. I have a very high diurnal temperature variation, you have a very low diurnal temperature variation. Climatology 101. Please tell me more about how my projects affect your life.

Edited by jragsdale, 02 June 2025 - 06:15 PM.

[CHASLX200]

Yeah, I built the fan for where I live, not for where you live. I have a very high diurnal temperature variation, you have a very low diurnal temperature variation. Climatology 101. Please tell me more about how my projects affect your life.

I have never used a fan on many scopes that had them.  No way i would be looking at planets at 45f or colder. I have a nasty soup when ya walk out it slaps in the face and you ask yourself am in on Venus?  You would roll over and die here if you felt my dew points.

Edited by CHASLX200, 02 June 2025 - 06:18 PM.

[jragsdale]

I have never used a fan on many scopes that had them.  

Yeah, you don't really need fans because the temp drop (diurnal temperature vatiation) is so small, your mirrors can always keep up. Like you said, if anything you need dew heaters.

 

Here it can drop 30-40°F overnight, even with fans, the mirror has a hard time getting to ambient. That's why people use reflectix insulation in these climates because it stops you from trying to reach ambient on sealed tube scopes and instead opts for insulating to keep the warm mirror and cold tube from creating internal tube currents.

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[CHASLX200]

Yeah, you don't really need fans because the temp drop (diurnal temperature vatiation) is so small, your mirrors can always keep up. Like you said, if anything you need dew heaters.

 

Here it can drop 30-40°F overnight, even with fans, the mirror has a hard time getting to ambient. That's why people use reflectix insulation in these climates because it stops you from trying to reach ambient on sealed tube scopes and instead opts for insulating to keep the warm mirror and cold tube from creating internal tube currents.

I do get some fast drops on a rare winter nite. Dew kills my Telrad in about 5 mins and SCT's go pretty fast as well.  I never get below 37f anymore.

[norvegicus]

Yeah, I built the fan for where I live, not for where you live. I have a very high diurnal temperature variation, you have a very low diurnal temperature variation. Climatology 101. Please tell me more about how my projects affect your life.

 

They affect my life because I am vicariously doing your projects.  

[Kasmos]

I painted the cutdown Counter Weight and the home made Swift 839 Hub.

I used Rustoleum metal etching primer on the CW followed by some Ace brand Satin Black.

I used the Ace paint because I had it on hand.

I'm not sure if I'll leave black or mix some paint to mimick the Hammer like original finish. My thought is to lower the pressure on the airbrush and it will give it a splattered finish with a slightly lighter charcoal gray. I've done this before with a brush but the airbrush will probably be faster.

 

The hub was primed long ago and the reason I used black is they don't make brown.

I'm going to mix up some brown and spray over it.

Gray wrinkle would probably be a better base coat but once again I already had this paint.

Would you believe this paint is from 1992?

I tested it 15 months ago on a tripod bracket for the ATCO 1252 and it worked fine.

 

Zynolyte was a  brand sold by Standard Brand Paint Co. in Southern California. 

It was great spray paint and also came in cans. I still have a few of those too.

Edited by Kasmos, 03 June 2025 - 03:10 AM.

[Kasmos]

Since I started painting it's hub, I tore into the Swift 839 mount.

(before the tear down) in need of a re-grease and touch ups

 

It felt really stiff and the grease was very sticky.

But because they are push to mounts (no slo-mos), should I use a thick semi-sticky grease?

...or is it just how you adjust it that mostly matters?

I have some heavy-duty stuff that is fairly thick so I may try it? 

Edited by Kasmos, 04 June 2025 - 02:31 PM.

[jragsdale]

Since I started painting it's hub, I tore into the Swift 839 mount.

839-Mount-B4.jpg

(before the tear down) in need of a re-grease and touch ups

 

It felt really stiff and the grease was very sticky.

But because they are push to mounts (no slo-mos), should I use a thick semi-sticky grease?

...or is it just how you adjust it that mostly matters?

I have some heavy-duty stuff that is fairly thick so I may try it? 

I always like thick grease on a mount, really smooths things out.

[deSitter]

Since I started painting it's hub, I tore into the Swift 839 mount.

839-Mount-B4.jpg

(before the tear down) in need of a re-grease and touch ups

 

It felt really stiff and the grease was very sticky.

But because they are push to mounts (no slo-mos), should I use a thick semi-sticky grease?

...or is it just how you adjust it that mostly matters?

I have some heavy-duty stuff that is fairly thick so I may try it? 

 

Yes I would use some Nyogel damping grease

 

-drl

[CHASLX200]

I never used any grease on a mount.  Just collects dirt.  I always cleaned the gunk off.

[starman876]

I never used any grease on a mount.  Just collects dirt.  I always cleaned the gunk off.

you should have been a consultant to the manufacturer.

[CHASLX200]

you should have been a consultant to the manufacturer.

Mount was way too small.

[norvegicus]

Yes I would use some Nyogel damping grease

 

-drl

Same.

[clamchip]

Today I bought a Nexstar 8. With older telescopes you get to do mechanical work. With these newer scopes

it's electronics you play with. Nexstar can't be operated unplugged, which is a bummer if it decides to stop working.

1999 Meade announced the computerized ETX-125EC. Celestron answered with the Nexstar 5, and early 2000

came out with the Nexstar 8. These scopes were something new, less expensive than the Meade LX200

and Celestron's Ultima 2000, these are "GoTo for the masses."

Mine is the first Nexstar 8 from 2000.

The handbox is unique to this 1st model only, and since my handbox was dead I had better make it work again. 

Which I did by cleaning the LCD ribbon cable. Battery tray is corroded and Keystone Electronics still makes

it, part #148.

A few other things about the first model is no ports on top of the drive base, and no quick release dovetail for the

optical tube, the OTA is part of the mount, attached with screws like a C8. Also the 1st model came with an aluminum

tripod. 

It's amazing telescopes like this have been around a quarter of a century. I didn't want to have anything to do with computerized GoTo telescopes. Now they are just becoming old enough I'm now interested.

Robert

 

Edited by clamchip, 08 June 2025 - 07:26 PM.

[ccwemyss]

The keys to good pointing with the Nexstar are entering accurate time and location, and precisely leveling the tripod.

 

One thing I enjoy doing is setting it up during the day, then doing an alignment on the sun (even just leaving the lens cap on and pointing it so the shadow falls straight down the tube), then having it goto bright double stars, or planets. 

 

The first year for the Nexstar GPS turns classic next year. 

 

Chip W. 

[CHASLX200]

Today I bought a Nexstar 8. With older telescopes you get to do mechanical work. With these newer scopes

it's electronics you play with. Nexstar can't be operated unplugged, which is a bummer if it decides to stop working.

1999 Meade announced the computerized ETX-125EC. Celestron answered with the Nexstar 5, and early 2000

came out with the Nexstar 8. These scopes were something new, less expensive than the Meade LX200

and Celestron's Ultima 2000, these are "GoTo for the masses."

Mine is the first Nexstar 8 from 2000.

The handbox is unique to this 1st model only, and since my handbox was dead I had better make it work again. 

Which I did by cleaning the LCD ribbon cable. Battery tray is corroded and Keystone Electronics still makes

it, part #148.

A few other things about the first model is no ports on top of the drive base, and no quick release dovetail for the

optical tube, the OTA is part of the mount, attached with screws like a C8. Also the 1st model came with an aluminum

tripod. 

It's amazing telescopes like this have been around a quarter of a century. I didn't want to have anything to do with computerized GoTo telescopes. Now they are just becoming old enough I'm now interested.

Robert

 

IMG_3435.JPG

I had a 5 that was freaky sharp.

[clamchip]

Here's cleaning the Nexstar handbox ribbon cable:

https://www.cloudyni...ntrol-lcd-weak/

I have saved two Celestron Nexstar handboxes over the years by cleaning the ribbon cable.

Both of these handbox have been early versions.

 

Robert

[ccwemyss]

Today was the annual battle with the paper wasps in the observatory. Next up will be vacuuming out the carcasses. Also need to clean all the insect droppings off of the scopes and mount. Ahhh... Spring!

 

Chip W. 

[deSitter]

Today was the annual battle with the paper wasps in the observatory. Next up will be vacuuming out the carcasses. Also need to clean all the insect droppings off of the scopes and mount. Ahhh... Spring!

 

Chip W. 

 

Red or yellow? The red wasps are very peaceful. Alas we can't have their nests everywhere.

 

-drl

[ccwemyss]

They looked black to me. The nests were at the back of the bay. Not as bad as the grapefruit-sized hornet's nest I found under the solar panel one year. Fortunately, we had a pro coming to deal with a carpenter ant infestation, so I left it to him to deal with it. The problematic location is when the mud wasps build under the lip at the top of the shutter. I have to cover everything and then spray up into the crack from inside. The yellow ones don't seem attracted to the observatory. But last year we had a colony that had found a hole into the stone surrounding our chimney, and from there into our attic. We had about ten of them coming into the house through the recessed lights every day.

 

Chip W.

[vintageair]

I bought an old 10 inch Meade Starfinder EQ off Craigslist that I'm going to take to a five day long star party this month and since there are no hook-ups for my RV I got a 100 watt solar panel to keep my battery topped off. Then I got to thinking that I could mount the solar panel on the EQ pedestal during the day and it would track the sun. It has an AC motor but even through an inverter it only takes half an amp to drive it so keeping it optimally aligned all day more than makes up for it.

 

[Airship]

"One thing I enjoy doing is setting it up during the day, then doing an alignment on the sun (even just leaving the lens cap on and pointing it so the shadow falls straight down the tube), then having it goto bright double stars, or planets."

 

I enjoy doing this as well. I have found that I can see stars down to about magnitude 3 if the air is very clear and dry. Nowadays I can do the same thing using my setting circles. I use the method described in the Unitron and/or Questar manuals to align my setting circles in daylight. Works great!

 

Enjoy!

[jragsdale]

Made a homemade 1.25" Ronchi eyepiece for checking some vintage scopes. 3D printed casing, 150lpi printer encoder, 22mm² microscope slide glass and all held in by the threaded barrel. I have some 360lpi encoder strips on the way too for more resolution. The ronchigram is from my Parks 6" f/6.

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